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Heat-Related vs. Cold-Related Deaths in the Czech Republic
Kysely, J. and Huth, R.  2004.  Heat-related mortality in the Czech Republic examined through synoptic and 'traditional' approaches.  Climate Research 25: 265-274.

What was done
The authors tested different ways of evaluating heat-related mortality over the nine-year period 1992-2000 in the Czech Republic by calculating deviations of the observed number of deaths from the expected number of deaths for each day of the year.

What was learned
Kysely and Huth discovered that "the distribution of days with the highest excess mortality in a year is clearly bimodal, showing a main peak in late winter and a secondary one in summer."  In the case of the smaller number of summer heat-wave-induced deaths, they also found that "a large portion of the mortality increase is associated with the harvesting effect, which consists in short-term shifts in mortality and leads to a decline in the number of deaths after hot periods (e.g. Rooney et al., 1998; Braga et al., 2002; Laschewski and Jendritzky, 2002)."  Specifically, they report that "the mortality displacement effect in the severe 1994 heat waves can be estimated to account for about 50% of the total number of victims."  In other words, as they put it, "people who would have died in the short term even in the absence of oppressive weather conditions made up about half of the total number of deaths."

What it means
Most everywhere in the world, the number of heat-related deaths generally cannot hold a candle to the number of cold-related deaths; and the case of the Czech Republic is no exception.  Not only are overall numbers of deaths smaller in the warmest part of the year than in the coldest part of the year, approximately half of the heat-related excess deaths typically would have occurred anyway, merely being hastened by a few days to a few weeks by the unseasonably warm temperatures that caused them.  Hence, as is evident in study after study [see our Major Report Enhanced or Impaired? Human Health in a CO2-Enriched Warmer World], cold (both seasonable and unseasonable) kills far more people than does heat.

Braga, A.L.F., Zanobetti, A. and Schwartz, J.  2002.  The effect of weather on respiratory and cardiovascular deaths in 12 U.S. cities.  Environmental Health Perspectives 110: 859-863.

Laschewski, G. and Jendritzky, G.  2002.  Effects of the thermal environment on human health: an investigation of 30 years of daily mortality data from SW Germany.  Climate Research 21: 91-103.

Rooney, C., McMichael, A.J., Kovats, R.S. and Coleman, M.P.  1998.  Excess mortality in England and Wales, and in Greater London, during the 1995 heat wave.  Journal of Epidemiology and Community Health 52: 482-486.

Reviewed 3 March 2004