[Udik]

I doubt that climate can shift so quickly that humans can't adapt at least their most important cultures. We're very good at this, and very quick, and we don't need to produce food anywhere near where it's consumed.

Although of course the ships that bring immense amounts of food across the globe have been built, and are operated, with fossil fuels. As is our agriculture. Again, increase the cost of the fuel that makes both possible, and people will die.