Stephen Hadley, a former national security adviser to President George W. Bush said that climate change has resulted in massive refugee flows that have threatened European unity and in turn will pose a massive national security issue for the incoming administration, Politico reported.

"I have not been particularly sensitive to the climate change issue," Hadley said at a Politico-sponsored event on Wednesday.

However, he added, "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."