Climate change is widely seen as an existential threat to humanity, a reality well recognized by the recently ratified Paris accord.  It turns out that even the world's coldest regions are quickly and negatively being affected/degraded by our collective greenhouse gas emissions. The Alaska Dispatch has done a wonderful job of documenting the changes being wrought by AGW in both Alaska and Canada's north. This week they have a great column on the disappearance of permafrost in North America's Arctic regions. The retreat of "perma" frost is driving changes in both the hydrology and the chemistry of the Yukon River basin. These changes cannot be overlooked and need to be addressed quickly.

https://www.adn.com/alaska-news/environment/2017/01/14/permafrost-thaw-altering-chemistry-of-yukon-river-signaling-profound-changes-for-entire-basin/