Climate change and forced migration: Observations, projections and implications

In 1990, the Intergovernmental Panel on Climate Change (IPCC) noted that the greatest single impact of climate change could be on human migration—with millions of people (the most common estimate is 200 million by 2050) displaced by shoreline erosion, coastal flooding and agricultural degradation. But with so many other social, economic and environmental factors at work, establishing a linear, causative relationship between anthropogenic climate change and forced migration has, to date, been difficult.

Predicting future flows of climate migrants is complex; stymied by a lack of baseline data, distorted by population growth and reliant on the evolution of climate change as well as the quantity of future emissions. Nevertheless the available science, summarized in the latest assessment report of the IPCC, translates into a simple fact: on current predictions the "carrying capacity" of large parts of the world will be compromised by climate change.

This paper was written as a thematic paper for the 2007/2008 Human Development Report of the UNDP, "Fighting Climate Change: Human Solidarity in a Divided World." The paper investigates the differing projections for forced migration over the next 50 years, discusses the problem of prediction and analyzes the development implications of large-scale migration. The paper sets out three broad scenarios, based on differing emissions forecasts, for what we might expect. These range from the best case scenario where serious emissions reductions happen and a "Marshall Plan" for adaptation is put in place, to the "business as usual" scenario, where the large-scale migration foreseen by the most gloomy analysts comes true, or is exceeded.