Not my theory - I thought I was clear I was clarifying the interpretation of the theory in the article.
If you bought shore-front property, it might not be a great investment. You'd have to have bought property currently under water to make a killing of an incipient ice age, as the current shore front property will end up 50 miles inland. I understand there used to be quite a market in Florida for such property. You've still got time to trade up.
Tropical beachfront is the way to go in an ice age. You could end up with miles of property as the shore recedes.