We have historical evidence of the solar cycles that produces minimums and periods of cold. The young lady has a hypothesis for how those cycles occur and a model that is prescriptive for an approaching period of cold that many of us will live to experience first hand. If she is correct, we face a coming period of famine when we can't produce sufficient food for the present population. The major Chinese dynasties have all failed coincident with such minimima.
Longer growing seasons allow crop varieties with about one-quarter more yield per acre. The shorter season stocks will still grow with short seasons and a lower growing degree day count.