Neg metrics are flawed---they ignore recycling and substitution.

It worth mentioning, though, that degrowthers aren’t just calling for unworkable solutions; they’re also incredibly sloppy in their predictions. For example, degrowthers regularly base their assessments of unsustainable resource use on aggregate measures of material usage. Here’s a typical example:

The British intellectual Jason Hickel also uses aggregate measures of resource use by gross tonnage to support his own jeremiads against growth.

This is a terrible metric, for several reasons. First, it includes materials that are recycled or sustainable (e.g. commercial forests, or farming itself). If resources shift to a more sustainable form — for example, the massive switch from fishing to fish farming — that won’t be recorded in these numbers.

Second, it ignores one of the most important sources of sustainability: resource substitution. When humans figure out how to substitute a commonly available resource for a scarce one, sustainability increases even if the gross tonnage used also increases. For example, if we use widely available magnesium instead of scarce lithium for our batteries, that increases sustainability even if tonnage doesn’t change. Humans are always looking for ways to substitute plentiful resources for scarce ones, and we often find them.

But no matter what metric they use, degrowthers always make the same fundamental mistake, and it’s the same one Paul Ehrlich made: trend extrapolation. The tweet above is just classic “line go up” thinking. And degrowthers treat the past correlation of economic growth and resource use as if it’s a law of the Universe, when there’s no reason to believe that correlation will continue. For example, many countries have managed to decouple their carbon emissions from their GDP growth:

When confronted with this blunt fact, the degrowthers, who have long claimed that this sort of absolute decoupling is impossible, will respond that all that matters is global emissions (which is true), and that although global GDP has grown much faster than emissions since 1990, the fact that global emissions are still up slightly since that time means these have not yet decoupled in an absolute sense.

This is, of course, nonsense. Absolute decoupling in countries like Mexico, Singapore, Germany and the U.S. shows that absolute decoupling is possible in every country; most countries consume just about as much carbon as they produce, which is why outsourcing of emissions basically doesn’t happen. There’s no reason that China, India, and the rest of the world can’t decouple as well, and with them, the world. Of course, it will take several years — perhaps a decade — to demonstrate global absolute decoupling, by which time our age of unrest will likely be behind us and degrowth will have faded just as surely as the population panic of the 70s.