Heat and health: a front-burner topic

1 September 2009  •  Seattle’s wilting heat wave this summer, which peaked on 29 July with the city’s all-time warmest low and high of 71°F and 103°F, respectively, didn’t produce an obvious spike in fatalities of the type seen in Chicago in 2005, where morgues filled to overflowing. But epidemologists may not know for months, if ever, exactly how many lives the Pacific Northwest’s unusual heat took. Missouri is the only state where health experts monitor mortality on a regular basis to determine how many people die from heat-related causes.

Heat and health

“We just don’t get the kind of data we’d hope [for],” said George Luber (U.S. Centers for Disease Control, or CDC) at an NCAR-hosted symposium in July on climate and health. Both climate and social change could make matters far worse, Luber pointed out. The world is gradually urbanizing and aging, both of which lead to more people at risk of heat stress, and heat waves are expected to increase in length and severity this century. Yet it can take years for public health experts to infer how many people die from heat in a given area. The 2003 heat wave in Europe may have killed more than 50,000 people. The United States sees an average of nearly 700 deaths per year from heat-related causes, though Luber believes the number is probably overcounted in heat waves and undercounted at other times.

The increasing risk of heat mortality brings matters of social equity to light, Luber adds. A recent study in Phoenix found a difference of 8°C (14°F) in average daily summer highs between a densely treed, historically white neighborhood and a more exposed area with a high immigrant population. “We’re highlighting a pretty important environmental justice issue,” says Luber. The good news: more cities are implementing cooling centers, phone trees to contact people at risk, and other techniques known to reduce mortality during
heat waves.

On the research front, CDC has launched several programs to train undergraduate and graduate students in emerging environmental threats, including climate change. This year NCAR is launching a new postdoctoral program in climate and human health, with the first two openings in vector-borne infectious diseases and environmental health. Participants will have mentors at two institutions, working with principal investigators Luber and Emily Zielinski-Gutierrez (CDC) and Mary Hayden (NCAR). For more information, contact Hayden at mhayden@ucar.edu.