An Inconvenient Truth

Deglaciation does not actually leave us with more land available for farming as the glacier scours out most if not all of the soil leaving the bare rock. As far as Canada and Alaska is concerned, much of Canada is made up of the Canadian shield, which is mostly unsuitable for highly intensive farming. Canadian Shield Much of the southern portion is made up of forests which would need to be harvested and the soil turned to agriculture, reducing the CO2 sink even further and I don't believe the soil is rich there either.The Same could be said for Norway, Sweden and Finland. There isn't much land available.I also have to wonder what the growing season would look like, with the upper latitudes not getting a lot of sun during winter.

Sure, we could easily add a ton of problems to be overcome. Much of what you bring up though, is a social or political problem area, which would be moot if there isn't the land available. I thought Holmes was speaking more directly of the geological availability of land as global warming occurs.