Water supply *could* be both elastic and mobile, but efforts to build proper markets around water run into a lot of political opposition, especially in California.

And consider:

Global consumption of wood has plateaued, contributing to a slight decline in the area of production forest since 1990.

Ok, but there are material substitutes for wood too, often energy-intensive ones, (where China has a comparative advantage from plentiful, cheap, and dirty coal) so less impact in one place could mean more in another. It’s like trying to push a snake through a pipe – you push in one side, but then it pops out the other. There are plastics and resins for furniture, fiber-materials for boats, metal and cement and composite polymers for construction, silicon chips and electricity for paper, etc.

Indeed, just on my own block in the last few years, I’ve watched projects that swapped out wood decks for composites, wood siding for vinyl (or something), cedar shake roofing for some kind of synthetic material, etc.

That probably sounds like a nitpick, but how do we make sure these anecdotal examples don’t aggregate into what turns out to be a giant shell game because of these forms of substitution? “A lot of things are ‘decoupling’, but then there’s this one thing over there that didn’t decouple, but that’s an exception.” Well, no, not if that ‘one thing over there’ is the reason everything is decoupling.

So that’s neither less material nor less impact, it’s a fallacy of getting an overall impression by counting by number of categories instead of applying some kind of sensible weighting to those categories.

Also, I’m not sure I buy the “decline in water per capita consumption” story as ‘decoupling’ at all, at least in terms of being caused solely by market forces and shifting consumer preferences. Dryer places continue to use all they can afford to get.

The annual water supply is pretty inelastic (go ask California, or Yemen), and water is very expensive to move, so as population grows in any area facing at the scarcity edge and facing supply constraints, it makes sense that the price would rise (or there would be rationing of some kind) and people would have to use less per capita, while still responding to the incentives of price signals and investing a lot more energy (substitution again!) into pumping a slightly greater amount up and around.