Unchecked Climate Change and Mass Migration

Abstract

With unchecked emissions of pollutants, global warming is projected to increase to 1.50C within 15 years; to 20C within 35 years and 40C by 2100. These projections are central values with a small (<5%) probability that warming by 2100 can exceed 60C with potentially catastrophic impacts on every human being, living and yet unborn. Climate is already changing in perceptible ways through floods, droughts, wildfires, heat waves and sea level rise, displacing communities and catalyzing migration. Climate migration describes the voluntary and forced movement of people within and across habitats due to changes in climate. While estimates vary from 25 million to as many as one billion climate change migrants by 2050, achieving reliable quantitative estimates of future climate migration faces forbidding obstacles due to: 1) a wide range of projected warming due to uncertainties in climate feedbacks; 2) the lack of a settled definition for climate migration; and 3) the causal complexity of migration due to variability in non-environmental factors such as bioregion, culture, economics, politics and individual factors. But waiting for reliable estimates this creates unacceptable ethical risks. Therefore, we advocate a probabilistic approach to climate migration that accounts for both central and low probability warming projections as the only ethical response to the unfolding crisis. We conclude that in the absence of drastic mitigation actions, climate change-induced mass migration can become a major threat during the latter half of this century.