I was thinking of countries other than Canada, but of course you're right that sheer acreage isn't the problem at the moment. The question is what we're willing to put up with. How inhospitable an environment will people accept in large numbers? Here in the US, for instance, how high will gas prices have to rise until people stop buying SUVs, for example? Some people say $3/gallon, I'm betting on $4.

Interesting tradeoff idea: sure, you can have the immortality formula, but you have to live on Ellesmere Island. Hibernating.