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Dying from Heat and Cold in Australia and the United Kingdom

Paper Reviewed
Vardoulakis, S., Dear, K., Hajat, S., Heaviside, C., Eggen, B. and McMichael, A.J. 2014. Comparative assessment of the effects of climate change heat- and cold-related mortality in the United Kingdom and Australia. Environmental Health Perspectives 122: 1285-1292.

In an article published in Environmental Heath Perspectives, Vardoulakis et al. (2014) state that "high and low ambient temperatures are associated with increased mortality in temperate and subtropical climates," and that "temperature-related mortality patterns are expected to change throughout this century because of climate change," which, however, appears to have stalled for most of the past two decades. Nevertheless, it is nice to know what might occur in this regard if it ever begins to warm again, which is what Vardoulakis et al. set out to determine.

First of all, the six scientists evaluated the mortality impacts of current weather patterns by region or city and various age groups in Australia and the United Kingdom, after which they applied these relationships to climate and population projections in order to estimate potential temperature-related deaths in various UK regions and large Australian cities over the next half-century or so.

In terms of the present, as they describe it, their analyses indicate that "in UK regions, cold-related mortality currently accounts for more than one order of magnitude more deaths than heat-related mortality (around 61 and 3 deaths per 100,000 population per year, respectively)," while "in Australian cities, approximately 33 and 2 deaths per 100,000 population are associated every year with cold and heat, respectively," which findings reveal that cold weather extremes are far more deadly than are warm weather extremes in both countries.

As for the future (if climate model projections are valid), Vardoulakis et al. report that cold-related mortality is projected to decrease due to global warming from 61 to approximately 42 deaths per 100,000 population per year in the UK regions studied, and from 33 to 19 deaths per 100,000 population per year in the Australian cities, while heat-related mortality is projected to increase to around 9 and 8 deaths per 100,000 population per year, respectively, by the 2080s, assuming no changes in susceptibility and structure of the population.

Therefore, we see that whereas the total number of deaths currently caused by both cold and hot weather extremes in the UK is approximately 64 per 100,000 people, it is projected to decline to about 51 per 100,000 people in the 2080s. Likewise, whereas the yearly number of current deaths caused by both cold and hot weather extremes in Australia is 35 per 100,000 people, this number is projected to decline to about 27 per 100,000 people in the 2080s. And these results suggest that even with what many believe to be erroneously projected global warming, there would still be less extreme-temperature-caused human mortality in both the UK and Australia than there is nowadays.

Posted 6 May 2015