thesis statement the effects of global warming

Sciencing_Icons_Science SCIENCE

Sciencing_icons_biology biology, sciencing_icons_cells cells, sciencing_icons_molecular molecular, sciencing_icons_microorganisms microorganisms, sciencing_icons_genetics genetics, sciencing_icons_human body human body, sciencing_icons_ecology ecology, sciencing_icons_chemistry chemistry, sciencing_icons_atomic & molecular structure atomic & molecular structure, sciencing_icons_bonds bonds, sciencing_icons_reactions reactions, sciencing_icons_stoichiometry stoichiometry, sciencing_icons_solutions solutions, sciencing_icons_acids & bases acids & bases, sciencing_icons_thermodynamics thermodynamics, sciencing_icons_organic chemistry organic chemistry, sciencing_icons_physics physics, sciencing_icons_fundamentals-physics fundamentals, sciencing_icons_electronics electronics, sciencing_icons_waves waves, sciencing_icons_energy energy, sciencing_icons_fluid fluid, sciencing_icons_astronomy astronomy, sciencing_icons_geology geology, sciencing_icons_fundamentals-geology fundamentals, sciencing_icons_minerals & rocks minerals & rocks, sciencing_icons_earth scructure earth structure, sciencing_icons_fossils fossils, sciencing_icons_natural disasters natural disasters, sciencing_icons_nature nature, sciencing_icons_ecosystems ecosystems, sciencing_icons_environment environment, sciencing_icons_insects insects, sciencing_icons_plants & mushrooms plants & mushrooms, sciencing_icons_animals animals, sciencing_icons_math math, sciencing_icons_arithmetic arithmetic, sciencing_icons_addition & subtraction addition & subtraction, sciencing_icons_multiplication & division multiplication & division, sciencing_icons_decimals decimals, sciencing_icons_fractions fractions, sciencing_icons_conversions conversions, sciencing_icons_algebra algebra, sciencing_icons_working with units working with units, sciencing_icons_equations & expressions equations & expressions, sciencing_icons_ratios & proportions ratios & proportions, sciencing_icons_inequalities inequalities, sciencing_icons_exponents & logarithms exponents & logarithms, sciencing_icons_factorization factorization, sciencing_icons_functions functions, sciencing_icons_linear equations linear equations, sciencing_icons_graphs graphs, sciencing_icons_quadratics quadratics, sciencing_icons_polynomials polynomials, sciencing_icons_geometry geometry, sciencing_icons_fundamentals-geometry fundamentals, sciencing_icons_cartesian cartesian, sciencing_icons_circles circles, sciencing_icons_solids solids, sciencing_icons_trigonometry trigonometry, sciencing_icons_probability-statistics probability & statistics, sciencing_icons_mean-median-mode mean/median/mode, sciencing_icons_independent-dependent variables independent/dependent variables, sciencing_icons_deviation deviation, sciencing_icons_correlation correlation, sciencing_icons_sampling sampling, sciencing_icons_distributions distributions, sciencing_icons_probability probability, sciencing_icons_calculus calculus, sciencing_icons_differentiation-integration differentiation/integration, sciencing_icons_application application, sciencing_icons_projects projects, sciencing_icons_news news.

• Share Tweet Email Print
• Home ⋅
• Science ⋅
• Nature ⋅
• Environment

Global Warming Thesis Statement Ideas

Economic Impact of Coastal Erosion

Global warming is a complex problem that often sparks policy debates. When writing about it, stick to the facts and make sure that your thesis statement -- the central assertion of your essay -- is supported by research. Some global warming topics have produced extensive research worldwide and can serve as topical guides in formulating your thesis statement.

Manmade Causes versus Natural Causes

The causes of global warming are complex, including natural and man-made emissions of carbon dioxide and methane. Use your thesis to highlight the difference between natural sources and man-made sources. For example, according to the Environmental Protection Agency, carbon dioxide concentrations in the atmosphere have risen from 280 parts per million in the 18th century to 390 parts per million in 2010. Human activities release more than 30 billion tons of carbon dioxide each year, or 135 times as much as volcanoes. Focus your thesis on this discrepancy, how man-made carbon dioxide sources such as fossil fuel consumption, have eclipsed natural sources of the gas.

Rising Temperatures and Declining Sea Ice

Your thesis statement may focus on the relationship between rising surface temperatures and declining sea ice, specifically ice in the Arctic. For instance, since 1901, sea surface temperatures have risen at an average rate of 0.13 degrees Fahrenheit per decade, with the highest rates of change occurring in the past three decades alone, according to the EPA.

Your thesis may establish the inverse relationship between these rising surface temperatures and the shrinking ice coverage in the Arctic. Arctic sea ice extent in December 2014, for instance, was the ninth lowest in the satellite record. The rate of decline for December ice alone is 3.4 percent per decade, according to the National Snow and Ice Data Center.

Effects of Melting Glaciers on Water Supply

Along with sea ice, many of the world’s glaciers are melting due to climate change. Since the 1960s, the U.S. Geological Survey has tracked the mass of two glaciers in Alaska and one in Washington state, all three of which have shrunk considerably in the past 40 years.

Research other mountain ranges and compare the glaciological data. Use your thesis to answer the question of what melting glaciers will mean for populations dependent on the ice flows for their fresh water supply. For example, much of Peru’s population depends on Andean glaciers not only for drinking water but for hydroelectricity.

Effects of Drought on Food Production

While global warming is projected to raise sea levels and flooding in coastal regions, it’s also been credited for changes in weather patterns and extreme drought, according to the EPA. In the arid American Southwest, for example, average annual temperatures have increased about 1.5 degrees Fahrenheit over the past century, leading to decreased snowpack, extreme drought, wildfires and fierce competition for remaining water supplies.

As drought still rages in this region, your thesis can explore the relationship between global warming and agriculture, specifically in California’s Central Valley, which provides produce for much of the country. It’s possible that hotter, longer growing seasons are beneficial to California crops, but that shrinking water supplies threaten the viability of commercial agriculture.

Ocean Acidification and Global Seafood Stocks

Increased carbon dioxide emissions don't just impact our air quality. These emissions also result in increased acidity of our planet's oceans. An immense range of shellfish and other molluscs, such as clams, oysters, crabs, lobsters and more, face immediate population decline due to ocean acidification weakening their calcium carbonate shells.

Your thesis can explore the mechanics of ocean acidification as well as the potential economic impact to the fisheries that rely upon these marine animals for survival. You can also explore the potential ecosystem impact for the predators that feed upon these animals.

Related Articles

Ice caps melting facts, efforts to protect the tundra, what drives the process of plate tectonics, effect of human activities on the environment, the top 10 topics for research papers, how to calculate a p-value, how to make a glacier, persuasive speech topics on water, brine vs. conductivity, how to do a bell curve on a ti, how to contact your representative about climate change, how to calculate exceedance probability, what is the meaning of sample size, the difference between an earthquake & a volcano, the history of volcanology, how bitcoin is polluting the planet, how to report a sample size, the effects of human intervention on the environment, the scientist henry hess invented what kind of devices.

• U.S. Environmental Protection Agency: Causes of Climate Change
• U.S. Environmental Protection Agency: Climate Change Indicators in the United States
• National Snow and Ice Data Center: Artic Sea Ice News and Analysis
• U.S. Geological Survey: 3-Glacier Mass Balance Summary
• National Geographic: Signs from Earth: The Big Thaw
• U.S. Environmental Protection Agency: Climate Impacts in the Southwest
• Alaska Public Media: Ocean Acidification

About the Author

Scott Neuffer is an award-winning journalist and writer who lives in Nevada. He holds a bachelor's degree in English and spent five years as an education and business reporter for Sierra Nevada Media Group. His first collection of short stories, "Scars of the New Order," was published in 2014.

Photo Credits

Purestock/Purestock/Getty Images

Find Your Next Great Science Fair Project! GO

Global Warming Topics with Thesis Statement Suggestions

It is hard to close your eyes to the fact that the current state of our ecosystem is in danger. This problem is not only a burden for scientists and scholars but all of us as well. When students try to get in-depth knowledge of global warming and overall ecological problems worldwide, it helps governments implement new precautions and climate-saving programs.

A conscious approach to topic selection helps students write an engaging piece of work that can impact our future. Therefore, in the guide prepared by our essay writing service , you can get powerful ideas for your eco projects that our specialists have prepared for you.

Causes of global warming

Understanding what is behind global warming is crucial for students’ research. Consider these problems as tips to choose a global warming topic.

• Factory farming and its vast volume of greenhouse cases.
• Biochemical pollution and a wide range of potentially lethal toxins from factories.
• Natural resource consumption in business and its impact on climate change.
• Forest destruction threatens to increase the global warming problem.
• Refusing plastic sorting is dangerous for the planet.
• Factors that contribute to temperature increase worldwide.
• Vanishing water resources.
• Ignoring the power of technology and communication solving the global warming catastrophe.
• Lack of global awareness campaigns.
• Landscape deformation and its effect on flora and fauna.

Actually, there are many fields that a student and an essay writer can consider while choosing the topic for their ecological research. In this article, you can find topics from many categories and select the most appealing for your task.

Essay topics on global warming and humanity’s influence

• How does the NRDC manage global warming?
• How does global warming affect American industry?
• What is the connection of global warming and the implications for Minnesota?
• What are global reports on climate change?
• Human endeavor in global warming.
• The influence of global warming on human behavior.
• Is global warming an anthropogenic cause or is it the nature of the Earth’s system?
• Can we sustain the discrepancy between those who deny it and the existence of solid evidence of global warming’s validity?
• Is global warming a myth?
• What are the effects of burning fossil fuel for transportation on global warming in Beijing, China, and possible solutions for the future?
• Does global warming increase the severity and frequency of hurricanes and typhoons? Compare and contrast evidence for the Pacific and Atlantic oceans.
• How dangerous is the threat of floods caused by global warming?
• What are consequences and remedies of global warming?
• Does tracking contribute to global warming?
• How does global warming impact the tourism and hospitality industry?
• If human activity is contributing to global warming, how significant is the contribution?
• What is the ethical standpoint of global warming?
• Should carbon trading policies be used to combat global warming?
• What has the insurance industry done, or what should they do with global warming?
• How will humanity fair in the future with current global warming rates?
• How big is your protein footprint? Does a meat-rich diet have a negative impact on our environment? Does it contribute to global warming?
• What to choose: global warming or global cooling?

Topics of global warming related to politics

• Do some governments have an interest in not preventing global warming?
• How does politics influence global warming?
• How do international treaties influence global warming?
• How can politics stop global warming?
• Can global warming be stabilized by politics?
• Are political decisions the main reason for global warming?
• What are politicians doing to prevent global warming, and is it enough?
• What is the political issue of global warming?
• What is the role of politics in global warming?
• What do politicians fail to do to stop global warming?

Topics of global warming related to biology

• What effect does global warming have on biodiversity?
• How does global warming influence food?
• Why do some people think that global warming is good for the animals?
• What are the effects of global warming on plants?
• What are solutions to protect animals from global warming?
• What is the phenomenon of global warming denial and its impact on animals?
• What is the relationship between global warming and extinction of species?
• Is global warming harmful to human health?
• What is the influence of global warming on population shift?
• What is the connection of human health and climate change?
• Global warming and climate control: is man the enemy of the planet?
• The shrinking of the Greenland ice sheet due to global warming.
• Death of coral reefs because of global warming.
• Is global warming a natural cycle?
• What is the effect of global warming on ecosystems?

Topics of global warming in history

• What is the evidence for environmental change during historic times?
• During their eight years in office, the Obama administration took concrete steps to limit climate change and foster adaptation and resilience in the USA and its territories. What are these steps?
• Where did global warming come from?
• When did the first evidence that polar bears are dying out because of the global warming appear?
• When did indigenous people in Alaska get exposed to global warming?
• How could we have stopped global warming ten years ago?
• When did scientists notice the effects of global warming on animals for the first time?
• How did chemical engineering influence global warming over time?
• Within our lifetime, how will global warming affect us, specifically, within the United States?
• How has agriculture been influenced by global warming over the past few years?
• What are the recent and anticipated physical, social (including health), and economic impacts of ongoing global warming on Australia?
• Problem and solution of global warming in the Pacific Ocean due to the rise of the sea and salinity levels in the past 20 years.

Global warming topics related to movies, articles, and books

• Analyze Al Gore’s documentary on global warming. What is the main theme of it?
• Analyze the Rolling Stone article on climate change and national security. Does this article address the issue of national security as implications of the phenomenon of climate change?
• According to computer climate models, how does the soil type result in different tree species becoming prevalent? Use the article “Crossroads of Climate Change” to answer the question.
• Analyze “Summary for Policymakers” from the 2014 Intergovernmental Panel on Climate Change (IPCC) synthesis report and express your attitude.
• Research the topic of the cartoon about global warming by Glenn McCoy, and write on the subject presented by the artist.
• Analysis of the argument on Bill Mckibben’s Rolling Stone article “Global Warming’s Terrifying New Math.”
• Analyze David Attenborough’s video on global impacts of climate change and present your attitude about it.

Global warming speech topics

• Negative impacts of a warmer global climate on human health.
• Negative impacts of a warmer global climate on northern Minnesota.
• The evidence that scientists use to study and make predictions about global climate change.
• Global warming effects on business in Florida.
• The change in the atmosphere that influences the change in the global climate.
• The difference between the war on global warming and the war on terror.
• The difference between natural and anthropogenic climate changes.
• The effect of global warming on rising sea levels.
• The theory that best explains why some countries are ignoring global warming and others are not.
• Connection between global warming and urbanization.

Global warming topics on the greenhouse effect

• What is the greenhouse effect and its influence on the Earth’s environment?
• What is the process by which greenhouse gasses absorb atmospheric heat and radiate it back onto the Earth’s surface?
• What are three things individuals can do to reduce greenhouse gas emissions?
• What are strategies for reducing greenhouse gas concentrations in the atmosphere?
• Why do Canada’s greenhouse gas emissions continue to increase?
• Pros and cons of the greenhouse effect.
• Possible caused human global warming due to greenhouse gas emissions.
• Ozone depletion and the green house effect.

Examples of thesis statements for global warming topics

Topic: Is global warming a catastrophe that warrants immediate action? Thesis statement: We do not see CO2. This is an invisible threat, but quite real. This means an increase in global temperatures, an increase in extreme weather events such as floods, melting ice, and rising sea levels, and an increase in ocean acidity.

Topic: Why is global warming influencing people? Thesis statement : Scientists, after analyzing the results of research in more than 60 fields of science, concluded that a change in temperature leads to a surge in aggression. Extensive research has revealed a strong relationship between outbreaks of aggression and global warming.

Topic: Is global warming a hoax or exaggerated? Thesis statement: Climate change leads to overflowing rivers all over the world, the water level in reservoirs will increase markedly, and heavy rains and storms in many regions will become even more devastating.

Topic: How does global warming affect the weather? Thesis statement: Environmentalists say that there are more and more frequent sharp changes in weather, storm winds, hurricanes, tornadoes, and abnormally high and abnormally low temperatures. According to experts, the cause of these phenomena is the global climate change.

Learn ecology better with a reliable writing service

Students who dive into global warming awareness become great activists that can save our planet. They awaken consciousness among various social groups and easily explain why saving the planet can be possible when each participates. Choosing the topic for an academic paper should be considered carefully because the work a student creates can be fundamental for a life-changing speech.

At our service, students can get educational assistance for a reasonable price. Find a custom writer by leaving an order with your specific instructions or read more articles in our blog. If you are engaged in ecological issues, you can read an extended list of ecology paper topics and discover more informative sources for your research. EssayShark is here so you can expand the horizons of your knowledge!

Pay for research paper or pay for term papers and get an original paper written in accordance with your requirements.

Photo by Pexels from Pixabay

7 thoughts on “ Global Warming Topics with Thesis Statement Suggestions ”

this post helped me not only with a topic but with a thesis on climate change too. Thanx!

Oh Lord, what a nice collection of topics!!!

Pretty helpful

looks like a helpful post to me

I was searching for climate change argumentative essay topics for 2 days! Thank god I found them!!!

It seems to me that here are the best climate change essay topics!!!

Leave a Reply Cancel reply

Your email address will not be published. Required fields are marked *

Save my name, email, and website in this browser for the next time I comment.

What our customers say

Our website uses secure cookies. More details

Get professional help from best writers right from your phone

Most Popular

13 days ago

The Role of Renewable Energy in Combating Climate Change

Climate change and its effects on local ecosystems, climate change thesis statement examples.

freepik.com

Climate change is an urgent global issue, characterized by rising temperatures, melting glaciers, and extreme weather events. Writing a thesis on this topic requires a clear and concise statement that guides the reader through the significance, focus, and scope of your study. In this piece, we will explore various examples of good and bad thesis statements related to climate change to guide students in crafting compelling research proposals.

Good Examples

Focused Approach: “This thesis will analyze the impact of climate change on the intensity and frequency of hurricanes, using data from the last three decades.” Lack of Focus: “Climate change affects weather patterns.”

The good statement is specific, indicating a focus on hurricanes and providing a time frame. In contrast, the bad statement is too vague, covering a broad topic without any specific angle.

Clear Stance: “Implementing carbon taxes is an effective strategy for governments to incentivize companies to reduce greenhouse gas emissions.” Not So Clear: “Carbon taxes might be good for the environment.”

The good statement takes a clear position in favor of carbon taxes, while the bad statement is indecisive, not providing a clear standpoint.

Researchable and Measurable: “The thesis explores the correlation between the rise in global temperatures and the increase in the extinction rates of North American mammal species.” Dull: “Global warming is harmful to animals.”

The good statement is researchable and measurable, with clear variables and a focused geographic location, while the bad statement is generic and lacks specificity.

Bad Examples

Overly Broad: “Climate change is a global problem that needs to be addressed.”

This statement, while true, is overly broad and doesn’t propose a specific area of focus, making it inadequate for guiding a research study.

Lack of Clear Argument: “Climate change has some negative and positive effects.”

This statement doesn’t take a clear stance or highlight specific effects, making it weak and uninformative.

Unoriginal and Unengaging: “Climate change is real.”

While the statement is factual, it doesn’t present an original argument or engage the reader with a specific area of climate change research.

Crafting a compelling thesis statement on climate change is crucial for directing your research and presenting a clear, focused, and arguable position. A good thesis statement should be specific, take a clear stance, and be researchable and measurable. Avoid overly broad, unclear, unoriginal, or unengaging statements that do not provide clear direction or focus for your research. Utilizing the examples provided, students can navigate the intricate process of developing thesis statements that are not only academically rigorous but also intriguing and relevant to the pressing issue of climate change.

Follow us on Reddit for more insights and updates.

Comments (0)

Welcome to A*Help comments!

We’re all about debate and discussion at A*Help.

We value the diverse opinions of users, so you may find points of view that you don’t agree with. And that’s cool. However, there are certain things we’re not OK with: attempts to manipulate our data in any way, for example, or the posting of discriminative, offensive, hateful, or disparaging material.

Cancel reply

Your email address will not be published. Required fields are marked *

Save my name, email, and website in this browser for the next time I comment.

More from Essay About Climate Change: Best Samples and Examples

< 1 min read

Is Sustainable Urban Planning Realistic?

