Britain's oldest think tank, the Royal United Services Institute, on Wednesday released a report saying climate change could cause global conflicts as large as the two world wars, according to various news reports.

The group's report says climate change could "become a primary driver of conflicts between and within states" as the fight for natural resources intensifies and hundreds of millions are displaced by droughts, floods and famine.

The think tank adds that such conflicts would last for centuries unless the problem is controlled and "slow and inadequate" responses to climate change turn to quick responses.

"We're preparing for a car bomb, not for 9/11," Nick Mabey, author of the report, "Delivering Climate Security: International Security Responses to a Climate Changed World," told the Daily Telegraph.

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Mabey said unless more investments are made in energy research and battling climate change, the world risks being caught completely unprepared if the climate reaches a "tipping point."

"Climate impacts will force us into a radical rethink of how we identify and secure our national interests," the report said.

• Click here for more on this story from the Daily Telegraph, here for the Reuters synopsis and here for the RUSI press release.