This figure shows the relationship between high temperatures and deaths observed during the 1995 Chicago heat wave. The large spike in deaths in mid-July of 1995 (red line) is much higher than the average number of deaths during that time of year (orange line), as well as the death rate before and after the heat wave. This increase in the rate of deaths occurred during and after the heat wave, as shown here by temperatures exceeding the 100 degree F during the day (green line). Humidity and high nighttime temperatures were also key contributing factors to this increase in deaths (Karl, T. R., and R. W. Knight, 1997). The number of excess deaths has been estimated to be about 700 based on statistical methods, but only 465 deaths in Cook County were classified as "heat related" on death certificates during this same period, demonstrating the tendency of direct attribution to undercount total heat-related deaths(Centers for Disease Control and Prevention, 1995). (Figure source: EPA, 2012)
Centers for Disease Control and Prevention (CDC), 1995: Heat-related mortality--Chicago, July 1995. Morbidity and Mortality Weekly Report, 44, 577-579
EPA, 2012: Climate Change Indicators in the United States, 2nd Edition. 84 pp., U.S. Environmental Protection Agency, Washington, D.C.
Karl, T. R., and R. W. Knight, 1997: The 1995 Chicago heat wave: How likely is a recurrence? Bulletin of the American Meteorological Society, 78, 1107-1119. doi:10.1175/1520-0477(1997)07
USGCRP, 2016: The Impacts of Climate Change on Human Health in the United States: A Scientific Assessment. Crimmins, A., J. Balbus, J.L. Gamble, C.B. Beard, J.E. Bell, D. Dodgen, R.J. Eisen, N. Fann, M.D. Hawkins, S.C. Herring, L. Jantarasami, D.M. Mills, S. Saha, M.C. Sarofim, J. Trtanj, and L. Ziska, Eds. U.S. Global Change Research Program, Washington, DC, 312 pp. http://dx.doi.org/10.7930/J0R49NQX