Heatwave Could Be The Next Big Killer

Healthy human adults cannot survive if the wet-bulb temperature (TW) exceeds 35℃, even in the shade, with an unlimited supply of drinking water.

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The unbearable heat is scorching a large part of the Earth, killing millions of people with no means of escape. Shallow water bodies are hotter than the blood flowing in people’s veins. Earlier, climate models suggested that it would take nearly another century of carbon pollution to generate heat waves that exceed the absolute limits of human tolerance. But according to the Inter-governmental Panel on Climate Change (IPCC) report, exclusively seen by Agence France-Presse ahead of its scheduled release in February 2022, estimates the unprecedented killer heat waves on the near horizon.

A chilling report from the United Nations Climate Science Advisory Panel paints a grim and deadly picture for a warming planet. If the World warmed by 1.5℃ – 0.4℃ above today’s levels – 14 percent of the population would be exposed to severe heat waves, at least once every five years a “significant increase in heatwave magnitude,” the report says. Going up half a degree, another 1.7 billion people will be added.

From Karachi to Kinshasa, Manila to Mumbai, Lagos to Manaus, the most affected megacities in the developing World will generate their own excess heat. It’s not just the thermometer reading that makes a difference – heat tends to be more deadly when combined with high humidity. In other words, it is easier to survive a high day temperature if the air is bone-dry, it is easier to survive a low-temperature day with a lot of humidity.

That steam-bath mixture has its own scale, known as the wet-bulb temperature. Experts say that healthy human adults cannot survive if the wet-bulb temperature (TW) exceeds 35℃, even in the shade, with an unlimited supply of drinking water.

Heat Stroke, Heart Attack

We have already seen the effects of deadly, sultry heat at very low thresholds, especially in the elderly are vulnerable. Two heat waves that hit 30℃ TW in Bharat and Pakistan in 2015 killed more than 4,000 people. And, the 2003 heatwave killed more than 50,000 people in Western Europe, with only recorded wet-bulb temperatures in the high 20s.

Extreme heatwaves in the Northern Hemisphere in 2019 — the second warmest year on record for the planet — also caused a significant number of additional deaths, but wet-bulb data are still lacking. Research from the Institute for Health Metrics and Evaluation reported just over 3,00,000 heat-related deaths worldwide in 2019 from all causes. About 37 percent of heat-related deaths — just over 1,00,000 — can be blamed on global warming, according to researchers led by Antonio Gasparini at the London School of Hygiene and Tropical Medicine.

In half-a-dozen countries — Brazil, Peru, Colombia, Philippines, Kuwait, and Guatemala — the percentage was 60 percent or more. Most of these deaths were probably caused by heatstroke, heart attacks, and dehydration from heavy sweating, and many could likely have been prevented.

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