[Lewis Thomson (OP)]

Art asks:

If you put a windmill on a platform in the ocean to generate electricity, and then used that electricity used to extract carbon dioxide from the atmosphere and convert it into dry ice, could you then compress the dry ice and sink it to the bottom of the ocean where the ocean pressure would keep it compressed? If so, could this be a solution to the problem of rising atmospheric carbon dioxide levels?

What do you think?

[chiralSPO]

Short answer: no.

Long answer:

There are a few problems with this approach. Firstly, it doesn't matter whether the CO₂ is solid liquid or gas, if it is not contained, releasing it into the bottom of the ocean is only going to lead to higher CO₂ levels in the ocean until the ocean becomes saturated and it begins to outgas.

So let's say it gets packaged and then sent somewhere. Assuming that the machine can remove the CO₂ from the atmosphere and compress it into dry ice with perfect efficiency, it will still take a lot of energy. Even if the power is "free" and doesn't produce any CO₂, it takes quite a bit of energy to remove CO₂ from the atmosphere at a useful rate. Air is only about 400-500 ppm CO₂, so even a process that removed 100% of the CO₂ in a single pass would need to treat two million cubic meters of air (at sea level) to remove one kg of CO₂. To remove one ton of CO₂ per day (global CO₂ emissions are about 75 million tons per day), a machine with an intake port of 100 square meters would need to pull air in at a speed just over 800 km per hour (operating continuously)!

This problem becomes much less of an issue when collecting much higher concentrations of CO₂, form instance capturing CO₂ at the point of production, before it gets diluted into the atmosphere. This is one of the ideas behind "clean coal." But we still have to put the CO₂ somewhere...

[evan_au]

Greenhouse gases like methane are already safely stored at the cold temperatures/high pressure of the sea floor, in the form of clathrates.

More scientists and engineers became aware of these ice-like compounds after they gummed up the Deepwater Horizon oil-well in the Gulf of Mexico.

There are suggestions that as the sea temperatures rise, these clathrates are starting to destabilise, releasing "burps" of methane into the atmosphere.

There are some projects that are looking at mining clathrates on the continental shelves, since burning methane to carbon dioxide produces less global warming than releasing the methane directly into the atmosphere (and you can get paid for the methane too).

See: https://en.wikipedia.org/wiki/Methane_clathrate

[syhprum]

I shuddered last night as I listened to president Trump extoling the virtues of beautiful clean coal.

[chiralSPO]

I shuddered last night as I listened to president Trump extoling the virtues of beautiful clean coal.

I didn't even watch/listen, and trying to read the transcript was too painful. Fortunately, I don't think anything Trump can do will revitalize the coal industry in the US. Unfortunately, coal mining and burning only seems to be accelerating in SE Asia (esp. China, India and Indonesia). https://www.mining-technology.com/features/featurethe-worlds-biggest-coal-consumers-4353695/

And environmentally, coal is probably the worst (even forgetting CO₂). The low energy density means we need much more of it to generate the same power as oil or gas. That it's a solid means that extraction is much more destructive. And more radioactive isotopes have been released in to the environment than from all nuclear plants combined (including Chernobyl, Fukushima, 3 mile Island etc.) https://www.scientificamerican.com/article/coal-ash-is-more-radioactive-than-nuclear-waste/

[alancalverd]

Plants extract CO2 from the atmosphere with no help from windmills and other expensive machinery, and produce lots of useful chemical energy as they do so. If we stopped farming animals and started burning wood and straw (i.e. the bits we can't eat) for fuel, we would have to find something else to blame for climate change.

[Bored chemist]

If we stopped farming animals and started burning wood and straw (i.e. the bits we can't eat) for fuel, we would have to find something else to blame for climate change.

Unless, of course, Alan is wrong and all the climate scientists are right- which isn't a possibility scientists should dismiss out of hand as he does.

[alancalverd]

On the contrary. What I have proposed is called an experiment, which is what scientists do to test a hypothesis. Merely repeating a hypothesis "because everyone else does" and pretending that it is beyond experimental investigation, is called religion. Religion is very dangerous.

I suppose the fact that my proposed experiment costs nothing, solves a few problems like world hunger and animal welfare, and begins with the same hypothesis as most self-styled climate "scientists" promote, makes it a Bad Idea, but I can't somehow see the logic in this.

[jeffreyH]

Well there is your problem, it costs nothing. So how are all the greedy £#@D%56 going to male any money out of it?

[Bored chemist]

If we stopped farming animals and started burning wood and straw (i.e. the bits we can't eat) for fuel, we would have to find something else to blame for climate change.

That's not proposing an experiment, it's making a statement. So this

What I have proposed is called an experiment, which is what scientists do to test a hypothesis.

is not true.

Merely repeating a hypothesis "because everyone else does" and pretending that it is beyond experimental investigation, is called religion

How fortunate, then that the climate studies are based on experimental observations.
Such things as
We put more CO2 in teh air.
It is getting warmer
CO2 absorbs IR

On the other  hand, saying that, in spite of those fact, we are not responsible for the rise in temperature is a religion.
(one of the other factors about religion which makes it dangerous  is the denial of observable truth- ask Galileo.)

I suppose the fact that my proposed experiment costs nothing, solves a few problems like world hunger and animal welfare, and begins with the same hypothesis as most self-styled climate "scientists" promote, makes it a Bad Idea, but I can't somehow see the logic in this.

Actually, it's what the climate scientists have been proposing all along
It's just that you are not willing to see the truth
This is a fairly old cartoon...


climat cartoon.JPG (61.65 kB . 504x342 - viewed 10172 times)