[SampleMan]

...you can't put the permafrost back once it's gone. "

Fascinating. If permafrost can't come back, then how was it orignially created???? Obviously these people are closet creationists.

[RightWhale]

If permafrost can't come back, then how was it orignially created????

It can, but it takes at least one cold summer. It also depends on snow cover. If there is no snow cover the cold can get very deep into the soil. Permafrost right here starts near the surface and goes down 20 feet. In some places it is 200 feet deep. The freezing/thawing cycle on naturally vegetated land mainly hits the top couple of feet.

[TheDon]

LOL!