Remember Me

Is English your native language ? Yes No

What is your profession ? Student Teacher Writer Other

Forgotten Password?

Username or Email

Essay Service Examples Environment Global Warming

Global Warming: Thesis Statement

The Role of Humans in Causing Global Warming

Introduction.

• Proper editing and formatting
• Free revision, title page, and bibliography
• Flexible prices and money-back guarantee

Research problems

Hypothesis:.

• Research: Humans do have a significant effect on the global warming process.

Research Plan

Bibliography.

• Chang, J. (2015). Impact of climate change and human activities on runoff in the Weihe River Basin. Retrieved from science direct: https://www.sciencedirect.com/science/article/pii/S104061821400192X
• Cook, J. (2016, April 13). Consensus on consensus: a synthesis of consensus estimates on human-caused global warming. Retrieved from iop science: https://iopscience.iop.org/article/10.1088/1748-9326/11/4/048002
• Haustein, K. (2017, November 13). A real-time Global Warming Index. Retrieved from nature: https://www.nature.com/articles/s41598-017-14828-5
• Nagelkerken, L., & Connell, S. (2015, October 27). Global alteration of ocean ecosystem functioning due to increasing human CO2 emissions. Retrieved from NCBI: https://www.ncbi.nlm.nih.gov/pubmed/26460052

Our writers will provide you with an essay sample written from scratch: any topic, any deadline, any instructions.

Cite this paper

Related essay topics.

Get your paper done in as fast as 3 hours, 24/7.

Related articles

Most popular essays

• Climate Change
• Global Warming

Global teenage climate activists and over 4 million people around the globe went on a strike last...

• Carbon Dioxide

Climate change isn’t just bad for the planet’s health, it's bad for people’s too. Since many...

Global Warming, you’ve probably heard this word before in places like school, on the news, or...

Earth’s climate is the impact of a adjust between the sum of approaching vitality from the sun and...

UN Climate Change News, 27 October 2020 – Increasing temperatures and sea levels, changing...

Global warming has been an ever-growing problem since the industrial revolution in 1770 yet we...

Imagine if this world ended because of natural disasters, and your family became one of the...

• Environmental Education

Professors are concerning about the knowledge of climate science and the scientific consensus on...

Are humans actually affecting global warming? Humans have been worsening the state of our planet...

Join our 150k of happy users

• Get original paper written according to your instructions
• Save time for what matters most

Fair Use Policy

EduBirdie considers academic integrity to be the essential part of the learning process and does not support any violation of the academic standards. Should you have any questions regarding our Fair Use Policy or become aware of any violations, please do not hesitate to contact us via [email protected].

We are here 24/7 to write your paper in as fast as 3 hours.

Provide your email, and we'll send you this sample!

By providing your email, you agree to our Terms & Conditions and Privacy Policy .

Say goodbye to copy-pasting!

Get custom-crafted papers for you.

Enter your email, and we'll promptly send you the full essay. No need to copy piece by piece. It's in your inbox!

• Games & Quizzes
• History & Society
• Science & Tech
• Biographies
• Animals & Nature
• Geography & Travel
• Arts & Culture
• On This Day
• One Good Fact
• New Articles
• Lifestyles & Social Issues
• Philosophy & Religion
• Politics, Law & Government
• World History
• Health & Medicine
• Browse Biographies
• Birds, Reptiles & Other Vertebrates
• Bugs, Mollusks & Other Invertebrates
• Environment
• Fossils & Geologic Time
• Entertainment & Pop Culture
• Sports & Recreation
• Visual Arts
• Demystified
• Image Galleries
• Infographics
• Top Questions
• Britannica Kids
• Saving Earth
• Space Next 50
• Student Center
• Introduction & Top Questions
• Climatic variation since the last glaciation
• The greenhouse effect
• Radiative forcing
• Water vapour
• Carbon dioxide
• Surface-level ozone and other compounds
• Nitrous oxides and fluorinated gases
• Land-use change
• Stratospheric ozone depletion
• Volcanic aerosols
• Variations in solar output
• Variations in Earth’s orbit
• Water vapour feedback
• Cloud feedbacks
• Ice albedo feedback
• Carbon cycle feedbacks
• Modern observations
• Prehistorical climate records
• Theoretical climate models
• Patterns of warming
• Precipitation patterns
• Regional predictions
• Ice melt and sea level rise
• Ocean circulation changes
• Tropical cyclones
• Environmental consequences of global warming
• Socioeconomic consequences of global warming

How does global warming work?

Where does global warming occur in the atmosphere, why is global warming a social problem, where does global warming affect polar bears.

• What is the Kyoto Protocol?

global warming

Our editors will review what you’ve submitted and determine whether to revise the article.

• U.S. Department of Transportation - Global Warming: A Science Overview
• NOAA Climate.gov - Climate Change: Global Temperature
• Natural Resources Defense Council - Global Warming 101
• American Institute of Physics - The discovery of global warming
• LiveScience - Causes of Global Warming
• global warming - Children's Encyclopedia (Ages 8-11)
• global warming - Student Encyclopedia (Ages 11 and up)
• Table Of Contents

Human activity affects global surface temperatures by changing Earth ’s radiative balance—the “give and take” between what comes in during the day and what Earth emits at night. Increases in greenhouse gases —i.e., trace gases such as carbon dioxide and methane that absorb heat energy emitted from Earth’s surface and reradiate it back—generated by industry and transportation cause the atmosphere to retain more heat, which increases temperatures and alters precipitation patterns.

Global warming, the phenomenon of increasing average air temperatures near Earth’s surface over the past one to two centuries, happens mostly in the troposphere , the lowest level of the atmosphere, which extends from Earth’s surface up to a height of 6–11 miles. This layer contains most of Earth’s clouds and is where living things and their habitats and weather primarily occur.

Continued global warming is expected to impact everything from energy use to water availability to crop productivity throughout the world. Poor countries and communities with limited abilities to adapt to these changes are expected to suffer disproportionately. Global warming is already being associated with increases in the incidence of severe and extreme weather, heavy flooding , and wildfires —phenomena that threaten homes, dams, transportation networks, and other facets of human infrastructure. Learn more about how the IPCC’s Sixth Assessment Report, released in 2021, describes the social impacts of global warming.

Polar bears live in the Arctic , where they use the region’s ice floes as they hunt seals and other marine mammals . Temperature increases related to global warming have been the most pronounced at the poles, where they often make the difference between frozen and melted ice. Polar bears rely on small gaps in the ice to hunt their prey. As these gaps widen because of continued melting, prey capture has become more challenging for these animals.

Recent News

global warming , the phenomenon of increasing average air temperatures near the surface of Earth over the past one to two centuries. Climate scientists have since the mid-20th century gathered detailed observations of various weather phenomena (such as temperatures, precipitation , and storms) and of related influences on climate (such as ocean currents and the atmosphere’s chemical composition). These data indicate that Earth’s climate has changed over almost every conceivable timescale since the beginning of geologic time and that human activities since at least the beginning of the Industrial Revolution have a growing influence over the pace and extent of present-day climate change .

Giving voice to a growing conviction of most of the scientific community , the Intergovernmental Panel on Climate Change (IPCC) was formed in 1988 by the World Meteorological Organization (WMO) and the United Nations Environment Program (UNEP). The IPCC’s Sixth Assessment Report (AR6), published in 2021, noted that the best estimate of the increase in global average surface temperature between 1850 and 2019 was 1.07 °C (1.9 °F). An IPCC special report produced in 2018 noted that human beings and their activities have been responsible for a worldwide average temperature increase between 0.8 and 1.2 °C (1.4 and 2.2 °F) since preindustrial times, and most of the warming over the second half of the 20th century could be attributed to human activities.

AR6 produced a series of global climate predictions based on modeling five greenhouse gas emission scenarios that accounted for future emissions, mitigation (severity reduction) measures, and uncertainties in the model projections. Some of the main uncertainties include the precise role of feedback processes and the impacts of industrial pollutants known as aerosols , which may offset some warming. The lowest-emissions scenario, which assumed steep cuts in greenhouse gas emissions beginning in 2015, predicted that the global mean surface temperature would increase between 1.0 and 1.8 °C (1.8 and 3.2 °F) by 2100 relative to the 1850–1900 average. This range stood in stark contrast to the highest-emissions scenario, which predicted that the mean surface temperature would rise between 3.3 and 5.7 °C (5.9 and 10.2 °F) by 2100 based on the assumption that greenhouse gas emissions would continue to increase throughout the 21st century. The intermediate-emissions scenario, which assumed that emissions would stabilize by 2050 before declining gradually, projected an increase of between 2.1 and 3.5 °C (3.8 and 6.3 °F) by 2100.

Many climate scientists agree that significant societal, economic, and ecological damage would result if the global average temperature rose by more than 2 °C (3.6 °F) in such a short time. Such damage would include increased extinction of many plant and animal species, shifts in patterns of agriculture , and rising sea levels. By 2015 all but a few national governments had begun the process of instituting carbon reduction plans as part of the Paris Agreement , a treaty designed to help countries keep global warming to 1.5 °C (2.7 °F) above preindustrial levels in order to avoid the worst of the predicted effects. Whereas authors of the 2018 special report noted that should carbon emissions continue at their present rate, the increase in average near-surface air temperature would reach 1.5 °C sometime between 2030 and 2052, authors of the AR6 report suggested that this threshold would be reached by 2041 at the latest.

The AR6 report also noted that the global average sea level had risen by some 20 cm (7.9 inches) between 1901 and 2018 and that sea level rose faster in the second half of the 20th century than in the first half. It also predicted, again depending on a wide range of scenarios, that the global average sea level would rise by different amounts by 2100 relative to the 1995–2014 average. Under the report’s lowest-emission scenario, sea level would rise by 28–55 cm (11–21.7 inches), whereas, under the intermediate emissions scenario, sea level would rise by 44–76 cm (17.3–29.9 inches). The highest-emissions scenario suggested that sea level would rise by 63–101 cm (24.8–39.8 inches) by 2100.

The scenarios referred to above depend mainly on future concentrations of certain trace gases, called greenhouse gases , that have been injected into the lower atmosphere in increasing amounts through the burning of fossil fuels for industry, transportation , and residential uses. Modern global warming is the result of an increase in magnitude of the so-called greenhouse effect , a warming of Earth’s surface and lower atmosphere caused by the presence of water vapour , carbon dioxide , methane , nitrous oxides , and other greenhouse gases. In 2014 the IPCC first reported that concentrations of carbon dioxide, methane, and nitrous oxides in the atmosphere surpassed those found in ice cores dating back 800,000 years.

Of all these gases, carbon dioxide is the most important, both for its role in the greenhouse effect and for its role in the human economy. It has been estimated that, at the beginning of the industrial age in the mid-18th century, carbon dioxide concentrations in the atmosphere were roughly 280 parts per million (ppm). By the end of 2022 they had risen to 419 ppm, and, if fossil fuels continue to be burned at current rates, they are projected to reach 550 ppm by the mid-21st century—essentially, a doubling of carbon dioxide concentrations in 300 years.

A vigorous debate is in progress over the extent and seriousness of rising surface temperatures, the effects of past and future warming on human life, and the need for action to reduce future warming and deal with its consequences. This article provides an overview of the scientific background related to the subject of global warming. It considers the causes of rising near-surface air temperatures, the influencing factors, the process of climate research and forecasting, and the possible ecological and social impacts of rising temperatures. For an overview of the public policy developments related to global warming occurring since the mid-20th century, see global warming policy . For a detailed description of Earth’s climate, its processes, and the responses of living things to its changing nature, see climate . For additional background on how Earth’s climate has changed throughout geologic time , see climatic variation and change . For a full description of Earth’s gaseous envelope, within which climate change and global warming occur, see atmosphere .

What evidence exists that Earth is warming and that humans are the main cause?

We know the world is warming because people have been recording daily high and low temperatures at thousands of weather stations worldwide, over land and ocean, for many decades and, in some locations, for more than a century. When different teams of climate scientists in different agencies (e.g., NOAA and NASA) and in other countries (e.g., the U.K.’s Hadley Centre) average these data together, they all find essentially the same result: Earth’s average surface temperature has risen by about 1.8°F (1.0°C) since 1880. 

( bar chart ) Yearly temperature compared to the twentieth-century average from 1850–2023. Red bars mean warmer-than-average years; blue bars mean colder-than-average years. (line graph) Atmospheric carbon dioxide amounts: 1850-1958 from IAC , 1959-2023 from NOAA Global Monitoring Lab . NOAA Climate.gov graph, adapted from original by Dr. Howard Diamond (NOAA ARL).

In addition to our surface station data, we have many different lines of evidence that Earth is warming ( learn more ). Birds are migrating earlier, and their migration patterns are changing.  Lobsters  and  other marine species  are moving north. Plants are blooming earlier in the spring. Mountain glaciers are melting worldwide, and snow cover is declining in the Northern Hemisphere (Learn more  here  and  here ). Greenland’s ice sheet—which holds about 8 percent of Earth’s fresh water—is melting at an accelerating rate ( learn more ). Mean global sea level is rising ( learn more ). Arctic sea ice is declining rapidly in both thickness and extent ( learn more ).

The Greenland Ice Sheet lost mass again in 2020, but not as much as it did 2019. Adapted from the 2020 Arctic Report Card, this graph tracks Greenland mass loss measured by NASA's GRACE satellite missions since 2002. The background photo shows a glacier calving front in western Greenland, captured from an airplane during a NASA Operation IceBridge field campaign. Full story.

We know this warming is largely caused by human activities because the key role that carbon dioxide plays in maintaining Earth’s natural greenhouse effect has been understood since the mid-1800s. Unless it is offset by some equally large cooling influence, more atmospheric carbon dioxide will lead to warmer surface temperatures. Since 1800, the amount of carbon dioxide in the atmosphere  has increased  from about 280 parts per million to 410 ppm in 2019. We know from both its rapid increase and its isotopic “fingerprint” that the source of this new carbon dioxide is fossil fuels, and not natural sources like forest fires, volcanoes, or outgassing from the ocean.

Philip James de Loutherbourg's 1801 painting, Coalbrookdale by Night , came to symbolize the start of the Industrial Revolution, when humans began to harness the power of fossil fuels—and to contribute significantly to Earth's atmospheric greenhouse gas composition. Image from Wikipedia .

Finally, no other known climate influences have changed enough to account for the observed warming trend. Taken together, these and other lines of evidence point squarely to human activities as the cause of recent global warming.

USGCRP (2017). Climate Science Special Report: Fourth National Climate Assessment, Volume 1 [Wuebbles, D.J., D.W. Fahey, K.A. Hibbard, D.J. Dokken, B.C. Stewart, and T.K. Maycock (eds.)]. U.S. Global Change Research Program, Washington, DC, USA, 470 pp, doi:  10.7930/J0J964J6 .

National Fish, Wildlife, and Plants Climate Adaptation Partnership (2012):  National Fish, Wildlife, and Plants Climate Adaptation Strategy . Association of Fish and Wildlife Agencies, Council on Environmental Quality, Great Lakes Indian Fish and Wildlife Commission, National Oceanic and Atmospheric Administration, and U.S. Fish and Wildlife Service. Washington, D.C. DOI: 10.3996/082012-FWSReport-1

IPCC (2019). Summary for Policymakers. In: IPCC Special Report on the Ocean and Cryosphere in a Changing Climate. [H.-O. Pörtner, D.C. Roberts, V. Masson-Delmotte, P. Zhai, M. Tignor, E. Poloczanska, K. Mintenbeck, A. Alegría, M. Nicolai, A. Okem, J. Petzold, B. Rama, N.M. Weyer (eds.)]. In press.

NASA JPL: "Consensus: 97% of climate scientists agree."  Global Climate Change . A website at NASA's Jet Propulsion Laboratory (climate.nasa.gov/scientific-consensus). (Accessed July 2013.)

We value your feedback

Help us improve our content

Related Content

News & features, 2017 state of the climate: mountain glaciers, warming waters shift fish communities northward in the arctic, climate & fish sticks, maps & data, past climate, future climate, land - terrestrial climate variables, teaching climate, toolbox for teaching climate & energy, student climate & conservation congress (sc3), climate youth engagement, climate resilience toolkit, arctic oceans, sea ice, and coasts, alaska and the arctic, food safety and nutrition.

MIT Global Change

Search form, the net environmental effects of carbon dioxide reduction policies, [ download ], abstract/summary:.

In response to the threat of global warming a variety of policy measures have been proposed to reduce the emissions of carbon dioxide (CO2). However, policies which reduce CO2 emissions will also decrease the emissions of greenhouse-relevant gases methane, nitrous oxide, nitrogen oxides, carbon monoxide, and sulfur oxides. When these additional effects are overlooked the net effect of CO2 reduction policies on global warming is understated. Thus, emissions of all greenhouse-relevant gases should be included when evaluating CO2 reduction policies.

Other proposals which recognize the need to reduce emissions of all greenhouse gases have called for the reduction of a “CO2-equivalent" amount. Policymakers evaluate these policies by using a Global Warming Potential (GWP) which is an index that supposedly indicates the relative radiative power of a greenhouse gas with respect to CO2 . This method, however, is flawed, as calculation of the GWP depends critically on the lifetime of the gas as well as the radiative effect of CO2 which can change depending on the composition of the atmosphere. When analyzing the effect of gases on global warming, an atmospheric chemistry model which describes the interactions of all the gases should be used in place of the GWP. In this case, specification of future emissions of all greenhouse-relevant gases is also required. This thesis addresses these two problems by developing a model which forecasts emissions of all greenhouse-relevant gases. This emissions model uses the GREEN model as the underlying economic model and incorporates the emissions of greenhouse-relevant gases from activities in energy, agriculture, industry, and land use. The results of the model are then fed into an atmospheric chemistry model to evaluate the effect on warming.

The atmospheric chemistry model is used to compare the results of a reference case with a Toronto-type agreement. The thesis finds that including other greenhouse-relevant gases results in an additional decrease of 40% in warming as compared to when only CO2 is specified. Additional analyses are performed to illustrate the interaction between chemical species and the importance of including all greenhouse-relevant gases when evaluating global warming policies.

• Student Dissertation or Thesis

Abstract/Summary: 

Search the United Nations

• What Is Climate Change
• Myth Busters
• Renewable Energy
• Finance & Justice
• Initiatives
• Sustainable Development Goals
• Paris Agreement
• Climate Ambition Summit 2023
• Climate Conferences
• Press Material
• Communications Tips

Causes and Effects of Climate Change

Fossil fuels – coal, oil and gas – are by far the largest contributor to global climate change, accounting for over 75 per cent of global greenhouse gas emissions and nearly 90 per cent of all carbon dioxide emissions.

As greenhouse gas emissions blanket the Earth, they trap the sun’s heat. This leads to global warming and climate change. The world is now warming faster than at any point in recorded history. Warmer temperatures over time are changing weather patterns and disrupting the usual balance of nature. This poses many risks to human beings and all other forms of life on Earth.

Causes of Climate Change

Generating power

Generating electricity and heat by burning fossil fuels causes a large chunk of global emissions. Most electricity is still generated by burning coal, oil, or gas, which produces carbon dioxide and nitrous oxide – powerful greenhouse gases that blanket the Earth and trap the sun’s heat. Globally, a bit more than a quarter of electricity comes from wind, solar and other renewable sources which, as opposed to fossil fuels, emit little to no greenhouse gases or pollutants into the air.

