Climate Change and National Security

Decades of scientific measurements from multiple, independent lines of evidence have established an unequivocal warming trend in the Earth’s climate. Rising temperatures in turn drives changes in a large number of Earth system processes in the atmosphere, ocean, freshwater, soil, ice masses, permafrost, and biosphere. Acidifying waters likewise drive a number of changes in the ocean. Through individual and compound action, climate-linked events are disruptive when they harm people directly or substantially undermine the systems that support people. Security outcomes include degradation of human security, political instability, social discohesion, heightened tensions over natural resources, uptick in humanitarian crises, increased human migration, adverse effects on militaries, new geostrategic domains, threats to global institutions, and heightened risk of climate-linked surprises