Is it true that there is more carbon trapped in the permafrost of the Arctic Region than is currently in our atmosphere. If so, is it substantially so and how much damage could it wreak if it is released?

https://www.quora.com/Is-it-true-that-there-is-more-carbon-trapped-in-the-permafrost-of-the-Arctic-Region-than-is-currently-in-our-atmosphere-If-so-is-it-substantially-so-and-how-much-damage-could-it-wreak-if-it-is-released/answer/TL-Winslow