A subpolar-focused stratospheric aerosol injection deployment scenario

I'd want there to be a 0% chance of unintended consequences before taking this seriously. And even then when there is no other choice.

The question of whether or not this type of intervention will be necessary comes down to the specifics of various climate tipping points.

There's evidence that we've already crossed a tipping point with regards to methane release (https://www.nature.com/articles/s41467-022-28989-z). The loss of arctic sea ice is another important one, as the albedo of the earth decreases as the reflective ice turns into water.

It seems likely to me that some amount of solar geoengineering will be needed to bridge the gap from now until we achieve a carbon drawdown.

Like volcanos

"Expected" - is the keyword here. No one should (and I belive will) agree for any kind of "geo-climate-engineering experiments" unless our science is actually capable of predicting/simulating exactly what's going to happen. Said understanding of the climate and ability can be proven by let's say consistently successful weather forecasts for 14 days in advance. Then we can talk.

Until then, even seriously considering it is stupidity of the worst kind exemplified by results of smaller attempts to "engineer" things we don't understand fully such as destruction of the Aral Sea and its ecosystem and many others.

"But, but, we _already_ "engineer" our climate by releasing large amounts of greenhouse gases!" say proponents of such ideas. To which I say, those things cannot be compared. During the earth's history there were many significant releases of co2 and methane we can study (from mega volcanoes, to asteroid impacts caused planet wide forest fires). There were times when the earth's atmosphere had 10 times the co2 it has now and it didn't cause a Venus-like runaway greenhouse effect some people are so keen on presenting as an almost certain scenario. The planet managed to reabsorb it.

We can mitigate many effects of climate change that manifests itself as few degrees of warming (including all the more intense weather events) much better than let's say a significant drop in temperature for a decade.

In 50 years we will think about such climate-engineering ideas the same we now think about ideas from 1950s to use nuclear explosions for building canals, and other "soil moving" ideas. Insanity.

We can guess by looking at the SO₂ deposited by volcanic eruptions

> [The 1991 eruption of Mount Pinatubo released] 17 megatons of sulfur dioxide into the atmosphere, causing global cooling by 0.5 °C (0.9 °F) between 1991–1993

> [It] oxidized in the atmosphere to produce a haze of sulfuric acid droplets, which gradually spread throughout the stratosphere over the year following the eruption

https://en.wikipedia.org/wiki/1991_eruption_of_Mount_Pinatub...