Mike, I am normally with you completely in all your conclusions, but this one, that we might need to carry out "Climate Engineering", would be probably the biggest mistake we could ever make as a species, maybe even worse than nuclear war.
I've done some stories trying to explain the dangers, firstly the effect on nature would be to scarcify the energy it needs and uses to survive. We already artificially scarcify energy to all humans by treating energy as a form of capital, when it isn't capital, it is something that dissolves capital, and our continued treatment of it as capital denies all humans the ability to live from the sun using established technology.
The currency of nature is energy. The "income" of all living things in nature except us humans is energy.
This is the fundamental difference between us and all of nature, and the thing that nature has right, and that we have so wrong.
We get paid in pounds dollars, euros, yen, sheckels, all representing fixed amounts of labor or energy, or goods, all kinds of capital.
Nature gets paid in raw energy, an unlimited, unconditional supply of it, which all comes from the sun.
Cutting that income in any way would have massive impact to nature.
We would be massively punished for trying to impose energy austerity on nature.
Above is maybe the less technical, more spiritual, moral way of looking at it, the view of nature as god.
We can get more technical by considering the effects on orbital dynamics, which plants actually have a hand in.
Foliage has to absorb more photons in the mornings when foliage is hungry for new photons, than in the evenings when it has been saturated with photons.
So in the mornings more photons are being absorbed than in the evenings.
In terms of reflectivity, the side of the planet turning away from the sun has to have higher reflectivity than the side approaching, therefore there is an imbalance in solar pressure from one side of the planet to the other, forming a motor effect, which happens to be in the same rotational direction as the planet is turning in.
It follows that reduction of this motor effect, by removal of foliage (or by artificially increasing the reflectivity of Earth), will manifest as reduction in the rotational speed of Earth. Sure enough, we see leap seconds indeed already need to be inserted in nuclear clocks, to adjust for the slowing of Earth rotation.
Conventional science puts that slowing down to friction between moon and Earth, but if this was the real reason, then the slowing down would be seen between moon and Earth, not between sun and Earth.
Therefore conventional science, invested as it is in existing intellectual property (another form of capital), does not correctly value the effect of the sun, nor take much account of the solar pressure on Earth, which should not be underestimated, because this is a vital component of the triad of forces at work maintaining the very delicate equilibrium of the orbit of Earth.
If we increase any one of these three forces, without correspondingly adjusting the others as needed to maintain equilibrium, then we break the orbital equilibrium of Earth, and we go out of orbit.
The orbit of Earth, or any planet is like the Earth being perfectly balanced on a tightrope. Any push, even a tiny one, is likely to push it off.
Sure enough, we see wandering dark planets in space using the latest space telescopes. (The implications of those indicating intelligent life is huge, pulling in even Annunaki folklore).
GeoEngineering, or climate Engineering, to reduce the heat on Earth would have to increase the reflectivity of Earth by definition, therefore increasing the solar pressure on Earth, therefore pushing it out of equilibrium, therefore out of orbit.
On timescales, only a few years, as many times as Earth might rotate around Earth, whilst falling off of the tightrope of its orbit.
Also, tipping it could not be undone. There would be no way we can reverse the effect started by just one application of Geo-Engineering.
Essentially, what we need to change, as a species, to align with nature, is our mistaken belief and limited understanding that money makes the world go round, when actually it isn't, it is energy, the energy of the sun, which mustn't be interfered with, because this is the real currency of nature.
A good start would be by the issue of Kardashev Money, which would be us bringing human money into alignment with energy, the currency of nature, making money function like the nutrients in a plant, conducting energy within the plant, in response to the photons received by its leaves.
This looks to me like the only way to rescue the value in money, which looks to be devaluing due to becoming increasingly moving away from repesenting the real thing of value, the energy now being received and put to economic use by many households, businesses, and communities, outside the traditional energy utilities companies.
Money which can only represent energy by extraction (money issued only as debt) has to devalue to zero, in the presence of the transition to the donated energy of the sun, as we have to, unless it is allowed to represent honestly the value of that energy being received, and the only way it can do that, is to be issued for free as stimulus to all people.
We know this can be done, and we saw the effects on environment when 4th per month was issued in the US, oil prices went negative, fish and coral stocks made a brief rally of recovery, and the dollar itself went up in markets.
As to what this does for nature, it removes our load from it, and we might realise our species looks very similar to the action of any baby being born, it removes the dependence it has on its mother for its energy in its infancy, and moves onto being sustained by the energy of its environment, even paying back the energy deficit owed to its mother in kind, throughout its adult life.
Right now, we could be being born as a species into adulthood, and there is every indication that after doing so, we will repay Earth in kind, for the energy we've taken from it.
Or we could be suffocating our mother of the energy she needs during our birth, as we would be with GeoEngineering.
My response to you is already crazy long and I've only just scratched the surface of all the reasons we need to go to Kardashev Money with no further delay.
But I hope it might help see why GeoEngineering would be like the opposite, having exactly the opposite effect, disempowering nature, and us, sentencing our planet to a fate pretty close to hell I think, with more certainty than even nuclear armageddon.