As global climate change affects livelihoods across the world, migration patterns are also changing. In a recent study published in Global Environmental Change, Clark Gray, Valerie Mueller, and I found that since the 1970s, climatic variations have been increasing internal migration across many South American countries, with few exceptions. And many people are headed to cities.

From Ukraine and the Middle East to sub-Saharan Africa and East Asia, the world is engulfed in a series of significant international crises. But despite such urgent issues, it would be a grave mistake to forget about the structural foreign policy challenges – such as access to water – that could become the crises of the future.