The 40-plus temperatures and melting asphalt of Australia’s latest heat wave seem hard to understand for North Americans shivering under a polar vortex, but both temperature extremes relate to climate change, and both can be deadly for vulnerable groups, including outdoor workers. On December 22, a new scientific paper was published in Environmental Research Letters and summarized in layman’s terms by Climate News Network as “Humidity is the real heat wave threat” (December 24). In “Temperature and humidity based projections of a rapid rise in global heat stress exposure during the 21st century” in Environmental Research Letters, scientists at Columbia University’s Lamont-Doherty Earth Observatory used numerous models to project frequency of high wet-bulb readings, (a scale which combines heat and humidity). The authors project that in the south-east U.S., where current wet-bulb temperatures now reach 29 or 30°C only occasionally, such highs could occur 25 to 40 days per year by the 2070’s or 2080’s, and wet-bulb temperatures of 35°C could occur on one or two days a year. (35°C on a wet-bulb scale is considered the limit of human survivability.)
The situation would be worse in parts of South America, China, and especially in Northeast India and coastal West Africa, where there is little cooling infrastructure, relatively low adaptive capacity, and rapidly growing populations. The authors conclude that “ heat stress may prove to be one of the most widely experienced and directly dangerous aspects of climate change, posing a severe threat to human health, energy infrastructure, and outdoor activities ranging from agricultural production to military training.” One might add, to any outdoor worker, including those in agriculture, construction , delivery, and emergency responders.
Similar warnings were published for farmers in Asia in “Deadly heat waves projected in the densely populated agricultural regions of South Asia” in Science Advances (August 2, 2017), summarized by Inside Climate News. Researchers at Massachusetts Institute of Technology and Loyola Marymount University in Los Angeles concluded “The most intense hazard from extreme future heat waves is concentrated around densely populated agricultural regions of the Ganges and Indus river basins.”
But a recent article from Climate News Network shows that we’re all in this together. ” Warming drives climate refugees to Europe” (Dec. 22) summarizes a study which combined EU asylum-application data with projections of future warming, and concludes that even under optimistic scenarios, asylum applications to the EU would increase by 28% by 2100 . The article concludes “Though poorer countries in hotter regions are most vulnerable to climate change, our findings highlight the extent to which countries are interlinked, and Europe will see increasing numbers of desperate people fleeing their home countries.”