Manufacturing goods

Manufacturing and industry produce emissions, mostly from burning fossil fuels to produce energy for making things like cement, iron, steel, electronics, plastics, clothes, and other goods. Mining and other industrial processes also release gases, as does the construction industry. Machines used in the manufacturing process often run on coal, oil, or gas; and some materials, like plastics, are made from chemicals sourced from fossil fuels. The manufacturing industry is one of the largest contributors to greenhouse gas emissions worldwide.

Cutting down forests

Cutting down forests to create farms or pastures, or for other reasons, causes emissions, since trees, when they are cut, release the carbon they have been storing. Each year approximately 12 million hectares of forest are destroyed. Since forests absorb carbon dioxide, destroying them also limits nature’s ability to keep emissions out of the atmosphere. Deforestation, together with agriculture and other land use changes, is responsible for roughly a quarter of global greenhouse gas emissions.

Using transportation

Most cars, trucks, ships, and planes run on fossil fuels. That makes transportation a major contributor of greenhouse gases, especially carbon-dioxide emissions. Road vehicles account for the largest part, due to the combustion of petroleum-based products, like gasoline, in internal combustion engines. But emissions from ships and planes continue to grow. Transport accounts for nearly one quarter of global energy-related carbon-dioxide emissions. And trends point to a significant increase in energy use for transport over the coming years.

Producing food

Producing food causes emissions of carbon dioxide, methane, and other greenhouse gases in various ways, including through deforestation and clearing of land for agriculture and grazing, digestion by cows and sheep, the production and use of fertilizers and manure for growing crops, and the use of energy to run farm equipment or fishing boats, usually with fossil fuels. All this makes food production a major contributor to climate change. And greenhouse gas emissions also come from packaging and distributing food.

Powering buildings

Globally, residential and commercial buildings consume over half of all electricity. As they continue to draw on coal, oil, and natural gas for heating and cooling, they emit significant quantities of greenhouse gas emissions. Growing energy demand for heating and cooling, with rising air-conditioner ownership, as well as increased electricity consumption for lighting, appliances, and connected devices, has contributed to a rise in energy-related carbon-dioxide emissions from buildings in recent years.

Consuming too much

Your home and use of power, how you move around, what you eat and how much you throw away all contribute to greenhouse gas emissions. So does the consumption of goods such as clothing, electronics, and plastics. A large chunk of global greenhouse gas emissions are linked to private households. Our lifestyles have a profound impact on our planet. The wealthiest bear the greatest responsibility: the richest 1 per cent of the global population combined account for more greenhouse gas emissions than the poorest 50 per cent.

Based on various UN sources

Effects of Climate Change

Hotter temperatures

As greenhouse gas concentrations rise, so does the global surface temperature. The last decade, 2011-2020, is the warmest on record. Since the 1980s, each decade has been warmer than the previous one. Nearly all land areas are seeing more hot days and heat waves. Higher temperatures increase heat-related illnesses and make working outdoors more difficult. Wildfires start more easily and spread more rapidly when conditions are hotter. Temperatures in the Arctic have warmed at least twice as fast as the global average.

More severe storms

Destructive storms have become more intense and more frequent in many regions. As temperatures rise, more moisture evaporates, which exacerbates extreme rainfall and flooding, causing more destructive storms. The frequency and extent of tropical storms is also affected by the warming ocean. Cyclones, hurricanes, and typhoons feed on warm waters at the ocean surface. Such storms often destroy homes and communities, causing deaths and huge economic losses.

Increased drought

Climate change is changing water availability, making it scarcer in more regions. Global warming exacerbates water shortages in already water-stressed regions and is leading to an increased risk of agricultural droughts affecting crops, and ecological droughts increasing the vulnerability of ecosystems. Droughts can also stir destructive sand and dust storms that can move billions of tons of sand across continents. Deserts are expanding, reducing land for growing food. Many people now face the threat of not having enough water on a regular basis.

A warming, rising ocean

The ocean soaks up most of the heat from global warming. The rate at which the ocean is warming strongly increased over the past two decades, across all depths of the ocean. As the ocean warms, its volume increases since water expands as it gets warmer. Melting ice sheets also cause sea levels to rise, threatening coastal and island communities. In addition, the ocean absorbs carbon dioxide, keeping it from the atmosphere. But more carbon dioxide makes the ocean more acidic, which endangers marine life and coral reefs.

Loss of species

Climate change poses risks to the survival of species on land and in the ocean. These risks increase as temperatures climb. Exacerbated by climate change, the world is losing species at a rate 1,000 times greater than at any other time in recorded human history. One million species are at risk of becoming extinct within the next few decades. Forest fires, extreme weather, and invasive pests and diseases are among many threats related to climate change. Some species will be able to relocate and survive, but others will not.

Not enough food

Changes in the climate and increases in extreme weather events are among the reasons behind a global rise in hunger and poor nutrition. Fisheries, crops, and livestock may be destroyed or become less productive. With the ocean becoming more acidic, marine resources that feed billions of people are at risk. Changes in snow and ice cover in many Arctic regions have disrupted food supplies from herding, hunting, and fishing. Heat stress can diminish water and grasslands for grazing, causing declining crop yields and affecting livestock.

More health risks

Climate change is the single biggest health threat facing humanity. Climate impacts are already harming health, through air pollution, disease, extreme weather events, forced displacement, pressures on mental health, and increased hunger and poor nutrition in places where people cannot grow or find sufficient food. Every year, environmental factors take the lives of around 13 million people. Changing weather patterns are expanding diseases, and extreme weather events increase deaths and make it difficult for health care systems to keep up.

Poverty and displacement

Climate change increases the factors that put and keep people in poverty. Floods may sweep away urban slums, destroying homes and livelihoods. Heat can make it difficult to work in outdoor jobs. Water scarcity may affect crops. Over the past decade (2010–2019), weather-related events displaced an estimated 23.1 million people on average each year, leaving many more vulnerable to poverty. Most refugees come from countries that are most vulnerable and least ready to adapt to the impacts of climate change.

Learn more about...

• What is climate change?

Our climate 101 offers a quick take on the how and why of climate change.

What is “net zero”, why is it important, and is the world on track to reach it?

Initiatives for action

Read about global initiatives aimed at speeding up the pace of climate action.

Facts and figures

• Causes and effects
• Myth busters

Cutting emissions

• Explaining net zero
• High-level expert group on net zero
• Checklists for credibility of net-zero pledges
• Greenwashing
• What you can do

Clean energy

• Renewable energy – key to a safer future
• What is renewable energy
• Five ways to speed up the energy transition
• Why invest in renewable energy
• Clean energy stories
• A just transition

Adapting to climate change

• Climate adaptation
• Early warnings for all
• Youth voices

Financing climate action

• Finance and justice
• Loss and damage
• $100 billion commitment
• Why finance climate action
• Biodiversity
• Human Security

International cooperation

• What are Nationally Determined Contributions
• Acceleration Agenda
• Climate Ambition Summit
• Climate conferences (COPs)
• Youth Advisory Group
• Action initiatives
• Secretary-General’s speeches
• Press material
• Fact sheets
• Communications tips

• ENVIRONMENT

What is global warming, explained

The planet is heating up—and fast.

Glaciers are melting , sea levels are rising, cloud forests are dying , and wildlife is scrambling to keep pace. It has become clear that humans have caused most of the past century's warming by releasing heat-trapping gases as we power our modern lives. Called greenhouse gases, their levels are higher now than at any time in the last 800,000 years .

We often call the result global warming, but it is causing a set of changes to the Earth's climate, or long-term weather patterns, that varies from place to place. While many people think of global warming and climate change as synonyms , scientists use “climate change” when describing the complex shifts now affecting our planet’s weather and climate systems—in part because some areas actually get cooler in the short term.

Climate change encompasses not only rising average temperatures but also extreme weather events , shifting wildlife populations and habitats, rising seas , and a range of other impacts. All of those changes are emerging as humans continue to add heat-trapping greenhouse gases to the atmosphere, changing the rhythms of climate that all living things have come to rely on.

What will we do—what can we do—to slow this human-caused warming? How will we cope with the changes we've already set into motion? While we struggle to figure it all out, the fate of the Earth as we know it—coasts, forests, farms, and snow-capped mountains—hangs in the balance.

Understanding the greenhouse effect

The "greenhouse effect" is the warming that happens when certain gases in Earth's atmosphere trap heat . These gases let in light but keep heat from escaping, like the glass walls of a greenhouse, hence the name.

Sunlight shines onto the Earth's surface, where the energy is absorbed and then radiate back into the atmosphere as heat. In the atmosphere, greenhouse gas molecules trap some of the heat, and the rest escapes into space. The more greenhouse gases concentrate in the atmosphere, the more heat gets locked up in the molecules.

Scientists have known about the greenhouse effect since 1824, when Joseph Fourier calculated that the Earth would be much colder if it had no atmosphere. This natural greenhouse effect is what keeps the Earth's climate livable. Without it, the Earth's surface would be an average of about 60 degrees Fahrenheit (33 degrees Celsius) cooler.

A polar bear stands sentinel on Rudolf Island in Russia’s Franz Josef Land archipelago, where the perennial ice is melting.

In 1895, the Swedish chemist Svante Arrhenius discovered that humans could enhance the greenhouse effect by making carbon dioxide , a greenhouse gas. He kicked off 100 years of climate research that has given us a sophisticated understanding of global warming.

Levels of greenhouse gases have gone up and down over the Earth's history, but they had been fairly constant for the past few thousand years. Global average temperatures had also stayed fairly constant over that time— until the past 150 years . Through the burning of fossil fuels and other activities that have emitted large amounts of greenhouse gases, particularly over the past few decades, humans are now enhancing the greenhouse effect and warming Earth significantly, and in ways that promise many effects , scientists warn.

Aren't temperature changes natural?

Human activity isn't the only factor that affects Earth's climate. Volcanic eruptions and variations in solar radiation from sunspots, solar wind, and the Earth's position relative to the sun also play a role. So do large-scale weather patterns such as El Niño .

You May Also Like

How global warming is disrupting life on Earth

These breathtaking natural wonders no longer exist

What if aliens exist—but they're just hiding from us? The Dark Forest theory, explained

But climate models that scientists use to monitor Earth’s temperatures take those factors into account. Changes in solar radiation levels as well as minute particles suspended in the atmosphere from volcanic eruptions , for example, have contributed only about two percent to the recent warming effect. The balance comes from greenhouse gases and other human-caused factors, such as land use change .

The short timescale of this recent warming is singular as well. Volcanic eruptions , for example, emit particles that temporarily cool the Earth's surface. But their effect lasts just a few years. Events like El Niño also work on fairly short and predictable cycles. On the other hand, the types of global temperature fluctuations that have contributed to ice ages occur on a cycle of hundreds of thousands of years.

For thousands of years now, emissions of greenhouse gases to the atmosphere have been balanced out by greenhouse gases that are naturally absorbed. As a result, greenhouse gas concentrations and temperatures have been fairly stable, which has allowed human civilization to flourish within a consistent climate.

Greenland is covered with a vast amount of ice—but the ice is melting four times faster than thought, suggesting that Greenland may be approaching a dangerous tipping point, with implications for global sea-level rise.

Now, humans have increased the amount of carbon dioxide in the atmosphere by more than a third since the Industrial Revolution. Changes that have historically taken thousands of years are now happening over the course of decades .

Why does this matter?

The rapid rise in greenhouse gases is a problem because it’s changing the climate faster than some living things can adapt to. Also, a new and more unpredictable climate poses unique challenges to all life.

Historically, Earth's climate has regularly shifted between temperatures like those we see today and temperatures cold enough to cover much of North America and Europe with ice. The difference between average global temperatures today and during those ice ages is only about 9 degrees Fahrenheit (5 degrees Celsius), and the swings have tended to happen slowly, over hundreds of thousands of years.

But with concentrations of greenhouse gases rising, Earth's remaining ice sheets such as Greenland and Antarctica are starting to melt too . That extra water could raise sea levels significantly, and quickly. By 2050, sea levels are predicted to rise between one and 2.3 feet as glaciers melt.

As the mercury rises, the climate can change in unexpected ways. In addition to sea levels rising, weather can become more extreme . This means more intense major storms, more rain followed by longer and drier droughts—a challenge for growing crops—changes in the ranges in which plants and animals can live, and loss of water supplies that have historically come from glaciers.

Related Topics

• ENVIRONMENT AND CONSERVATION
• CLIMATE CHANGE

The Gulf of Maine is warming fast. What does that mean for lobsters—and everything else?

What is the ozone layer, and why does it matter?

Why deforestation matters—and what we can do to stop it

There's a frozen labyrinth atop Mount Rainier. What secrets does it hold?

Chile’s glaciers are dying. You can actually hear it.

• Perpetual Planet
• Environment

History & Culture

• History & Culture
• Race in America
• Mind, Body, Wonder
• Paid Content
• Terms of Use
• Privacy Policy
• Your US State Privacy Rights
• Children's Online Privacy Policy
• Interest-Based Ads
• About Nielsen Measurement
• Do Not Sell or Share My Personal Information
• Nat Geo Home
• Attend a Live Event
• Book a Trip
• Inspire Your Kids
• Shop Nat Geo
• Visit the D.C. Museum
• Learn About Our Impact
• Support Our Mission
• Advertise With Us
• Customer Service
• Renew Subscription
• Manage Your Subscription
• Work at Nat Geo
• Sign Up for Our Newsletters
• Contribute to Protect the Planet

Copyright © 1996-2015 National Geographic Society Copyright © 2015-2024 National Geographic Partners, LLC. All rights reserved

An official website of the United States government

The .gov means it’s official. Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

The site is secure. The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

• Publications
• Account settings

Preview improvements coming to the PMC website in October 2024. Learn More or Try it out now .

• Advanced Search
• Journal List
• Int J Occup Environ Med
• v.8(1); 2017 Jan

Global Warming and Its Health Impact

Since the mid-19 th century, human activities have increased greenhouse gases such as carbon dioxide, methane, and nitrous oxide in the Earth's atmosphere that resulted in increased average temperature. The effects of rising temperature include soil degradation, loss of productivity of agricultural land, desertification, loss of biodiversity, degradation of ecosystems, reduced fresh-water resources, acidification of the oceans, and the disruption and depletion of stratospheric ozone. All these have an impact on human health, causing non-communicable diseases such as injuries during natural disasters, malnutrition during famine, and increased mortality during heat waves due to complications in chronically ill patients. Direct exposure to natural disasters has also an impact on mental health and, although too complex to be quantified, a link has even been established between climate and civil violence.

Over time, climate change can reduce agricultural resources through reduced availability of water, alterations and shrinking arable land, increased pollution, accumulation of toxic substances in the food chain, and creation of habitats suitable to the transmission of human and animal pathogens. People living in low-income countries are particularly vulnerable.

Climate change scenarios include a change in distribution of infectious diseases with warming and changes in outbreaks associated with weather extreme events. After floods, increased cases of leptospirosis, campylobacter infections and cryptosporidiosis are reported. Global warming affects water heating, rising the transmission of water-borne pathogens. Pathogens transmitted by vectors are particularly sensitive to climate change because they spend a good part of their life cycle in a cold-blooded host invertebrate whose temperature is similar to the environment. A warmer climate presents more favorable conditions for the survival and the completion of the life cycle of the vector, going as far as to speed it up as in the case of mosquitoes. Diseases transmitted by mosquitoes include some of the most widespread worldwide illnesses such as malaria and viral diseases. Tick-borne diseases have increased in the past years in cold regions, because rising temperatures accelerate the cycle of development, the production of eggs, and the density and distribution of the tick population. The areas of presence of ticks and diseases that they can transmit have increased, both in terms of geographical extension than in altitude. In the next years the engagement of the health sector would be working to develop prevention and adaptation programs in order to reduce the costs and burden of climate change.

Introduction

In the last decade, the interest in the effect of climate change on human health has increased. The impact of Homo sapiens and his activities on the Earth's complex ecosystem have started since the beginning of farming, but it is only with the industrial revolution in the 18 th century that the changes produced by human activities on planet Earth have been accelerating exponentially. Precisely, because of the role played by Homo sapiens in changing the ecosystem in order to ensure his survival and his development, the actual geological era, which follows the Holocene, is called the Anthropocene. 1

The Fifth Assessment Report of IPCC (Intergovernmental Panel n Climate Change), finalized in November 2014 confirms that human activities have produced since the mid-19 th century, an increase in greenhouse gases such as carbon dioxide, methane, and nitrous oxide in the Earth's atmosphere and an increase in average temperature without comparison in human history. The Earth's temperature has been relatively constant over many centuries ago, meanwhile in the last two centuries the changes registered are unprecedented on time scales ranging from decades to millennia. The rate of change in climate is faster now than in any other period in the past thousand years.

Weather and Climate

Two key concepts in climate science are “weather” and “climate.” Weather refers to the conditions of the atmosphere at a certain place and time with reference to temperature, pressure, humidity, wind, and other key parameters (meteorological elements), the presence of clouds, precipitation and the presence of special phenomena, such as thunderstorms, dust storms, tornados and others. Climate is defined as the average weather, or as the statistical description in terms of the mean and variability of relevant quantities over a period of time ranging from months to thousands or millions of years. 2

Temperature

The global average surface temperature has increased by 0.6 °C since the late 1950's and snow cover and ice extent have diminished. An average rise of 10–20 cm in the sea level has been reported and the temperature of the oceans has increased. 3

The fourth Assessment Report (AR4) projected changes in climate until 2100 foresee including higher maximum temperature and more hot days, and higher minimum temperature and fewer cold days, as virtually certain; increase in the length and intensity in warm spells, hot waves, and precipitation, as very likely; and droughts or dryness, changes in intensity, frequency, and duration of tropical cyclone activity, and increase in extreme sea level, as likely, excluding tsunami. 2 , 4

Effects of Global Warming

The effects of rising temperature include soil degradation, loss of productivity of agricultural land and desertification, loss of biodiversity, degradation of ecosystems, reduced fresh-water resources, acidification of oceans, and the disruption and depletion of stratospheric ozone. 5

A great attention has been given to the relationship between climate change and rising risk of infectious diseases, mostly to the vector-borne infections. However, non-communicable diseases can also heavily affect human health.

The increase in average temperature has consequences that occur acutely—such as during natural disasters and extreme events like floods, hurricanes, droughts, heat waves—or it can occur over time through reduced availability of water, drying up the soil, alterations and shrinking arable land, increased pollution, and creation of habitats favorable to the transmission of human and animal pathogens, either directly or via insect vectors.

Populations living in delta regions, low lying small island states, and many arid regions where drought and availability of water are already problematic, are at risk of suffering the effects of global warming. 6 People living in low-income countries, disposing of less technological resources either to protect themselves against extreme events are particularly vulnerable.

