Climate change and international migration: Exploring the macroeconomic channel

RESEARCH ARTICLE Climate change and international migration: Exploring the macroeconomic channel Albano RikaniID1,2,3*, Katja Frieler1, Jacob Schewe1 1 Potsdam Institute for Climate Impact Research, Potsdam, Germany, 2 Department of Physics and Astronomy, University of Potsdam, Potsdam, Germany, 3 INSERM, Pierre Louis Institute of Epidemiology and Public Health, Sorbonne Universite´, Paris, France * rikani@pik-potsdam.de Abstract International migration patterns, at the global level, can to a large extent be explained through economic factors in origin and destination countries. On the other hand, it has been shown that global climate change is likely to affect economic development over the coming decades. Here, we demonstrate how these future climate impacts on national income levels could alter the global migration landscape. Using an empirically calibrated global migration model, we investigate two separate mechanisms. The first is through destination-country income, which has been shown consistently to have a positive effect on immigration. As countries’ income levels relative to each other are projected to change in the future both due to different rates of economic growth and due to different levels of climate change impacts, the relative distribution of immigration across destination countries also changes as a result, all else being equal. Second, emigration rates have been found to have a complex, inverted U-shaped dependence on origin-country income. Given the available migration flow data, it

is unclear whether this dependence—found in spatio-temporal panel data—also pertains to changes in a given migration flow over time. If it does, then climate change will additionally affect migration patterns through origin countries’ emigration rates, as the relative and abso- lute positions of countries on the migration “hump” change. We illustrate these different pos- sibilities, and the corresponding effects of 3˚C global warming (above pre-industrial) on global migration patterns, using climate model projections and two different methods for estimating climate change effects on macroeconomic development. 1 Introduction Future global warming is projected to impact both natural and human systems, increasing the climate-related risks to health, food security and economic growth, among others [1]. These climate change impacts may affect human migration flows [2]. Estimating the magnitude and pattern of such phenomenon might be of crucial importance for preparing future societies, and to understand if these responses will act to lower or amplify other climate-related risks, e.g. population’s exposure or vulnerability. However, only few studies have attempted to esti- mate the effects of climate change on future migration. PLOS ONE PLOS ONE | https://doi.org/10.1371/journal.pone.0276764 November 16, 2022 1 / 25 a1111111111 a1111111111 a1111111111 a1111111111 a1111111111 OPEN ACCESS Citation: Rikani A, Frieler K, Schewe J (2022) Climate change and international migration: Exploring the macroeconomic channel. PLoS ONE 17(11): e0276764. https://doi.org/10.1371/journal.

pone.0276764 Editor: Luca De Benedictis, University of Macerata, ITALY Received: March 24, 2022 Accepted: October 13, 2022 Published: November 16, 2022 Copyright: © 2022 Rikani et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Data Availability Statement: All relevant data are within the manuscript and its Supporting information files. Funding: Author: J. S. Project and grant number: FUME: 870649 Funder: European Union Horizon 2020 programme URL: https://ec.europa.eu/info/ research-and-innovation/funding/funding- opportunities/funding-programmes-and-open- calls/horizon-2020_en Author: A. R. Porject and grant number: HABITABLE: 869395 Funder: European Union Horizon 2020 programme URL: https://ec.europa.eu/info/research-and-innovation/