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Summer in the City 2050: City Swelter, Rural Roast
15 Oct, 2007 11:00 am
Global warming could nearly double heat-related mortality in the New York City metropolitan region by the 2050s. Researchers projected the future impacts of climate change on summer heat-related premature deaths, using computer models to simulate current and future conditions in urban, suburban and rural counties. Even with acclimatization, ie, increased use of air conditioning, heat alerts, cooling shelters and gradual physiological adaptation, summer temperatures and heat-related mortality are projected to increase in both city and countryside.
That day may be sooner than we think, and closer to home.
Research described in the November 2007 issue of the American Journal of Public Health (Knowlton et al. AJPH 2007) considers how global warming could affect heat-related mortality by mid-century in and around New York City. Researchers used computer models to simulate summer temperatures now and in the 2050s, to project how heat-related deaths might change with global warming.
Summer heat stress already affects the health of people in the region. In a 2006 summer heat wave in New York City, 46 people died of heat stroke and 100 more from conditions like heart or lung disease that were considered “excess” deaths — more than would be expected during ordinary summer weather. Even people with air conditioning were among those affected by the heat.
What the study found is that global warming could double the number of heat-related deaths in a typical summer of the 2050s. Climate change is anticipated to increase the number of hot days in the summer and also increase the severity of heat on those days, leading to greater levels of premature summer deaths from heat. The study suggests that both urban areas and suburbs -- even the countryside -- will be affected by hotter summer temperatures. What’s interesting to note is that they’ll be affected in slightly different ways. Temperature-wise, a majority of the rural counties and the suburbs will see a slightly greater relative increase in temperature than the urban areas, so there will be a greater difference in the heat they’re used to now compared to the heat they’ll experience in the future. However, urban counties like the 5 boroughs of NYC will see hotter overall temperatures in the future and see the greatest loss of life due to the heat.
People perish not only from heat stroke, but also from a range of heart and lung diseases that are exacerbated by heat. On sweltering summer days the heart and lungs have to work harder to keep the body cool, and people with respiratory and heart illness are most at risk – and that includes many elderly people.
While Southern cities tend to have nearly universal air conditioning, in northern regions like New York many households lack air conditioning, which not everyone can afford to purchase or operate. With the aging of the US population, population growth, continued lack of universal access to air conditioning and global warming, millions more people in the NY region will be at risk of heat-related illness and death in the summertime. This study only considered heat’s effect on mortality rates, yet global warming will have a much wider range of human health impacts, affecting air quality, infectious diseases, storms, floods, food and water supplies.
But it doesn’t have to be this way. This increase in heat-related deaths can be minimized. Supporting mandatory federal regulation of greenhouse gases now will help limit even more warming in future. The report shows that if global warming emissions are reduced soon, that in a typical summer in the 2050s at least 300 lives could be saved because less greenhouse gas emissions means more modest temperature increases.
We can also offer ways for people to cope with and adapt to increasing summer heat. The simple steps everyone can take during sweltering heat? Stay hydrated; spend time in air-conditioned places; wear loose, light-colored clothing; check on people you know who are socially isolated, ill, elderly, or otherwise at risk. Simple steps like these may help people become physiologically acclimated to heat - but it takes time & everyone is different. Cities and communities can take bigger steps. Some cities have instituted heat-health warning systems that offer coordinated alerts of coming heat waves. Communities can target education to the most vulnerable communities, especially to the elderly, and offer free transportation to public cooling centers. Using “green design” in the built environment, like green/living or light-colored urban roofs, passive ventilation, and carefully selected bldg materials help make the urban environment cooler, and planting urban trees to provides more shade.
There are many people coming together in NYC and around the world to reduce global warming and, at the same time, to help the most vulnerable communities be prepared, rolling up their sleeves and taking action toward a cooler, healthier future.
Knowlton K, Lynn B, Goldberg Richard, et al. Projecting Heat-Related Mortality Impacts Under a Changing Climate in the New York City Region. In the November issue of American Journal of Public Health; first published online in AJPH, September 27, 2007.
Abstract available at: http://www.ajph.org/cgi/content/abstract/AJPH.2006.102947v1