After three years of record-breaking heat, this one is set to be yet another scorcher. Air-conditioning? Not going anywhere. The International Energy Agency projects that the number of AC units will triple by 2050. That's good for health-one Lancet study estimated that AC prevented nearly 200,000 premature deaths in 2019 alone-but bad for the planet....

This is today's edition of The Download, our weekday newsletter that provides a daily dose of what's going on in the world of technology. These new solid-state ACs promise a cool future. Scientists aren't so sure. After three years of record-breaking heat and another scorcher underway, air-conditioning isn't going anywhere. That's good for our health,...