Well put. But of course we cannot and will never know how long the earth will take to recover the level of species diversity it had before humans started our series of major extinction events. After the other great mass extinction events, it took in the range of millions to tens of millions of years for recovery. But humans are messing with life on so many levels, it could take another order of magnitude or so longer which pushes us into the time frame where the expanding sun makes any life on earth impossible.
Remember, human-driven extinctions started at least 100,00 years ago and happened every time humans entered a new ecosystem. Agriculture, starting about 10,000 years ago represented an even fuller war on anything that wasn't a crop or animal domesticated for human use. The age of European colonialism introduced an increasingly lethal form of life-annihilating technologies and ideologies to the globe, culminating with our current rapacious global industrial capitalism.
Along the way, humans brought thousands (at least) of species into areas they never would have entered (or only after many millennia, with time for adjustments by local populations), often with devastating results for local species.
Industrial production of chemicals has introduced tens of thousands of compounds that never would have been produced and that existing species have no way of breaking down or using.
We have unearthed and generated massive quantities of radioactive materials, with much more on the way if start a new round of nuclear plants or get into a nuclear war.
We have undermined the ozone shield that protects life from over-exposure to ultraviolet radation.
We have directly destroyed ecosystems, not only through agriculture, but through building cities, suburbs, paving over living soil with roads and parking lots...setting fires...dumping slag...strip mining...
We have fished most major food fish to depletion probably setting many on a path to extinction.
We have, through fishing, pollution and other means, destroyed most of aquatic life and we're still going at it.
We have created great death zones in the ocean where essentially nothing can live.
We have scattered vast quantities of plastics, including what amounts to nearly a new floating mini-continent of plastic in the Pacific, which actively kills creatures, and as if very slowly breaks down into smaller and smaller indigestible pieces continues to kill smaller and smaller creatures.
We have interrupted migratory patterns and avenues for species to move in responses to the other shocks we give them by creating vast monocultures (modern industrial farms), huge paved areas, highways...
All of these and more created what most biologists by the nineties recognized as the sixth great mass extinction event. But it turns out we were just barely getting started. The effects of global warming are just barely revving up.
A very sudden change in global temperatures by 6+degrees C (a sure thing now, according to more and more researchers) will make it impossible for most species (those that have survived our depredations up to now, that is) to survive in their current habitat, and as noted, we have made it extremely difficult for even mobile species to migrate to new areas. And of course for the many species adapted to mountain habitats, they will keep moving further up the mountain till there's no mountain left.
But CO2 isn't just overheating the planet; it's also acidifying the upper levels of the oceans where the plankton live that create most of our oxygen.
...I could go on, but I've gone too long already and we all know the drill by now. Humans are at war with the living earth, and we are close to a near total victory. At this point, even if we laid down our weapons (stopped extracting fossil fuels...) and our lives (stop having kids and extending life of the dying, or something more dramatic), the processes we have started, especially runaway global warming, would almost surely continue to wipe out most life on earth and existing infrastructure and pollution would continue to kill and to hamper adaption to a rapidly changing world.
As Elizabeth Kolbert pointed out in her recent article in The New Yorker, the asteroid that caused the K-T extinction event (if that was what did it) was basically a really bad afternoon in the history of life on earth. We've been a bad 100,000 years, with the last century being the worst of all.
And yes, it is awe inspiring in its way, I guess.
But don't count on getting by unscathed. When the summer north polar ice cap totally melts in the next few months or years, it will create havoc with the climate at least in the northern hemisphere and with the ocean currents and sea life (though of course companies are salivating at the chance to access yet more fossil fuels and other resources and transport corridors).link