Climate change and increase in greenhouse gases can be considered universal, while land use changes have only local impacts. However, despite they occur locally, they have also a feed-back to the global climate and bio-geochemistry. 7

Agriculture and Water Resources

The effect of temperature on agriculture is linked to the availability of water and food production, which can be threatened by prolonged periods of drought or by the excessive rainfall. The agricultural sector employs 70% of water resources, representing the largest user of fresh water. During the last century, irrigated areas have risen fivefold. For 2025 forecast shows that 64% of the world's population will live in water-stressed basins. 8

According to AR4, the variation in the amount and intensity of rainfall will have an overall negative impact on agriculture. Indeed, in areas where precipitation decreases, the availability of total water resources will be reduced, while in areas where an increase in precipitation is expected, the variability and intensity of rainfall could have a negative impact on the seasonal distribution of rainfall and raise the risk of flood and water pollution.

Rising temperature is not the only cause of soil aridity; exploitation of the environment, deforestation, and loss of biodiversity are also important contributing factors. It is estimated that a 2.5 °C increase in global temperature above the pre-industrial level may produce major biodiversity losses in both endemic plants and animals; 41%–51% of endemic plants in southern Africa would be lost, and so do between 13% and 80% of various fauna in the same region. Globally, 20%–30% of all plant and animal species assessed so far would be at high risk of extinction with such a temperature rise. 4

Higher temperatures may also facilitate the introduction of new pathogens, vectors, or hosts that result in increasing need of pesticides and fertilizers in agriculture. These toxic substances accumulate in the food chain, pollute ground water resources, and could be easily spread through the air. Risks from many pathogens, particulate and particle-associated contaminants could thus significantly increase human exposures to pathogens and chemicals in agricultural and even in temperate regions ( Table 1 ). 9

Effect of Extreme Events

An extreme weather event is one that is rare at a particular place and/or time of year. A single extreme event cannot generally be directly attributed to anthropogenic influence, although the change in likelihood for the event to occur has been determined for some events by accounting for observed changes in climate. 2

Unlike geophysical disasters whose causes have not been influenced by human action, hydro-meteorological and climate-related events are the result of the burning of fossil fuels and deforestation. Since 1950, the frequency, intensity, spatial extent, and duration of these events have changed and projections show that they continue to increase with climate change. 10

Even in temperate regions, the climate forecasting models indicate that the total rainfall will decrease but will tend to increase their intensity. 11 When the climate system acquires more energy from higher average air temperatures and the latent heat of increased water vapor, the frequency of extreme weather events (storms, hurricanes, rain-related floods, droughts, etc ) is expected to increase. 2

In 2012, about 32 million people fled their homes because of catastrophes. The higher burden of natural disasters is endured by people living in low-income countries because they are directly affected by environmental degradation and they have less chance to defend themselves against the threat of their immediate environment and health. 12

Direct Exposure of Extreme Weather Events

The potential health impacts of extreme weather events include both direct effects, such as traumatic deaths, and indirect effects, such as illnesses associated with ecologic or social disruption. 13

The consequences in the immediate term are an increased mortality due to injuries, while afterwards there could be an effect on water quality, which could be contaminated by pathogens or chemicals. Floods have already been demonstrated to enhance the contamination of water bodies by pesticides and are followed by outbreaks of infectious diseases. 14

The effect of drought is manifested in an immediate way on the populations of the poorest countries. The loss of crops or livestock has an immediate consequence on the nutritional status of the population, causing malnutrition, under-nutrition, and compromised childhood development due to declines in local agriculture. Recurrent famine due to drought led to widespread loss of livestock, population displacement, and malnutrition in the Horn of Africa. In 2000, after three years of drought, famine has placed an estimated 10 million persons at risk of starvation. Malnutrition and measles were reported to be important causes of mortality among people aged <14 years. 15

Impact on Mental Health and Conflicts

There is an increased burden of psychological diseases and injuries related to natural disasters potentially wide but under-examined, underestimated and not adequately monitored. The mental health situation may be directly connected to the event, as in post-traumatic stress disorder (PTSD) or become chronic. 12 Rubonis and Bickmann reported an increase of approximately 17% in the global rate of psychopathology during disasters. They affirmed that psychological morbidity tends to affect 30%–40% of the disaster population within the first year, with a persistent burden of disease expected to remain chronic. 16 PTSD does not only affect victims of disasters but also has a prevalence of 10%–20% among rescue workers. 17

Another aspect related to the impact the climate change can have on communities is linked to the onset of conflicts. Without interventions designed to protect the most fragile ecosystems, desertification threatens the economies based on subsistence agriculture. This can generate conflicts regarding the access to water resources, and can increase tension between populations of farmers and nomadic herders. Statistical studies have linked climate and civil violence. Regression models have been applied to identify relationships between measures of civil conflict and climate variables, such as rainfall and temperature. Burke, examining the period 1981–2002 in sub-Saharan Africa, found a relationship between the annual incidence of civil conflict resulting in at least 1000 deaths and warmer temperatures in the same and preceding years. However, although climate change could be seen as a risk of civil violence, a quantitative model could also consider other drives to explain the origin of conflicts. 18

The damage to agriculture could indirectly affect distant countries from the concerned regions. The loss of about one-third of the grain produced due to the extreme heat and fires during the summer 2010 in western Russia, has increased the price of the wheat worldwide. In fact, in the Russian Federation the flour prices were increased by 20%, and finally urban populations in low-income countries like Pakistan and Egypt, were challenged. 19

Effects of Heat Waves

Heat waves lead to an excess mortality, even in developed countries, because mortality generally increases at temperatures both above and below an optimum value. In cold areas the increase in mortality is more closely related to cold season 20 because of the epidemic spread of air-borne viral infections ( Table 2 ) 21 - 26 and secondary bacterial infections and cardiovascular complications. Low temperatures cause cardiovascular and respiratory alterations including bronchoconstriction, and reduction in mucociliary defense and other immunological reactions. These conditions make people more receptive to air-borne pathogens. Transmission of infections is also favored by staying in closed crowded spaces, which is not uncommon during cold seasons.

Populations residing in colder climates are more sensitive to heat and heat waves. It was estimated that the heat wave that occurred in Europe, especially France, during August 2003 caused an excess mortality of 14800 deaths. 27 Patients with chronic diseases such as hypertension, heart disease, diabetes, and obesity are more vulnerable to excessive temperatures and at risk of complications. 28 - 30 Beginning with each heat wave period and slightly during its course, a 14% increase in the risk of out-of-hospital cardiac arrest has been reported. 31 Patients suffering from asthma are more hospitalized during extreme heat and precipitation events. It has been hypothesized that thunderstorm events or periods of heavy rainfall and intense wind can trigger the release of fungal spores that are carried by wind, resulting in increased exposure to these allergens. 32 - 35 Another event reported during hot season is the rise in the incidence of urolithiasis. This is believed to be attributed the physiological link between high heat exposure, sweat function, dehydration, and kidney function, with a consequent apparent increase in kidney stone incidence in hotter climate. 29 , 36

Near the polar ice cap at 81° North of Svalbard (Andrew Shiva, CC BY-SA 4.0)

Parched earth, typical of a drought (Atmospheric Research, CSIRO, CC BY 3.0)

Satellite image of Hurricane Isabel about 650 km North of Puerto Rico on September 14, 2003 (Jacques Descloitres, MODIS Rapid Response Team, NASA/GSFC)

El Niño

El Niño Southern Oscillation is a climate event that originates in the Pacific Ocean but has wide-ranging consequences for weather around the world. Globally, it is linked to an increased impact of natural disasters and is especially associated with droughts and floods and with transmission of infectious disease, water-borne and vector-borne diseases, 37 particularly malaria. 38 , 39 Although cholera outbreaks occur in Burundi, Rwanda, Democratic Republic of Congo, Tanzania, Uganda, and Kenya almost every year since 1977, in African Great Lakes Region (AGLR) the incidence of cholera greatly increases during years of El Niño warm events and decreases or remains stable between these periods. 40

El Niño events can produce significant abnormalities in atmospheric general circulations and weather conditions. El Niño events cause changes in sea surface temperature (SST) in the Pacific Ocean, impact the Walker Circulation, and displace the convective area. These changes in atmospheric circulation cause abnormalities in the monsoon system and moisture fields in eastern Asia.

As El Niño has an influence on rainfall and wind speed, it can affect the persistence or moving polluting dust. The 2015 El Niño has had significant effects on air pollution in eastern China, especially in the region including the capital city of Beijing where aerosol pollution was significantly enhanced. 41 The relationship between air pollution and asthma has been well-established. Air pollution is made up of gases and particulate matters that can be transported into the alveoli depending on their size. Particulate matters can produce damage to the whole respiratory apparatus. Exposure to these agents can cause acute pulmonary diseases such as chronic obstructive pulmonary disease (COPD), asthma, and if continues for a long time, it can activate cellular mediators leading to pulmonary fibrosis. 42

Finally, in rural setting, a neglected effect of warm temperature is the increased exposure to snakebites. Snakes are ectothermic organisms whose distribution, movement, and behaviors change as a function of weather fluctuations. In Costa Rica, high numbers of snakebites occur during the cold and hot phases of El Niño. Like other tropical diseases, snakebites occur more frequently in poor settings, thus reflecting the general vulnerability of impoverished human populations to the adverse effects of climate change. 43

Climate Change and Infectious Diseases

Climate mainly affects the range of infectious diseases, whereas weather affects the timing and intensity of outbreaks. Climate change scenarios include a change in the distribution of infectious diseases with warming and changes in outbreaks associated with weather extremes. 44 Statistical models are used to estimate the global burden of some infectious diseases as a result of climate change. According to the models, by 2030, 10% more diarrheal diseases are expected, affecting primarily the young children.

If global temperature increases by 2–3 °C, as it is expected to, the population at risk for malaria could increase by 3%–5%. 45

Infectious Diseases during Extreme Events

Floods not only have direct effects but also increase the risk of microbiological water pollution. Excess cases of leptospirosis and campylobacter enteritis have been reported after flooding in the Czech Republic 46 and in coastal areas of Maryland during extreme precipitation events 47 . Similarly, an outbreak of cryptosporidiosis began six weeks after the peak of an extensive river flooding in Germany. 48

Global warming also affects the water heating and transmission of water-borne pathogens, through the establishment of a more suitable environment for bacterial growth. The higher sea surface temperature and sea level has resulted in rising water-borne infectious and toxin-related illnesses such as cholera and shellfish poisoning. 44

Proliferation of micro-organisms such as Vibrio vulnificus and V. cholerae non-O1/O139, 49 and infection of wounds and sepsis affecting bathers have been reported as consequence of water temperatures above the average in the Baltic Sea and the North Sea during the hot summer of 2006. 50

Vector-borne Diseases and Mosquitoes

The transmission of infectious diseases through vectors is more complex, particularly when humans or livestock, in the case of diseases of veterinary interest, are not the only reservoir. The key elements in the epidemiology of vector-borne diseases include the ecology and behavior of the host, the ecology and behavior of the carrier, and the level of immunity of population.

Pathogens transmitted by vectors are particularly sensitive to climate change because they spend a good part of their life cycle in an ectothermic invertebrate host whose temperature is similar to the environment. 51 A warmer climate presents a more favorable condition for the survival and completion of the life cycle of the vector, going as far as to speed it up as in the case of mosquitoes.

Comparing the maturation of mosquitoes in huts in forest areas and in deforested areas, in which there was a difference of a few degrees, has allowed to estimate the percentage of insects that are passed by the larval form to the adult form (from 65% to 82%) and the reduction of the period required for the development, which passed from 9 to 8 days, in warmer areas. 52

Mosquitoes are found worldwide, except in regions permanently covered by ice. There are about 3500 species of mosquitoes, almost three-quarters of which are present in tropical and subtropical wetlands. Mosquitoes typical of temperate regions have had to develop strategies to survive the winter, as well as pathogens that can be transmitted. In tropical regions, similarly, adaptations were needed to survive the unfavorable times of prolonged drought. In both cases, these adaptive mechanisms have affected the seasonality of transmission. 53

Rising temperature has allowed the extension of the area of distribution of certain diseases. Diseases transmitted by mosquitoes include some of the most widespread illness worldwide. Some of them are caused by parasites, such as Plasmodium spp , the agent of malaria, the main parasitic disease, causing 214 million of new cases in 2015. 54

Temperature affects each stage of mosquitoes' lifecycle. 55 , 56 There is a minimum and maximum temperature threshold above and below which the development and survival of the vector and the parasite are not possible. Above a certain temperature anopheles mosquito vectors of malaria, cannot survive; 57 their life cycle is so fast that does not allow the development of Plasmodium within their salivary glands. The temperature is a variable that affects development of both the vector population and the parasite within the vector; meanwhile the availability of water and moisture affects the vector only. 58 In recent decades, outbreaks of malaria have been reported from many mountainous regions of Kenya, Uganda, and Rwanda, 58 but a high degree of temporal and spatial variation in the climate of East Africa suggests further that claimed associations between local malaria resurgence and regional changes in climate are overly simplistic. Increases in malaria have been attributed to migration, breakdown in both health service provision and vector control operations, and deforestation. Economic, social, and political factors can therefore, explain recent resurgence in malaria rather than climate change. 59 Models have been elaborated to predict in the next years the distribution of malaria. They forecast an extension of areas of endemic malaria and a shift in the affected areas.

Patterns considering Anopheles gambiae vector complex species estimate that climate change effects on African malaria vectors are shifting their distributional potential from West to East and South. Although it is likely a reduction of the malaria burden, these epidemiological changes will pose novel public health problems in areas where it has not previously been common. 60

The reintroduction of malaria in previously endemic areas of Europe and in temperate regions is theoretically possible. In case of the reappearance of the vector, the human carriers of gametocytes, the forms of the parasite transmissible to the mosquito, would also be present in adequate numbers and for a sufficient period to support the transmission. 61 , 62 That is why in southern Europe even though the vector circulates, a limited number of subjects were involved during outbreaks. 63 - 65

Mosquitoes can also transmit viral infections to humans and other vertebrates. Regarded as a typical of tropical or subtropical regions, these diseases and their vectors have begun to be reported in temperate regions. In recent decades, epidemics with autochthonous transmission of dengue fever and chikungunya, both carried by the mosquito Aedes albopictus , have been described in Europe and the USA. 66 These outbreaks were introduced by travelers from endemic areas, but the presence of a vector has allowed the transmission to local population. 67 , 68 Although generally considered a secondary vector of dengue fever, A. albopictus is also able to transmit other viruses including yellow fever. It was introduced in Europe in the 1970's and now it is present in at least 12 states and could go until reach even Scandinavia. 69

Recently, Zika virus has emerged as a “public health emergency of international concern,” according to World Health Organization. Whether the risk of outbreaks or autochthonous cases of Zika virus infections during the summer season in Europe is possible due to the presence of Aedes , is not yet established. 70

For these viruses, which are limited to humans, vector control measures have allowed to contain the spread of the disease. Conversely, a virus such as the West Nile virus, which has a large reservoir constituted by wild birds, could easily become endemic. 71 After the first outbreak reported in Europe in the South of France, and in the USA in the city of New York, West Nile virus is now firmly established in these areas. 72 Their diffusion is supported by mild winters, springs and dry summers, heat waves early in the season and wet fall. 73

Vector-borne Diseases and Ticks

Ticks are responsible for the transmission of both viruses and bacteria. Rising temperature accelerates the cycle of development, the production of eggs, and the density and distribution of their population. 74 , 75

The areas of presence of ticks and diseases that can be transmitted have increased in terms of geographical extension and in altitude. It is possible that the rising temperature could already lead to change in the distribution of the population of Ixodes ricinus , vector of viral infections such as tick-borne encephalitis and Lyme disease in Europe.

The increased incidence of tick-borne encephalitis has also been linked to milder and shorter winters and the consequent extension of the period of tick activity. 76 - 79

In addition to climate change, among the leading causes of increased transmission of tick-borne diseases the abandoning of agricultural lands would also be considered, which has allowed the proliferation of rodents reservoir, and the establishment of ecological niches suitable to ticks in urban parks ( Table 3 ). 80

The global changes that we are currently experiencing have never happened before. They include climate change and variability, change of composition of the atmosphere, use of the earth's surface for expansion of agricultural lands and deforestation. Other changes include an extension of the inhabited rural areas, urbanization, globalization of trade and transports, displacement of populations, diffusion of new plant species, spread of human and animal diseases, and improvements in conditions of life and diffusion of advanced technologies worldwide. 81

Climate change represents one of the main environmental and health equity challenges of our time because the burden of climate-sensitive diseases is the greatest for the poorest populations. 82 Many of the health impacts of climate are a particular threat to poor people in low- and middle-income countries. For example, the mortality rate derived from vector-borne diseases is almost 300 times greater in developing nations than in developed countries, posing as a significant cause of death, disease burden and health inequity, as brake on socioeconomic development, and as a strain on health services. 83

In urban setting, the local climate conditions, where people live and work, create most of the direct human health hazards, such as those due to the urban-heat-island effect. Therefore, a more indirect health effects is often associated with global or large-scale regional climate change. Like other effects of rising temperature, the consequences of global warming are also worse in low-income countries where urbanization have occurred rapidly and without planning. 84

In the next years, in order to contain the global warming, technologies that reduce greenhouse emissions and the consumption of water resources would be needed. A constant need to ensure access to food and availability of protein to the growing world population through agricultural techniques that increase the productivity without depleting the soil would be experienced. Finally, it is important not to forget the most directly and indirectly exposures to damages and results of climate change.

The engagement of the health sector would deal with the increasing pollution-related diseases, to extreme weather events, and would develop knowledge and skills in local prevention/adaptation programs, in order to reduce the costs and burden of the consequences of climate change. 85 Health system needs to strengthen primary health care, develop preventive programs, put special attention towards the vulnerable communities and regions, encourage community participation in grass root planning, emergency preparedness, and make capacity to forecast future health risks. 86

To prevent the spread of infectious and vector-borne diseases, it would be necessary to establish an integrated notification network of veterinary, entomological and human survey, with particular attention to avoid the introduction of new human and animal pathogens. 87

Health professionals everywhere have a responsibility to put health at the heart of climate change negotiations. Firstly, because climate change already has a major adverse impact on the health of human populations. Secondly, because reducing greenhouse gas emissions has unrivalled opportunities for improving public health. 88

Conflict of Interest:

None declared.

Cite this article as: Rossati A. Global warming and its health impact. Int J Occup Environ Med 2017;8:7-20. doi: 10.15171/ijoem.2017.963

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

• View all journals
• Explore content
• About the journal
• Publish with us
• Sign up for alerts
• Open access
• Published: 04 June 2024

Global groundwater warming due to climate change

• Susanne A. Benz   ORCID: orcid.org/0000-0002-6092-5713 1 , 2 ,
• Dylan J. Irvine   ORCID: orcid.org/0000-0002-3543-6221 3 ,
• Gabriel C. Rau 4 ,
• Peter Bayer   ORCID: orcid.org/0000-0003-4884-5873 5 ,
• Kathrin Menberg 6 ,
• Philipp Blum 6 ,
• Rob C. Jamieson 1 ,
• Christian Griebler 7 &
• Barret L. Kurylyk   ORCID: orcid.org/0000-0002-8244-3838 1  

Nature Geoscience volume  17 ,  pages 545–551 ( 2024 ) Cite this article

10k Accesses

1 Citations

466 Altmetric

Metrics details

• Climate-change impacts
• Projection and prediction

Aquifers contain the largest store of unfrozen freshwater, making groundwater critical for life on Earth. Surprisingly little is known about how groundwater responds to surface warming across spatial and temporal scales. Focusing on diffusive heat transport, we simulate current and projected groundwater temperatures at the global scale. We show that groundwater at the depth of the water table (excluding permafrost regions) is conservatively projected to warm on average by 2.1 °C between 2000 and 2100 under a medium emissions pathway. However, regional shallow groundwater warming patterns vary substantially due to spatial variability in climate change and water table depth. The lowest rates are projected in mountain regions such as the Andes or the Rocky Mountains. We illustrate that increasing groundwater temperatures influences stream thermal regimes, groundwater-dependent ecosystems, aquatic biogeochemical processes, groundwater quality and the geothermal potential. Results indicate that by 2100 following a medium emissions pathway, between 77 million and 188 million people are projected to live in areas where groundwater exceeds the highest threshold for drinking water temperatures set by any country.

