What at first glance appears to be simple causality – climate change leading to more and more migration – has triggered intense academic debate over the past ten years because the circumstances are complex. There is need for a thorough analysis in the ground between denying the problem and asserting immediate causality. In international relations, migration induced by climate change and environmental degradation is increasingly recognized as a problem, whether in the framework of international climate policy, international migration policy, development cooperation, or international crisis management. But considering the dimension of these major challenges, only small steps have been taken so far. The scope of the problem continues to be underestimated. Climate change is jeopardizing the livelihoods of more and more people. It is a risk multiplier. Although understanding of the connection between climate change and migration has increased, many questions have yet to be answered. We need more knowledge to better support the people affected.