This assumes that global warming is the problem, but arguably the most pressing aspect of carbon pollution is the acidification of the oceans which this plan would not address. It might make more sense to focus on capturing carbon pollution than to mitigate some of the side effects of rampant carbon pollution.
I think the most sensible use of SRM is to head off positive feedbacks. With increasing temperature, the planet starts emitting greenhouse gases on its own, from permafrost melt, forest fires, etc. We can see it in the geological record, where orbital variations cause a modest initial warming, then CO2 increases a lot and warms the planet several degrees more.
SRM could help prevent that by directly lowering temperature, which means less CO2 released and less ocean acidification. And it buys us time to decarbonize before things all fall apart.
It also turns out that SRM might not even be able to save us if things get really bad. The marine stratocumulus clouds they talk about depend on being able to cool to space (at the top). If you increase CO2 too much, this can no-longer happen, causing a collapse of the cloud system and a large decrease in planetary albedo (and hence warming) [0]. These SRM techniques are no silver bullet.
However, as other have pointed out, this might be able to buy us some time to develop negative emissions technology (which is ultimately the only way out). Hopefully we would use that time wisely.
Why argue global warming is not a massive existential threat? Both are huge problems, we have the resources to begin tackling/experimenting on both areas, so why downplay solutions to either? The sea is expanding in size as it heats, more ice is melting as it heats as well. This will devastate billions of coast-adjacent humans. It's pretty hard to argue against preventing catastrophic sea-level rise, never mind acidification also being a huge problem.
Do you have a source for the argument that acidification is worse than warming? I'm more familiar with the pressing problem of positive feedback effects, like accelerated release of natural stores of carbon and methane.
https://en.m.wikipedia.org/wiki/Climate_change_feedback#:~:t....
There is a moral threat of "with climate management tools, we don't need to act on carbon reduction." I think that is less dangerous than the threat of "we have no validated climate management tools to deal with rapidly accelerated climate change." Ideally, we would research and develop the science and technology of weather control and climate management now so we don't feel compelled to do anything drastic in the near future. For instance, we know that dumping sulfur in the upper atmosphere can cool the earth for <$10b/year. But we don't want to be in that position. Instead, maybe we mandate that all container ships loft saltwater droplets to support cloud formation.
Also, keep in mind that some approaches might be applied locally to protect certain ecosystems rather than aiming for a global effect. E.g., cloud brightening R&D to cool areas with lots of melting permafrost. We should be spending billions on this r&d.
We need time to transition, it's happening. In 20-30 years, we will have a much cleaner global economy, with no coal and minimal oil. But we don't want to have the permafrost melt in the meantime!
I had a nightmare where we tried to bioengineer something to eat the ocean plastics and it was too successful. It ate all plastic but turned the ocean full of algae killing nearly all marine life.
I'm not sure I buy that, but sure, both are important problems.
Question, what do we know about the ocean as a carbon sink? Is it's capture rate variable with anthing? Is it easier to capture carbon from the ocean than in the air? Could we try to increase the capture rate into the ocean and then extract rapidly from the same area?
It's "easier" to capture from water in chemical terms but harder to actually move the water. I think the economy of moving the weight of water makes this a nonstarter.
Also yes, ocean acidification is likely to be the bigger immediate problem. People depend heavily on fish protein and other sealife. That plus poor farming yields will be bad.
I imagine any CO2 capture system that uses ocean water would be placed in the ocean, not have the water pumped into it.
CO2 is easier to chemically react when dissolved into water, and its mobility is about the same as on air. So the decision is about engineering something that can survive being immersed on the ocean vs. engineering something that can use atmospheric CO2. I believe there's no general answer, we can only answer that question for specific designs.
Mechanical and electrical engineering aren’t going to do you enough good quickly enough.
But can you think of any forms of life on the bottom of the food chain that depend on carbon inputs as part of its own metabolic processes in order to reproduce itself? Because if you want a self-sustaining ocean-based carbon capture solution, that’s where I would look.
e.g, instigate some large bloom of plant matter or algae, and engineer/find the right conditions for the matter to sink to the bottom of the ocean without decomposing.
At least the first part. There’s an easy profit motive: increasing the base of the food chain feeds the rest of it, and some of those are products we like to eat.
The second part, if you can find a profit motive to compost the ocean floor and actually do it in a profitable way, then it will get done. Else we’re stuck relying on natural processes.
The problem with GMO life is an organism trying to reproduce plus your goal is inherently less fit than an organism merely trying to reproduce. This really only works at accelerating a reset after a mass die off.
There are some feedback effects to acidification, one of which is that plankton will struggle. They absorb a lot of CO2.
Someone else pointed out that we can cause blooms. That's basically what you want, because plankton or algae sequester it. I don't know that we can "hack" that without risking damaging the oceans though. They're pretty good at what they do as is.
It is a gas exchange though, so heat and pressure have an impact. They're not great for marine life though. Surface area does as well, though it'd be hard to meaningfully change the ocean's surface area.
The bigger issue would be containment. The ocean is huge, and a very good CO2 sink. Anything that's going to make a significant dent in the total CO2 absorption of the ocean is going to have to happen over a very large area. Things aren't going to be much better if we sterilize the ocean in the process.
