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by promocha 856 days ago
> Spraying a form of sulfur from a plane is incredibly cheap. A full programme would cost less than $20b per year. That’s much cheaper than carbon removal ($600b per year, to remove just 10% of annual emissions @ $100 / tCO2).

It is 30x higher both in time and cost to capture carbon. At $20B/yr geoengineering the atmosphere can be done for 50+ yrs. In 50yrs, carbon capture would need $30T vs only $1T for spraying sulfur. Carbon capture as a long-term solution doesn't make sense. Also, how much carbon you can capture in 50yrs? At 10% of annual emissions, you can probably reach 30% by the end of 50yrs. Carbon capture is still leaving 70% carbon in the environment. It's a make believe solution build to give us false sense of action for saving climate.

3 comments

Among other downsides, spraying sulphur in the atmosphere doesn't remove any Carbon at all. It just tries to balance one pollutant out with another. I'd rather have the sunshade, honestly.

I'm not a physical scientist, but I'd imagine that the amount of Carbon you can capture is fundamentally proportional to the energy you can use on Carbon Capture. That's why I believe a large expansion of Nuclear Energy would be needed.

Alongside a continued reduction in emissions, this is a practical path forward. Throwing new curveballs at the earth, while not addressing the present level of Carbon, is not.

That's not the point the author is trying to make. What he's saying is, whether you like it or not, it's cheap enough that somebody will do it, either a desperate government or an individual American technocrat.
If I did my back of the envelope math right, direct air capture (DAC) at the currently commercially feasible efficiency, powered by nuclear power could capture annually about as much CO2 as we emit annually if powered by around 2300 large nuclear plants.

It could also be done with roughly a million km^2 worth of solar panels.

I'm curious...do we have the resources to build either that many large nuclear power plants or that many solar panels?

In the United States I strongly suspect that at least one major political party's reaction to sulfur spraying would be to try to increase the production and use of coal and oil.

I suspect that this reaction would not be confined to the US.

We could end up in a situation where greenhouse gas levels in 50-100 years are massively higher than they are now, with heating being held in check by continual sulphur spraying.

It would then only take for something to disrupt the sulphur spraying for a year to have sudden massive warming.

It would make more sense to save sulphur spraying for after we are firmly on the road to zero emissions and have reached the point where it is not economically feasible to revive coal and oil. Then sulphur spraying as a temporary measure to lower temperature until our falling emissions make it unnecessary might be safe.

That won't be easy for them to justify when solar, wind and battery prices are cheaper.
What do sulfur damages to crops cost?
And can we breathe that? At some point it's gonna be noticeable, right?
sulfur is one of those things people can detect in ppm... so yeah maybe

we screwed up the earth so much the only way to keep it livable to is to make it smell like farts