There is a tiny problem with that hypothesis - there are I think at most 3 potentially viable climate reversal options - DAC, sun shield and aerosol injection in the atmosphere. All 3 options are likely cost through the nose and will require sums and efforts on a global scale. Any single country attempting them on its own, would require to set aside double digit amounts of its GDP for decades, effectively crippling itself economically, while the world passes them by. And all option would require decades, if not centuries of constant work because we don't have any meaningful net negative DAC tech, we don't have any sun shield expertise outside of the JWST and a few small science experiments, and we don't have the required planes to seed atmosphere and neither they are net negative yet. By we I mean both whole globe or any single country.
I saw those too. They look wildly optimistic, on top of being based on a wildly optimistic efficiency of the aerosols themselves, compounding the issue. But even assuming that - I read that multiple tens of megatons of aerosols need to be dispersed each year, on a regular basis. That alone doesn't look like a 2-3 measly billion job. Just a small fleet of 10 old narrowbody jets would cost at least 1 billion per year to operate. And someone need to prepare all that reagents, ship them, construct machinery etc. Then there is a problem that GH gas emissions are constantly rising and old gasses are not removed, so the heating accelerates. What requires 10-20Mt of aerosols today, will require more in a decade, then even even more and more. And as soon as injection stop, we are back to square 1 and heating will resume even harder.
Now that I think about - this is actually a motivation for China to do all that expenses. Establish themselves as a monopoly caretaker of the program, wait out until alternative programs will ramp down due to lowering interest, and then start blackmailing the world to conform to their demands or else they will stop injecting sulfur. That would be an incredible power play :) .
'Termination shock' will be a very real threat, and lets not pretend that injecting sulfides into the atmosphere is going to improve air quality or help the ozone layer. Best option is to rapidly cut emissions, but I think we can already see that we're not going to chose the best option here. Hopefully SAI can give us the time we need to decarbonize, but I'm sick that we're gonna have to geoengineer at all.
Yeah, that too is a huge concern for me. But we do need to start at least something, anything and not a day to soon. The oven is heating up and fiddling with temp regulator between III or II or I won't matter one bit in the end, the oven will heat up to 250 degrees eventually, unless we either stop electricity or actively externally cool it somehow.
Game of chicken. Wait as long as you can because as it starts to get worse for everyone, maybe more and more countries will join in on the efforts.
I don't know if any country has the industrial base to do it yourself, as you say, but if any does, it's almost certainly China just due to manufacturing output and expertise alone. They're, what, 30-35% of the world's output? Set aside 30% of that and they can still feed a lot of exports to other countries - more than anyone else - to bring in money. And nobody else has anything close to the leading-edge hands-on know-how to build all the stuff that would be required. As you mention, there's a lot nobody has yet. So the country best at building cutting-edge hardware is gonna have the head start.
If you're a western pessimist, that whole mega-project could easily unlock even more manufacturing, materials science, etc, progress that could be applied to the rest of their output too, furthering the gap between them and everyone else. (But I guess if they did single-handedly save however many billion people from displacement, and the majority of developed countries from massive crisis/invasion/etc, that's probably the least of our worries!)
It looks like we are in agreement about rough requirements, but estimate consequences differently. That's precisely what I was talking about - even for China powerhouse it would require 30% of GDP (example number, but it's good enough). My point was that 30% of GDP is an incredibly, astonishingly expensive amount of money to be diverged to a completely new activity.
Just to illustrate - NATO countries are currently haggling about spending even 3% on a military out of all things, and military spending is famously popular in most of the countries among people of power, due to all the corruption and jobs and factories and manufacturing and prestige etc. Poland ramping up spending to 4-5% is seen as extremely overspending (it's rational for survival reasons, but economy may not bear that long term). 30% spending on a thing not benefiting rich class in short to mid term is anathema. Not even grandpa Xi with his totalitarian power would manage that.
Also let's not forget that grandpa Xi has this tiny little victorious invasion of the independent Taiwan planned, likely done in a double push together with his puppet Kim against Korea, and simultaneously conducting a total blockade of the South China Sea for a many years. China may even manage that, but that won't be profitable in the slightest, and during the war all that economy engine will stall due to disrupted shipping and sanctions. They just won't have those 30% of GDP to spend on a side.
