Climate change is a “threat multiplier”, said 11 retired three- and four-star U.S. generals and admirals who make up a military advisory board put together by the non-profit CNA Corporation. They warned Monday that many Asian, African and Middle Eastern nations could fail, opening the door for terrorists and drawing the U.S. into a variety of new conflicts.

“Great instability comes with climate change and that could be a big problem for us,” said Lt. Gen. Lawrence P. Farrell Jr. (Ret.), former deputy chief of staff for plans and programmes at the U.S. Air Force Headquarters.

Farrell pointed out that four billion people live within 45 miles of the world’s coastlines, and even a small sea level rise could have a huge impact on hundreds of millions of people.

Forty percent of the world’s population derives at least half their drinking water from snow melt from mountain glaciers — many of which will disappear in the decades ahead, said the report, “National Security and the Threat of Climate Change”.

The ice and snow sheet of the Himalayas is the third largest after Antarctica and Greenland. Continued melting means that parts of India and Bangladesh will experience more floods, while China and much of Southeast Asia will suffer water shortages, said Farrell at a press conference Monday.

The U.S. military takes a pragmatic view and “wants to reduce the potential for conflict and its own dependence on fossil fuels,” he said.

However, increased conflict is unavoidable in the view of the British-based charity Christian Aid.