A new study conducted by researchers from King’s College London explored the risks we’re likely to face with even the slightest increases in global warming.
In brief ...
Impact on Habitable Areas: The study finds that if global temperatures exceed 2°C above preindustrial levels:
- 6% of the world (roughly the size of the U.S.) will be too hot for young, healthy adults to live in.
- 35% of the world will be too hot for adults over the age of 60 to live in.
Heatstroke Risk: In such hot conditions, even with shade, breeze, and hydration, prolonged outdoor exposure could cause lethal heatstroke, presenting a significant increase in heat-related mortality risk.
Unsurvivable Heat: The study found that the unsurvivable threshold has not yet been reached for younger adults but has been briefly exceeded for older adults in less than 2% of the world’s land area.
Health Risks of Rising Temperatures: The study concludes that higher levels of warming, particularly 4°C above preindustrial levels, would have devastating health effects, with widespread areas of the world becoming uninhabitable due to extreme heat.
About the study
Their work found that if the average global temperature exceeds 2 degrees Celsius, or 35.6 degrees Fahrenheit, above the preindustrial age, large portions of the world will be uninhabitable.
For starters, 6% of the world – or an area around the size of the U.S. – would be too hot for young, healthy adults to live. However, for adults over the age of 60, 35% of the world would be too hot to live.
“Our findings show the potentially deadly consequences if global warming reaches 2°C,” researcher Dr. Tom Matthews said in a news release.
“In such conditions, prolonged outdoor exposure – even for those in the shade, subject to a strong breeze, and well hydrated – would be expected to cause lethal heatstroke. It represents a step-change in heat-mortality risk.”
The older population is at the highest risk
The researchers explained that there are two key terms in determining the long-term health risks for consumers: the uncompensable threshold and the unsurvivable threshold.
Their report states that the uncompensable threshold is “beyond which human core body temperature rises uncontrollably,” while the unsurvivable threshold is a “lethal core temperature increase within [six hours].”
Based on their research, they found that healthy adults between the ages of 18 and 60 have been less likely to reach the uncompensable threshold between 1994 and 2023. For adults in this age bracket, 2% of the world’s land area have exceeded this measure; comparatively, about 21% of the world’s land area has exceeded this measure for adults over 60.
When assessing the unsurvivable threshold, the researchers found that this metric hasn’t yet been exceeded for younger adults. For older adults, it has exceeded briefly, with less than 2% of the world’s land area being affected.
This means that parts of the world that reach either of these thresholds would have temperatures too high for humans – even young, healthy adults – to live.
A look into the future
In projecting into the future, the researchers found that these figures – and subsequent health risks – are going to be considerably higher if global warming continues to escalate.
They determined that if the global temperature goes 2 degrees Celsius above preindustrial temperatures, 6% of the world’s total land area will exceed the uncompensabe threshold for younger adults.
Dr. Matthews explained that the higher the global temperature, the greater the risk to consumers of all ages.
“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,” Dr. Matthews 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.”