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by TMWNN·6y ago·view on hn ↗
My understanding is that the bulk of the US's arable land (i.e., the Midwest) won't be much affected by climate change. It might move sideways, but it won't turn into desert.

Conversely, Canada is not expected to be a great beneficiary of climate change (except for the Northwest Passage becoming passable), because most of what is not currently used isn't because of temperature, but because it is muskeg.

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> My understanding is that the bulk of the US's arable land (i.e., the Midwest) won't be much affected by climate change. It might move sideways, but it won't turn into desert.

From David Wallace-Wells's "The Uninhabitable Earth":

In 1879 the naturalist John Wesley Powell [..] divined a natural boundary running due North along the 100th meridian. It separated the humid—and therefore cultivatable—natural farmland of what became the Midwest from the arid, spectacular, but less farmable land of the true West. The divide ran through Texas, Oklahoma, Kansas, Nebraska, and the Dakotas, and stretches north into Manitoba, Canada, separating more densely populated communities full of large farms from sparser, open land that was never truly made valuable by agriculture. Since just 1980 that boundary has moved fully 140 miles east, almost to the 98th parallel, drying up hundreds of thousands of square miles of farmland in the process.

Maybe it won't turn into desert exactly but it won't be productive for growing food.

Here is an extensive 2018 study on climate impacts in the Midwest: https://nca2018.globalchange.gov/chapter/21/

There are expected to be agricultural impacts:

> The Midwest is a major producer of a wide range of food and animal feed for national consumption and international trade. Increases in warm-season absolute humidity and precipitation have eroded soils, created favorable conditions for pests and pathogens, and degraded the quality of stored grain. Projected changes in precipitation, coupled with rising extreme temperatures before mid-century, will reduce Midwest agricultural productivity to levels of the 1980s without major technological advances.

I know you're responding to a comment talking about climate refugees ... the HN comments often jump quickly from realistic scenarios to Mad Max.

But even the projected impacts are significant. Other concerns are impacts to the Great Lakes and to extreme heat events. All covered in the link, which is really very good.

I don't know if you live there or keep in touch with people there. The changes in snow and rain patterns since my childhood in the 70s/80s seem noticeable to me -- although I'm open to correction since I haven't looked at the numbers and this kind of change is not covered in the above report. I don't remember rain in February in Kansas, for instance, but it happens now.

I grew up and currently live in Michigan, in around the same areas (within an hour or so of each other) - anecdotally, our winters of late have been odd. The last couple years before 2019-20 saw a great deal of icefall around March, as well as the arctic vortices where we got down to -20 degress F, which were a bit odd but not crazy, but this last winter was very strange in how unbelievably warm it was, and I've never seen it like that.

I realize that Global Warming != Warming Winters because climate is more complex than that, and odd weather has always been a staple of Michigan on account of the Great Lakes, but this just felt unprecedented, and a bit concerning if it continues in this direction.

Canadians are throwing away farmland to build McMansions and freeways at a record pace, so I don't think there's anything sensible to the commenter's line about Canadians "wanting more farmland" (which makes no sense anyways).

Source: I live rural on farmland in greenbelt in Ontario.

It'll be largely underwater. See Hudson Bay? It's going to expand.
Not catastrophically though, and "largely underwater" seems incorrect, especially since the land around Hudson Bay is part of the Canadian shield, with only a thin layer of dirt over rock [1]. Even if all polar ice melted, and the sea rose 70m [2], it looks like Hudson Bay would only increase in area by ~20%: https://www.floodmap.net/?ll=62.144976,-87.451172&z=4&e=70

By contrast, practically all of Florida would be gone with that rise.

[1] https://en.wikipedia.org/wiki/Canadian_Shield

[2] https://www.usgs.gov/faqs/how-would-sea-level-change-if-all-...