As we have said before, these people will be flash frozen statues in their own lawns before they realize they got it wrong.
That's assuming that they survive to that point without food, since you can kiss that goodbye if the climate continues to cause crop failures at the rate we are seeing now.
This is why I want my permaculture lab to be inside. Outside and fortified isn't good enough for me. I am convinced it may become simply too cold to grow most food topside without a reliable underground heated environment.