This article is from The Spark, MIT Technology Review's weekly climate newsletter. To receive it in your inbox every Wednesday, sign up here. When I get home in the evening on a sweltering summer day, the first thing I do is beeline to my window air-conditioning units and crank them up. People across the city,...

This is today's edition ofThe Download,our weekday newsletter that provides a daily dose of what's going on in the world of technology. Your AC habits aren't unique. Here's why that's a problem. -Casey Crownhart When I get home in the evening on a sweltering summer day, the first thing I do is crank up my...