[sethrin]

No, those regions will not become good for agriculture just by being heated. There is no soil there.

In places where the ground is frozen permanently (permafrost), i.e. most places above the Arctic Circle, there is essentially no decomposition, and hence no soil production. You can often estimate the soil depth by looking at the tree height; the tundra supports no trees, and most of the rest of Alaska has pine and spruce that grow to maybe 5 meters.

The other thing to consider is the effect of heating permafrost, which is well-known. Well. To Alaskans anyway. Houses in permafrost zones are built on stilts, because anything that generates heat will turn the ground beneath it into a bog. If you heat Alaska and Siberia, they will turn into an unimaginable morass (and remain so for the indefinite future) and release gigatonnes of CO2 and CH4. That will wipe out any existing human habitation as well.

In short, I cannot imagine the confusion of ideas that would lead you to suggest such a thing.

[kpierre]

most of the siberia is below arctic circle. where i'm from we've got a lot of soil, but not enough heat to have good agriculture.

what kind of the confusion would lead you to suggesting permafrost occupies most of the siberia and north america? however, your point is correct for antarctica i suppose.