Paper Reviewed
Zhou, X., Zhao, A., Meng, X., Chen, R., Kuang, X., Duan, X. and Kan, H. 2014. Acute effects of diurnal temperature range on mortality in 8 Chinese cities. Science of the Total Environment 493: 92-97.

In introducing their intriguing study, Zhou et al. (2014) indicate that an increase in diurnal temperature range (DTR) has been found to lead to an increase in daily mortality in several Chinese cities, including Shanghai (Kan et al., 2007), Guangzhou (Luo et al., 2013; Yang et al., 2013), Taiwan (Liang et al., 2009), and Hong Kong (Tam et al., 2009). And, therefore, they decided to search out still further evidence for this relationship across a broader north-south swath of the country that included, moving from north to south, the cities of Anshan, Tangshan, Xi'an, Nanjing, Suzhou, Wuhan, Shanghai and Guangzhou.

As a result of this massive undertaking, which they describe as "the largest epidemiologic study to date in China to examine the association of DTR with daily mortality," the seven scientists found that "the increased risk of mortality from total, cardiovascular diseases and respiratory diseases in a full year attributable to a 1°C increase in DTR were 0.18%, 0.25% and 0.38%, respectively."

Most interestingly, however, the work of Karl et al. (1984, 1991) indicates that the global warming of Earth's recent past was characterized by daily minimum temperatures rising three times more than daily maximum temperatures, thereby significantly reducing the DTR and saving a significant number of lives worldwide. What more could one possibly ask of much-maligned global warming?

References
Kan, H., London, S.J., Chen, H., Song, G., Chen, G., Jiang, L., Zhao, N., Zhang, Y. and Chen, B. 2007. Diurnal temperature range and daily mortality in Shanghai, China. Environmental Research 103: 424-431.

Karl, T.R., Jones, P.D., Knight, R.W., Kukla, G., Plummer, N., Razuvayev, V., Gallo, K.P., Lindseay, J., Charlson, R.J. and Peterson, T.C. 1984. A new perspective on recent global warming: asymmetric trends of daily maximum and minimum temperature. Bulletin of the American Meteorological Society 74: 1007-1023.

Karl, T.R., Kukla, G., Razuvayev, V.N., Changery, M.J., Quayle, R.G., Heim, Jr., R.R., Easterling, D.R. and Fu, C.B. 1991. Global warming: evidence for asymmetric diurnal temperature change. Geophysical Research Letters 18: 2253-2256.

Liang, W.M., Liu, W.P. and Kuo, H.W. 2009. Diurnal temperature range and emergency room admissions for chronic obstructive pulmonary disease in Taiwan. International Journal of Biometeorology 53: 17-23.

Luo, YU., Zhang, Y., Liu, T., Rutherford, S., Xu, Y., Xu, X. et al 2013. Lagged effect of diurnal temperature range on mortality in a subtropical megacity of China. PLOS ONE 8: e55280.

Tam, W.W., Wong, T.W., Chair, S.Y. and Wong, A.H. 2009. Diurnal temperature range and daily cardiovascular mortalities among the elderly in Hong Kong. Archives of Environmental and Occupational Health 64: 202-206.

Yang, J., Liu, H.Z., Ou, C.Q., Lin, G.Z., Zhou, Q., Shen, G.C., Chen, P.Y. and Guo, Y.M. 2013. Global climate change: impact of diurnal temperature range on mortality in Guangzhou, China. Environmental Pollution 175C: 131-136.