Trump says climate change doesn’t endanger public health – evidence shows it does, from extreme heat to mosquito-borne illnesses
On February 12, 2026, the Trump administration took a major step forward in its efforts to dismantle America’s climate policy. She moved to overturn the 2009 threat finding, a formal determination that greenhouse gas emissions, such as carbon dioxide and methane from the burning of fossil fuels, endanger public health and welfare. But the administration’s arguments for dismissing the health risks of climate change are not only factually flawed, they are also profoundly dangerous to the health and safety of Americans.
As physicians, epidemiologists and environmental health scientists, we are seeing growing evidence of the links between climate change and harm to human health.
Here’s a look at the health risks everyone faces due to climate change.
Extreme heat
Greenhouse gases from vehicles, power plants and other sources build up in the atmosphere, trapping heat and holding it near the Earth’s surface like a blanket. Too much of it causes global temperatures to rise, exposing more people to dangerous heat more often.
Most people with minor heat-related illnesses will recover, but more extreme exposure, especially without sufficient hydration and a way to cool down, can be fatal. People who work outdoors, are elderly, or have underlying illnesses such as heart, lung, or kidney disease are often at greatest risk.
Heat-related deaths increased globally, by 23% between the 1990s and the 2010s, when the average year saw more than half a million heat-related deaths. Here in the United States, the 2021 Pacific Northwest heat dome killed hundreds of people.
Climatologists predict that as climate change advances, many parts of the world, including U.S. cities like Miami, Houston, Phoenix and Las Vegas, will face many days each year hot enough to threaten human survival.
Extreme weather conditions
Warmer air holds more moisture, so climate change leads to increased precipitation and storm intensity and worsened flooding, as many U.S. communities have experienced in recent years. Warmer ocean water also fuels more powerful hurricanes.
Increased flooding leads to health risks including drownings, injuries, and water contamination with human pathogens and toxic chemicals. People who clean up flooded homes also face risks of mold exposure, injury and mental distress.
Climate change is also making droughts worse, disrupting food supplies and causing dust-related respiratory illnesses. Rising temperatures and aridity are drying out forests and grasslands, making them a breeding ground for wildfires.
Air pollution
Wildfires, along with other climate effects, are deteriorating air quality across the country.
Wildfire smoke is a toxic soup of microscopic particles (called fine particulate matter, or PM2.5) that can penetrate deep into the lungs, and dangerous compounds such as lead, formaldehyde and dioxins generated when homes, cars and other materials burn at high temperatures. Plumes of smoke can travel thousands of miles downwind and trigger heart attacks and increase the risk of lung cancer, among other harms.
Meanwhile, warmer conditions promote the formation of ground-level ozone, an irritant to the heart and lungs. Burning fossil fuels also generates dangerous air pollutants that cause a long list of health problems, including heart attacks, strokes, asthma flare-ups and lung cancer.
Infectious diseases
Because they are cold-blooded organisms, insects are directly influenced by temperature. So, with rising temperatures, mosquito bite rates also increase. Warming also accelerates the development of mosquito-borne pathogens.
Mosquito-borne dengue has appeared in Florida, Texas, Hawaii, Arizona and California. New York State has just experienced its first local case of chikungunya virus, also transmitted by mosquitoes.
And it’s not just insect-borne infections. Warmer temperatures increase diarrhea and foodborne illnesses due to Vibrio cholerae and other bacteria, while heavy rains increase overflows of sewage-contaminated stormwater into lakes and streams. At the other aquatic extreme, drought in the desert southwest increases the risk of coccidioidomycosis, a fungal infection known as valley fever.
Other impacts
Climate change threatens health in many other ways. Longer pollen seasons increase exposure to allergens. Declining agricultural yields reduce access to nutritious food.
Mental health also suffers, with anxiety, depression and post-traumatic stress following disasters, as well as increased rates of violent crime and suicide linked to hot days.
Young children, the elderly, pregnant women and people with pre-existing health conditions are among the groups most at risk. Low-income people also face higher risks due to higher rates of chronic diseases, greater exposure to climate hazards, and fewer resources for protection, medical care, and recovery after disasters.
Developing policy-based evidence
The evidence linking climate change to health has increased considerably since 2009. Today, it is indisputable.
Studies show that heat, air pollution, the spread of disease and food insecurity linked to climate change are worsening and costing millions of lives around the world each year. This evidence is also consistent with the experiences of Americans. Anyone who has gotten sick during a heat wave, struggled while breathing wildfire smoke, or been injured during a hurricane cleanup knows that climate change can threaten human health.
Yet the Trump administration is deliberately ignoring this evidence by proclaiming that climate change does not endanger health.
His decision to reverse the 2009 threat findings, which underpin many climate regulations, is part of a broader set of policy measures, including reducing support for renewable energy and subsidizing fossil fuel industries that endanger public health. In addition to rescinding the endangerment findings, the Trump administration also moved to lower vehicle emissions limits — the largest source of carbon emissions in the United States and a major contributor to air pollutants such as PM2.5 and ozone.
It’s not just about endangerment
The evidence is clear: climate change endangers human health. But there is another side to the story.
When countries work to reduce the causes of climate change, they help address some of the world’s greatest health challenges. Cleaner vehicles and cleaner electricity mean cleaner air – and less heart and lung disease. More walking and cycling on safe sidewalks and bike paths means more physical activity and less risk of chronic disease. The list is long. By confronting climate change, we promote good health.
To make America truly healthy, in our view, the nation should recognize the facts behind the discovery of the threat and redouble its efforts in its transition from fossil fuels to a healthy, clean energy future.
This article includes material from a story originally published November 12, 2025.
This article is republished from The Conversation, an independent, nonprofit news organization that brings you trusted facts and analysis to help you make sense of our complex world. It was written by: Jonathan Levy, Boston University; Howard Frumkin, University of Washington; Jonathan Patz, University of Wisconsin–Madisonand Vijay Limaye, University of Wisconsin–Madison
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Jonathan Levy receives funding from the National Institutes of Health, the Federal Aviation Administration, the City of Boston, the Massachusetts Attorney General’s Office, and the Mosaic Foundation.
Howard Frumkin has no financial conflicts of interest to report. He is a member of the advisory boards (or equivalent committees) of the Planetary Health Alliance; the Harvard Center for Climate, Health and the Global Environment; the Medical Society Consortium on Climate Change and Health; the Global Consortium on Climate and Health Education; the Yale Center on Climate Change and Health; and EcoAmerica’s Climate for Health program, and chairs the National Academy of Medicine’s Committee on the Roadmap for Transformative Action to Achieve Health for All at Net-Zero Emissions – all voluntary, unpaid positions.
Jonathan Patz receives funding from the National Institutes of Health. He is affiliated with the Medical Society Consortium for Climate and Health and its affiliate Healthy Climate Wisconsin.
Vijay Limaye is affiliated with the Natural Resources Defense Council.
