This Earth Day, there are some reasons to be hopeful about the climate

Yes, the headlines are bleak. Yes, scientists are sounding the alarm. Yes, a growing pile of studies warn that the world is “on the brink of irreversible climate disaster,” as a recent “state of the climate” report put it. It’s easy to feel like the planet is on fire — because, well, sometimes it literally is. But even amid the floods, droughts and devastating forecasts, it’s not all doom: Innovators are reimagining how we power our lives, nature is pulling off surprising comebacks, cities are cleaning their air and nations are opening their wallets. This Earth Day, take a break...