A Half-Degree Rise In Global Warming Will Triple Earth’s Areas Too Hot For Humans

Eddie Gonzales Jr. – MessageToEagle.com – A new assessment warns that an area the size of the USA will become too hot for even healthy young people to maintain a safe body temperature if temperatures rise 2°C above preindustrial levels.

Image credit: photo-graphe – Pixabay

For those over 60, this 2°C increase would push over a third of the planet’s land into dangerous ‘overheating’ territory.

An international group of scientists, led by King’s College London, has revealed how continued global warming will lead to more parts of the planet becoming too hot for the human body over the coming decades.

If global warming reaches 2°C above the preindustrial average, land too hot for healthy young humans to maintain a safe body temperature will triple to about 6%, an area nearly the size of the US. The area at risk for those over 60 could increase to about 35%.

Last year was the first calendar year with a global mean temperature of more than 1.5°C above the pre-industrial average, and at current rates of warming, 2°C could be reached by mid to late century.

Dr Tom Matthews, Lead author and Senior Lecturer in Environmental Geography, at King’s College London said: “Our findings show the potentially deadly consequences if global warming reaches 2°C.”

For their assessment, the team drew together scientific findings to link physical climate science with heat mortality risk, including crossing ‘uncompensable’ and ‘unsurvivable’ thresholds. Scientists distinguish between uncompensable thresholds, beyond which human core body temperature rises uncontrollably, and unsurvivable thresholds, where the body’s core temperature increases to 42°C within six hours.

Between 1994-2023, human thermal tolerances, the combination of temperature and humidity, above which the human body can’t cope – were breached for about 2% of the global land area for adults under 60. More than 20% of the Earth’s land surface crossed this threshold for older adults, who are more vulnerable to heat stress.

Whilst uncompensable thresholds have been passed for all ages, unsurvivable thresholds have so far only been passed briefly for older adults.

For higher warming levels of 4-5°C above preindustrial, older adults could experience uncompensable heat across around 60 % of the Earth’s surface during extreme events. At this level of warming, unsurvivable heat would also begin to emerge as a threat to younger adults in the hottest subtropical regions.

Certain regions are more at risk of crossing the critical uncompensable and unsurvivable thresholds, with people in Saharan Africa and South Asia most in the firing line.

Dr Matthews said anticipating the magnitude of future heat extremes and their worst-case impacts is critical to understanding the costs of failing to mitigate climate change. It is also crucial for targeting adaptation efforts at those communities most in need.

“What our review really shows very clearly is that, particularly for higher levels of warming such as 4°C above the pre-industrial average, the health impacts of extreme heat could be extremely bad,” he said. “At around 4°C of warming above preindustrial levels, uncompensable heat for adults would affect about 40% of the global land area, with only the high latitudes, and the cooler regions of the mid-latitudes, remaining unaffected.

“Interdisciplinary work is vital to improving our understanding of unprecedented heat’s deadly potential and how it can be reduced. As more of the planet experiences outdoor conditions too hot for our physiology, it will be essential that people have reliable access to cooler environments to shelter from the heat”.

Since 2000, over 260, 000 heat-related fatalities have occurred in the deadliest events, highlighting extreme heat’s threat to human life. The three worst events this century caused nearly 200, 000 deaths: about 72, 000 across Europe in 2003, another 62, 000 in Europe in 2022, and about 56, 000 during Russia’s 2010 heatwave.

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Written by Eddie Gonzales  Jr. – MessageToEagle.com Staff Writer