Climate change poses a threat to peace in countries around the world in the coming decade, according to an annual peace index released on Wednesday that factored in the risk from global warming for the first time.

Nearly a billion people live in areas at high risk from global warming and about 40 percent of them are in countries already struggling with conflict, said the Australia-based Institute for Economics and Peace (IEP).

Climate change causes conflict due to competition over diminishing resources and may also threaten livelihoods and force mass migration, it said.