3.5 billion people may face ‘unlivable’ heat in 50 years
Posted on May 9, 2020
Every degree of global warming will push a billion people out of the human survival zone
by Ian Angus
How dangerous is global warming? By 2070, up to 30% of the world’s population could face temperatures that are literally unlivable.
Climate studies project business-as-usual global temperature increases of 2 or 3 degrees in that time — but those are averages that include the cooler oceans, covering 70% of the globe. The temperature increase on land will be higher, and temperatures in areas that are already warm will be higher still.
If the global average rises 3 degrees, the places where people actually live will be at least 6 degrees hotter than today — and huge areas will be too hot to live in.
“Future of the human climate niche,” a study published this week in the Proceedings of the National Academy of Sciences (PNAS), finds that for at least 6,000 years, almost all humans have lived in areas where the mean annual temperature is between 11º and 25º. That’s the human “climate niche,” the temperature range in which outdoor work isn’t deadly, and in which we have been able to raise enough food to survive.