By Jackie Flynn Mogensen , Scientific American.  Excerpt: A Wisconsin-sized region of frozen soil is thawing fast, releasing three trillion more gallons of water per year than it did just four decades ago. Thawing permafrost  is among climate science’s worst “positive feedback loops”: As the world warms, permafrost—essentially frozen soil—thaws, releasing fresh water and carbon  into the environment . That release further fuels climate change, driving more warming. (Thawing permafrost has also  raised concerns  about unleashing new pathogens on humanity.) ...And in Alaska, the loop seems to be speeding up....  Full article at https://www.scientificamerican.com/article/the-alaskan-permafrost-is-thawing-heres-why-thats-so-worrying/ .