The Download: the year's most-read climate stories, and Amazon's chatbot

Wildfires, floods and heatwaves displaced and killed thousands of people across the world as extreme weather events worsened, and scientists have concluded the past 12 months were the hottest since records began. Our climate experts James Temple and Casey Crownhart have been covering the most promising technologies that could make a difference. Take a look back over some of MIT Technology Review's most-read climate stories of the year--and make sure you keep up-to-date with all the latest news by subscribing to The Spark, our weekly climate and energy tech newsletter. This geothermal startup showed its wells can be used like a giant underground battery. If Fervo Energy's field results work at commercial scale, it could become cheaper and easier to green the grid.