When it comes to the climate crisis, there’s barely a day that goes by when we don’t hear about rising sea levels and storm-driven tides. But Harvard professors Jaqueline Bhabha and Hannah Teicher say there’s another rising tide that’s not getting as much attention, despite its potential to reshape our world. It’s the wave of climate migrants—people who have been and will be driven from their homes by rising seas, extreme heat, catastrophic weather, and climate-related famine and economic hardship. Some will try to relocate within their home countries, others across international borders, but most experts predict that there will be hundreds of millions of them. In fact the United Nations says hundreds of millions of people globally have already been forced to relocate for climate-related reasons, and experts say as many as a billion people could be seeking new homes by 2050. Meanwhile, immigration is already a political third rail in many countries, including the United States, and has driven a rise in both authoritarianism and ethnonationalism. So where will they go? And what kind of welcome will they receive when they get there? Bhabha and Teicher are working on those questions, examining everything from the language we use when we talk about climate migration to international law and human rights to urban planning policies that can help create win-win situations when newcomers arrive. They say major changes to our climate and to the earth’s habitable spaces are coming, and a large part of adjusting to that successfully will involve another difficult change—to our way of thinking about how we share the world with our fellow humans.