Almost continuous warm, moist air invasions of the Arctic during fall and winter of 2016 and 2017 have resulted in the lowest sea ice refreeze rates on record. As a result, the amount of ice covering sections of the Northern Hemisphere ocean is now remarkably lower than during past comparable periods. In other words, we’ve never seen a winter in which Northern Hemisphere sea ice was so weak and reduced.

One key measure, sea ice volume, has shown particular losses when compared to past years. And even taking into account a long term trend of ice losses for the northern polar region that has been ongoing since the 20th Century, the 2016-2017 losses stand out like a flashing red indicator light. A trend directly related to the human-forced warming of our world through fossil fuel burning and related greenhouse gas emissions.

(Significant sea ice losses during the winter of 2016-2017…