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Comment by sebmellen | Hacker News Reader

The immediate cure for heatstroke is LITERALLY an "arctic dive" in the form of immersion in an ice bath https://www.mayoclinic.org/diseases-conditions/heat-stroke/d....

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I didn't say ice bath, I said freedive, precisely for the reason that one is much more easily reversible than the other once you reach a sustainable temperature. If it was as easy to remove SO2 from the atmosphere as it would be to step out of an ice bath, then I would have said ice bath.

I think doing a small amount of aerosol injection right now is an appropriate way to confirm that we understand how they work/what the effects will be. I hope that the work this company is doing is being adequately studied.

Yes, SO2 falls out of the atmosphere after about one year. We already have proof of this in the form of volcanic eruptions: https://en.wikipedia.org/wiki/Stratospheric_aerosol_injectio....

SO2 is a short-term, fast-acting, and reversible cooling option. That is why we need to massively adopt it ASAP.

Conveniently in such conversations people never bring up where these compounds go when they "fall out". In fact they precipitate or are deposited on surfaces in the form of sulfuric acid. This harms plants and causes all manner of respiratory issues. There's a reason the EPA has fought so hard to reduce SO2 emissions.

I get the impulse for unilateral techno-optimist solutions but continually releasing sulfur dioxide into the air is not a sustainable option in any respect. Sustainability and "more, faster" ideologies are not compatible. You will be imposing health risks on plants and animals that many simply will not be able to mitigate for themselves. It is always apparent very quickly in conversations like this that the people proposing such "solutions" spend most of their time indoors in filtered air.

As a co-founder of Make Sunsets, I'd like to clarify the role of SO2 in climate control. SO2 is considered "easily removable" because, when combined with water, it forms sulfuric acid and precipitates out. This mechanism partially explains why 2023 was the hottest year on record; the EPA's stringent regulations on SOx emissions have significantly reduced the aerosols in our troposphere, removing critical reflective materials.

The impact of SO2, including its effectiveness and atmospheric residence time, varies based on its deployment location (latitude, longitude, altitude), concentration, and particle size.

For instance, the International Maritime Organization (IMO) 2020 regulations have reduced SO2 emissions from cargo ships in the troposphere, leading to decreased respiratory illnesses near ports and less acid rain. However, this reduction in SO2 has also warmed ocean shipping lanes, prompting discussions about reintroducing sulfur into the troposphere. [1]

Deploying SO2 in the stratosphere, above most of the atmospheric water vapor and where winds reach speeds of 200kph, allows it to spread globally and remain airborne longer (1 to 3 years). This higher placement necessitates less frequent applications for the desired reflective effect. The 1991 eruption of Mt. Pinatubo demonstrated this, injecting 20 million tons of SO2 into the stratosphere [2], cooling the Earth by 0.5°C and, according to some models, temporarily reversing decades of warming.

Stratospheric aerosol injection (SAI) is likened to Earth's sunscreen, [3] a temporary measure to reflect the Sun's energy and mitigate warming while we address the larger challenge of removing over a trillion tons of greenhouse gases emitted since the 1850s and transitioning away from fossil fuels.

Climate change demands immediate action, and SAI offers us the critical time needed to live in a world with fewer catastrophic climate events.

[1] https://docs.google.com/document/d/1vGEDuEn6uikvGZpR9oZplPPh...

[2] For reference, estimates suggest that global SO2 emissions were around 131 million tons in 1970 and continued to rise, peaking at approximately 150 million tons by the late 1980s in the troposphere.

[3] https://twitter.com/MakeSunsets/status/1741336520366444822

It is absolutely unbelievable that we now just dump SO2 in the ocean...

Pinatubo had effects on ozone too and not good ones, just like the recent Australian wildfires.

> Dr. David W. Fahey, Director of the National Oceanic and Atmospheric Administration’s Chemical Sciences Laboratory revealed that studies show sulfur aerosols from stratospheric aerosol injection could impact the ozone layer, but not catastrophically. The 1991 Mount Pinatubo volcanic eruption demonstrated the ozone layer's resilience after temporarily cooling the planet by 0.5°C. Despite uncertainties, these findings suggest geoengineering methods like SAI could be explored without causing irreversible damage to the ozone layer.

Source: https://www.nytimes.com/2023/01/09/climate/ozone-hole-restor...

Thanks for the link. I was going off some Susan Solomon papers about Australian wildfires citing Pinatubo.

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