A monorail would be practical...
Alan B,
I used to cop a lot of opposition on OLO to such claims !

With all due respect Dr. Turnbull, tethering a currency to a "Sustainability Index" might sound sensible, but the devil is in the details. Nobody knows how to calculate a sustainability Index. We've been trying for decades (see Costanza, et al x many times) to determine a monetary value for ecosystems and biological resources. It just ain't very easy to do. And what is a "bioregion?" Just dividing renewable energy by total energy consumed leaves about 95% of the value of Sustainability (water, air, land, food, wildlife, etc.) unaccounted for. That isn't the way to build confidence in a new currency.

Certainly paper money is a social construct, and a very useful one so far. If we all agree that it is useful for what it is intended, then we can all go about our business and produce the goods and services that we all find useful.

I'll admit I don't really follow the details of the other aspects of your paper, but as an environmental guy with some experience looking at ecosystem value and the myriad elements of sustainability, I think the "Sustainability Index" aspect of your plan needs a lot of fleshing out.