Climate change & migration

I have heard a lot about climate change fueling conflict, including perhaps the current Syrian civil war, but I hadn't thought much about how climate change is likely to fuel migration. It's obvious: I mean, if conflict becomes more common, then people fleeing the conflicts will be more common. And of course economic migrants- changing temperatures could easily set off another round of migrants like those in the Grapes of Wrath, fleeing the dust bowl in 1930's USA. If those people can be accommodated, they can help with the agriculture in the places they migrate, since climate change will make formerly cold places more ag-friendly. Unfortunately, it seems more likely that people continue to talk about building walls....