The Arctic sea ice shrank this summer to the smallest surface area in human recording.
Joe Romm at Climate Progress has been posting on the implications.
The National Snow & Ice Data Center has multiple images of the changes.
Loss of sea ice is loosening up the spinning top of the world, unraveling the Jet Stream. The Jet Stream now loops further into the mid-latitudes, creating blocking patterns that shape droughts, heat waves and inundations. Jennifer Francis of Rutgers University gave a succinct presentation for scientists about the Arctic and extreme weather in the Northern Hemisphere. Those with sufficient motivation are encouraged to watch.