Global Warming and Deaths from Heat Stroke

Summary

For the past two decades, the number of heat-related deaths in Japan has been increasing along with the global warming trend. To assess the effect of hot weather on human health, we investigated heat-related deaths in Japan from 1968 through 1997, analyzing the data with reference to the distribution of the deaths by age and the incidence of hot days in summer. Vital Statistics of Japan, published by the Ministry of Health and Welfare of Japan, was the source of the heat-related mortality data employed in this study. Meteorological data were obtained from the District Meteorological Observatories in Tokyo and Osaka, the two largest cities in Japan. Heat-related deaths were most prone to occur on days with a peak daily temperature greater than 38°C, and the incidence of these deaths showed an exponential dependence on the number of hot days. Thus, even a small rise in atmospheric temperature may lead to a considerable increase in heat-related mortality, indicating the importance of combating global warming. Furthermore, half (50.1%) of the heat-related deaths occurred in children (≤4 years of age) and the elderly (≥70 years) irrespective of gender, indicating the vulnerability of these age groups to heat. More comprehensive measures should be adopted for children 4 years of age or less and the elderly to prevent heat-related deaths in these age groups.