So, there is a natural carbon cycle, natural nitrogen cycle etc.
On planet earth, the nitrogen cycle of the whole planet is only 50% of what humans need to eat every year. If you don't have artificial fertilizers, tractors, refrigerators etc etc, there is no way people can be fed even if they are everything that nature created.
We are locked into an artificial life support system. Our agriculture system creates more CO2 than all the cars being driven by a factor of 3.
We have no technology that is waiting to fix this. There is no "fix" where lots of people wouldn't die directly.
We DO NOT have sustainable technologies. For humans, we are committed to planetary overshoot if we stay alive, we have been in planetary overshoot for many generations already.
Your list of "solutions" are not real things that make significant change. Sorry. They slow down the worsening but they will not even extend civilization by one extra generation. You have been duped into thinking about this the wrong way.
Cities are giant factories that require the constant cycling of goods (food, water and other materials) using a transportation grid and they also require constant energy inputs to remove waste materials. Our ancestors didn't build cities to permanently live in until they had cheap surplus energy and a way to store it. I have something to warn you about...so your idea about edencity and public transportation is like you almost see how unsustainable cities are, and why.
The idea that wind and solar are infinitely scalable has actually been properly studied in the literature. For example, Mark Jacobson has a fully elucidated picture of what that would look like globally. If I remember correctly, he calls for every river on earth to be dammed for hydro, windmills covering every continent and around 200 solar panels for every living human AND major deductions in energy usage. This is a more highly industrialized future than any previous human project. He did not explore the material or energy costs of building this system. So for instance, on a planet where we cannot feed, build houses and build transport for everyone it's surprising if we can build them all windmills, batteries, wiring, solar panels and power dams. But...you know...we have to dream right? The main headline is that "the possibility is infinite". I actually don't believe that, it seems like all these large scale programs are already failing in many ways. Not that they aren't the best idea we have, they are just not working out.
By the way , we could also eat insects ground into a protein mush instead of actual vegetables.
Those are also technologies, just not high tech.
Here is a question then:
According to the science, the ocean current changes are going to start driving climate change via a doubling of present day CO2. When the permafrost melts it will create as much additional CO2 as all human industry does on a repeating annual basis right now. This is an all natural process where CO2 pollution will snowball faster and faster with no human ability to adjust it.
so, do you think natural processes like growing trees have the potential where they going to erase that much feedback? Keeping in mind that the peat bogs, forests and ocean plankton we have today in a less damaged ecosystem ALREADY failed to curtail a much smaller human created CO2 pulse?
Hmm?
What you're talking about is BECCS, by the way. Believe me or don't, but the UN climate change panel already included this in all the accounting! Like, what the projections for the future say is that we are going to invent these technologies and deploy them and erase the CO2, and that's assumed to be real and already factored into all the future projections...and they are still talking about 8 degrees of warming even including that. Notwithstanding that we have never done this yet and don't know if it works.