The Trump administration on Thursday revoked a scientific finding that climate change poses a danger to public health, a concept President Donald Trump dismissed as “a scam.” However, numerous scientific studies demonstrate that climate change is causing measurable harm to human health across the United States and globally.

The 2009 Environmental Protection Agency finding, established during the Obama administration, has served as the legal foundation for nearly all U.S. regulations addressing global warming over the past 15 years. Public health experts have expressed shock at the decision to rescind it.

“It boggles the mind that the administration is rescinding the endangerment finding; it’s akin to insisting that the world is flat or denying that gravity is a thing,” said Dr. Howard Frumkin, a physician and professor emeritus of public health at the University of Washington who previously served as director of the National Center for Environmental Health under President George W. Bush.

Thousands of scientific studies published in recent years have examined the relationship between climate change and public health, with the vast majority concluding that warming temperatures are increasingly dangerous to human wellbeing. Many studies estimate that thousands of Americans have died and many more have fallen ill due to climate-related causes in recent decades.

Heat-related mortality, in particular, shows alarming trends. According to research published in the Journal of the American Medical Association, annual heat-related deaths in the United States have more than doubled since 1999, rising from 1,069 to a record 2,325 in 2023.

A 2021 study in Nature Climate Change analyzed 732 locations across 43 countries, including 210 in the United States, and determined that more than a third of heat-related deaths worldwide can be directly attributed to human-caused climate change. This translates to more than 9,700 global deaths annually linked to warming caused by burning fossil fuels.

More recently, research published just this week found that 2.2% of summer deaths in Texas between 2010 and 2023 were heat-related, a trend researchers connect to more frequent and intense heat waves driven by climate change.

The scientific evidence linking climate change to health impacts has grown substantially over time. The National Library of Medicine’s PubMed research database contains more than 29,000 peer-reviewed studies examining the intersection of climate and health since the EPA’s 2009 endangerment finding, with more than 5,000 focused specifically on the United States. Notably, over 60% of these studies have been published in the last five years, indicating rapidly growing scientific concern.

At a White House event on Thursday, Trump rejected the scientific consensus, claiming climate change “has nothing to do with public health. This is all a scam, a giant scam.”

Health experts strongly disagree with this assessment. Dr. Jonathan Patz, a physician who directs the Center for Health, Energy and Environmental Research at the University of Wisconsin-Madison, pointed to the 2021 heat dome that killed more than 600 people in the Northwest as an example of climate change’s deadly impact. “The new climate attribution studies show that event was made 150-fold more likely due to climate change,” Patz noted.

While heat-related deaths receive significant attention, research has identified numerous other health impacts from climate change. Studies have documented increases in waterborne infections causing diarrhea, mental health issues, and nutritional problems associated with changing climate conditions.

Climate change also contributes to extreme weather events like 2017’s Hurricane Harvey, intensifies wildfires, worsens air pollution, and expands the range of disease vectors like mosquitoes that spread illnesses such as malaria.

“Public health is not only about prevention of diseases, death and disability but also well-being. We are increasingly seeing people displaced by rising seas, intensifying storms and fires,” said Dr. Lynn Goldman, a physician and dean emeritus at the George Washington University School of Public Health. “We have only begun to understand the full consequences of a changing climate in terms of health.”

The issue becomes more complex when considering that cold-related deaths are decreasing due to warming temperatures. Studies show that in the United States, there are currently 13 times more deaths from cold exposure than from heat exposure.

Some research suggests that until global temperatures rise another 2.7 degrees Fahrenheit (1.5 degrees Celsius), overall temperature-related mortality might not change dramatically because decreases in cold-related deaths could offset increases in heat-related deaths. However, beyond that threshold, if societies fail to adapt to increasing heat, “total mortality rises rapidly.”

Last year, researchers attempting to quantify the global health costs of climate change analyzed various mortality factors—including heat waves, extreme weather events, wildfires, air pollution, and vector-borne diseases—and concluded that climate change is responsible for hundreds of thousands of deaths worldwide annually. Using the EPA’s own value of human life calculation ($11.5 million in 2014 dollars), they estimated a global annual cost “on the order of at least $10 billion.”