Air conditioning poses a climate conundrum

This week, much of the US is suffering from yet another heat wave. So far this year, 15 countries have set records for high heat. Last July, the average global temperature, factoring in heat waves in multiple regions around the world, was likely the hottest in 120,000 years. Heat stress already kills about 500,000 people around the world yearly—a number the World Health Organization expects will rise five-fold by 2050.