In the Arctic, changes have been driven largely by manmade climate change, CO2 and methane emmisions. Sea ice has thinned and shrunk and the Greenland ice sheet has lost ice, fueling Arctic warming to reinforce itself, which has sent temperatures there rising twice as fast. the Greenland Ice Sheet had the second earliest onset of the spring melt season on record, according to the annual Arctic Report Card released on Tuesday by the National Oceanic and Atmospheric Administration. These changes have had considerable impacts on Arctic ecosystems and native communities, as well as opening up the fragile region to more commercial activity. The Arctic has continued to warm at twice the rate of the planet as a whole, and 2016 reinforced that trend. The annual average temperature (from October 2015 to September 2016) was 3.5° Fahrenheit (2°Celsius) above the 1981-2010 average, the highest in records that go back to 1900. Since that time, the Arctic has warmed 6.3° Fahrenheit (3.5° Celsius). The decrease in area covered by sea ice means that there is less sunlight being reflected back by that sea ice and more being absorbed by dark, newly exposed ocean waters, driving the amplified warming in the Arctic.
http://www.livescience.com/57206-arctic-report-card-grim-evaluation.html
http://www.livescience.com/57206-arctic-report-card-grim-evaluation.html