The world at the end of this century won't look the same as it does today. It will be hotter and drier, with far less available space in which to grow food -- and the crop that will be doing the best in the US under that new system won't be a food crop at all. The USDA put out this chart detailing which crops Americans can expect to rise and fall in the next 65 years. I'd previously covered a USDA projection that wheat will unseat corn as the fastest growing of America's staple crops by 2080. By 2060, however, hay will be growing even faster, and by 2080 it will have completely overshadowed the growth of all other food crops combined.
Hay is not a food for people at all, but for livestock. Essentially, it's food once removed. We could feed more cattle with that extra hay, but they will also need more water and more space, both of which will be in short supply.
In other words, it's hard to think of a worse crop for the needs of a growing future population. It highlights one of the big problems with farming in a changing climate. Some crops will do better in the hotter, drier climate than others, but we can't choose which crops those will be -- and, although there will be losses and gains on both sides, they will by no means be equal.
Top image: Satellite view of farms in Brazil / Terry Virts, NASA Johnson
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