Climate Change, Population Growth, and Population Pressure

We develop a novel method for assessing the effect of constraints im- posed by spatially-fixed natural resources on aggregate economic out- put. We apply it to estimate and compare the projected effects of cli- mate change and population growth over the course of the 21st century, by country and globally. We find that standard population growth pro- jections imply larger reductions in income than even the most extreme widely-adopted climate change scenario (RCP8.5). Climate and popu- lation impacts are correlated across countries: climate change and pop- ulation growth will have their most damaging effects in similar places. Relative to previous work on macro climate impacts, our approach has the advantages of being disciplined by a simple macro growth model that allows for adaptation and of assessing impacts via a large set of climate moments, not just annual average temperature and precipitation. Fur- ther, our estimated effects of climate are by construction independent of country-level factors such as institutions.