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Dying from Heat and Cold in Sao Paulo, Brazil: Which Kills More?

Paper Reviewed
Son, J.-Y., Gouveia, N., Bravo, M.A., de Freitas, C.U. and Bell, M.L. 2016. The impact of temperature on mortality in a subtropical city: effects of cold, heat, and heat waves in Sao Paulo, Brazil. International Journal of Biometeorology 60: 113-121.

In their important contribution to the subject, Son et al. (2016) examined how mortality in Sao Paulo, Brazil, was affected by extremes of heat and cold over the 14.5-year period stretching from 1996 to 2010, which they accomplished via the use of "over-dispersed generalized linear modeling and Bayesian hierarchical modeling." And what did they thereby learn?

The six scientists report that "cold effects on mortality appeared higher than heat effects in this subtropical city with moderate climatic conditions," where "heat was associated with respiratory mortality and cold with cardiovascular mortality." More specifically, they say that the "risk of total mortality was 6.1% higher at the 99th percentile of temperature than the 90th percentile (heat effect) and 8.6% higher at the 1st compared to the 10th percentile (cold effect)."

Consequently, and since Donat et al. (2013) report that "globally averaged minimum temperature extremes are warming faster than maximum temperature extremes," it would appear that current global warming is actually helping to reduce the yearly number of temperature-related deaths across the globe. Yet, somehow, this good news never seems to get reported in the media.

Donat, M.G., Alexander, L.V., Yang, H., Durre, I., Vose, R., Dunn, R.J.H., Willett, K.M., Aguilar, E., Brunet, M., Caesar, J., Hewitson, B., Jack, C., Klein Tank, A.M.G., Kruger, A.C., Marengo, J., Peterson, T.C., Renom, M., Rojas, C.O., Rusticucci, M., Salinger, J., Elrayah, A.S., Sekele, S.S., Srivastava, A.K., Trewin, B., Villarroel, C., Vincent, L.A., Zhai, P., Zhang, X. and Kitching, S. 2013. Updated analyses of temperature and precipitation extreme indices since the beginning of the twentieth century: The HadEX2 dataset. Journal of Geophysical Research (Atmospheres) 118: 2098-2118.

Posted 12 September 2016