A Candid Conversation About Climate Change

Gregory Wellenius is the Beverly A. Brown Professor for the Improvement of Urban Health at Boston University School of Public Health, where he serves as director of the Center for Climate and Health. As an environmental epidemiologist, Dr. Wellenius is dedicated to addressing the health impacts of climate change through research, teaching, and engagement. His research examines how climate hazards like extreme heat affect human health and generates actionable evidence to inform interventions that meaningfully reduce the burden of extreme weather events.

Public Health Post spoke with Dr. Wellenius to learn more about his research, today’s climate hazards, and who they affect.

PHP: Could you share a bit about your research? What made you interested in studying climate hazards?

Gregory Wellenius: It seems like a lifetime ago when I started my PhD. During my study, I worked with a group that wanted to understand the health impacts of air pollution, which laid the foundation for the first two decades of my career. Around 2015, when I was working at Brown University, the Rhode Island Department of Health approached us with a question: “How many people die from heat?”

We didn’t know the number, so we thought about how to find out. We partnered with the local health department, who gave us access to data on deaths, emergency department visits, and hospitalizations. We produced initial estimates for the state, then more broadly for a coalition of 15 cities across Rhode Island, New Hampshire, and Maine.

The numbers showed that heat had a substantial impact on hospitalizations and emergency department visits, but a less pronounced impact on deaths. In other words, a lot more people got sick or experienced symptoms than those who died. It got me thinking about the full suite of health impacts of phenomena like heat, but this was only the tip of the iceberg. With the tools and expertise to find more answers, we have extended this work to hurricanes, flooding, and wildfires to help inform solutions today.

Your research emphasizes producing “actionable evidence.” What does this look like in practice?

We’ve done public health a disservice by talking about climate change broadly, rather than as an immediate threat to our health today. For instance, heat waves are killing people today. Cities across the globe are interested in understanding how to reduce that burden of disease and suffering—and there are real things they can do. One strategy is to open cooling or heat relief centers, but anecdotal stories show most people don’t utilize them. So, then the question is, why?

Even though it sounds like a good solution, we never know what will work in different settings. What excites me about my research is the opportunity to help these cities figure out their next best step. And there isn’t one answer to that; it’s specific to each community and population. Trying to help students in school will look different from trying to help those in public housing or nursing home facilities. The fact that it is complicated makes actionable evidence a prime target for academic research, and relevant to the moment today. 

You have testified before Congress about air pollution, once in 2011 and again in 2014. Can you share more about the expert testimony you provided to lawmakers?

Yes, I gave two testimonies with different purposes. The one in 2011 was more controversial. At the time, I was helping the Environmental Protection Agency (EPA) conduct integrated science assessments on the six criteria pollutants. A House subcommittee had proposed the Farm Dust Regulation Prevention Act of 2011 to prevent the EPA from regulating dust, which is larger and coarser than PM2.5.

PM2.5, or fine particulate matter, is small enough to enter the lungs and increase the risk of cardiovascular conditions. I discussed why PM2.5 is regulated, what evidence shows about larger particles, and what is still unknown. The bill wanted to limit EPA authority even though the agency had never proposed regulating dust, and it ultimately did not advance out of committee.

In 2014, I spoke before a Senate subcommittee about the health effects of ozone, but it wasn’t tied to legislation. Senator Sheldon Whitehouse from Rhode Island invited me to discuss why we should consider additional measures to reduce ozone exposure. (I testified right after Gina McCarthy, who was the EPA administrator under President Obama, which was a lot of fun!)

What are some underrecognized ways that heat impacts our health, especially when it intersects with race, class, occupation, age, or geography?

The heart of the problem is human discomfort. Evidence shows that rising temperatures are affecting our physical and mental health. Students perform worse on tests when taken on hot days compared to cooler days. We see more firearm injuries, occupational accidents, and car accidents on super-hot days. These impacts on hospitalizations are very important to drive policy, but there are also several less obvious impacts.

Heat affects our ability to reason, sleep, and even connect with others. These are pathways that can impact the most vulnerable individuals, especially those without consistent air conditioning or electricity. This includes outdoor workers, like delivery drivers, landscapers, and construction workers, who are active during the hottest hours of the day. People once thought the elderly were the most vulnerable to heat. Now we have a long roster, including people with preexisting heart conditions, pregnant people, infants, and service workers. The reality we are moving towards is that everybody is exposed to heat.

What exactly are “extreme weather events,” and how have they evolved?

In the United States, the number of severe weather events causing loss of life or infrastructure damage has steadily increased over the past three decades. We see the damage vary greatly by region. Wildfires are more common in the western U.S., while hurricanes and inland flooding occur more frequently in eastern regions. At the same time, our exposure to these events is also increasing. Addressing the issue requires strengthening resilience at all levels. It requires a commitment to reduce greenhouse gas emissions, upgrade power grids, and better equip the people facing extreme weather events.

In your experience, which strategies show the most promise to protect health from climate hazards? Is there an accessible habit I can adopt to support the environment?

At its core, climate change is a systems problem. Solutions must be locally informed and customized to the resources, concerns, and vulnerabilities of a specific community. For example, the Cities 1.5 podcast discusses how the mayor of Austin, Texas, is doing different things than the mayor of London. It gives me hope to hear how people are approaching the challenge in very different ways.

That said, we all can make a difference. The largest one of them is probably voting. There are also smaller ways to reduce your environmental impact and carbon footprint over time. One example is to try public transportation, or active transportation like walking or biking, and make the healthier choice to reduce vehicle emissions when possible. Similarly, reducing red meat consumption can also lower emissions and improve health. You should feel good about doing these things because they help the environment, and most importantly, your health.

This conversation has been edited for length and clarity.