This planet is made for us, we are made for it. We need a top down approach to limit damage to nature and make sustainability the "GDP" of tomorrow.
I'm ready to say that most us know, instinctively, what the solution needs to be. It's just that we are morally obliged not to even consider it, let alone propose it.
Thanos lacked ambition.
But it does matter regardless, because rewilding in the future is distinctly possible. If we're able to rebuild an acceptable habitat, and we have the genetic information on hand, we can conceivably unextinct a species and reintroduce it. Without the genetic material, this is impossible.
It's similar to the logic of cryostorage, although I would estimate the odds of it working for wild species to be much higher than those for frozen humans, let alone their brains.
In my suggestion, we tranquilize an animal, take a blood sample, and extract marrow from the hip. We then perform a full genome sequence on the blood, and freeze the marrow down, with compounds which vitrify the cells such that they can be revived at any point in the future.
We should do both. But the latter has advantages: the animal stays in the wild, it scales better, and the only ongoing input is a bit of energy to keep the cells cold.
We don't have the technology to print a whole genome from a file, but I expect we will. Stem cell cloning is well understood, and will only get better.
Doing this to as many individuals as possible will preserve genetic diversity. It's insurance, basically.
It's (past) time to start collecting genomes and marrow samples from as many critically endangered species as possible. Unextinction is a difficult problem, but without the necessary material, it's impossible.
Sure, that's going to favor charismatic megafauna. But we like those, it's right in the name. And it's no substitute for building wildlife corridors, managing park lands better, extirpating invasives, and all the rest. But it doesn't draw resources away from those things either.