More than a fifth of humanity potentially affected. The policies currently in place to limit global warming will expose two billion people to extreme and potentially deadly heat by the end of the century, researchers warn in a study, Monday, May 22.
The Earth’s surface temperature is on track for a 2.7°C increase by 2100 compared to the pre-industrial era. This should push more than 2 billion people – or 22% of the world’s population by this deadline – out of the climatic comfort zone that has allowed humanity to develop for millennia, according to the study published in Nature Sustainability.
India, Nigeria or Indonesia are the countries with the highest number of people who could face deadly heat. Respectively, 600 million, 300 million and 100 million people are likely to be exposed in these countries by 2100.
“This represents a profound reshaping of the habitability of the planet’s surface and could potentially lead to a large-scale reorganization of where people live.”
Tim Lenton of Britain’s University of Exeter, lead author of the study
By limiting warming to 1.5°C, the number of people exposed to these risks would be reduced to less than half a billion people. The world is already experiencing a warming close to 1.2°C due to human activity, in particular the use of fossil fuels. Climatic disasters – heat waves, droughts, forest fires – are already increasing with this level of warming. “For every 0.1°C of warming above current levels, an additional 140 million people will be exposed to dangerous heat”warns Tim Lenton.
The threshold of “dangerous heat” was set in the study at 29°C mean annual temperature.