When you picture the rugged coastlines of Norway, tropical heat probably doesn’t come to mind, but it should. Even in the country’s Arctic reaches, the coast is typically free from ice and snow, and the weather is often more Seattle than Anchorage.

How can that be? Residents can thank the Gulf Stream, an ocean conveyor belt that pushes warm water their way from the tropics.

And Northern Europeans aren’t the only ones who should be thankful, either. Much of Europe and the east coast of