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Comment by bradfa | Hacker News Reader

Doesn’t SO2 in the upper atmosphere help to prevent the sun from warming the Earth as much?

Yes. Some climate scientists believe that the unexpected increase in warming over the last couple of years is an unintended consequence of SO2 reduction.

As climate warming impact from CO2 emissions was limited by SO2 emissions before?

The general quote from NASA climate scientists and others is that the recent years increase in warming is unexpected even after accounting for the reduction in marine fleet SO2 emmissions and the parallel increase in high atmosphere SO2 from a large volcanic eruption.

If they only took marine SO2 reduction in account it could still be because of other places where there was a reduction in SO2 pollution?

SO2 sources are fairly well known, Acid Rain was first extensively studied back in the mid 1960s - https://en.wikipedia.org/wiki/Acid_rain

Marine fuels were the last remaining stronghold of anthropogenic SO2.

The two large scale changes in recent years of atmospheric makeup were the SO2 generation reduduction from marine fuel phase outs and the unuual high altitude water vaper injection from a volcanic eruption.

Atmospheric gas makeup changes are mapped from a number of global sites, and recently mutlispectral orbiting gas sensors have been fine scale mapping sources.

* https://www.carbonbrief.org/analysis-how-low-sulphur-shippin...

* https://research.noaa.gov/hunga-tonga-2022-eruption/

* https://research.csiro.au/acc/capabilities/cape-grim-baselin...

And cause health problems, acid rains and much more. It is not a solution.

With complex systems touching a variable impacts a lot of places, something that may become obvious in hindsight. Undoing how we triggered climate change, that is first drastically reducing emissions and then capturing the excess of greenhouse gases, looks like a less disruptive way to effectively solve the problem.

I mean it kills people so even less air pollution in the long run. [Ok, ok I am too mean.]

It is kinda nihilist statement. But most efficient tool against climate change is population reduction in places that produce most emissions per capita.

My prediction is that at some point in the next 50 years the problems of SO2 will be considered an acceptable tradeoff for the cooling. At least one major world government (or perhaps sufficiently wealthy oligarchs) will begin intentionally pumping SO2 into the atmosphere.

I suppose then we will get to learn about the consequences of global dimming.

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