For a couple of years, I adopted a site on the Duwamish Waterway, coming back regularly to monitor and work on that one place. Through this time a small group of volunteers cleared trash, pulled out invasive plants and planted native species. That it’s called “Waterway” rather than simply “River” is a hint about how engineered the setting is. This was where we maintained a little tidal marsh in a cove that almost looked plausibly natural.

In theory, we gave salmon a set of things they needed. For the adults: a calm backwater to rest on their way upstream. For the young: some places to hide from predators on their way to sea, and native plants that draw insects for them to eat. We haven’t seen salmon breed on this river yet. At times the whole exercise feels like the proverbial cargo cult, building a simulacrum of habitat in the hope that one day the salmon will return. No matter what we do here it will still be a tiny refuge among the acres of concrete, the miles of straight lines and the thousands of cars.

Even if we had all the volunteers needed to restore the whole length of riverbank, the sediment would still be loaded with chemicals toxic to fish and humans. If the Superfund cleanup is ever completed, the surrounding industry and roads would continue to seep more pollutants with every rain storm; a continuous slow-motion oil spill. If we solved that, the river would still be too warm and oxygen deficient, because two thirds of the water that used to flow into this channel has been diverted. If all of that were undone, uprooting all the people who now live in the historic channels, lakes and wetlands, only a fraction of the original salmon population could return, because the overfished ocean simply can’t support as many as it used to. And if some magic brought all those fish back they would still be in danger. The climate change locked in by greenhouse gases already emitted will wreak havoc with the whole system all over again.

So why do we bother?

There’s a vast spectrum between concrete hell-hole and pristine idyll, so falling short of perfection is no reason to give up. Complete success is not even a desirable state, given that we’d have to erase ourselves to achieve it. As Sterling put it: “There’s no one so green as the dead”. But to defend our intervention as even a partial success, we have to understand why inaction would be a mistake. The Viridian Principles start with a useful reminder:

It’s perfectly acceptable to supersede some time-honored tool or practice. However, you should take pains to fully comprehend the thing you have rendered obsolescent.

Our ancestors didn’t fully comprehend what they were throwing away when they cut down the trees, paved the land and changed the course of rivers. They had a vision of what they wanted to make, but they either ignored or didn’t understand the cost, and we are left with fewer fish and more floods. There’s no point in being angry with long-dead humans for their lack of foresight, but there’s plenty we can do to improve our situation. Back to the Viridian Principles:

A 21st century avant-garde must deal with those consequences and thrive in that world. We have already painted flowers. We want to know what a flower means when a flower has onboard processing, amped- up genetics, and its own agenda. Thus a central Viridian aesthetic dictum: “A Rose is No Longer a Rose.”

The flower will have to speak for itself, but we humans have our own agenda. Many of us do habitat restoration to improve our own living conditions and those of other people around us. Sometimes we even succeed. Here are some questions to clarify when a restoration project was worth the time and effort:

Does it create or enhance a place of refuge? You don’t have to dislike the city to appreciate its quiet, green spaces — just look at the popularity of Central Park with proud New Yorkers. Urban habitat restoration is much harder work than locking up remote reserves and keeping people out, but it’s worthwhile precisely because it makes better spaces that people can use.

Does it give humans a more hospitable habitat? The benefits of restoring a site often extend far beyond that site itself. Tear up some concrete to expose old soil and the people living downstream of you get less flooding and cleaner water. Plant a barren strip of ground and the people downhill are less likely to suffer landslides. Bring back native pollinators and your neighbours’ gardens will also thrive.

Will it leave us with more resources? In between Edenic idylls and dark satanic mills lies a range of futures. We restore what we can because each step leaves us with some more fish to eat, not because we expect to get all of them back.

Is it resilient? Often the work of habitat restoration is to take a monoculture—whether a field or a neglected corner overrun with blackberries—and replace it with a diverse mixture of plants. This doesn’t have to be driven by a blind faith in the “natural”. Experience has shown that these mixtures do better in the face of predators, disease and environmental disturbance. Climate change, which promises some degree of disturbance to every place on Earth, makes this more important.

Simplest of all: is it beautiful? Big engineering projects can be quite beautifuland natural systems thoroughly ugly, but our civilisation is full of ugly, neglected fringes of industrial sites. Making ugly sites beautiful has a value in itself.

If we understand habitat restoration as an effort to undo history, it is always doomed to fail because humans have changed our world so dramatically. If we view restoration as an effort to make the world better for ourselves in particular, well-understood ways, then much has been achieved, and there’s plenty to keep working for.