Similar content being viewed by others

Evapotranspiration depletes groundwater under warming over the contiguous United States

Recent and projected precipitation and temperature changes in the Grand Canyon area with implications for groundwater resources

Global peak water limit of future groundwater withdrawals

Earth’s climatic system warms holistically in response to the radiative imbalance from increased concentrations of greenhouse gases 1 . While the ocean absorbs most of this additional heat 2 , the terrestrial subsurface and groundwater also function as a heat sink. With a stable climate, seasonal temperature variation penetrates to a depth of 10–20 m, below which temperatures generally increase with depth in accordance with the geothermal gradient 3 . However, present-day borehole temperature–depth profiles frequently show an inversion (that is, temperature decreasing with depth) for up to 100 m due to recent, decadal surface warming 4 . Deviations from steady-state subsurface temperatures in deep boreholes (for example, >300 m) have been used to evaluate terrestrial heat storage and to estimate past, pre-observational surface temperature changes at a global scale 5 . Previous multi-continental synthesis studies on subsurface warming provide critical information on climate dynamics, but impacts on groundwater resources and associated implications are commonly ignored.

With the advent of the Gravity Recovery and Climate Experiment (GRACE) satellites, global datasets and global hydrological models, there is an emerging body of global-scale groundwater research 6 , 7 , 8 , 9 . However, global-scale groundwater studies so far have focused on resource quantity (for example, levels, recharge rates and gravity signals), whereas global-scale research into groundwater quality, including temperature, is rare. Furthermore, prominent syntheses of the relationship between anthropogenic climate change and groundwater (for example, refs. 10 , 11 ) concentrate on quantity leaving quality aspects unexplored 12 . Water temperature, sometimes known as the ‘master environmental variable’ (ref. 13 ), is an understudied groundwater quality parameter in the context of climate change.

Whereas global studies of river and lake warming have been conducted 14 , 15 , there are no global assessments of climate change impacts on groundwater temperatures (GWTs). This is despite the high importance of groundwater, which represents the largest global reservoir of unfrozen freshwater 16 , providing at least part of the water supply for half the world 17 and close to half of the global irrigation demand 18 . It also sustains terrestrial and aquatic ecosystems 19 , particularly in the face of climate change 10 . Given the role of temperature as an overarching water quality variable and observational evidence of groundwater warming in different countries in response to recent climate change 4 , 20 , 21 , the potential impact of climate warming on groundwater temperatures at a global scale remains a critical knowledge gap.

Groundwater temperature influences a suite of biogeochemical processes that alter groundwater quality 22 . For example, an increase in temperatures reduces gas solubility and raises metabolism of organisms, with an increased rate of oxygen consumption and a shift in redox conditions 23 . Because many aquifers already possess low oxygen concentrations, a small change in temperature could trigger a shift from an oxic to a hypoxic or even an anoxic regime 24 , 25 . This switch can in turn facilitate the mobilization of redox-sensitive constituents such as arsenic, manganese and phosphorus 26 , 27 . Increases in soluble phosphorus in groundwater discharging to surface water can trigger harmful algal blooms 28 , and elevated arsenic and manganese contents in potable water supplies pose direct risks to human health 29 . Groundwater warming will also cause a shift in groundwater community composition with a challenge to biodiversity and the risk of an impaired cycling of carbon and nutrients 24 , 25 . Shallow soil and groundwater warming may also cause temperatures in water distribution networks to cross critical thresholds, with potential health implications such as the growth of pathogens such as Legionella spp. 30 .

Diffusive discharge of thermally stable groundwater to surface water bodies modulates their temporal thermal regimes 30 . Also, focused groundwater inflows can create cold-water plumes that provide thermal refuge for stressed aquatic species 31 , including many prize cold-water fish. Accordingly, groundwater warming will increase ambient water temperatures in surface water bodies and the temperatures of groundwater-sourced thermal refuges. Spring ecosystems will also be affected. For example, crenobionts (true spring water species) have a very narrow temperature optimum and tolerance; hence, warming groundwater near the mouths of springs will lead to changes in their reproduction cycles, food web interactions and finally a loss of sensitive species 32 .

Groundwater warming can also have positive effects as the accumulated thermal energy can be recycled through shallow, low-carbon geothermal energy systems 33 . Whereas studies typically focus on recycling the waste heat from anthropogenic sources, particularly from subsurface urban heat islands 34 , the subsurface heat accumulating due to climate change also has the potential to sustainably satisfy local heating demands 35 . However, increased warming will make cooling systems less efficient 36 .

Here we develop and apply a global-scale heat-transport model (thermal diffusion) to quantify groundwater temperatures in space and time and their response to recent and projected climate change (Fig. 1a,b ). Our objective is to reveal the potential magnitude and long-term implications of ongoing shallow groundwater warming and to identify ‘hotspots’ of concern. The model utilizes standard climate projections to drive global groundwater warming down to 100 m below ground surface but with a focus on temperatures at the depth of the water table. We discuss (1) where aquifer warming will influence the viability of shallow geothermal heat recycling in the shallow subsurface (Fig. 1c ), (2) given how it impacts microbial activity and groundwater chemistry, where groundwater temperature may cross key thresholds set by drinking water standards (Fig. 1d ) and (3) where discharge of warmed groundwater will have the most pronounced impact on river temperatures and aquatic ecosystems (Fig. 1e ). Our model is global, and its resolution limits detailed capture of small-scale processes, producing conservative results based on tested hydraulic and thermal assumptions, including realistic advection from basin-scale recharge. More localized processes may lead to higher groundwater temperatures in areas with increased downward flow (for example, river-based recharge) or elevated surface temperatures (for example, urban heat islands) (Supplementary Note 1 provides details).

a – e , Increases in surface air and ground surface temperatures ( a ) drive increases in groundwater temperatures ( b ) that, in turn, impact the geothermal potential for shallow geothermal energy systems ( c ), groundwater chemistry and microbiology, which in turn impacts water quality ( d ) and groundwater-dependent ecosystems ( e ). Figure created with images from the UMCES IAN Media Library under a Creative Commons license CC BY-SA 4.0 .

Groundwater temperatures

We use gridded data to calculate transient subsurface temperature–depth profiles across the globe ( Methods ). Besides past and current temperatures, we present potential (modest mitigation) and worst-case (no mitigation) projections to 2100 based on the Shared Socioeconomic Pathway (SSP) 2–4.5 or SSP 5–8.5 climate scenarios of phase 6 the Coupled Model Intercomparison Project (CMIP6) (ref. 37 ). Results can be accessed and visually explored using an interactive Google Earth Engine app available at https://susanneabenz.users.earthengine.app/view/subsurface-temperature-profiles . Figure 2a–c displays maps of mean GWT at the depth of the water table and at 5 and 30 m below ground surface for 2020.

a – c , Map of modelled mean annual temperatures at the depth of the water table ( a ), at 5 m below ground surface ( b ) and at 30 m below ground surface ( c ) in 2020. d , Comparison of modelled and observed groundwater temperatures. Blue markers are (multi-) annual mean temperatures observed between 2000 and 2015 at an unspecified depth against modelled temperatures of the same time period at 30 m depth. Grey markers are temperatures of a single point in time versus modelled temperatures of the same time and depth. A histogram of the errors (observed minus modelled temperatures) is shown in the upper left corner. e , Modelled temperature–depth profiles showing mean annual temperatures and the seasonal envelope for the locations displayed in a . Please note that we use bulk thermal properties, and the water table depth is thus not an input parameter into our model.

Comparison with measured data demonstrates a good accuracy of the model given the global scale with a root mean square error of 1.4 °C and a coefficient of determination of 0.75 (Fig. 2d ). An in-depth discussion on model reliability, uncertainty and limitations is given in Supplementary Note 2 .

The median GWT at the water table in 2020 was 21.0 °C (5.6 °C, 29.3 °C; 10th, 90th percentile; Fig. 2a ). In comparison, using the same ECMWF re-analysis (ERA-5) data product, air temperatures in 2020 were lower at 17.6 °C (1.4 °C, 27.0 °C). This thermal offset is attributable to various processes and conditions including snow pack insulation in colder climates 38 and increased temperatures with depth following the geothermal gradient.

Simulated temperature–depth profiles are displayed at six example locations in Fig. 2e , including their seasonal envelope. Supplementary Note 3 provides a discussion of seasonality. Whereas all locations show an inversion of the temperature–depth profile, the depth at which this thermal gradient ‘inflection point’ (ref. 4 ) is reached varies greatly based on the rate and duration of recent climate change. At the example location in Mexico, temperatures begin to increase with depth (as expected based on the local geothermal gradient) from approximately 10 m downwards, whereas at the example location in Brazil, the inflection point reaches a depth of 45 m (Fig. 2c ). Globally, it has reached 15 (<1, 40) m (Extended Data Fig. 1a ). Heat advection from vertical groundwater flow may also influence the depth of the inflection point 4 , but only heat diffusion is considered in our model as this is the dominant heat-transport mechanism at the modelled spatial scale ( Methods ).

To better assess the impact of recent climate change on groundwater temperatures at the water table depth, we compare annual mean GWTs from 2000 and 2020. Over this 20-year period, GWTs increased on average by 0.3 (0.0, 0.8) °C (Fig. 3a ). We do not find any distinct large-scale patterns. However, some of the highest temperature increases occur in parts of Russia (for example, > + 1. 5 ∘ C north of Novosibirsk), while parts of Canada experienced cooling (for example, < −0. 5 °C in Saskatoon) between the two years. Both regions have shallow water tables, with GWTs tightly coupled to seasonal surface temperature variations and short-term intra-annual changes, rather than just the long-term surface temperature signals. As such, one hot summer can drastically alter the modelled GWT difference between 2000 and 2020. The influence of weather conditions for a given year is also notable in the depth profiles for six selected locations (Fig. 3d ). Noticeable variations occur in the upper 5 m of mean temperature range profiles with temperature changes of 1.1 °C at the location in Australia, compared with 0.5 °C at the location in Nigeria. These effects of intra-annual and short-term interannual variations in weather are attenuated at greater depths (for example, 30 m). Long-term (climate change) effects penetrate deeper, although groundwater warming may be less pronounced with depth due to the time lag between surface and subsurface temperature signals (Fig. 3c ).

a – d , Recent (2000 to 2020) changes. e – h , Projected (2000–2100) changes. a , e , Map of the change in annual mean temperature at the depth of the water table. The line in the legend indicates 0 °C. b , c , f , g , Temperature change 5 m below the land surface ( b , f ) and 30 m below the land surface ( c , g ). d , h , Change in temperatures between 2000 and 2020 ( d ) and difference between 2000 and 2100 ( h ) as depth profiles for selected locations (symbols in a and e ). Lines in h indicate median projections, whereas 25th to 75th percentiles (pct.) are presented as shading.

Over the entire century (between 2000 and 2100), groundwater warming is also projected to increase; globally averaged GWTs at the water table (at its current level) increase by 2.1 (0.8, 3.0) °C following SSP 2–4.5 median projections (Fig. 3e–g ; Extended Data Fig. 2 for 25th (1.7 (0.6, 2.5) °C) and 75th percentile (2.6 (1.0, 3.6) °C) projections) and by 3.5 (1.0, 5.5) °C following SSP 5–8.5 median projections (Extended Data Figs. 3a–d and 4 ; 25th percentile projections 3.0 (0.8, 5.8) °C; 25th percentile projections 4.6 (1.3, 7.1) °C).

We observe a clear signal of climate change by studying the depth down to which the temperature profile is reversed and temperatures are decreasing outside of seasonal effects. In 2100 the geothermal gradient inflection point is projected to reach 45 (9, 90) m on average following SSP 2–4.5 median projections (40 (6, 90) m for 25th percentile and 45 (15, 80) m for 75th percentile projections) or 60 (40, 100) m following SSP 5–8.5 median projections (60 (35, >100) m for 25th percentile and 60 (45, >100) m for 75th percentile projections; Extended Data Figs. 1b,c and 5 ).

Accumulated energy

The overall increase in GWT can be quantified as accumulated energy ( Methods ). By 2020, a net energy amount of 14 × 10 21  J has already been absorbed by the terrestrial subsurface (Fig. 4a ; 119 (45, 202) MJ m −2 ) since the beginning of the industrial revolution. In comparison, 436 × 10 21  J or about 25 times more has been absorbed by the oceans over a similar time period 39 . A review of Earth’s energy imbalance identifies a total heat gain of 358 × 10 21  J for the time period 1971–2018 only, attributing about 6% of that to land areas including permafrost regions (21 × 10 21  J, that is, a similar magnitude as our estimate) 40 . In a similar range is the 23.8 × 10 21  J that was stored in the continental landmass since 1960 following a recent study; 90% is from heat storage 41 .

a – c , Current status in 2020. d – f , Projected status in 2100 under SSP 2–4.5. a , d , Accumulated heat from the surface to 100 m depth. The line in the legend indicates 0 MJ m −2 . b , e , Map showing locations where maximum monthly GWTs at the thermal gradient inflection point (coldest depth) are above guidelines for drinking water temperatures (DWTs) 43 . c , f , GWT changes between 2000 and 2020 ( c ) and between 2000 and 2100 ( f ) at stream sites with a groundwater signature 49 . The line in the legend indicates 0 °C.

We project that by 2100 accumulated subsurface energy will be 41 × 10 21  J following SSP 2–4.5 median projections (343 (251, 463) MJ m −2 ; Fig. 4d ), 30 × 10 21  J following 25th percentile projections (255 (162, 361) MJ m −2 ) and 50 × 10 21  J following 75th percentile projections (424 (324, 560) MJ m −2 ; Extended Data Fig. 6 ). Under SSP 5–8.5 we get 62 × 10 21  J for the median projections (518 (384, 689) MJ m −2 ; Extended Data Fig. 3e ), 49 × 10 21  J for the 25th percentile projections (412 (285, 564) MJ m −2 ) and 77 × 10 21  J for the 75th percentile projections (644 (493, 844) MJ m −2 ; Extended Data Fig. 7 ). This accumulated heat can be extracted from the subsurface through wells in productive aquifers, but in lower-permeability zones and the unsaturated zone, less-efficient borehole heat exchangers would be necessary 33 . Hence, we assessed the energy accumulated in the saturated zone only (below the current water table) in Extended Data Fig. 8 —on average, there is 68 (13, 133) MJ m −2 of heat in the global subsurface saturated zone in 2020.

By comparing the accumulated aquifer thermal energy in the United States (about 45 MJ m −2 ) with local residential heating demands (about 35,000 MJ per household in 2015 following the US Energy Information Administration 2015 Energy Consumption Survey), we find that, if recycled, the energy accumulated below an average home (250 m 2 for the floor area in new single-family houses following the 2015 ‘Characteristics of new housing’ report, US Department of Commerce) in 2020 would fulfil about four months of heating demands. However, by 2100, global heat storage in the saturated zone is projected to increase to 233 (75, 363) MJ m −2 following SSP 2–4.5 and 352 (105, 536) MJ m −2 following SSP 5–8.5 median projections (Extended Data Figs. 8 and 9 for 25th and 75th percentile projections). With heating demands projected to decline due to higher temperatures and improved building insulation, recycling this subsurface heat will therefore become more feasible and is a carbon-reduced heat source that will benefit from climate change 35 . Conversely, cooling systems that rely on geothermal sources will be less efficient.

Implications for drinking water quality

Whereas groundwater warming offers benefits for geothermal heating systems, the accumulated heat also threatens water quality. In many developing countries or in poor and rural areas within developed countries, groundwater may be consumed directly without treatment or storage. It may also indirectly impact temperatures of drinking water within pipes 42 . In these regions in particular, the changes in water chemistry or microbiology that are associated with groundwater warming have to be carefully considered.

According to the World Health Organization, only 18 of 125 countries have temperature guidelines for drinking water 43 . These temperature guidelines, which are often aesthetic guidelines, range from 15 °C to 34 °C, with a median of 25 °C. Figure 4b shows where annual maximum groundwater temperatures at the geothermal gradient inflection point, that is, the most conservative depth as it is the coldest point in the temperature–depth profile, are above these thresholds in 2020. At this time, more than 29 million people live in areas where our modelled maximum GWT exceeded 34 °C. If water is extracted at the depth of the water table, this increases to close to 31 million (Extended Data Fig. 10 ). Following SSP 2–4.5 median projections by 2100, these numbers will increase to 77 million to 188 million depending on the depth of extraction (72 to 101 for 25th percentile projection; 86 to 395 for 75th percentile projections; Fig. 4d and Extended Data Figs. 5 and 9 ). Following SSP 5–8.5 median projections, 59 million to 588 million people will live in areas where maximum GWTs exceed the highest thresholds for drinking water temperatures (54 to 314 for 25th percentile projection; 66 to 1,078 for 75th percentile projections; Extended Data Figs. 3f , 6 and 9 ). Due to the different population distributions, SSP 5–8.5 projects fewer people at risk than SSP 2–4.5 for the lower estimates.

Implications for groundwater-dependent ecosystems

The ecosystems most dependent on groundwater are those in the aquifers themselves. A temperature increase may threaten groundwater biodiversity and ecosystem services 44 , 45 . Also, the increased metabolic rates of microbes caused by warming will accelerate the cycling of organic and inorganic matter, additionally fuelled by the increasing importance of dissolved organic carbon to the subsurface 46 . Combined with decreasing groundwater recharge as projected for many North African, southern European and Latin American countries 47 , this may transform oxic subsurface environments into anoxic 24 .

Groundwater warming also threatens many riverine groundwater-dependent ecosystems and the industries (for example, fisheries) that they support 48 . To capitalize on past continental-scale research related to groundwater, river temperature and ecosystems, we compare our modelled spatial patterns of groundwater warming in the conterminous United States to a recent distributed analysis of 1,729 stream sites 49 . The amplitude and phase of seasonal temperature signals in these surface water bodies were used to reveal the thermal influence and source depth of groundwater discharge to these streams, with about 40% classified as groundwater dominated. Our results show that GWT at the water table for the groundwater-dominated stream sites increased by 0.1 (0.0, 0.4) °C between 2000 and 2020 and 1.3 (0.3, 2.6) °C and 1.9 (0.4, 4.5) °C between 2000 and 2100 following SSP 2–4.5 and SSP 5–8.5 median projections, respectively (Fig. 4c,f and Extended Data Fig. 3g ). Twenty-fifth percentile projections reveal 0.7 (−0.1, 1.5) °C and 1.0 (0.0, 2.9) °C and 75th percentile projections 2.0 (0.5, 4.0) °C and 2.9 (0.6, 6.7) °C between 2000 and 2100 following SSP 2–4.5 and SSP 5–8.5, respectively (Extended Data Figs. 6 and 7 ).

