Scott Dodd's Blog
Are we ready for more heat waves and their impact on our health?
August 26, 2008
Posted by Scott Dodd in Health and the Environment , Solving Global Warming
Two years ago, while taking a year off to get a master’s degree at Columbia University (yeah, some "year off"), I took a fascinating class on the public health impacts of climate change -- a rapidly emerging field that’s just now beginning to get the attention it deserves.
One of the professors, Kim Knowlton, is now one of my colleagues at NRDC. She’s continuing to study the public health impacts of climate change, and I’m continuing to learn from her about the myriad implications of global warming for human health, as well as the health of our communities.
This week, the nation’s top environmental health journal published a new study by Kim (excuse me, I should say Dr. Knowlton in this context) and several of her colleagues here at NRDC and at the California Department of Public Health. The report in Environmental Health Perspectives looks at the record-setting July 2006 heat wave, which affected large swaths of North America. (Along with Knowlton, the study’s authors include Miriam Rotkin-Ellman, Galatea King, Helene G. Margolis, Daniel Smith, Gina Solomon, Roger Trent and Paul English.)
The 2006 heat wave struck parts of central California especially hard, according to the National Oceanic and Atmospheric Administration, with soaring daytime temperatures that barely cooled off overnight, providing residents with no relief from the sweltering heat for nearly two weeks. Sacramento, for example, experienced 11 consecutive days of triple-digit heat "This event impacted California's economy, energy supply and health," NOAA scientists reported. More than 160 deaths were blamed on the heat in California, and more than 200 died nationwide.
A Heated Concern
It's no surprise that heat waves can kill -- especially in areas such as the central coast of California, where residents are used to milder conditions. (Think of Mark Twain’s widely repeated but apparently apocryphal quote about the coldest winter he ever experienced being a summer in San Francisco.)
The 1995 Chicago heat wave, chronicled in Eric Klinenberg’s book Heat Wave: A Social Autopsy of Disaster in Chicago, killed more than 700 people, mostly the elderly poor who lacked air conditioning or anyone to check on them. In the summer of 2003, an intense heat wave was blamed for an estimated 35,000 deaths across large swaths of Europe, partly because it struck during August, when many doctors were vacationing outside the major cities. Both examples point toward the important role of social nets and the public health care system -- and what can happen when they break down.
What's different about this new study by Knowlton and her colleagues is that it goes beyond mortality, also documenting the thousands of people who got sick as a result of the 2006 heat wave. From July 15 through August 1 in California, the study reports, hospitals saw more than 16,000 additional emergency room visits and nearly 1,200 additional hospital admissions. The heat-related ailments ranged from diabetes to cardiovascular diseases to acute renal failure.
As might be expected, children and the elderly were at the greatest risk. An accompanying economic analysis shows that the increased hospitalizations and health care needs cost California’s economy more than $133 million dollars. (See NRDC's press release about the study.)
It’s always important to point out that it’s difficult to blame any one particular extreme weather event on global warming. But the 2007 report from the Intergovernmental Panel on Climate Change says it’s likely that heat waves have already become more frequent over most of the world due to climate change and that they’ll continue to grow in intensity, causing more heat-related illnesses and deaths.
Mapping the Consequences
I found it particularly interesting to read NRDC's findings this week because I had just finished The Ghost Map, a great book by science writer Steven Johnson about London's 1854 cholera outbreak. Johnson chronicles an investigation by maverick physician John Snow and clergyman Henry Whitehead, which demonstrated that contaminated water was the source of the outbreak, despite the leading theory that said disease was spread by smell.
Snow's work is considered a watershed moment in the development of public health as a science. (You may have heard it condensed as the story of how the pump handle to the Broad Street well was removed, arresting the course of the epidemic.) The “ghost map” of the book’s title, which showed that the deaths were largely dependent on proximity to the Broad Street pump versus other sources of water, was something that Snow created not to solve the case -- he had already amassed sufficient proof for his theory -- but to make the case to others.
Perhaps the most significant part of Snow and Whitehead’s work was convincing the nascent public health officials of the day that something needed to be done about contaminated water (it seems amazing that they needed to be convinced, but then again, no one knew about the existence of germs and bacteria yet). Their efforts ultimately resulted in one of the greatest building projects in London’s history: a sewer system that flushed contaminated water out of the city and away from drinking water supplies, eradicating cholera from London.
NRDC’s work on global warming and health has a similar aim: not just documenting the impacts of climate change, but looking for ways that communities can do something to cope with them. Heat wave early warning systems and methods for helping vulnerable populations -- think the “cooling centers” that some cities open during warm spells -- are already being used in some places. Knowlton and her colleagues urge public health officials to consider other measures, as well.
Additional Resources
NRDC has been tracking selected global warming “hot spots” -- places across the world where climate change is already having an impact on human health -- as well as locations where communities have taken steps to cope with the changes. You can learn more about NRDC’s global warming and health program and explore the hot spots map at our website.
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