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.

But not everyone is sure that President-elect Donald Trump’s talk of annexing Canada and Greenland and reclaiming the Panama Canal is driven by a deeper strategy.

Former Trump national security advisor Robert O'Brien told FNC's "Sunday Morning Futures" why Donald Trump is talking about buying Greenland and seizing back control of the Panama Canal. About the Panama Canal: "We love the Panamanians.