And the problem won't be as simple as girding inland cities to support an influx of new residents, either: plenty of folks will be unwilling or unable to leave their slowly flooding regions. In this way, Hauer writes, sea level rise could also create millions of "trapped" people. New Yorkers will move away from neighborhoods that are perpetually flooded, crowding into relatively dry zones while still sitting quite exposed to future floods on the coast. And while Hauer posits that the wealthy might choose to adapt to sea level rise instead of moving, research from the Intergovernmental Panel on Climate Change suggests that it’s actually low-income people who will remain. During Hurricane Katrina, many residents remained behind because they lacked cars, money for gas, food, and hotels, and—perhaps most importantly—friends or family outside of the region with whom they could ride out the storm.