http://wapo.st/1N1hzaDAnd now this week brings news of another potential mega-scale perturbation. According to a new study just out in Nature Climate Change by Stefan Rahmstorf of the Potsdam Institute for Climate Impact Research and a group of co-authors, we’re now seeing a slowdown of the great ocean circulation that, among other planetary roles, helps to partly drive the Gulf Stream off the U.S. east coast. The consequences could be dire – including significant extra sea level rise for coastal cities like New York and Boston.