The EU analysis of the security threats posed by global warming predicts social unrest as an influx of immigration sweeps "destination" Europe, following failing harvests and environmental conflicts in the world's poorest countries.

"There will be millions of 'environmental' migrants by 2020, with climate change as one of the major drivers of this phenomenon," states the report.

"Such migration may increase conflicts in transit and destination areas. Europe must expect substantially increased migratory pressure."

The stark report, written by Javier Solana, the EU foreign policy chief, and Benita Ferrero-Waldner, the Commissioner for External Relations, forecasts the rise of vicious new conflicts following the impact of climate change.

"The inability of a government to meet the needs of its population as a whole or to provide protection in the face of climate change-induced hardship could trigger frustration, lead to tensions between ethnic and religious groups within countries and to political radicalisation."

"This could destabilise countries and even entire regions," says the report.