Whilst am all for optimism, I am not convinced fossil fuels are the biggest challenge.
See the atmosphere is adiabatic.
This means there is no blanket effect from CO2, nor any other gas.
Either the atmosphere is adiabatic, or there are greenhouse gases, it can't be both. I am more inclined to stick with it being adiabatic

(Edit, following some comments to what I said here — That last sentence is sarcasm, in case anyone is confused, it’s not a physical option to decide negative is positive).

How did the theory of greenhouse gases become so popular despite being obviously not the truth - it makes profit. Lots of business for profit exists now to work on C02 so it can't be bad, it makes profit and gives some folk careers and businesses and jobs, so it's a success, right?
Wrong. With greenhouse gases gone, it has to be something else at the root of the problem, and we won't fix it, not knowing what it is by accident.
To me, applying formal systems Engineering techniques and long experience to this, the most complex systemic problem we ever faced, the global energy problem for seven years and counting, the temperature rise traces to extracted energy, not just fossil fuels but all extracted energy.
Its the constant conversion of everything that was not heat, previously created by nature, to heat, whilst nature tries to do the opposite, it takes sunlight which would have been heat if not used, and converts it to things other than heat. So nature tries to cool, reducing entropy, whilst we are much busier creating heat, ignoring what we really could do, exclusively with solar if we were to go photosynthetic like nature.
More and more evidence, and corroborating systems theory is appearing corroborating this. But more worrying is the realisation we are acting like swarming ants, under an emergent property associated with us, whilst the availability of extracted energy has already peaked, impacting all profit margins, because profit is the energy extracted that we put to use, profit is the energy payload transported by us via the masses, back to the core.
What has to happen next, with nothing changed, is the worker ants are supposed to annihilate one another, when profitability becomes no longer possible.
Notice genocide has already started.
If we never become aware of this, we are unlikely to avoid it, it seems to me.
But if we do become aware of it we could cheat it's dastardly plan, by issuing solar indexed stimulus necessary to keep everyone from annihilating one another, This would be how to put an infusion of energy independently of profit into the places most needing it, stopping the genocide underway.
It would also be how to empower them to move immediately to domestic and community based solar hydrogen, to maximise solar indexed stipend, and to produce valuable fuel product from sunlight, which would further boost their quality of living, by being exchangeable for money paid by aerospace, which will never be battery powered, so will need hydrogen when fossil fuels stop.
The places most likely to be most effective at production of that from solar are the places with the most sun.
So if we want hydrogen for aerospace rather than genocide in the areas we are seeing it starting, we should be showering them already with money printed by equating product already created from solar, like sugar dropped on swarming ants in process of annihilating one another.
Otherwise we are likely to see the genocide propagating all the way back up all affected supply lines, if it is allowed to continue.
And of course the planetary temperature will keep on rising to flashpoint in all forested areas, expanding the desertification to cover all the places we might have thought were safe, because we ourselves might have been doing just fine, earning a crust doing some bullshit business pretending to be fixing the planetary problem, when actually we were fixing nothing, just making it worse, because it was profit that was the problem all along.