If you can get water to the desert. Too much rain in the Corn Belt doesn't necessarily translate into enough rain elsewhere. Besides rain you need a long enough growing season not cut short by hard freezes. A grand solar minimum will bring much colder temps that start earlier and end later than now. During the Maunder Minimum the Thames River in London froze solid. If our grain yields are greatly reduced we won't be able to raise livestock on the same scale we do now. It's not that there won't be any food, just shortages. With a population like ours that will lead to rationing. In exceptionally crowded countries could see mass starvation.The point is that as the weather patterns change, land that is not arable now can and will become arable. As for technology, I was watching a video about infusing desert land with microscopic clay to support mycorrhiza and begin building soil into the sand. Between that and regenerative agriculture we stand a chance at maintaining food production at levels high enough to support our population.
As for energy production, when enough people start having a hard time staying warm, resistance to newer nuclear technology and geothermal will start to drop and we'll have those bases covered. Being too warm isn't enough of a motivator to come up with cheaper and cleaner energy solutions, but being too cold sure will be. If we get that licked, green houses and aquaponic systems may become more viable as well. But that's just me, and I prefer to remain optimistic.