The impact of climate change on migration has gained both academic and public interest in recent years. Here we employ a meta-analysis approach to synthesize the evidence from 30 country-level studies which estimate the effect of slow and rapid-onset events on migration worldwide. Most studies find that environmental hazards affect migration, although with contextual variation. Migration is primarily internal or to low-and middle-income countries. The strongest relationship is found in studies with a large share of non-OECD countries, particularly from Latin America and the Caribbean and Sub-Saharan Africa, and in studies of middle-income and agriculturally dependent countries. Income and conflict moderate and partly explain the relationship between environmental change and migration. Combining our estimates for differential migration responses with the observed environmental change in these countries during the past decades illustrates how the meta-analytic results can provide useful insights for the identification of potential hotspots of environmental migration.

Public support is fundamental in scaling up actions to limit global warming. Here, we analyze the impact of exposure to climate extremes on environmental concern and Green voting for 29 and 24 European countries, respectively. Combining high-resolution climatological data with regionally aggregated and harmonized Eurobarometer surveys and European Parliamentary electoral data at the subnational level, we find a significant and sizeable effect of temperature anomalies, heat episodes and dry spells on environmental concern and voting. The effect sizes differ substantially and are most pronounced in regions with a cooler Continental or temperate Atlantic climate, and weaker in regions with a warmer Mediterranean climate. The relationships are moderated by regional GDP suggesting that climate change experiences increase public support for climate action but only under favorable economic conditions. The findings have important implications for the current efforts to promote climate protection in line with the Paris Agreement.