The warming groundwater will inevitably raise the ambient temperature of surface water systems thermally influenced by groundwater discharge. Furthermore, such groundwater warming will even more strongly impact the thermal regimes of groundwater-fed thermal refuges (for example, at the outlets of springs or groundwater-dominated tributaries flowing into rivers) and cause them to more regularly cross critical temperature thresholds for resident species seeking relief from thermal stress. Given the connection between aquifer thermal regimes and river sediment temperatures 50 , groundwater warming also threatens the thermal suitability of benthic ecosystems and spawning areas for fish 51 , posing a major risk to fisheries and other dependent industries.

Summary and model application

In summary, global climate change is leading to increased atmospheric and surface water temperatures, both of which have already been assessed across spatial scales ranging from local to global. Here we contribute to the global analyses of environmental temperature change and of groundwater resources through the presentation of projected groundwater temperature change to 2100 at a global scale. Our analyses are based on reasonable hydraulic and thermal assumptions providing conservative estimates and allow for both the hindcasting and forecasting of groundwater temperatures. Future groundwater temperature forecasts are based on both SSP 2–4.5 and 5–8.5 climate scenarios. We provide global temperature maps at the depth of the water table, 5 and 30 m below land surface, and these highlight that places with shallow water tables and/or high rates of atmospheric warming will experience the highest groundwater warming rates globally. Importantly, given the vertical dimension of the subsurface, groundwater warming is inherently a three-dimensional (3D) phenomenon with increased lagging of warming with depth, making aquifer warming dynamics distinct from the warming of shallow or well-mixed surface water bodies.

To facilitate more detailed future analyses, the temperature maps are included in a Google Earth Engine app at https://susanneabenz.users.earthengine.app/view/subsurface-temperature-profiles . The gridded GWT output could be integrated with global river temperature models 52 to more holistically understand future warming in aquifers and connected rivers. Whereas the warming of Earth’s groundwater poses some opportunities for geothermal energy production, it increasingly threatens ecosystems and the industries depending on them, and it will degrade drinking water quality, primarily in less-developed regions.

Diffusive heat transport

We hindcast monthly subsurface temperatures (and therefore also groundwater temperatures (GWTs) based on the assumption of local equilibrium) from the surface to a depth of 100 m for the years 2000 to 2020. We also force our model with future projections following SSP 2–4.5 and SSP 5–8.5 up to the year 2100. Subsurface temperatures in the shallow crust are generally controlled by one-dimensional (1D) (vertical) diffusive heat transport. Heat advection due to water flow plays a lesser and often inconsequential role in controlling subsurface temperatures 54 , 55 , 56 , particularly at larger spatial scales that average out focused groundwater flows in faults and fractures and groundwater exchange with surface water bodies. We adopt our 1D diffusion-dominated approach rather than a 3D numerical model of coupled groundwater flow and heat transfer as there are presently neither the parameterization data nor the computing power to enable such a coupled, 3D water and thermal transport model at a global scale. Also, whereas the influence of heat advection on steady-state or transient, subsurface temperature–depth profiles can be detected with precise temperature loggers and yields valuable insight into vertical groundwater fluxes when heat is used as a groundwater tracer 57 , the rate of shallow groundwater warming is often not thought to be strongly influenced by typical basin-average, vertical groundwater flux rates. Accordingly, heat advection has been ignored in some past local-scale groundwater warming studies (for example, ref. 58 ). However, to further investigate the thermal effects of multi-dimensional flow, we run a suite of scenarios and find that advection only exerts a minor influence on groundwater warming rates for typical groundwater flow conditions (Supplementary Note 1 ), enabling us to employ our approach.

Appropriate initial conditions can be far more important for reliable simulation of temperature–depth profiles than the inclusion of heat advection 59 . To ensure our initial conditions are not influenced by any preceding climate change, we initiate our model in 1880 when the industrial revolution had not yet increased atmospheric greenhouse gasses and the climate was relatively stable. As default initial setting, we define a temperature–depth profile that increases linearly with depth z from the surface T S in accordance with the geothermal gradient a : T ( z ) =  T S  +  a z (ref. 55 ). In permafrost regions, warming above critical thresholds requires latent heat to thaw ground in addition to the sensible heat to raise the temperature. As we do not include latent heat effects, model results are not presented for permafrost regions 60 .

We use the following analytical solution to the transient 1D heat diffusion equation for a semi-infinite homogeneous medium subject to a series of n step changes in surface temperature 55 :

where j is a step change counter (counting by month), t is time, T S ( t ) is the time series of the ground surface temperature, D is the thermal diffusivity and erfc is the complementary error function. This equation is often used in an inverse manner to reconstruct pre-observational ground surface temperature history from observed, deep temperature–depth profiles, demonstrating its utility for investigating the response of subsurface thermal regimes to surface warming.

We run our model in Google Earth Engine (GEE) 61 , and the results are presented in the form of a Google Earth Engine app openly accessible at https://susanneabenz.users.earthengine.app/view/subsurface-temperature-profiles . The application presents zoomable maps of annual mean, maximum and minimum GWT at different depths and seasonal variability (maximum minus minimum) for selected years and climate scenarios. All datasets were created at a native 5 km resolution at Earth’s surface. However, Google Earth Engine automatically rescales images shown on the map based on the zoom level of the user. Charts that represent temperatures at a given location at a 5 km scale are created by clicking on the map and can be exported in CSV, SVQ or PNG file formats. For all analyses showing annual mean data at the water table depth, we first calculate monthly temperatures at the associated monthly groundwater level before averaging the results.

Ground surface temperatures

We use two distinct ground surface temperature time series: (1) one for the analysis of current (2020) temperatures based primarily on the ERA-5 data 62 and (2) one for the analysis of projected changes based on CMIP6 data 37 . On the basis of available computational power and data, we are not able to utilize monthly temperatures for the entire time period between the years 1880 and 2100. Instead, we present monthly temperatures from 1981 onwards and annual mean temperatures for 1880. The threshold 1981 is selected as ERA-5 data were available in Google Earth Engine from this point on when developing the model.

As these data are input into the analytical step function model (equation ( 1 )), we supplement them with mean temperatures of the early 1980s (that is, three-year mean 1981 to 1984) to reduce artefacts of the sudden onset of seasonal signals in our data. An example of the ground surface temperature time series is shown in Supplementary Fig. 11 .

For the analysis of current GWT, we use monthly mean soil temperature at 0–7 cm depth for the years 1981 to 2022 based on the ERA-5-Land monthly average reanalysis product 62 to form the ground surface temperature boundary condition for equation ( 1 ). These data have a native resolution of 9 km at the surface and are available through the GEE data catalogue. We also used annual ground temperature anomalies of 1880 of the top layer following the Goddard Institute for Space Studies (GISS) atmospheric model E 63 . This dataset gives the temperature difference between 1880 and 1980 in a horizontal resolution of 4° × 5° (approximately 444 km × 555 km at the equator) and can be extracted from https://data.giss.nasa.gov/modelE/transient/Rc_ij.1.11.html . To obtain absolute temperatures of 1880, we subtract the anomalies from three-year mean temperatures (1981 to 1984) of the ERA-5 data.

Future projections of ground surface temperatures are based on monthly soil temperatures closest to the surface for scenarios SSP 2–4.5 and SSP 5–8.5 from the CMIP6 programme available from 2015 to 2100. Model selection and methodology follow previous work 64 , but were updated to CMIP6 based on availability. In total we use nine models: BCC-CSM2-MR, CanESM5, GFDL-ESM4, GISS-E2-1-G, HadGEM3-GC31-LL, IPSL-CM6A-LR, MIROC6, MPI-ESM1-2-LR, NorESM2-MM. Where available, we used data from the variant label r1i1p1f1; however, for GISS-E2-1-G and HadGEM3-GC31-LL, these were not available, and we had to use r1i1p1f2 or r1i1p1f3 instead. Furthermore NorESM2-MM was missing data for January 2015; thus, we replaced them with data from December 2014 from the historic scenario. Data were collected from the World Climate Research Programme at https://esgf-node.llnl.gov/search/cmip6/ . In addition, monthly data of the historic scenario were prepared for January 1981 to December 2014 and the annual mean data for 1880. To account for the difference between the CMIP6 models and ERA-5 reanalysis, we adjust the CMIP6 outputs based on mean temperatures \(\overline{T}\) from ERA-5 between 1981 and 2014 (that is, the overlap between ERA-5 and the CMIP6 historic scenario) for each of the CMIP6 models separately as follows:

Temperatures are determined for each model before being presented as the median and the 25th and 75th percentiles.

Thermal diffusivity

For our analysis we use the ground thermal diffusivity D :

where λ (W m −1  °C −1 ) is the bulk thermal conductivity and C V (J m −3  °C −1 ) is the bulk volumetric heat capacity. Ground thermal conductivity and volumetric heat capacity for various water saturation values are derived following previous examples 35 , 65 . This method links λ and C V values for different soil and/or rock types following the VDI 4640 guidelines 66 to a global map of soil and/or rock type. This map is based on grain size information of the unconsolidated sediment map database (GUM) 67 . Where there is no available sediment class, we link to soil type in GUM. When this is also not available, we rely on the global lithological map database (GLiM) 68 . All required datasets were uploaded to Google Earth Engine in their native resolution. For assigned values, refer to Supplementary Table 1 .

We acknowledge that the distribution of subsurface thermal properties is heterogeneous. However, specific heat capacity and thermal conductivity for rocks are both well constrained to within less than half an order of magnitude 69 , 70 compared with the many orders of magnitude for hydraulic conductivity 71 . We also note that water saturation can change the individual thermal properties and have accordingly run our model for six example locations with three different diffusivity values: (1) a dry soil, (2) a moist soil (default) and (3) a water saturated soil (Supplementary Fig. 12 ). The influence of water saturation on thermal diffusivity can be complex as both the heat capacity and thermal conductivity increase with water content (equation ( 3 )). Overall, for locations with unconsolidated material in the shallow subsurface, groundwater warming rates increase with water saturation. However, the effect is nonlinear and the overall impact of water saturation on the thermal diffusivity is negligible for relative saturation values between 0.5 and 1 (ref. 72 ). A map of the diffusivity utilized here is given in Supplementary Fig. 13a .

Geothermal gradient

When advection is absent, the geothermal gradient a (°C m −1 ; equation ( 1 )) is the rate of temperature change with depth due to the geothermal heat flow Q (W m −2 ) and thermal conductivity λ (W m −1  °C −1 ):

with global values for λ derived as described earlier, and the mean heat flow Q available as a global 2° equal area grid (about 222 km at the equator) 73 . Due to their resolution, these data do not incorporate fractures and major faults, and we thus are not able to estimate groundwater temperatures at these locations properly. The grid was uploaded to GEE in its native resolution for analysis (Supplementary Fig. 13b ).

Water table depth

Much of our analysis and interpretation focuses on the future projection of temperatures at the water table depth. We therefore use the results of a previously published global groundwater model 74 , 75 with a 30 sec grid (about 1 km at the equator) to obtain the mean water table depth for 2004 to 2014. These data are available as monthly averages that we uploaded to GEE in their native resolution. In temperate climates, the model underestimates the observed water table depth by 1.5 m, and we therefore set the minimum water table depth to 1.5 m as was done in a previous study 35 . Still, whereas the global-scale hydro(geo)logical model of Fan et al. 74 , 75 can reveal large-scale patterns, it is of limited use for small-scale analysis and must be used with caution. Hence we run additional information for best- and worst-case scenarios where we add or subtract 10 m to the depth of the water table (Supplementary Note 4 ).

To calculate mean annual GWTs at the water table, temperatures for each month were determined at the corresponding water table depth by setting z in equation ( 1 ) to this depth. Future changes of water table elevation are challenging to predict, and we therefore base our analysis on the assumption that future water table elevations are unchanging. If we assume that the water table will rise, then warming would be more extreme; should the water table lower, warming as projected here is overestimated. A more detailed discussion, modelling water table changes of ± 10 m, can be found in Supplementary Note 4 . However, we note that a modelled temperature–depth profile (equation ( 1 )) is not impacted by the choice of the water table depth, and thus the results at 10 and 30 m are independent of the water table model.

Model evaluation

To assess the performance of our GWT calculations, we use two datasets of measured GWT or borehole temperatures. First, we compare our data to (multi-)annual mean shallow GWTs introduced in Benz et al. 35 . These data comprise more than 8,000 individual locations, primarily in Europe, where GWTs were measured at least twice between 2000 and 2015 at less than 60 m depth. Measurements are filtered based on their seasonal radius, a measure describing if a well was observed uniformly over the seasons and mean temperatures are therefore free of seasonal bias 76 . Second, we compare our data to temperature–depth profiles from the Borehole Temperatures and Climate Reconstruction Database at https://geothermal.earth.lsa.umich.edu/core.html . For these data, an exact date and depth of measurement are known. We filter the database based on time of measurement and depth of the first measurement, using only data taken after the year 2000 and starting at less than 30 m depth, resulting in 72 borehole measurements. To evaluate the model, we compare it to the observed groundwater temperatures described above. We compare the shallow (multi-)annual mean temperatures to mean temperatures at 30 m depth (the middle between 0 m and 60 m, the maximum depth of the observations) between 2000 and 2015. For the dataset of one-time borehole temperature–depth profiles, we compare the shallowest data points to temperatures from our model at the same depth (rounded to the nearest metre), month and year.

Example locations

We use six locations distributed over all latitudes as examples in many of our figures, with locations in Australia (longitude 149.12°, latitude −35.28°), Brazil (−47.92°, −15.77°), China (116.39°, 39.90°), Mexico (−99.12°, 19.46°), Norway (10.74°, 59.91°) and Nigeria (7.49°, 9.05°). For convenience, each point is at the location of the capital city. However, as our model is not able to adequately describe the impact of urban heat on measured groundwater temperatures, groundwater at these locations is expected to be warmer, potentially by several degrees. Our focus is on the rate of warming in response to climate change.

Depth of the geothermal gradient ‘inflection point’

To find the depth d i down to which annual mean temperature–depth profiles T ( z ) are inverted (that is, decrease with depth as opposed to increase following the geothermal gradient 4 ), we find the maximum depth where T ( d i ) >  T ( d i +1 ). Given our computational resources, we test this at a resolution of 1-m steps for the first 10 m, then in 5-m steps down to 50 m depth and lastly in 10-m steps down to the maximal depth of 100 m.

To quantify shallow subsurface accumulated energy I (J m −2 ), we compare mean annual temperature–depth profiles down to 100 m depth to the initial conditions T ( z ) =  T S ( t  = 1,880) +  a z by solving the following integral in 1-m steps:

This analysis utilizes annual mean subsurface temperatures \(\overline{T}(z)\) for 2020 or 2100 for the current and projected analyses, respectively. The volumetric heat capacity C V ( z ) of the unsaturated zone (for z above the water table) and the saturated zone (for z below the water table) uses discrete values given in Supplementary Table 1 .

Drinking water temperature thresholds

To assess the impact of groundwater warming on drinking water resources, we compare annual maximum groundwater temperatures to thresholds for drinking water temperatures summarized by the World Health Organization 43 . We do so for temperatures at the depth of the thermal gradient inflection point, the coldest point in the temperature profile and thus a best-case scenario, and for the depth of the water table to capture the 6% to 20% of wells that are no more than 5 m deeper than the water table 77 . To quantify populations at risk of exceeding the threshold, we compare the resulting maps with population counts. For temperatures in 2022, we use the 2015 United Nations-adjusted population density from the Population of World Version 4.11 Model 78 . For future scenarios, we rely on the global population projection grids for 2100 from the SSPs 79 , 80 . These data are available through the socioeconomic data and applications centre.

Impact on surface water bodies

Temperatures in surface water bodies are strongly influenced by atmospheric heat fluxes, but groundwater discharge and other processes can decouple temperatures in the atmosphere and water column. In the United States, 1,729 stream sites have been analysed by Hare et al. 49 to determine the dominance of groundwater discharge and to ascertain the relative depth (shallow or deep) of the associated aquifers. We use these sites to extract changes in mean annual groundwater temperature at the depth of the water table from our results to assess the impact of groundwater warming on these surface water bodies.

Data availability

Raster files (5 km resolution, in the GeoTIFF format) and tables (.CSV) used to create all figures of this study are made available at the Scholars Portal Dataverse at https://doi.org/10.5683/SP3/GE4VEQ (ref. 81 ). An online tool to facilitate exploration of our groundwater temperature model is available at https://susanneabenz.users.earthengine.app/view/subsurface-temperature-profiles .

Code availability

All codes used are also available at the Scholars Portal Dataverse under https://doi.org/10.5683/SP3/GE4VEQ (ref. 81 ). This includes codes written with Jupyter Notebook (Python) and Google Earth Engine (Javascript and GoogleColab/Python) and a detailed description of the process (readme.txt).

Meinshausen, M. et al. Historical greenhouse gas concentrations for climate modelling (CMIP6). Geosci. Model Dev. 10 , 2057–2116 (2017).

CAS   Google Scholar  

Arias, P. et al. in Climate Change 2021: The Physical Science Basis (eds Masson-Delmotte, V. et al.) 33–144 (Cambridge Univ. Press, 2021).

Kurylyk, B. L. & Irvine, D. J. Heat: an overlooked tool in the practicing hydrogeologist’s toolbox. Groundwater 57 , 517–524 (2019).

Bense, V. F. & Kurylyk, B. L. Tracking the subsurface signal of decadal climate warming to quantify vertical groundwater flow rates. Geophys. Res. Lett. https://doi.org/10.1002/2017gl076015 (2017).

Smerdon, J. E. & Pollack, H. N. Reconstructing earth’s surface temperature over the past 2000 years: the science behind the headlines. WIREs Climate Change 7 , 746–771 (2016).

Google Scholar  

Döll, P. & Fiedler, K. Global-scale modeling of groundwater recharge. Hydrol. Earth Syst. Sci. 12 , 863–885 (2008).

Famiglietti, J. S. The global groundwater crisis. Nat. Clim. Change 4 , 945–948 (2014).

Wada, Y. et al. Global depletion of groundwater resources. Geophys. Res. Lett. https://doi.org/10.1029/2010gl044571 (2010).

Gleeson, T., Befus, K. M., Jasechko, S., Luijendijk, E. & Cardenas, M. B. The global volume and distribution of modern groundwater. Nat. Geosci. 9 , 161–167 (2015).

Taylor, R. G. et al. Ground water and climate change. Nat. Clim. Change 3 , 322–329 (2012).

Green, T. R. et al. Beneath the surface of global change: impacts of climate change on groundwater. J. Hydrol. 405 , 532–560 (2011).

Rodell, M. et al. Emerging trends in global freshwater availability. Nature 557 , 651–659 (2018).

Hannah, D. M. & Garner, G. River water temperature in the United Kingdom. Prog. Phys. Geogr. 39 , 68–92 (2015).

