ARB Research Seminar

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Heat Vulnerability in California Under Future Climate Change (A Spatial Synoptic Classification Approach)

Scott C. Sheridan, Ph.D., and Cameron C. Lee, Ph.D. Candidate, Department of Geography, Kent State University, Ohio

February 17, 2011
Cal EPA Headquarters, 1001 "I" Street, Sacramento, CA

Research Project


Excessive heat significantly impacts the health of Californians during irregular but intense heat events. Through the 21st century, a significant increase in impact is likely, as the state experiences a changing climate as well as an aging population. To assess this impact, future heat-related mortality estimates were derived for nine metropolitan areas in the state for the remainder of the century.

First, oppressive weather events were predicted for future years by first correlating past surface weather types with circulation patterns, and then predicting them in the future using projections of future atmospheric circulation at three levels. Second, we estimated heat-related mortality by initially determining historical weather-type mortality relationships for each metropolitan area. These were then projected into the future based on predicted weather types. Estimates account for several levels of uncertainty: for each metropolitan area, mortality values are produced for five different climate model-scenarios, three different population estimates (along with a no-growth model), and two different levels of acclimatization (along with no acclimatization). Results show a significant increase in heat events over the 21st century, with oppressive weather types potentially more than doubling in frequency, and with heat events of two weeks or longer becoming up to ten times more common at coastal locations. Major urban centers could have a greater than tenfold increase in heat-related mortality in the over 65 age group by the 2090s.

Speaker Biography

Scott C. Sheridan, Ph.D., is an Associate Professor of climatology in the Department of Geography at Kent State. Dr. Sheridan's research interests include several different areas of applied climatology, mostly involving the effects of climate on humans. Through several contracts from NOAA among other agencies, he has worked on the development of heat watch-warning systems for over two dozen cities in the United States, Canada, South Korea, and Italy. With support from USEPA, he has explored public perception of and behavior during heat warnings, and has recently completed a project funded by the California Air Resources Board to examine the potential for changed frequency of heat waves in the future. Dr. Sheridan is presently working with the New York State Department of Health in assessing the relationship between weather and hospital admissions for a number of causes. Dr. Sheridan currently serves as editor-in-chief of the International Journal of Biometeorology.

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