Michael B. Gerrard, associate faculty chair at Columbia University’s Earth Institute, is the Andrew Sabin professor of professional practice and director of the Sabin Center for Climate Change Law at Columbia Law School.
Toward the end of this century, if current trends are not reversed, large parts of Bangladesh, the Philippines, Indonesia, Pakistan, Egypt and Vietnam, among other countries, will be under water. Some small island nations, such as Kiribati and the Marshall Islands, will be close to disappearing entirely. Swaths of Africa from Sierra Leone to Ethiopia will be turning into desert. Glaciers in the Himalayas and the Andes, on which entire regions depend for drinking water, will be melting away. Many habitable parts of the world will no longer be able to support agriculture or produce clean water.
The people who live there will not sit passively by while they and their children starve to death. Tens or hundreds of millions of people will try very hard to go somewhere they can survive. They will be hungry, thirsty, hot — and desperate. If the search for safety involves piling into perilous boats and enduring miserable and dangerous journeys, they will do it. They will cross borders, regardless of whether they are welcome. And in their desperation, they could become violent: Forced migration can exacerbate ethnic and political tensions. Studies show that more heat tends to increase violence.