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Comment by Koffiepoeder | Hacker News Reader

Makes me think of the last time we shot metals through our exhausts. Do we really know all the consequences of algae growth and iron particle rain this time around? Or are we going to have a leaded gasoline, chapter 2?

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I feel like this is a logical fallacy. Do we know all the consequences of trying to solve other problems? Of course not. Imagine if we stopped trying to solve any problem due to a “precautionary principle.”

Very valid point. I think for me an important distinction here is the problem size and complexity. The larger your problem, the more certainty you need that your solution works. This is also why we write thousands of tests for large software projects, while just a couple might suffice for a hobby project.

Does this mean that we should not explore new science and innovative solutions? Certainly not.

But before you start engaging in macro-ecological interventions, you better be damn sure that what you are doing is safe, now and tomorrow, both in first, second and nth order effects.

Agree! If the only way to test these technologies was at a massive scale, I’d be worried. But they can all be tested at a small scale. That’s the other logical fallacy: e.g., just because the intention is large scale deployment doesn’t mean the testing requires large scale deployment.

So, to your point, we really need to be investing in testing these different possibilities. Meanwhile, many scientists are trying to ban research in the area. I don’t get it. https://climateandcapitalism.com/2022/01/17/climate-scientis...

If only that sort of testing had been done before we added two and a half trillion tons of CO2 to the atmosphere.

Sadly, now we don't have a choice between making a massive change or making no change. We just have a choice between leaving one change in place that we know is massively harmful, or using another method to reverse that change.

I think this is actually the fallacious statement. Failing to list any consequences doesn’t require listing all consequences to rectify. I agree with the statement that saying risks are “very low” is insufficient, especially when considering pumping a ton of stuff into the atmosphere. Rather one would expect a thoughtful analysis of what “very low” risks have been identified and why they’re low risk.

Yeah, I mean, honesty this sounds like it is an innovation coming from a some guy (or girl) in a garage. But I’m pretty ok with that. Let’s see if they can take it forward.

Am I wrong to think that it would be professionally toxic for a “real” climate scientist to work on a project like this?

They knew that leaded gas was a bad idea before it even hit the market. The inventor himself suffered from lead poisoning mere weeks before a major product announcement.

https://en.wikipedia.org/wiki/Thomas_Midgley_Jr.#Leaded_gaso...

According to the source, "Current man-made and natural ISA emissions total over 100,000 tonnes and have many beneficial climate effects". They are not advocating for doing anything particularly new, just scaling up those (partially natural) emissions by a factor of 2. Of course, that doesn't necessarily mean it's a good idea. Forest fires are natural, but we would need to study very carefully before we attempted to double the amount of forest fires by artificial means.

In my opinion, though, it would take some pretty strong evidence that this would be actively harmful to dissuade me from wanting to run large scale experiments. Shoot, if leaded gasoline had the potential to slow down climate change it might even be worth bringing it back, considering the damage that climate change has already begun to cause and is projected to cause.

I mean, we do know that lead is somewhat different than iron (one is required for us to live, the other is extremely harmful in tiny amounts).

The chemistry sounds well understood, so probably not going to create exotic compounds that are bad for us.

I wouldn't worry about it getting too much traction. Even stratospheric injection of sulfiric acid (something that volcanoes do) is blackballed from even being researched, let alone considered.

This idea actually seems safer to me, since rather than just blocking the sun, it actually takes our excess CO2 emissions back out of the atmosphere.

And also methane. It's the first idea I've seen for doing that.

And doesn't produce acid rain, like sulfur does.

Acid rain resulted from the 30+ million tons of sulfur dioxide released into the lower atmosphere. To cut global warming in half, 25,000 tons of sulfur dioxide would be needed in the upper atmosphere. So, 3 orders of magnitude less SO2. Meaning, mitigating global warming with SO2 would not meaningfully increase acid rain.

Source: https://www.technologyreview.com/2013/02/08/84239/a-cheap-an...

That 25,000 tons figure sounds really controversial. Even the article mentions

> David [Keith] thinks it is going to be easy and cheap, and I don’t agree,” says Robock. He estimates that several million tons of sulfur would have to be injected into the atmosphere annually to offset doubled levels of carbon dioxide, but if the particles clump together, “it could be many times that.”

I found a review of sulfate injection geoengineering studies[0] published in 2017 and with a quick read I can't find any mentions under millions of tons annually.

[0] https://acp.copernicus.org/articles/17/3879/2017/acp-17-3879...

Fair enough. We really should be able to test this at some scale that we could know the order of magnitude required for efficacy. We are dangerously ignorant about the solution space.

Sulfuric acid is one of the most well understood stratospheric nanoparticles because we have millions of years of geological data to correlate with the climate history. If you're worried about unintended consequences and models being insufficient for prediction, you want to be as conservative as possible with your nanoparticle choices. Terraforming is not something to treat lightly.

From the article:

> Current man-made and natural ISA emissions total over 100,000 tonnes and have many beneficial climate effects.

They're only talking about adding another 200,000. And...

> By directly copying the main planetary cooling mechanism from the ice ages, ISA has at least twelve identified cooling effects, presenting a balanced natural process.

So this also has geological history to draw on.

Despite this, they're currently only proposing a small trial, to make sure of safety for more trials. I don't think they're treating anything lightly.

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