Climate crisis is cooking up a lethal mix of heat and humidity, according to a study released at COP26.
One billion people will be at risk of extreme heat stress if global warming causes the world’s temperature to rise by 2C, new modeling shows.
A study by the Met Office, the U.K.’s national meteorological service, warned that a 2C rise could lead to a 15-fold increase of a potentially fatal cocktail of heat and humidity across the planet. A 4°C rise would mean that nearly half of the world’s population could be living in affected areas, according to the research, released at the COP26 climate conference in Glasgow.
The Met Office used an indicator that combines warmth and humidity, known as wet-bulb temperature, to assess heat stress risk. Once this measure passes 32°C, people are at extreme risk of adverse health effects, particularly those with physical outdoor jobs, according to Andy Hartley, climate impacts lead at the Met Office.
The study was derived from the EU-funded Helix project, which also maps drought, food insecurity, river flooding and wildfire risk. While tropical countries including Brazil and Ethiopia are most at risk from those hazards, Richard Betts, leader of the Helix project, warned that most regions of the world are likely to suffer from the impacts of climate change.
“The higher the level of warming, the more severe and widespread the risks to people’s lives,” Betts said. However, researchers view some risks as avoidable if swift global action is taken to limit temperature rises.
Limiting global warming to 1.5C is a key goal of this year’s climate talks, where “keeping 1.5 alive” has become an unofficial motto. Without quick action, climate impacts could present “a scary vision of the future”, according to Andy Wiltshire, head of earth system and mitigation science at the Met Office.
“Severe climate change will drive many impacts, and some regions will be affected by multiple factors,” Wiltshire said. “Rapid emission reductions are required if we are to avoid worst consequences of unmitigated climate change.”