Fabien Prieur, Ingmar Schumacher, “The impact of conflicts on climate and migration policy,” Journal of Public Economic Theory, forthcoming.

It is no longer a question of whether or not climate change may seriously impact humankind. Instead, the important question we now face is how we can reduce the extent of climate change while coping with its economic and social impacts. There is mounting evidence that climate change is going to have the strongest impact on poor developing countries, with migration often being the last resort. Migrants tend to then target developed countries as their destination. While one may argue that rich countries should allow immigration exclusively for humanitarian reasons, history instead has shown that immigration policies tend to be framed on both economic as well as social grounds. In particular, migration is well-known for potentially creating (social) conflicts in the recipient country, which must be taken into account when trying to understand the optimal policy responses As United Nations Secretary-General Ban Ki-moon (11/23/11) aptly noted: “Climate change… could well trigger large-scale migration… These and other implications for peace and security have implications for the United Nations itself.”

We develop a theoretical model to study the relationship between climate change, migration and conflicts from the perspective of the recipient countries, which we call collectively the North. The North chooses the number of immigrants it wants to accept together with the amount of climate change mitigation. The potential number of migrants is determined by the extent of climate change in the South. Accepting more migrants allows the North to increase local production but it also exacerbates climate change and gives rise to internal conflicts. Those potential migrants that want to migrate North due to climate change but are not allowed to immigrate may induce external conflicts. We find that a policy maker, subject to the threat of both internal and external conflicts, may either choose a policy that relies more on mitigation with less immigration, or less mitigation and more immigration. Which policy ought to be pursued depends on the relative cost of internal and external conflicts, and the mitigation cost. If either the threat of external or internal conflicts are negligible, then we find that the optimal mitigation and immigration policies are not interdependent any longer. We also discuss when mitigation and immigration policies are substitutes or complements.