OTTAWA — Canada's spy service warns that dramatic shifts caused by climate change and the ensuing fractious upheaval around the world could leave Canada vulnerable, imperilling its food and water supplies, energy security and Arctic sovereignty. Global warming will threaten security as countries and other actors seek to either bolster their economic positions or exploit their adversaries' climate change-related weaknesses, says a newly released Canadian Security Intelligence Service analysis. "Climate change will almost certainly heighten competition between nations, contribute to instability, strain capabilities and become the source of international tensions," the CSIS analysis says. The Canadian Press used the Access...