Scientists have shown that unusual changes in atmospheric jet stream circulation caused the exceptional surface melt of the Greenland Ice Sheet in summer 2012.
via ScienceDaily: Latest Science News http://www.sciencedaily.com/releases/2013/06/130617111255.htm?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+sciencedaily+%28ScienceDaily%3A+Latest+Science+News%29