Washington Post: Last year, a bombshell scientific study suggested a scenario that has long worried scientists was coming to pass: a slowdown in the North Atlantic ocean currents that usually redistribute warm and cold waters, thanks to massive ice melts in Greenland and other Arctic changes. If this is really happening, its a big deal. The circulation, sometimes called the Atlantic meridional overturning circulation or AMOC, transports enormous amounts of warmth northward from lower latitudes. If it slows down,...