We have no idea if plant life will still exist in a billion years.
We do know that any life that does exist will have evolved to fit to the contemporaneous environment, even though we have no idea what that will be. No comment about plant life today can be meaningful in such unknowns.
If you’re drawing your questions about the future of life on Earth from your religious beliefs, then that’s where you need to be drawing your answers from, too.
I would have to disagree with that statement 100%. Whatever is happening on this earth plan or no plan I believe is happening 100% under the laws of physics. If in fact there was some point where intervention took place I would believe that to be at the time of the big bang or before. I am in no way convinced that there is a long term plan but there are things that make me wonder. Humans will likely be the cause of mass extinctions but evolution will continue, and the complexity of the organisms seems to grow at exponential rates. At that rate in 1 billion years we will be seeing stuff start trek never imagined.
I believe it is a common misunderstanding to believe that evolution has a natural speed. It can take a billion years or a hundred, for a distinct new organism to develop from existing ones. What changes are the circumstances and the opportunities (is there an existing organism available to exploit this new niche?). Time is immaterial, except as it delineates a generation.
I’m placing my bet on house-cats.
Cats IMHO are marvels of evolution. With their combination of speed, agility, stealth, intelligence, adaptability and killer instinct, I don’t believe there are many/any species that could dominate cats pound for pound, nor out-compete them for habitat.
And cats already have impressive numbers: ~220-million owned and ~480-million strays. If humans disappeared and all the house-cats became feral, I believe they would quickly fill many niches and evolve larger and more intelligent as needed, in the wild.
Carboniferous resources may be reconstituted, but what about iron? I think the readily exploited sources have been depleted.
This is so absurd that I don’t even know where to start debunking it. What would make you think such a thing?
Suffice it to say that life absolutely does not need humanity to put carbon back in the atmosphere, and that our doing so will have harmful and possibly catastrophic effects on life on earth.
All of this sequestered carbon that has been collecting for 200 million years or so is not available to build carbon-based life forms. The primary generator of carbon the volcanoes have become much less active and will continue to decrease their activity as time goes on. Carbon levels have been slowly dropping and that trend would have continued until carbon levels became too low. This is not a pattern that you wait until the last minute to jump in and fix. There is a lot we can do with the environment including slowing down the use of fossil fuels that will help to mitigate the effects of higher carbon. Whether humans are here or not the earth will need that carbon and humans have been the only creature so far with the ability and the motivation to harvest it.
If you are talking about carbon theoretically becoming locked up in mineral form a few billion years in the future, humanity isn’t going to stop that. The CO2 would be locked up in carbonate form, unsuitable for extracting energy. We might delay that process by a few thousand years. On the other hand, we’re on the cusp of causing mass extinctions right now in the present.
If all of the humans disappeared, then so would most of the cats. If we die off suddenly, it’s likely that whatever killed us would kill them, too. Even if it didn’t, the vast majority of housecats are completely dependent on us, and don’t have the skills needed to survive on their own. And if we gradually dwindled to nothing, they’d dwindle along with us.
The species we consider pests – rats, cockroaches, pigeons – are the ones most likely to outlast us. They’ve been able to adapt to us and take advantage of our presence, but they can also adapt to other circumstances, including our absence.
I have no doubt it will, even if not on Earth.
Pretty much life on Earth has no more than another 4-5 Billion years or so before we have a little problem with the Sun.
Where does the iron go? I mean we shot a little into space (and meteorites make that up, easy), but the rest is still around in one form or another.
I don’t believe that would be the case. ~480-million stray cats already survive without humans. Assuming the ~220-million owned cats survive whatever kills humans and they can get outside (I believe most would find a way), I think a significant % would adapt easily to a feral life.
As one data point, I submit my cat Benny. I adopted Benny as a kitten and I raised him as a 100% indoor cat. He never got outside…except for one time. I opened the sliding glass door to retrieve a healthy adult bird that had gotten into the lanai. Benny slipped past me, leapt high in the air, swatted the in-flight bird down and had it half-way down his throat by the time I got him a couple seconds later. The bird’s neck was already broken. Cats are incredible predators and domestication hasn’t stifled that instinct very much at all.
And an increased rodent population would benefit cats even more. An easy supply of food.
One thing to bear in mind in your analysis of humans as God’s way of bringing carbon back into the atmosphere is that the bulk of the carbon we are returning to active cycling through the ecosystems was sequestered in unusual circumstances. We won’t necessarily see the same level of geologic carbon sequestration again. And ecosystems weren’t at risk of running out of carbon before the arrival of humans.
Yes, as one data point. I trust your assessment that Benny would do just fine without humans, and I’ve known a number of cats who would do likewise. I didn’t say that all cats were completely dependent on us, just most.
Cats have the same chances of survival without human beings as any equivalent sized carnivore. Not more. There is nothing special about cats, evolutionarily speaking, except that we like them and bring them everywhere we go.
Because many cats have fairly un-manipulated phenotypes (unlike dogs), they have a better chance at feral survival than many other domestic animals. Other good candidates would be horses and cattle, which are adaptable to many climates and large enough to not fall prey to most apex predators (unlike sheep and goats).
Well, up till a couple weeks ago, Benny was our only cat. But, thanks to my animal-loving, though disobedient daughter we now have 5 indoor cats. 
I’m confident that Coconut, PP, Fish and even tubby Snowball would turn into stone-cold killers too, given the opportunity.
I disagree that there is nothing special about cats, evolutionary speaking. They should be regarded as apex predators in their niche. Here’s a few articles that touch on this:
The definition of an apex predator is that it is not prey for other animals. Not true of cats.
Talking about cats, there is a place in South Texas just overrun with feral pigs. The adults have no natural predators but Bobcats over there are as thick as house cats in the city. I am pretty sure they are feasting on the babies.
I said they are apex predators in their niche.
Of course house cats are easily killed by larger predators. But, if you adjust for size, the tables turn. For example, I don’t believe a 150lb wolf would stand a chance against a 150lb house-cat.
Give house-cats time to evolve and they could very well enlarge to a size needed to compete against larger predators, if that’s the niche they need to expand into.
Perhaps they would also evolve to become group hunters as well, to compete against pack-hunting predators. Lions are social group hunters, so the potential is in the feline gene pool.
This could be interesting in the U.S. Coyotes have become urban predators, their primary target is House cats. There would be an immediate war there and only the biggest strongest house cats would survive it. Smarts might help a bit here also. I don’t believe the war would stretch out much more than 2 years at the most.