Mentioned in Arctic Rising; increased arable land in northern countries will lead to all sorts of interesting effects:

Corn’s new appeal to Canada’s prairie farmers is based on two things: climate change and price. Growing seasons in the prairie provinces—which border Minnesota, North Dakota, and Montana—have lengthened about two weeks to up to 120 days in the past half-century. The mean annual temperature is likely to climb by as much as 3C (6F) in the region by 2050, according to Canadian researchers.