Millions of people around the world could be exposed to dangerous levels of heat stress – a dangerous condition which can cause organs to shut down. Many live in developing countries, and do jobs that expose them to potentially life threatening conditions. These include being out in the open on farms and building sites or indoors in factories and hospitals.
Global warming will increase the chances of summer conditions that may be “too hot for humans” to work in. A system known as the Wet Bulb Globe Temperature (WBGT) measures not only heat but also humidity and other factors to give a more realistic description of the conditions. Back in the 1950s, the US military used it to work out guidelines for keeping soldiers safe. When the WBGT reaches 29C, for example, the recommendation is to suspend exercise for anyone not acclimatised. And at the top of the scale – when the WBGT registers 32C – the US says strenuous training should stop because the risk becomes “extreme”.
As global temperatures rise, more intense humidity is likely as well which means more people will be exposed to more days with that hazardous combination of heat and moisture. Prof Richard Betts of the UK Met Office has run computer models which suggest that the number of days with a WBGT above 32C are set to increase, depending on whether greenhouse gas emissions are cut. And he spells out the risks for millions of people already having to work in the challenging combination of extreme heat and high humidity. “We humans evolved to live in a particular range of temperatures, so it’s clear that if we continue to cause temperatures to rise worldwide, sooner or later the hottest parts of the world could start to see conditions that are simply too hot for us.”
Source: BBC
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