WASHINGTON (AP) — As President Donald Trump's administration looks to reverse a cornerstone finding that climate change endangers human health and welfare, scientists say they just need to look around because it's obvious how bad global warming is and how it's getting worse.

New research and ever more frequent extreme weather further prove the harm climate change is doing to people and the planet, 11 different scientists, experts in health and climate, told The Associated Press soon after word of the administration's plans leaked out Wednesday. They cited peer-reviewed studies and challenged the Trump administration to justify its own effort with science.

“There is no possible world in which greenhouse gases are not a threat to public health,” said Brown University climate scientist Kim Cobb. “It’s simple physics coming up against simple physiology and biology, and the limits of our existing infrastructure to protect us against worsening climate-fueled extremes.”

EPA's original finding on danger of greenhouse gases

Environmental Protection Agency chief Lee Zeldin has privately pushed the White House for a rewrite of the agency's finding that planet-warming greenhouse gases put the public in danger. The original 52-page decision in 2009 is used to justify and apply regulations and decisions on heat-trapping emissions of greenhouse gases, such as carbon dioxide and methane, from the burning of coal, oil and natural gas.

“Carbon dioxide is the very essence of a dangerous air pollutant. The health evidence was overwhelming back in 2009 when EPA reached its endangerment finding, and that evidence has only grown since then,” said University of Washington public health professor Dr. Howard Frumkin, who headed the National Center for Environmental Health at the time. "CO2 pollution is driving catastrophic heat waves and storms, infectious disease spread, mental distress, and numerous other causes of human suffering and preventable death.”

That 2009 science-based assessment cited climate change harming air quality, food production, forests, water quality and supplies, sea level rise, energy issues, basic infrastructure, homes and wildlife.

A decade later, scientists document growing harm

Ten years later, a group of 15 scientists looked at the assessment. In a paper in the peer-reviewed journal Science they found that in nearly all those categories the scientific confidence of harm increased and more evidence was found supporting the growing danger to people. And the harms were worse than originally thought in the cases of public health, water, food and air quality.

Those scientists also added four new categories where they said the science shows harm from climate change caused by greenhouse gas emissions. Those were in national security, economic well-being of the country, violence and oceans getting more acidic.

On national security, the science team quoted Trump's then-defense secretary, chairman of the joint chiefs of staff and a Pentagon authorization bill that Trump signed in his first term. It also quoted a study that said another 1.8 degrees Fahrenheit (1 degree Celsius) of warming in the next 75 years would effectively reduce the U.S. gross domestic product by 3%, while another study said warming would cost the American economy $4.7 trillion to $10.4 trillion by the end of the century.

“Overall, the scientific support for the endangerment finding was very strong in 2009. It is much, much stronger now,” Stanford University environment program chief Chris Field, a co-author of the 2019 Science review, said in a Wednesday email. "Based on overwhelming evidence from thousands of studies, the well-mixed greenhouse gases pose a danger to public health and welfare. There is no question.”

Long list of climate change's threats to health

"There is global consensus that climate change is the biggest threat of our to time to both health and health systems," said Dr. Courtney Howard, a Canadian emergency room physician and vice chair of the Global Climate and Health Alliance. He ticked off a long list: heat-related illnesses, worsening asthma, heart diseases worsened by wildfire smoke, changing habit for disease-carrying mosquitoes, ticks and other insects, and crop failures that drive hunger, war and migration.

Kristie Ebi, a public health and climate scientist at the University of Washington, said a big but little-discussed issue is how crops grown under higher carbon dioxide levels have less protein, vitamins and nutrients. That's 85% of all plants, and that affects public health, she said. Field experiments have shown wheat and rice grown under high CO2 have 10% less protein, 30% less B-vitamins and 5% less micronutrients.

It's these indirect effects on human health that are "far-reaching, comprehensive and devastating," said Katharine Hayhoe, an atmospheric scientist at Texas Tech and chief scientist at The Nature Conservancy. She said rising carbon dioxide levels in the air even " affect our ability to think and process information."

Scientists said the Trump administration will be hard-pressed to find scientific justification — or legitimate scientists — to show how greenhouse gases are not a threat to people.

“This one of those cases where they can’t contest the science and they’re going to have a legal way around," Princeton University climate scientist Michael Oppenheimer said.

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Associated Press writer Matthew Daly contributed.

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Follow Seth Borenstein on X at @borenbears

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Read more of AP's climate coverage at http://www.apnews.com/climate-and-environment

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FILE - Firefighters protect a structure as the Eaton Fire advances, Jan. 8, 2025, in Altadena, Calif. (AP Photo/Ethan Swope, File)

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