Previews: Short-Term Unsurvivable Wet-Bulb Temperatures Popping Up In ME, Asia
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In most places, extreme heatwaves outside the usual range for a region will cause problems, from disrupting the economy to widespread mortality, particularly among the young and old. Yet in places in the Middle East and Asia something truly terrifying is emerging: the creation of unliveable heat. While humans can survive temperatures of well over 50C when humidity is low, when both temperatures and humidity are high, neither sweating nor soaking ourselves can cool us. What matters is the “wet-bulb” temperature – given by a thermometer covered in a wet cloth – which shows the temperature at which evaporative cooling from sweat or water occurs. Humans cannot survive prolonged exposure to a wet-bulb temperature beyond 35C because there is no way to cool our bodies. Not even in the shade, and not even with unlimited water.
A 35C wet-bulb temperature was once thought impossible. But last year scientists reported that locations in the Persian Gulf and Pakistan’s Indus river valley had already reached this threshold, although only for an hour or two, and only over small areas. As climate change drives temperatures upwards, heatwaves and accompanying unliveable temperatures are predicted to last longer and occur over larger areas and in new locations, including parts of Africa and the US south-east, over the decades to come.
What can governments, companies and citizens do? First, cut off the supply of ever more extreme heatwaves by halving carbon dioxide emission this decade, then reaching net zero emissions by 2050. Second, prepare for the inevitable heatwaves of the future. Emergency public health planning is the initial priority: getting essential information to people and moving vulnerable people into air-conditioned locations. Heatwave forecasts should include wet-bulb temperatures so that people can learn to understand the dangers.
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The final task is future-proofing agriculture and the wider ecosystems we all ultimately rely on. Heat can cause havoc with crop production. In Bangladesh, just two days of hot air in April this year destroyed 68,000 hectares of rice, affecting over 300,000 farmers with losses of US$39m (£28m). New heat-tolerant varieties of crops need developing and deploying. The alternative is higher food costs and food price spikes with the increased poverty and civil unrest that typically accompanies them.
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https://www.theguardian.com/commentisfree/2021/jun/30/canada-temperatures-limits-human-climate-emergency-earth
