Your opinion: Are you in favor of geoengineering our oceans to combat climate change?

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Hi there scienceforums,

I recently came across a very interesting review paper, which I will link below, just in case you wish to read it for yourself:

https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2016RG000533

I will give you an abridged and highly simplified version here:

Rising CO2 levels are not only an issue for the global climate, but will also affect the pH of the oceans. This is because atmospheric CO2 dissolves in ocean water according to the simple equation:

CO2 + H2O --> H2CO3 (carbonic acid) --> HCO3(-) (bicarbonate) + H(+)

The important part is that the reaction above releases protons (H[+]) into solution, which causes the pH to go down (acidification). The more CO2 in your atmosphere the more pressure you put on this reaction. Why is this a problem? Because it turns out a lot of marine organisms do not like acidification of their habitat (especially corals do not tend to appreciate this at all). In the worst case scenario this could cause extinction of susceptible marine species. There is usually a whole system of other processes that maintain balance between atmospheric CO2 and seawater pH, which can shift over geologic timescale. It's not important here what these processes are, since you're not here to listen to a lecture in geochemistry (and I can't give you one). Suffice it to say that, human CO2 emissions could potentially upset this natural balance by introducing a lot of CO2 in a very short time. This could potentially overwhelm the oceans' capacity to counteract acidification.

However: In theory, if you introduce and dissolve sufficient quantities of certain minerals (e.g. Calcite) in the ocean, the reaction above becomes the following:

CO2 + H2O + CaCO3 (calcite) --> 2HCO3(-) + Ca(+2)

(analogous for several other minerals)

Not only does this prevent acidification by preventing the release of H(+) during CO2 dissolution, but it also actively draws CO2 from the atmosphere, storing it as HCO3(-) dissolved in seawater. In addition HCO3(-) is a potential acceptor for H(+). And simply put, this means that increased amount of it can stabilize the pH of the ocean against acidification.

The article then goes on to illustrate potential engineering solutions on how this large scale introduction of mineral material into the oceans could be implemented and goes over model scenarios that highlight what the potential consequences may be on a global scale. One of the main issues they point out is that it is currently not fully understood what kind of effect modifying ocean chemistry in this manner might have on marine ecology.

In summary. Here are the main pros and cons of this method:

Pros:

- Will actively reduce CO2 levels and may even reverse emissions entirely

- Will stabilize the ocean against acidification, which would for example protect coral reefs

Cons:

- It's not entirely clear what the ecological and/ or environmental effects of such an unprecedented modification of ocean chemistry might be; if we interfere with the ecological balance of the oceans we may actually do more harm than good

- The technology to effectively implement this on a sufficient scale does not currently exist

- International law may prohibit geoengineering projects that interfere with ocean chemistry on a global scale

Obviously there will be more research in the future and ultimately the leading experts will come to some sort of consensus. But here I'm more interested in the public perception of such a project:

What is your opinion on this concept? Do you think it's fundamentally a good idea? Do you think we should do it before it may be "too late"? Or should we wait until there is more research available? Or do you prefer to withhold judgement entirely and trust the experts to make the right decision?

I realize these might be loaded questions, but my goal is not to pass moral judgement on anyone here. I'm just curious about what people think. I'd simply love to hear your opinion on this.

Cheers.

Edited September 7, 2021 by 0100110101000101