In places like Canada and Siberia, a memory of ice ages long past is locked away in the very soil. There, dig about three feet down, and you’ll encounter a layer of frozen earth running from 200 feet to almost a mile deep in some places. It’s like a great glacier secreted away underground and covering about 19 million square kilometers of the Northern Hemisphere. We call this frozen ground permafrost.
An Enormous Pile of Sequestered Carbon
Permafrost generally forms in regions where the mean annual temperature is below zero degrees Celsius. And the presently large expanse of permafrost has formed over the past 2-3 million years in which long, cold ice ages and short, and somewhat warmer interglacial periods have dominated.
(Recent research indicates that up to 120 billion tons of carbon could release from thawing permafrost this Century due to the warming that is now being caused…
View original post 1,040 more words