The Unassuming Economist

From a VoxEU post by Giovanni Peri, and Akira Sasahara:

“Though the economic consequences of climate change will be felt across the globe, not all populations will be affected equally. This column examines the impact of rising temperatures on migrant communities. Using historical data from three decades (1970-2000), it finds that higher temperatures increased the number of rural-to-urban migrations in middle-income countries while decreasing rural-to-urban migrations in poor countries. The prospect of climate change leaving large rural populations trapped in poverty adds urgency to the case for addressing the asymmetric effects of global warming. 

The annual average temperature is projected to increase by up to 4° Celsius in the coming century (World Bank, 2018). Rising temperatures have been shown to influence various aspects of our economies, including GDP growth (Dell et al. 2012), local conflicts (Bosetti et al. 2018), mortality (Burgess et al. 2014), and agricultural and non-agricultural productions (Burke et al. 2015, Garcia-Verdu et al. 2019). Given the economic effects of weather shocks, we can expect the rise in temperatures to significantly affect migration patterns. The goal of this column is to provide new insight on expected migration responses to climate change by exploiting historical variations in temperatures and migrations.

Net migration rates at the grid cell level

We employ grid cell level data at the 0.5 x 0.5 degree resolution, where one grid cell covers the area of 56 km x 56 km at the equator for three decades: 1970-1980, 1980-1990, and 1990-2000. Decennial net migrations (the number of in-migrants minus the number of out-migrants) come from de Sherbinin et al. (2015) and population data are obtained from Yamagata and Murakami (2015). We define net migration rates by dividing net migration during the decade by the population at the beginning of the decade. Figure 1 shows a map of Europe describing net migrations during the 1990s. Red-coloured cells indicate positive net migration rates (meaning that in-migrations were greater than out-migrations) while blue cells indicate negative net migration rates.”

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