In a high-emissions scenario where little is done to curb planet-heating gases, global mortality rates will be raised by 73 deaths per 100,000 people by the end of the century. This nearly matches the current death toll from all infectious diseases, including tuberculosis, HIV/Aids, malaria, dengue and yellow fever. A more moderate path, where emissions are rapidly cut, will see temperature-related deaths less than a third of the more severe scenario, the researchers found.
“A lot of older people die due to indirect heat affects,” said Amir Jina, an environmental economist at the University of Chicago and a co-author of the study, published by the National Bureau of Economic Research. “It’s eerily similar to Covid – vulnerable people are those who have pre-existing or underlying conditions. If you have a heart problem and are hammered for days by the heat, you are going to be pushed towards collapse.”
Poorer societies that occupy the hottest areas of the world are set to suffer worst. As already baking temperatures climb further this century, countries such as Ghana, Bangladesh, Pakistan and Sudan face an additional 200 or more deaths per 100,000 people. Cooler, richer countries such as Norway and Canada, meanwhile, will see a drop in deaths as fewer and fewer people perish due to extreme cold such as hypothermia.
“You see the really bad impacts at the tropics,” said Jina. “There’s not one single worldwide condition, there’s a lot of different changes with poorer people much more affected with limited ability to adapt. The richer countries, even if they have increases in mortality, can pay more to adapt to it. It’s really the people who have done the least to cause climate change who are suffering from it.”
Within richer countries, places already used to the heat will have an adaptation head start on areas only now starting to experience scorching conditions. “A really hot day in Seattle is more damaging than a really hot day in Houston because air conditioning and other measures are less widespread there,” said Bob Kopp, a co-author and climate scientist at Rutgers University.
The economic loss from the climate crisis, as well as the cost of adaption, will be felt around the world, including even in the wealthier countries. The economic cost of these deaths is set to be severe, costing the world 3.2% of global economic output by the end of the century if emissions aren’t tamed.