NOAA has released its Arctic Report Card for 2017. It sounds like 2017 was relatively cool, but the longer-term trend is still sharply warmer.
Taken alone, observations made in spring and summer 2017 might encourage a relaxation in the concerns over environmental conditions in the Arctic. However, when taken in context, there are many strong signals that continue to indicate that the Arctic environmental system has reached a ‘new normal’. While modulated by natural variability in regional and seasonal fluctuations, this ‘new normal’ is characterized by Arctic air temperatures that are warming at double the rate of the global temperature increase. Accordingly, there are pronounced decade-long declines in the extent and volume of the sea ice cover, the extent and duration of the winter snow cover, and the mass of the Greenland Ice Sheet and Arctic glaciers. Temperatures are increasing in the surface of the Arctic Ocean, contributing to later formation of the sea ice cover in the autumn. Temperatures are also increasing in the permafrost on the adjacent continents. Arctic paleo-reconstructions, which extend back millions of years, indicate that the magnitude and pace of the 21st century sea-ice decline and surface ocean warming is unprecedented in at least the last 1,500 years and likely much longer.