What struck John Kerry the most about this week's landmark U.N. report on climate change? "The irreversibility" of some of the most catastrophic effects of global warming, he tells Audie Cornish. Kerry, the U.S. Special Envoy for Climate, tells NPR the U.N. report underscored the need for the world to respond more forcefully to climate change — and he's called an upcoming U.N. climate summit in Scotland the "last best hope" for global action. At the same time, the Biden administration faces an uphill battle to take major action on climate at home. Hear more on that from the NPR Politics Podcast via Apple, Spotify, or Google. In participating regions, you'll also hear a local news segment that will help you make sense of what's going on in your community.Email us at considerthis@npr.org.