Bosmans, J. et al. FutureStreams, a global dataset of future streamflow and water temperature. Sci. Data https://doi.org/10.1038/s41597-022-01410-6 (2022).

O’Reilly, C. M. et al. Rapid and highly variable warming of lake surface waters around the globe. Geophys. Res. Lett. https://doi.org/10.1002/2015gl066235 (2015).

Ferguson, G. et al. Crustal groundwater volumes greater than previously thought. Geophys. Res. Lett. https://doi.org/10.1029/2021gl093549 (2021).

Zektser, I. S. & Everett, L. G. Groundwater Resources of the World and Their Use (UNESCO, 2004).

Siebert, S. et al. Groundwater use for irrigation—a global inventory. Hydrol. Earth Syst. Sci. 14 , 1863–1880 (2010).

de Graaf, I. E. M., Gleeson, T., van Beek, L. P. H. R., Sutanudjaja, E. H. & Bierkens, M. F. P. Environmental flow limits to global groundwater pumping. Nature 574 , 90–94 (2019).

Chen, C.-H. et al. in Groundwater and Subsurface Environments (ed. Taniguchi, M.) 185–199 (Springer, 2011).

Benz, S. A., Bayer, P., Winkler, G. & Blum, P. Recent trends of groundwater temperatures in Austria. Hydrol. Earth Syst. Sci. 22 , 3143–3154 (2018).

Riedel, T. Temperature-associated changes in groundwater quality. J. Hydrol. 572 , 206–212 (2019).

Cogswell, C. & Heiss, J. W. Climate and seasonal temperature controls on biogeochemical transformations in unconfined coastal aquifers. J. Geophys. Res. https://doi.org/10.1029/2021jg006605 (2021).

Griebler, C. et al. Potential impacts of geothermal energy use and storage of heat on groundwater quality, biodiversity, and ecosystem processes. Environ. Earth Sci. https://doi.org/10.1007/s12665-016-6207-z (2016).

Retter, A., Karwautz, C. & Griebler, C. Groundwater microbial communities in times of climate change. Curr. Issues Mol. Biol. 41 , 509–538 (2021).

Bonte, M. et al. Impacts of shallow geothermal energy production on redox processes and microbial communities. Environ. Sci. Technol. 47 , 14476–14484 (2013).

Bonte, M., van Breukelen, B. M. & Stuyfzand, P. J. Temperature-induced impacts on groundwater quality and arsenic mobility in anoxic aquifer sediments used for both drinking water and shallow geothermal energy production. Water Res. 47 , 5088–5100 (2013).

Brookfield, A. E. et al. Predicting algal blooms: are we overlooking groundwater? Sci. Total Environ. 769 , 144442 (2021).

Bondu, R., Cloutier, V. & Rosa, E. Occurrence of geogenic contaminants in private wells from a crystalline bedrock aquifer in western Quebec, Canada: geochemical sources and health risks. J. Hydrol. 559 , 627–637 (2018).

Agudelo-Vera, C. et al. Drinking water temperature around the globe: understanding, policies, challenges and opportunities. Water 12 , 1049 (2020).

Mejia, F. H. et al. Closing the gap between science and management of cold-water refuges in rivers and streams. Glob. Chang. Biol. 29 , 5482–5508 (2023).

Jyväsjärvi, J. et al. Climate-induced warming imposes a threat to north European spring ecosystems. Glob. Chang. Biol. 21 , 4561–4569 (2015).

Stauffer, F., Bayer, P., Blum, P., Molina Giraldo, N. & Kinzelbach, W. Thermal Use of Shallow Groundwater (CRC Press, 2013).

Epting, J., Müller, M. H., Genske, D. & Huggenberger, P. Relating groundwater heat-potential to city-scale heat-demand: a theoretical consideration for urban groundwater resource management. Appl. Energy 228 , 1499–1505 (2018).

Benz, S. A., Menberg, K., Bayer, P. & Kurylyk, B. L. Shallow subsurface heat recycling is a sustainable global space heating alternative. Nat. Commun. https://doi.org/10.1038/s41467-022-31624-6 (2022).

Schüppler, S., Fleuchaus, P. & Blum, P. Techno-economic and environmental analysis of an aquifer thermal energy storage (ATES) in germany. Geotherm. Energy https://doi.org/10.1186/s40517-019-0127-6 (2019).

Eyring, V. et al. Overview of the Coupled Model Intercomparison Project Phase 6 (CMIP6) experimental design and organization. Geosci. Model Dev. 9 , 1937–1958 (2016).

Zhang, T. Influence of the seasonal snow cover on the ground thermal regime: an overview. Rev. Geophys. 43 , RG4002 (2005).

Zanna, L., Khatiwala, S., Gregory, J. M., Ison, J. & Heimbach, P. Global reconstruction of historical ocean heat storage and transport. Proc. Natl Acad. Sci. USA 116 , 1126–1131 (2019).

von Schuckmann, K. et al. Heat stored in the earth system: where does the energy go? Earth Syst. Sci. Data 12 , 2013–2041 (2020).

Cuesta-Valero, F. J. et al. Continental heat storage: contributions from the ground, inland waters, and permafrost thawing. Earth Syst. Dyn. 14 , 609–627 (2023).

Nissler, E. et al. Heat transport from atmosphere through the subsurface to drinking-water supply pipes. Vadose Zone J. 22 , 270–286 (2023).

A Global Overview of National Regulations and Standards for Drinking-Water Quality 2nd edn (WHO, 2021); https://apps.who.int/iris/handle/10665/350981

Griebler, C. & Avramov, M. Groundwater ecosystem services: a review. Freshw. Sci. 34 , 355–367 (2015).

Mammola, S. et al. Scientists’ warning on the conservation of subterranean ecosystems. BioScience 69 , 641–650 (2019).

McDonough, L. K. et al. Changes in global groundwater organic carbon driven by climate change and urbanization. Nat. Commun. https://doi.org/10.1038/s41467-020-14946-1 (2020).

Atawneh, D. A., Cartwright, N. & Bertone, E. Climate change and its impact on the projected values of groundwater recharge: a review. J. Hydrol. 601 , 126602 (2021).

Meisner, J. D., Rosenfeld, J. S. & Regier, H. A. The role of groundwater in the impact of climate warming on stream salmonines. Fisheries 13 , 2–8 (1988).

Hare, D. K., Helton, A. M., Johnson, Z. C., Lane, J. W. & Briggs, M. A. Continental-scale analysis of shallow and deep groundwater contributions to streams. Nat. Commun. 12 , 1450 (2021).

Caissie, D., Kurylyk, B. L., St-Hilaire, A., El-Jabi, N. & MacQuarrie, K. T. Streambed temperature dynamics and corresponding heat fluxes in small streams experiencing seasonal ice cover. J. Hydrol. 519 , 1441–1452 (2014).

Wondzell, S. M. The role of the hyporheic zone across stream networks. Hydrol. Process. 25 , 3525–3532 (2011).

Liu, S. et al. Global river water warming due to climate change and anthropogenic heat emission. Glob. Planet. Change 193 , 103289 (2020).

Tissen, C., Benz, S. A., Menberg, K., Bayer, P. & Blum, P. Groundwater temperature anomalies in central Europe. Environ. Res. Lett. 14 , 104012 (2019).

Bodri, L. & Cermak, V. Borehole Climatology (Elsevier, 2007).

Carslaw, H. S. & Jaeger, J. C. Conduction of Heat in Solids (Oxford Univ. Press, 1986).

Turcotte, D. L. & Schubert, G. Geodynamics (Cambridge Univ. Press, 2014).

Kurylyk, B. L., Irvine, D. J. & Bense, V. F. Theory, tools, and multidisciplinary applications for tracing groundwater fluxes from temperature profiles. WIREs Water https://doi.org/10.1002/wat2.1329 (2018).

Taylor, C. A. & Stefan, H. G. Shallow groundwater temperature response to climate change and urbanization. J. Hydrol. 375 , 601–612 (2009).

Bense, V. F., Kurylyk, B. L., van Daal, J., van der Ploeg, M. J. & Carey, S. K. Interpreting repeated temperature-depth profiles for groundwater flow. Water Resour. Res. 53 , 8639–8647 (2017).

Brown, J., Ferrians, O., Heginbottom, J. A. & Melnikov, E. Circum-Arctic map of permafrost and ground-ice conditions, version 2. NSIDC https://nsidc.org/data/GGD318/versions/2 (2002).

Gorelick, N. et al. Google Earth Engine: planetary-scale geospatial analysis for everyone. Remote Sens. Environ. 202 , 18–27 (2017).

ERA5-Land monthly averaged data from 2001 to present. Copernicus Climate Data Store https://cds.climate.copernicus.eu/doi/10.24381/cds.68d2bb30 (2019).

Hansen, J. et al. Climate simulations for 1880–2003 with GISS modelE. Clim. Dyn. 29 , 661–696 (2007).

Soong, J. L., Phillips, C. L., Ledna, C., Koven, C. D. & Torn, M. S. CMIP5 models predict rapid and deep soil warming over the 21st century. J. Geophys. Res. https://doi.org/10.1029/2019jg005266 (2020).

Huscroft, J., Gleeson, T., Hartmann, J. & Börker, J. Compiling and mapping global permeability of the unconsolidated and consolidated earth: GLobal HYdrogeology MaPS 2.0 (GLHYMPS 2.0). Geophys. Res. Lett. 45 , 1897–1904 (2018).

VDI 4640—Thermal Use of the Underground (VDI-Gesellschaft Energie und Umwelt, 2010).

Börker, J., Hartmann, J., Amann, T. & Romero-Mujalli, G. Terrestrial sediments of the earth: development of a global unconsolidated sediments map database (GUM). Geochem. Geophys. Geosyst. 19 , 997–1024 (2018).

Hartmann, J. & Moosdorf, N. The new global lithological map database GLiM: a representation of rock properties at the earth surface. Geochem. Geophys. Geosyst. https://doi.org/10.1029/2012gc004370 (2012).

Clauser, C. in Thermal Storage and Transport Properties of Rocks, I: Heat Capacity and Latent Heat (ed. Gupta, H. K.) 1423–1431 (Springer, 2011).

Clauser, C. in Thermal Storage and Transport Properties of Rocks, II: Thermal Conductivity and Diffusivity (ed. Gupta, H. K.) 1431–1448 (Springer, 2011).

Rau, G. C., Andersen, M. S., McCallum, A. M., Roshan, H. & Acworth, R. I. Heat as a tracer to quantify water flow in near-surface sediments. Earth Sci. Rev. 129 , 40–58 (2014).

Halloran, L. J., Rau, G. C. & Andersen, M. S. Heat as a tracer to quantify processes and properties in the vadose zone: a review. Earth Sci. Rev. 159 , 358–373 (2016).

Davies, J. H. Global map of solid earth surface heat flow. Geochem. Geophys. Geosyst. 14 , 4608–4622 (2013).

Fan, Y., Li, H. & Miguez-Macho, G. Global patterns of groundwater table depth. Science 339 , 940–943 (2013).

Fan, Y., Miguez-Macho, G., Jobbágy, E. G., Jackson, R. B. & Otero-Casal, C. Hydrologic regulation of plant rooting depth. Proc. Natl Acad. Sci. USA 114 , 10572–10577 (2017).

Benz, S. A., Bayer, P. & Blum, P. Global patterns of shallow groundwater temperatures. Environ. Res. Lett. 12 , 034005 (2017).

Jasechko, S. & Perrone, D. Global groundwater wells at risk of running dry. Science 372 , 418–421 (2021).

Gridded population of the world, version 4 (GPWv4): population density adjusted to match 2015 revision UN WPP country totals, revision 11. CIESIN https://sedac.ciesin.columbia.edu/data/set/gpw-v4-population-density-adjusted-to-2015-unwpp-country-totals-rev11 (2018).

Gao, J. Global 1-km downscaled population base year and projection grids based on the shared socioeconomic pathways, revision 01. CIESIN https://doi.org/10.7927/q7z9-9r69 (2020).

Gao, J. Downscaling Global Spatial Population Projections from 1/8-Degree to 1-km Grid Cells (NCAR/UCAR, 2017); https://opensky.ucar.edu/islandora/object/technotes:553

Benz, S. Global groundwater warming due to climate change. Borealis https://doi.org/10.5683/SP3/GE4VEQ (2024).

Download references

Acknowledgements

S.A.B. was supported through a Banting postdoctoral fellowship, administered by the government of Canada, and since October 2022 as a Freigeist fellow of the Volkswagen Foundation. B.L.K. was supported through the Canada Research Chairs programme. K.M. was supported by the Margarete von Wrangell programme of the Ministry of Science, Research and the Arts Baden-Württemberg (MWK). We thank C. Tissen for sharing data she collected in her study on groundwater temperature anomalies in Europe 53 and the many other people and agencies collecting groundwater temperature data and making them available through (publicly accessible) databases. Without these data, successful validation of our method would not have been possible.

Open access funding provided by Karlsruher Institut für Technologie (KIT).

Author information

Authors and affiliations.

Centre for Water Resources Studies and Department of Civil and Resource Engineering, Dalhousie University, Halifax, Nova Scotia, Canada

Susanne A. Benz, Rob C. Jamieson & Barret L. Kurylyk

Institute of Photogrammetry and Remote Sensing, Karlsruhe Institute of Technology, Karlsruhe, Germany

Susanne A. Benz

Research Institute for the Environment and Livelihoods, Charles Darwin University, Casuarina, Northern Territory, Australia

Dylan J. Irvine

School of Environmental and Life Sciences, The University of Newcastle, Callaghan, New South Wales, Australia

Gabriel C. Rau

Department of Applied Geology, Martin Luther University Halle-Wittenberg, Halle, Germany

Peter Bayer

Institute of Applied Geosciences, Karlsruhe Institute of Technology, Karlsruhe, Germany

Kathrin Menberg & Philipp Blum

Department of Functional and Evolutionary Ecology, University of Vienna, Vienna, Austria

Christian Griebler

You can also search for this author in PubMed   Google Scholar

Contributions

S.A.B., B.L.K. and D.J.I. designed the study. S.A.B., B.L.K., D.J.I., G.C.R., P. Blum, K.M. and P. Bayer developed the methodology. S.A.B. prepared all data and code for analysis and designed figures. D.J.I. designed Fig. 1 . D.J.I. and G.C.R. designed, performed and led the discussion of the analysis in Supplementary Note 1 . S.A.B., B.L.K., D.J.I. and G.C.R. wrote the manuscript. All authors interpreted results and edited the manuscript together.

Corresponding authors

Correspondence to Susanne A. Benz or Barret L. Kurylyk .

Ethics declarations

Competing interests.

The authors declare no competing interests.

Peer review

Peer review information.

Nature Geoscience thanks Maria Klepikova and the other, anonymous, reviewer(s) for their contribution to the peer review of this work. Primary Handling Editor: Thomas Richardson, in collaboration with the Nature Geoscience team.

Additional information

Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Extended data

Extended data fig. 1 depth to the inflection point..

Shown is the depth down to which we can trace the impact of climate change in form of inverted temperature-depth profiles, that is temperature is decreasing with depth and not increasing with depth as expected based on the geothermal gradient. a and b , The depth to the geothermal inflection point in 2020 and 2100 following SSP 2-4.5. c , The depth to the geothermal inflection point in 2100 following SSP 5-8.5.

Extended Data Fig. 2 Change in groundwater temperatures following SSP 2-4.5, 25th and 75th percentile projections.

a – f , Map of the change in annual mean temperature between 2000 and 2100 following SSP 2-4.5 at the depth of the water table (under consideration of its seasonal variation). Temperatures in 2000 are based on the historic CMIP6 scenario. The line in the legend indicates 0 ∘ C. b and e , Annual mean groundwater temperature 5 m below the surface. c and f , Annual mean groundwater temperature 30 m below the surface. a – c , Annual mean groundwater temperature 25th percentile projected changes. d – f , Annual mean groundwater temperature 75th percentile projected changes.

Extended Data Fig. 3 Change in groundwater temperatures between 2000 and 2100 and implications following SSP 5-8.5.

a , Map of the change in annual mean temperature between 2000 and 2100 following SSP 5-8.5 (median projections) at the depth of the water table (under consideration of its seasonal variation). Temperatures in 2000 are based on the historic CMIP6 scenario. The line in the legend indicates 0 ∘ C. b , temperature change 5 m below the surface, and c , 30 m below the surface. d , Change in temperatures between 2000 and 2100 as depth profiles for selected locations. Lines indicate median projections whereas 25th to 75th percentile are presented as shading. e , Accumulated heat down to 100 m depth. The line in the legend indicates 0 MJ per m 2 . f , Map showing locations where maximum monthly GWTs at the thermal gradient inflection point (that is coldest depth) in 2100 are above guidelines for drinking water temperatures (DWTs). g , GWT changes between 2000 and 2100 at stream sites with a groundwater signature.

Extended Data Fig. 4 Change in groundwater temperatures following SSP5-8.5, 25th and 75th percentile projections.

a and d , Map of the change in annual mean temperature between 2000 and 2100 following SSP5-8.5 at the depth of the water table (under consideration of its seasonal variation). Temperatures in 2000 are based on the historic CMIP6 scenario. The line in the legend indicates 0 ∘ C. b and e , Annual mean groundwater temperature 5 m below the surface. c and f , Annual mean groundwater temperature 30 m below the surface. a to c , Annual mean groundwater temperature 25th percentile projected changes. d to f , Annual mean groundwater temperature 75th percentile projected changes.

Extended Data Fig. 5 Depth to the inflection point for 25th and 75th SSP projections.

The depth down to which we can trace the impact of climate change in form of inverted temperature-depth profiles, that is temperature is decreasing with depth and not increasing with depth as expected based on the geothermal gradient. a and b , The inflection point for SSP2-4.5 in 2100 based on 25th percentile or 75th percentile projections, respecively. c and d , The inflection point for SSP5-8.5 in 20100 based on 25th percentile or rather 75th percentile projections.

Extended Data Fig. 6 Implication of groundwater warming for SSP 2-4.5 25th and 75th percentile projections.

a and d , Accumulated heat down to 100 m depth for SSP 2-4.5 25th and 75th percentile projections, respectively. The line in the legend indicates 0 MJ per m 2 . b and e , Locations where maximum monthly GWTs at the thermal gradient inflection point (that is coldest depth) in 2100 are above guidelines for drinking water temperatures (DWTs) for SSP 2-4.5 25th and 75th percentile projections, respectively. c and f , GWT changes between 2000 and 2100 at stream sites with a groundwater signature for SSP 2-4.5 25th and 75th percentile projections, respectively.

Extended Data Fig. 7 Implication of groundwater warming for SSP 5-8.5 25th and 75th percentile projections.

a and d , Accumulated heat down to 100 m depth for SSP 5-8.5 25th and 75th percentile projections, respectively. The line in the legend indicates 0 MJ per m 2 . b and e , Locations where maximum monthly GWTs at the thermal gradient inflection point (that is coldest depth) in 2100 are above guidelines for drinking water temperatures (DWTs) for SSP 5-8.5 25th and 75th percentile projections, respectively. c and f , GWT changes between 2000 and 2100 at stream sites with a groundwater signature for SSP 5-8.5 25th and 75th percentile projections, respectively.

