Climate change and human conflict

There are fears that a lack of resources - particularly water - will fuel social strife. This could amount to local conflicts, or escalate to inter-ethnic or even national wars.

In the UK, a respected military thinktank, the Royal United Services Institute, has issued apocalyptic warnings about the impact of climate change, calling for a 10-fold increase in expenditure on energy research:

"If climate change is not slowed and critical environmental thresholds are exceeded, then it will become a primary driver of conflicts between and within states."

A 2007 report for the United Nations Environment Programme, written by German and Swiss academics, came to similar conclusions. It pointed out that the population of areas such as North Africa and the Eastern Mediterranean are likely to grow by 40 per cent by 2025, while rainfall and agricultural production will fall. Particularly vulnerable are states with unstable political structures, weak economies and large populations.

Meanwhile, David Zhang of the University of Hong Kong has identified links between temperature shifts and conflict, local and global. Following an initial study of wars in Eastern China between 1000 and 1911, a 2007 analysis of 4500 recorded wars between 1400 and 1900 revealed that conflicts coincided with periods around 1450, 1640 and 1820 when temperatures fell significantly.

Conflict was probably driven by hardship resulting from declines in agriculture, rather than the temperature change itself.