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Comment by asdfman123 | Hacker News Reader

You can sequester carbon with plants, but you can't let them decay or it will release it back into the environment (it's called the "carbon cycle" of a reason).

A startup has solved this problem the following way (for example): grow microalgae near a very dry desert, and bury it in trenches. It never decays and thus never releases CO2 due to lack of water.

Basically, we'd have to permanently stick it back underground again.

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You don't necessarily have to bury the plants to sequester the carbon. A lot of oceanic carbon just sinks to the bottom and is eventually covered over, especially near estuaries that spew silt.

To me, this is great that demonstrates how ridiculous carbon capture and storage is. I just can't imagine us paying to do something like this at scale, when we have a much more straightforward alternative: Stop burning fossil fuels, and use clean energy instead. Right? Like why even both going through the effort of carbon capture, when we're still going to have to stop burning fossil fuels anyways, in order to fix the climate?

We'll have to do both I imagine by the time we realize it's too late.

If you can find a way to get other people to stop burning carbon, let us know.

I know that sounds dismissive but I mean it. There's no magic wand.

Exactly. Getting other people to behave a certain way is different from a team going off and doing something, like marine cloud brightening to raise the Earth's albedo.

Think of it like a battery. We pour sunlight into the plant at one end and then we take this gasoline from the other side of the battery and burn it. The end-result is that we have full fuel cycle powered by the Sun.

This kind of battery is useful. All human hearts together produce about the same power in beating as a Falcon 9 in the final stage but you can't use hearts like that.

Carbon capture is already done at scale because CO2 is commercially valuable.

The proposed carbon storage is permanent in the form of carbonates. This is a variant of the Solvay process used to make washing powder.

Chalk cliffs were once the shells of sea creatures. That's a whole load of sequestered carbon right there.

I was under the impression that commercial CO₂ was produced by mining chalk.

Yes, lime kilns use the reverse process -- heating chalk to drive off the CO2.

Just popping in here to say that the IPCC has no model for a stable climate that doesn’t involve removing many billion tons of carbon dioxide alongside complete decarbonization, so unfortunately simply stopping emissions at this point isn’t enough. Some level of carbon dioxide removal is required to maintain a stable climate.

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