BETWEEN BAD AND TERRIBLE.” By the end of the century, almost half the people on Earth will face deadly heat and humidity for more than 20 days a year, according to a study by Camilo Mora, a researcher at the University of Hawaii. And that’s the best-case scenario, with drastic reductions in carbon emissions. If emissions continue on their current trajectory, three-quarters of humanity will face deadly heat. Regions in the Persian Gulf, Bangladesh, and northeast India may become so hot and humid that, in the words of another recent study, they pass the “upper limit on human survivability,” deadly to anyone who ventures outside for more than a few hours. “Our choices now are between bad and terrible,” Mora said.

BETWEEN BAD AND TERRIBLE.”

By the end of the century, almost half the people on Earth will face deadly heat and humidity for more than 20 days a year, according to a study by Camilo Mora, a researcher at the University of Hawaii. And that’s the best-case scenario, with drastic reductions in carbon emissions. If emissions continue on their current trajectory, three-quarters of humanity will face deadly heat. Regions in the Persian Gulf, Bangladesh, and northeast India may become so hot and humid that, in the words of another recent study, they pass the “upper limit on human survivability,” deadly to anyone who ventures outside for more than a few hours. “Our choices now are between bad and terrible,” Mora said.