Researchers at the University of California, Berkley and New York and Stanford universities combined historical data on the incidence of civil war in sub-Saharan Africa with rainfall and temperature records. Their results showed that between 1980 and 2002, the incidence of civil war was significantly higher in warmer than average years. A 1°C rise in temperature increased the likelihood of conflict by 4.5 per cent in that year, and a 0.9 per cent increase in the following year. When the analysis was restricted to countries with a history of conflict, the 1°C rise in temperatures led to a 49 per cent increase in civil violence.

Using climate predictions from 20 global climate models, they then projected their results forward to 2030. The results of this analysis suggested that the incidence of civil war could increase by around 55 per cent.

‘Given the strong historical relationship between temperature rise and conflict, the expected future rise in temperature is enough to cause big increases in the likelihood of conflict,’ said David Lebell, of Stanford University, one of the study’s co-authors.

February 2010