US Vulnerability To Heat Waves Varies Substantially by Location

June 24, 2009

Temperatures are expected to increase in many locations as climate change continues. It is well known that short- or long-term heat waves can cause deaths and illness for some people.

In order to better predict urbanized areas that are more vulnerable to this health threat, a team of US researchers has undertaken a detailed analysis of about 40,000 census tracts in the larger US metropolitan areas, and mapped out the degree of risk. The findings include a fine-grained enlargement of four metro areas — New York City, Chicago, Los Angeles, and Dallas-Fort Worth — that illustrate the detailed level of information that is available.

Their analysis, which was funded by EPA, was based on a host of factors, including education level, percentage of those in poverty, age, nonwhite racial status, percentage of people living alone, those with a lack of air conditioning, prevalence of diabetes, and extent of open space.

The most vulnerable areas tend to be the Pacific coast states, the Northeast, the Midwest, Appalachia, and a few locations in the Southeast. Keep in mind that even in these generally vulnerable areas there are a number of exceptions. On the other hand, inner-city areas in most locations tend to have more vulnerable populations. And other studies have found that people in rural areas can be at increased risk, though appropriate data wasn't available to evaluate those areas in this study.

A general thread that has been supported by earlier research is that locations that are somewhat cooler now are less prepared technologically for greater heat (e.g., relatively low prevalence of air conditioning), and tend to have fewer targeted medical and social services in place. In addition, individuals may have developed less physiological resilience to cope with heat.

The new information can serve as a hook to cover how well your community is preparing for any increase in heat-related risk.