If populations don’t move, global warming is likely to have disastrous consequences.
44% of the world’s population lives within 150 kilometres of a coastline, so rising sea levels may prove fatal (United Nations 2013).
Millions of people in the tropics may see their livelihoods destroyed by falling crop yields as climate change pushes temperatures above certain thresholds (Intergovernmental Panel on Climate Change 2007).
Faced with this dismal prospect, policy makers have mainly focused on two strategies: mitigation and adaptation. By ‘mitigation’, we mean trying to slow global warming by reducing carbon emissions through efforts such as the Kyoto Protocol. ‘Adaptation’ means trying to reduce the negative impact of the climate change that will occur, through things like protecting low-lying coastal areas or by using air conditioning.
Learning from previous climatic change
In recent research, we argue that the world has seen climate change before, and how it adapted then – when modern adaptive strategies were not available – may provide valuable lessons for the challenges we face today (Desmet and Rossi-Hansberg 2012):
- During the Medieval Warm Period, roughly spanning the 9th to the 14th centuries, the world experienced temperature rises of up to two degrees celsius.
According to Fagan (2008), this “brought bounty to some areas, but to others, prolonged droughts that shook established societies to their foundation”. For example, northern Europeans and Inuits benefited enormously whereas native Americans and other Mesoamerican societies lost out.
Today’s responses to climate change would not have been much help then. There certainly was no possibility of changing the course of temperature increases, and technologies to mitigate their impact were limited. Instead, as Fagan (2008) argues: “the only protection against such disasters was movement”.