Extended Data Fig. 8 Accumulated heat in the saturated zone (that is, below the water table) down to 100 m depth.

a , Accumulated heat in the saturated zone in 2020. b and c , Accumulated heat in the saturated zone in 2100 following median projections of SSP2-4.5 and SSP5-8.5, respectively.

Extended Data Fig. 9 Accumulated heat in the saturated zone (defined as below the water table down to 100 m depth) and maximum temperatures (based on monthly GWTs) at the depth of the geothermal inflection point showing exceedence of guideline thresholds for drinking water temperatures (DWTs) for 25th and 75th percentile SSP projections.

a and b , Accumulated heat in the saturated zone for SSP 2-4.5 25th and 75th percentile projections, respectively. c and d , Locations where maximum temperatures exceed guideline thresholds for drinking water temperatures (DWTs) for SSP 2-4.5 25th and 75th percentile projections, respectively. e and f , Accumulated heat in the saturated zone for SSP 5-8.5 25th and 75th percentile projections, respectively. g and h , Locations where maximum temperatures exceed guideline thresholds for DWTs for SSP 5-8.5 25th and 75th percentile projections, respectively.

Extended Data Fig. 10 Locations where maximum monthly GWTs at the depth of the water table exceed guideline thresholds for drinking water temperatures (DWTs).

a , Maximum monthly GWTs at the depth of the water table in 2020. b and c , Maximum monthly GWTs at the depth of the water table in 2100 following median projections of SSP2-4.5 and SSP5-8.5, respectively.

Supplementary information

Supplementary information.

Supplementary Notes 1–4, Figs. 1–17 and Tables 1–5.

Rights and permissions

Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/ .

Reprints and permissions

About this article

Cite this article.

Benz, S.A., Irvine, D.J., Rau, G.C. et al. Global groundwater warming due to climate change. Nat. Geosci. 17 , 545–551 (2024). https://doi.org/10.1038/s41561-024-01453-x

Download citation

Received : 31 May 2023

Accepted : 12 April 2024

Published : 04 June 2024

Issue Date : June 2024

DOI : https://doi.org/10.1038/s41561-024-01453-x

Share this article

Anyone you share the following link with will be able to read this content:

Sorry, a shareable link is not currently available for this article.

Provided by the Springer Nature SharedIt content-sharing initiative

This article is cited by

Groundwater warming.

• Maria Klepikova

Nature Geoscience (2024)

Quick links

• Explore articles by subject
• Guide to authors
• Editorial policies

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Paragraph on the Effects of Global Warming

Ai generator.

In a somber paragraph, the effects of global warming, spurred by climate change , loom large. Deforestation compounds this crisis, releasing carbon dioxide into the atmosphere and disrupting ecosystems. Paragraph Rising temperatures fuel extreme weather events, imperiling lives and livelihoods. Urgent action is imperative to mitigate these consequences and safeguard the planet for future generations.

Checkout → Free Paragraph Writer Tool

Short Paragraph on the Effects of Global Warming

Global warming has far-reaching effects on the environment and human life. Rising temperatures lead to more frequent and severe weather events, such as hurricanes, droughts, and heatwaves. Melting polar ice caps and glaciers contribute to rising sea levels, threatening coastal communities. Additionally, global warming disrupts ecosystems, endangering wildlife and biodiversity.

Medium Paragraph on the Effects of Global Warming

The effects of global warming are increasingly evident and alarming, impacting the environment, human health, and economies. As global temperatures rise, we experience more frequent and intense weather events, including hurricanes, droughts, and heatwaves. Melting polar ice caps and glaciers contribute to rising sea levels, which threaten coastal communities and increase the risk of flooding. Furthermore, global warming disrupts ecosystems, leading to habitat loss and endangering wildlife. The shifting climate also affects agriculture, reducing crop yields and exacerbating food insecurity. Human health is impacted through increased heat-related illnesses and the spread of diseases. Addressing global warming requires urgent action to reduce greenhouse gas emissions and mitigate its devastating effects.

Long Paragraph on the Effects of Global Warming

The effects of global warming are profound and multifaceted, posing significant challenges to the environment, human health, and global economies. One of the most noticeable impacts is the increase in frequency and intensity of extreme weather events, such as hurricanes, droughts, heatwaves, and heavy rainfall. These events cause widespread damage to infrastructure, disrupt communities, and result in substantial economic losses. The melting of polar ice caps and glaciers due to rising temperatures leads to rising sea levels, which threaten coastal cities and small island nations with increased flooding and erosion. Additionally, global warming disrupts natural ecosystems, causing shifts in habitat ranges and endangering species that cannot adapt quickly enough. Coral reefs, which are vital to marine biodiversity, are particularly vulnerable to ocean warming and acidification. Agricultural productivity is also affected, as changing weather patterns and increased temperatures reduce crop yields and lead to food shortages. Human health suffers from the spread of vector-borne diseases, heat-related illnesses, and respiratory issues due to increased air pollution. Furthermore, global warming exacerbates social inequalities, as vulnerable populations bear the brunt of its impacts. Addressing these challenges requires concerted global efforts to reduce greenhouse gas emissions, implement sustainable practices, and develop adaptive strategies to mitigate the far-reaching effects of global warming.

Tone-wise Paragraph Examples on the Effects of Global Warming

Formal tone.

The effects of global warming are extensive and multifaceted, significantly impacting the environment, human health, and global economies. Rising temperatures contribute to the increased frequency and intensity of extreme weather events, such as hurricanes, droughts, and heatwaves, causing widespread damage and economic losses. Melting polar ice caps and glaciers lead to rising sea levels, threatening coastal communities with flooding and erosion. Additionally, global warming disrupts ecosystems, endangering species and altering habitats. Agricultural productivity is affected by changing weather patterns, leading to food shortages. Human health is compromised by the spread of diseases and heat-related illnesses. Addressing these issues necessitates urgent, coordinated global action to reduce greenhouse gas emissions and develop adaptive strategies.

Informal Tone

Global warming is having some pretty serious effects on our planet and our lives. We’re seeing more intense weather events like hurricanes and heatwaves, and the melting ice caps are causing sea levels to rise, which threatens coastal areas. Wildlife and ecosystems are also being disrupted, and crops are suffering from changing weather patterns. Plus, our health is at risk from heat-related illnesses and spreading diseases. We need to act quickly to cut down on greenhouse gas emissions and tackle these problems.

Persuasive Tone

Consider the urgent and wide-ranging effects of global warming on our planet. Rising temperatures lead to more extreme weather events like hurricanes and droughts, causing significant damage and economic loss. Melting ice caps result in rising sea levels, threatening coastal communities. Wildlife and ecosystems are disrupted, and agriculture suffers, leading to food shortages. Our health is also at risk from heat-related illnesses and spreading diseases. We must take immediate action to reduce greenhouse gas emissions and implement sustainable practices to mitigate these impacts and protect our future.

Reflective Tone

Reflecting on the effects of global warming, it becomes clear how deeply it impacts our world. The increase in extreme weather events, melting ice caps, and rising sea levels highlight the environmental challenges we face. Wildlife and ecosystems are under threat, and agriculture is struggling with changing weather patterns. Human health is also affected by heat-related illnesses and the spread of diseases. Addressing global warming requires us to rethink our actions and prioritize sustainable practices to protect our planet and future generations.

Inspirational Tone

Embrace the challenge of combating the effects of global warming to protect our planet for future generations. Global warming leads to extreme weather events, melting ice caps, and rising sea levels, threatening our environment and communities. Wildlife and ecosystems are disrupted, and agriculture faces new challenges. Our health is also at risk. Let us come together to reduce greenhouse gas emissions, adopt sustainable practices, and inspire others to take action. By working collectively, we can mitigate these impacts and ensure a healthier, more sustainable world for all.

Optimistic Tone

The effects of global warming are significant, but we have the power to make a difference. Rising temperatures cause extreme weather, melting ice caps, and rising sea levels, but by reducing greenhouse gas emissions, we can mitigate these impacts. Wildlife and ecosystems can recover, and sustainable agricultural practices can adapt to changing weather patterns. Our health can improve with cleaner air and better preparedness for heat-related illnesses. Together, we can create a more sustainable future and protect our planet.

Urgent Tone

The effects of global warming demand immediate attention and action. Rising temperatures lead to more frequent and severe weather events, such as hurricanes, droughts, and heatwaves, causing extensive damage and economic loss. Melting ice caps result in rising sea levels, threatening coastal communities. Wildlife and ecosystems are under threat, and agriculture suffers, leading to food shortages. Human health is at risk from heat-related illnesses and spreading diseases. We must act now to reduce greenhouse gas emissions and implement sustainable practices to combat these urgent issues and safeguard our future.

Word Count-wise Effects of Global Warming Paragraph Examples

The effects of global warming are increasingly evident and alarming, impacting how we communicate, access information, and entertain ourselves. Platforms such as Facebook, Twitter, and Instagram enable us to stay connected with friends and family, no matter the distance. They provide a space for sharing experiences, photos, and updates, fostering a sense of community. Social media also serves as a powerful tool for news dissemination, allowing users to stay informed about global events in real time. Moreover, it offers various forms of entertainment, from funny videos to engaging content creators.

The effects of global warming are profound and multifaceted, posing significant challenges to the environment, human health, and global economies. One of the most noticeable impacts is the increase in frequency and intensity of extreme weather events, such as hurricanes, droughts, heatwaves, and heavy rainfall. These events cause widespread damage to infrastructure, disrupt communities, and result in substantial economic losses. The melting of polar ice caps and glaciers due to rising temperatures leads to rising sea levels, which threaten coastal cities and small island nations with increased flooding and erosion. Additionally, global warming disrupts natural ecosystems, causing shifts in habitat ranges and endangering species that cannot adapt quickly enough.

The effects of global warming are profound and multifaceted, posing significant challenges to the environment, human health, and global economies. One of the most noticeable impacts is the increase in frequency and intensity of extreme weather events, such as hurricanes, droughts, heatwaves, and heavy rainfall. These events cause widespread damage to infrastructure, disrupt communities, and result in substantial economic losses. The melting of polar ice caps and glaciers due to rising temperatures leads to rising sea levels, which threaten coastal cities and small island nations with increased flooding and erosion. Additionally, global warming disrupts natural ecosystems, causing shifts in habitat ranges and endangering species that cannot adapt quickly enough. Coral reefs, which are vital to marine biodiversity, are particularly vulnerable to ocean warming and acidification.

The effects of global warming are profound and multifaceted, posing significant challenges to the environment, human health, and global economies. One of the most noticeable impacts is the increase in frequency and intensity of extreme weather events, such as hurricanes, droughts, heatwaves, and heavy rainfall. These events cause widespread damage to infrastructure, disrupt communities, and result in substantial economic losses. The melting of polar ice caps and glaciers due to rising temperatures leads to rising sea levels, which threaten coastal cities and small island nations with increased flooding and erosion. Additionally, global warming disrupts natural ecosystems, causing shifts in habitat ranges and endangering species that cannot adapt quickly enough. Coral reefs, which are vital to marine biodiversity, are particularly vulnerable to ocean warming and acidification. Agricultural productivity is also affected, as changing weather patterns and increased temperatures reduce crop yields and lead to food shortages. Human health suffers from the spread of vector-borne diseases, heat-related illnesses, and respiratory issues due to increased air pollution.

Text prompt

• Instructive
• Professional

10 Examples of Public speaking

20 Examples of Gas lighting

Climate Change: Evidence and Causes: Update 2020 (2020)

Chapter: conclusion, c onclusion.

This document explains that there are well-understood physical mechanisms by which changes in the amounts of greenhouse gases cause climate changes. It discusses the evidence that the concentrations of these gases in the atmosphere have increased and are still increasing rapidly, that climate change is occurring, and that most of the recent change is almost certainly due to emissions of greenhouse gases caused by human activities. Further climate change is inevitable; if emissions of greenhouse gases continue unabated, future changes will substantially exceed those that have occurred so far. There remains a range of estimates of the magnitude and regional expression of future change, but increases in the extremes of climate that can adversely affect natural ecosystems and human activities and infrastructure are expected.

Citizens and governments can choose among several options (or a mixture of those options) in response to this information: they can change their pattern of energy production and usage in order to limit emissions of greenhouse gases and hence the magnitude of climate changes; they can wait for changes to occur and accept the losses, damage, and suffering that arise; they can adapt to actual and expected changes as much as possible; or they can seek as yet unproven “geoengineering” solutions to counteract some of the climate changes that would otherwise occur. Each of these options has risks, attractions and costs, and what is actually done may be a mixture of these different options. Different nations and communities will vary in their vulnerability and their capacity to adapt. There is an important debate to be had about choices among these options, to decide what is best for each group or nation, and most importantly for the global population as a whole. The options have to be discussed at a global scale because in many cases those communities that are most vulnerable control few of the emissions, either past or future. Our description of the science of climate change, with both its facts and its uncertainties, is offered as a basis to inform that policy debate.

A CKNOWLEDGEMENTS

The following individuals served as the primary writing team for the 2014 and 2020 editions of this document:

• Eric Wolff FRS, (UK lead), University of Cambridge
• Inez Fung (NAS, US lead), University of California, Berkeley
• Brian Hoskins FRS, Grantham Institute for Climate Change
• John F.B. Mitchell FRS, UK Met Office
• Tim Palmer FRS, University of Oxford
• Benjamin Santer (NAS), Lawrence Livermore National Laboratory
• John Shepherd FRS, University of Southampton
• Keith Shine FRS, University of Reading.
• Susan Solomon (NAS), Massachusetts Institute of Technology
• Kevin Trenberth, National Center for Atmospheric Research
• John Walsh, University of Alaska, Fairbanks
• Don Wuebbles, University of Illinois

Staff support for the 2020 revision was provided by Richard Walker, Amanda Purcell, Nancy Huddleston, and Michael Hudson. We offer special thanks to Rebecca Lindsey and NOAA Climate.gov for providing data and figure updates.

The following individuals served as reviewers of the 2014 document in accordance with procedures approved by the Royal Society and the National Academy of Sciences:

• Richard Alley (NAS), Department of Geosciences, Pennsylvania State University
• Alec Broers FRS, Former President of the Royal Academy of Engineering
• Harry Elderfield FRS, Department of Earth Sciences, University of Cambridge
• Joanna Haigh FRS, Professor of Atmospheric Physics, Imperial College London
• Isaac Held (NAS), NOAA Geophysical Fluid Dynamics Laboratory
• John Kutzbach (NAS), Center for Climatic Research, University of Wisconsin
• Jerry Meehl, Senior Scientist, National Center for Atmospheric Research
• John Pendry FRS, Imperial College London
• John Pyle FRS, Department of Chemistry, University of Cambridge
• Gavin Schmidt, NASA Goddard Space Flight Center
• Emily Shuckburgh, British Antarctic Survey
• Gabrielle Walker, Journalist
• Andrew Watson FRS, University of East Anglia

The Support for the 2014 Edition was provided by NAS Endowment Funds. We offer sincere thanks to the Ralph J. and Carol M. Cicerone Endowment for NAS Missions for supporting the production of this 2020 Edition.

F OR FURTHER READING

For more detailed discussion of the topics addressed in this document (including references to the underlying original research), see:

• Intergovernmental Panel on Climate Change (IPCC), 2019: Special Report on the Ocean and Cryosphere in a Changing Climate [ https://www.ipcc.ch/srocc ]
• National Academies of Sciences, Engineering, and Medicine (NASEM), 2019: Negative Emissions Technologies and Reliable Sequestration: A Research Agenda [ https://www.nap.edu/catalog/25259 ]
• Royal Society, 2018: Greenhouse gas removal [ https://raeng.org.uk/greenhousegasremoval ]
• U.S. Global Change Research Program (USGCRP), 2018: Fourth National Climate Assessment Volume II: Impacts, Risks, and Adaptation in the United States [ https://nca2018.globalchange.gov ]
• IPCC, 2018: Global Warming of 1.5°C [ https://www.ipcc.ch/sr15 ]
• USGCRP, 2017: Fourth National Climate Assessment Volume I: Climate Science Special Reports [ https://science2017.globalchange.gov ]
• NASEM, 2016: Attribution of Extreme Weather Events in the Context of Climate Change [ https://www.nap.edu/catalog/21852 ]
• IPCC, 2013: Fifth Assessment Report (AR5) Working Group 1. Climate Change 2013: The Physical Science Basis [ https://www.ipcc.ch/report/ar5/wg1 ]
• NRC, 2013: Abrupt Impacts of Climate Change: Anticipating Surprises [ https://www.nap.edu/catalog/18373 ]
• NRC, 2011: Climate Stabilization Targets: Emissions, Concentrations, and Impacts Over Decades to Millennia [ https://www.nap.edu/catalog/12877 ]
• Royal Society 2010: Climate Change: A Summary of the Science [ https://royalsociety.org/topics-policy/publications/2010/climate-change-summary-science ]
• NRC, 2010: America’s Climate Choices: Advancing the Science of Climate Change [ https://www.nap.edu/catalog/12782 ]

Much of the original data underlying the scientific findings discussed here are available at:

• https://data.ucar.edu/
• https://climatedataguide.ucar.edu
• https://iridl.ldeo.columbia.edu
• https://ess-dive.lbl.gov/
• https://www.ncdc.noaa.gov/
• https://www.esrl.noaa.gov/gmd/ccgg/trends/
• http://scrippsco2.ucsd.edu
• http://hahana.soest.hawaii.edu/hot/

Climate change is one of the defining issues of our time. It is now more certain than ever, based on many lines of evidence, that humans are changing Earth's climate. The Royal Society and the US National Academy of Sciences, with their similar missions to promote the use of science to benefit society and to inform critical policy debates, produced the original Climate Change: Evidence and Causes in 2014. It was written and reviewed by a UK-US team of leading climate scientists. This new edition, prepared by the same author team, has been updated with the most recent climate data and scientific analyses, all of which reinforce our understanding of human-caused climate change.

Scientific information is a vital component for society to make informed decisions about how to reduce the magnitude of climate change and how to adapt to its impacts. This booklet serves as a key reference document for decision makers, policy makers, educators, and others seeking authoritative answers about the current state of climate-change science.

READ FREE ONLINE

Welcome to OpenBook!

You're looking at OpenBook, NAP.edu's online reading room since 1999. Based on feedback from you, our users, we've made some improvements that make it easier than ever to read thousands of publications on our website.

Do you want to take a quick tour of the OpenBook's features?

Show this book's table of contents , where you can jump to any chapter by name.

...or use these buttons to go back to the previous chapter or skip to the next one.

Jump up to the previous page or down to the next one. Also, you can type in a page number and press Enter to go directly to that page in the book.

Switch between the Original Pages , where you can read the report as it appeared in print, and Text Pages for the web version, where you can highlight and search the text.

To search the entire text of this book, type in your search term here and press Enter .

Share a link to this book page on your preferred social network or via email.

View our suggested citation for this chapter.

Ready to take your reading offline? Click here to buy this book in print or download it as a free PDF, if available.

Get Email Updates

Do you enjoy reading reports from the Academies online for free ? Sign up for email notifications and we'll let you know about new publications in your areas of interest when they're released.