A collage of melting sea ice in the Kane Basin between Greenland and Canada’s Ellesmere Island. As extraordinarily warm temperatures continue in the Arctic — temperatures tens of degrees Fahrenheit above normal for this time of year in some locations — Arctic sea ice, a key indicator of the overall state of this system, seems to be responding in kind. It is kind of unbelievable: On Nov. 19, the extent of Arctic sea ice was nearly 1 million square kilometers lower (8.633 million vs 9.504 million) than it was on that date during the prior record low year of 2012, according to data from the National Snow and Ice Data Center. On Nov. 20, the gap widened further, with 8.625 million square kilometers in 2016 versus 9.632 million in 2012. This is happening in a time of year […]