Prime farmland is land with the growing season, moisture supply, and soil quality needed to sustain high yields. Image credit:USDA, via Heinz Center
People who've never been to a wilderness area treasure the idea that they one day could. (This explains broad public support for Federal and State wilderness protections.) City dwellers think if they can learn how grow a tomato in a bucket they could live off the land - if needed. A person 'texting' while driving believes he'll never get in an accident, 'unlike those other dummies.' Here's the climate adaptation corollary : 'If it gets really bad, we'll move to upstate New York or to Saskatchewan or something and farmers farther north will grow more food for the nation.' Wrong.Aside from the fact that the fantasy neighbors may not welcome a stream of climate refugees - absence of an NRA sticker on the front door does not, by the way, mean soup's on, come on in - such thinking is dangerously delusional.
The best land for raising cash crops in North America is already in production and that land could be vulnerable to flooding or drought. Looking out your airplane window and seeing all that seemingly vacant land between the coasts bears no evidence whatsoever on agricultural potential. There are no extra millions of green acres (that there might be, is the New Garden of Eden Myth).
In the US South, extended, severe drought has taken the upper hand over many farms. For details on what this may mean, see: Will Climate Again Drive US Internal Migrations? I also strongly recommend West Palm Beach Florida Has Just A Few Week's Worth of Water Left...Gulp
It's true there are good soils in the Great White North. But, the total combined acreage of such soils is small and the suitability for corn and soy is very limited. Take, for example, the New York State Soil, which is called Honeye Soil. There are only about 500,000 acres of it in the entire state - the best they have.
Honeoye soils are used for corn, soybeans, wheat, oats, vegetables, alfalfa, grass pasture and hay, and grape and apple orchards. Woodlots contain sugar maple, white ash, red and white oak, hickory, and associated species. These productive soils occur on about 500,000 acres in New York
Michigan's State Soil is mainly good for stumps, taters, and strawberries. That's why they make cars!
Kalkaska soils formed in sandy deposits left by the glaciers that once covered Michigan. These soils are used primarily for hardwood timber, namely sugar maple and yellow birch. Some areas are used for the production of Christmas trees or for specialty crops, such as potatoes and strawberries
The State of Washington has more than 1,000,000 acres of 'Tokul soils.' These State Soils are on the western side of the Cascade Mountains along the Puget Trough, from south of Seattle north to the Canadian border.
Keep in mind, the growing season along much of the northern border of the US, regardless of how good the State Soil happens to be, is relatively short compared to the former mesic prairie acres of Southern Minnesota, Iowa and Illinois, for example. These are the acreages that beat all others in productivity. If they are lost to climate change, we are in deep crap.
Also good to remember: the farmers in Saskatchewan are up on the hockey stick and know how to use it.
Don't assume that Southern farms lost to extreme drought will be replaced in the northerly states with similar cropping systems and that the replacement acres will reach comparable levels of productivity in time to save our obese asterisks.
Northern soils and cropping practices are very different than in the South; and, while the climate is in long-term transition there is no assurance that first and last frost dates in the north will be predictable and steady. No climate model has enough resolution to put a risk number on this issue. So ask yourself, do you feel lucky?
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