Global warming is making both places more important to global shipping and trade. To imagine the kind of future a hotter, dryer climate may bring, and the geopolitical challenges it will create, look no farther than two parts of the world that Donald Trump wants America to control: Greenland and the Panama Canal.

Trump's former White House national security advisor made veiled threats against a NATO ally, taking the Greenland issue in a bizarre direction.

Former national security adviser Robert O’Brien said in a Sunday interview that Denmark should let the U.S. “buy” Greenland if it cannot defend the self-governing country, noting the territory

Denmark needs to do more than add dog sleds to defend Greenland, given its icy territory has it “on the front lines of the war against Russia and China,” ex-National Security Adviser Robert O’Brien said Sunday.