You are mainly talking about what is expected to happen outside the area I was talking about.
Besides, anywhere from 30-40% of food produced in the US currently goes to waste so we have a big cushion.
"Wasted: How America Is Losing Up to 40 Percent of Its Food from Farm to Fork to Landfill"
https://www.nrdc.org/resources/wasted-how-america-losing-40-percent-its-food-farm-fork-landfill
We also export about 50% of the soybeans and 55% of the rice grown in this country. Overall, we export about 20% of food produced in this nation.
https://www.fas.usda.gov/data/percentage-us-agricultural-products-exported
I live in Upper Michigan north of Wisconsin and if one drives down most any county road, you'll see many barns and acres and acres of former farmland. So sure, the land is not as fertile as land in Iowa or Nebraska but it could be brought back into production.
The US could suffer a major decrease in overall food production because of climate change but with less waste, a reduction in exports, and bring back former farmland in use, there may well be enough to feed the population.