Expert Q&A: Why climate health research matters more than ever under new federal stance
The U.S. president who called climate change “the greatest con job ever perpetuated on the world,” has reversed the Environmental Protection Agency’s (EPA) landmark judgment, called the “Endangerment Finding,” that greenhouse gas emissions endanger Americans’ health, welfare, and environment.
In toppling the 2009 finding, the Trump administration has essentially revoked the government’s authority to control the greenhouse gases that are overheating the earth or to take other steps to try to stop or reverse climate change. That clears a path for the administration to remove regulatory limits primarily on the automotive industry, which contributes heavily to the release of greenhouse gases – that contributes to climate change.
The revocation, announced February 12, 2026, drew immediate opposition from many of the world’s leading climate change scientists, as well as informed citizens who have tracked the hundreds of studies that backed the original finding, which noted that six key “well-mixed” greenhouse gases—carbon dioxide, methane, nitrous oxide, hydrofluorocarbons, perfluorocarbons and sulfur hexafluoride—in the atmosphere, “threaten the public health and welfare of current and future generations.”
What does this mean for public health? And how will it impact the group of scientists at UC Berkeley School of Public Health who spend their days researching the myriad ways climate change harms public health—and searching for solutions?
We spoke with David J. X. González, assistant professor of environmental health sciences, whose research focuses on how pollution from extractive industries and climate-driven disasters, affects public health.
UC Berkeley School of Public Health: Can you tell me what effect you think the EPA’s reversal of the endangerment finding will have?
David J.X. González: Repealing the endangerment means that there will no longer be a legal requirement to regulate emissions of greenhouse gases from cars, airplanes, power plants, and other emitters. This will result in higher emissions of greenhouse gases than in a world where the endangerment finding wasn’t repealed; which in turn means that we’ll be likely to see more frequent and severe heat waves, wildfires, droughts. This has consequences for health, and also for economics, with higher costs for food and home insurance.
How did the EPA interpret the Clean Air Act before 2009?
Initially, the Clean Air Act gave the EPA responsibility to regulate the types of air pollutants that harm human health, and typically, that has meant pollutants that have a direct impact: fine particulates, ozone, and lead. We have a very strong base of epidemiological evidence of public health science that has found that when people breathe these air pollutants, it causes lots of different health harms: cardiovascular harm, respiratory harm, complications for pregnancy, those kinds of things.
In 2009 the EPA recognized, based on the scientific evidence, that some other pollutants that don’t have direct health impacts have an indirect and very profound health impact. This is through the greenhouse effect, when what we call “greenhouse gasses” such as carbon dioxide trap excess heat radiated from Earth’s surface that would otherwise harmlessly travel out into space.
What are the primary sources of carbon dioxide?
It’s also produced when fossil fuels are consumed. So, by our vehicles, if they’re running on gas and not electric, and fossil fuel power plants, such as coal power plants, natural gas power plants, and all the production that goes into extracting and moving around fossil fuels.
The EPA recognized that there are profound impacts of increasingly severe and frequent heat waves, wildfires, and other extreme weather events that are tied to these greenhouse warming gasses. We have a growing body of scientific evidence that I’ve contributed to alongside my colleagues, that has found that these extreme events have profound impacts on our health.
And so to me, the new stance denies what we know about the harms of these sorts of events and, ultimately, the harms of greenhouse gasses like carbon dioxide.
How does your own research fit in?
The impacts of climate change are many—and part of what I do is climate epidemiology, studying the extent to which the changing climate impacts our health. I think denying those harms is ultimately going to hurt the American people, and it’s going to hurt people around the world. It already is.
The rescission of the endangerment finding means that the EPA will no longer be regulating greenhouse gases. That’s if this goes into effect. I say if because a coalition of environmental and health groups have already sued the EPA over the rescission.
My understanding is that the endangerment finding has already been adjudicated in the courts and been supported. This [the rescission] is a reinterpretation of that finding, without any substantive change in the law or our scientific knowledge. The scientific evidence, if anything, has mounted. We have a lot more understanding of what the health harms are of wildfires we’re seeing. Many of us are breathing more smoke, seeing more wildfires, experiencing more heat.
Can you tell me about a specific disaster that spread more toxic wildfire smoke?
We have to point to the wildfire disaster that happened Los Angeles in January 2025 as a very stark example. We’re only now starting to understand what are the health harms; not just for people that were directly impacted when the fire burned through their neighborhoods, but also the people that have been impacted when they breathed the highly toxic smoke that sat over the city for several days.
We increasingly have tools to know that we can attribute some of these harms to climate change through attribution science. For example, a 2023 study estimated that, across the Western U.S. and Canada, the fires that burned over one-third of the land area between 1986 and 2021 are attributable to carbon emissions.
Emissions from fossil fuel consumption contribute to conditions that make wildfires more likely, and larger—producing more smoke and making it more likely that people who live in places like California and elsewhere are going to breathe that smoke. And what we’re finding when we do the research is that wildfire smoke is impacting our health in numerous ways.
Can you, can you give me an overview of recent research by you and your colleagues?
We’re finding that chronic exposure to smoke, over the course of a few years, is associated with higher risk of death among older adults. As a field, among people with more exposure to wildfire smoke, researchers are finding higher risk for complicated pregnancies, such as delivering a baby preterm or with low birthweight; having a higher risk of heart attack, and respiratory distress.”
The researchers I mentor are studying the health impacts of heat and how being exposed to a heat wave during pregnancy affects maternal health. Our colleagues across the U.S. are studying what happens when heat and smoke coincide, and preliminarily, researchers are finding that it heightens risks.
Are you studying any health risks related to drought?
My colleague Justin Remais and his group work on Valley Fever. It’s a fungal infection that comes from breathing dust that’s full of spores. If the conditions are drier and hotter, you’re more likely to breathe that dust. [Read Remais’ latest paper here.]
What are you most worried about, if the courts don’t block the rescission of the endangerment finding?
I’d be worried about more health problems. I’d be worried about more disasters, and more and more severe and more frequent disasters like wildfires and heat waves and droughts. And we know that the impacts of many of these disasters are heavier on people that are low income, and people who live in neighborhoods that have been neglected or marginalized. I worry about those kinds of disparities getting worse.
