Photo by Katie Orlinsky @katieorlinsky | Scientist Sergey Zimov looks out over the Arctic Ocean at a Siberian research station, 70 miles north of his home in Cherskiy, Russia. He uses the metal rod in his hand to quickly test the depth of frozen ground. Zimov is a world-renowned, eccentric permafrost scientist who has spent decades unearthing the mysteries of a warming Arctic. He was the first to figure out that permafrost stores far more carbon than scientists once thought. More recently, he was one of the first scientists to grasp that Arctic permafrost is thawing much faster than expected, releasing carbon gases that could drastically speed up climate change. Learn more online in "The Carbon Threat" for @natgeo (link in my bio @katieorlinsky).