Climate change has historically pushed people to migrate. There is widespread belief - fear? - that rising sea levels will force millions of people to migrate out of Bangladesh and Vietnam. If that happens, these migrants will spill into neighboring countries many of which are unlikely to be ready to take on migrants. Many will also sooner or later spread into far away countries in Australia, Asia, Europe and North America.
What concerns me more is that this simplistic viewpoint has very little factual analytical backing. Data on migration trends over time are bad. Data on climate change as they relate to migration are even worse. What is worse, migration experts are not necessarily talking to the experts on climate change.
A conversation with Vijay Jagannathan, a water expert and good friend, alerted me to another low probability but high impact event - the melting of the glaciers on the Himalayas. If that happens - the probability is low, but if it does - China and India on either side are likely to be affected, posing more serious geopolitical risks than the rising sea level.
A starting point for analytical work in this area would be gathering relevant data on migration - probably at zipcode level from household surveys wherever they exist - and link that to climate change data which are more likely to exist in many countries. (Recall the saying that, unlike an economist, the weatherman is usually right about the past!)
While every one is thinking about how climate change affects migration, I wonder if we should also worry about how migration affects climate change. For one, if harsh regions are populated through immigration, does that deplete resources? Does that contribute to global warming?