Stephen Hadley, President George W. Bush’s national security adviser, warned that climate change will be a major national security threat for the next administration.

“I have not been particularly sensitive to the climate change issue,” he said. “Climate change and a lot of other economic dislocations have put a lot of people out of work, they are on the move and they have no place to go and it means they are recruiting grounds for terrorists and extremists and potential refugee flows that will tax Europe even more.” As an example, he pointed to climate change as a cause of an influx of refugees in Europe.