Indicators of 21st century socioclimatic exposure.

Policies that attempt to curb greenhouse gas emissions, allocate emissions rights, or distribute compensation to those most damaged by climate change must explicitly incorporate the international heterogeneity of the climate change threat. To capture the distinct susceptibilities associated with lack of infrastructure, potential property loss, and gross human exposure, we develop an integration of climate change projections and poverty, wealth, and population metrics. Our analysis shows that most nations of the world are threatened by the interaction of regional climatic changes with one or more relevant socioeconomic factors. Nations that have the highest levels of poverty, wealth, and population face greater relative exposure in those dimensions. However, for each of those socioeconomic indicators, spatial heterogeneity in projected climate change determines the overall international pattern of socioclimatic exposure. Our synthesis provides a critical missing piece to the climate change debate and should facilitate the formulation of climate policies that account for international variations in the threat of climate change across a range of socioeconomic dimensions.