This summer has been a parade of broken climate records. June was the hottest June and July was not just the hottest July but the hottest month ever on record. At the same time, it looks like we are at the start of a green revolution: Decarbonization efforts have gone far better than what many had hoped for just a few years ago, and renewable energy is getting cheaper. How should we make sense of these seemingly mixed signals? What does it mean to hold the pessimism of climate disaster and the optimism of climate action together? There are few individuals better suited to navigate these questions than Kate Marvel, a senior climate scientist at Project Drawdown. In a conversation with guest host David Wallace-Wells, Marvel explores whether climate change is “accelerating,” why reducing air pollution will lead to more warming before it leads to less; how the human response to a changing climate can be more unpredictable than the climate itself; how witch burnings increased during the last major change in climate; what the relationship is between hotter weather and social unrest; how decarbonization sets us on track to avoiding the worst-case climate models; why, despite all the challenges ahead, there are still immeasurable benefits to fighting for a cleaner planet and much more. This episode was hosted by David Wallace-Wells, a writer at The New York Times Magazine and the author of “The Uninhabitable Earth: Life After Warming.” He also writes a newsletter for New York Times Opinion that explores climate change, technology and the future of the planet and how we live on it.

In his latest work, “The Last White Man,” the award-winning writer Mohsin Hamid imagines a world that is very like our own, with one major exception: On various days, white people wake up to discover that their skin is no longer white. It’s a heavy premise, but one of Hamid’s unique talents as a novelist is his ability to take on the most difficult of topics — racism, migration, loss — with a remarkably light touch. “How do you begin to have these conversations in a way that allows everybody a way in?” Hamid asks at one point in our conversation. “How do you talk about these things in a way that’s open to everyone?” What sets Hamid apart is his capacity to do just that — both in his fiction and in our conversation. We discuss: How Hamid experienced what it was like to lose his whiteness after 9/11 What happens to a society when suddenly we can’t sort ourselves by race The origins of modern humans’ fear of death — and how to overcome it Why Hamid thinks future humans will look back at the idea of borders with moral horror Why Hamid believes that pessimistic realism is a “deeply conservative” worldview Hamid’s process for imagining optimistic futures Why Hamid believes that the very notion of the self is a fiction Why we turn to activities like sex, drugs and meditation when we get overwhelmed How America’s policies toward immigrants and refugees should challenge our “heroic” sense of national identity What Toni Morrison taught Hamid about how to read and write And more.