After decades of research, EI affiliate and UVA environmental scientist Bob Davis says we’re only beginning to understand the link between extreme weather due to climate change and how the body responds.

headshot of Bob Davis
University of Virginia environmental scientist Bob Davis has dedicated more than three decades to studying the impacts of extreme weather due to a changing climate on human health.

“How people respond to weather is actually less predictable than the weather itself!” University of Virginia environmental scientist Bob Davis recently stated. Davis has dedicated years of research to learning more.

For more than three decades, Davis has been examining the link between extreme weather related to climate change (such as record-breaking heatwaves and severe cold temperatures) and the impact on human health. A climatologist by training, Davis has seen the acceleration in how scientists are gathering, interpreting, and applying climate-related data, especially in healthcare contexts. While it’s a puzzle coming together slowly, scientists like Davis can say that extreme weather increases hospital visits.

Davis came to the University of Virginia in 1988 from the University of Delaware, where he studied atmospheric circulation, jet stream variability, and variations within large-scale weather features such as cyclones.

“But I was also getting interested in the effects of climate on health,” said Davis of this time. “This was before climate change was a widely discussed issue.”

Davis found that one information stream was clear on the health impacts of climate change: death data.

“It might sound morbid, but the advantage of working with mortality data is that there’s no quibbling about the outcome,” explained Davis. “You know how many people died on a given day, and you can look back at the climate situation. The thing is, it’s hard to know why people get sick. We all have completely different responses to the same weather event.”

These varied responses human beings have to weather events have animated much of Davis’s recent work.

“Say a heat wave comes along, and you and I both become ill. You delay visiting the Emergency Room (ER) while I go immediately. It’s tricky to pin someone’s response on a precipitating event, but with mortality, you know when they died, even if you don’t know when they got sick.”

He sees the health response to climate events - especially extremes of heat and cold - as a pyramid. At the top is the most acute response (death) but lower down, there are hospital admissions, ER visits, visits to a doctor’s office, and at the base of the pyramid are those who are sick but untreated. While researchers understand the acute side well, scientists like Davis are still assessing the total impact of climate and extreme weather on health.

“Some of us are ‘weather-sensitive’,” said Davis, “the kind of person who’ll claim their lung function changes during a cold front. But most of us are ‘weather health unaware’.” This is something that’s especially dangerous for seniors who, for instance, have a reduced perspiration response during hot weather.

In a project seed-funded by UVA’s Environmental Institute, Davis and a team started to unlock some of the data on extreme weather and health impacts. In a published paper comparing emergency department visits in Roanoke, Va. and Charlottesville, Va., Davis found some interesting demographic indicators. For example, the data suggested the effect of thermal extremes tended to be larger for non-whites and that elderly white females seemed more susceptible to extreme cold.

Yet work remains to be done and Davis will welcome a Climate Fellow with support from the Environmental Institute next academic year to advance this research. The goal is to discover if, and where, there are racial, ethnic, and gender differences in health responses to climate factors. The findings will inform public health messaging and an understanding of population responses to climate extremes, which should aid in preparing for future climate-related emergencies.  

Davis has learned that while human bodies respond differently to extreme conditions, predicting weather events can help hospitals prepare.

“If you know there’s a heatwave coming on Monday, and can predict a 10% increase in hospital admissions, you can increase staffing,” Davis explained. “I’ve talked to ER doctors who find that notification useful.”

Providing good information to the public is another challenge. The message is getting lost on people. For instance, the media focuses on high temperatures, but cold can be more dangerous. Increased awareness of exactly how the body responds to temperature extremes should reduce health issues. Trying to get the word out that there are real medical consequences to climate extremes is critical.

Davis states the key is to bring disciplines together. He envisions projects where climatologists work with medical doctors. His concern today is that while there is an understanding of how heat and climate affect the body overall, there still isn’t enough detail to create positive solutions.

 More funding and better data are still needed. “There are more federal grants and growing attention to this issue,” Davis shared. “That’s good because there’s so much more to be done.”