Presently, we are focused on migration of refugees from war and issues of statelessness. As this piece warns, we soon will be seeing refugees from sea level rise.

Emerging threats- As a rising tide of migration. Two excerpts:

With sea levels on the rise, several island nations are scrambling to stay above water and ensure citizens will have a place to go when the ocean engulfs their homeland. The humanitarian-crisis phase of climate change has officially begun.
In total, climate change may displace up to a quarter-billion people by 2050, according to research cited by the Office of the United Nations High Commissioner for Refugees. That means, within our lifetimes, climate change could become a human rights emergency that grinds global governance to a halt. How the global community chooses to address this seemingly inevitable problem will help define international relations for the rest of this century.”