[sillywalk]

A newer larger pilot plant is set to remove 4000 metric tons / year. Annual emissions are > 36 Billion tons. Even if the 'commercial scale plant' could remove 4 million tons / year, and they would need to make thousands to really make a difference.

It's unclear how many emissions are required operate it. How much rock is required, and how many emissions does it take to mine/process/transport it to the plant, and then put the processed rock somewhere else?

[yodon]

Running the math on scaling any proposed systems up to a rate where they can actually make a dent on the atmosphere is VERY depressing.

It doesn't matter what sequestration process you want to use. The volume of material you end up with after removing a couple hundred gigatons out of the atmosphere isn't a pile and isn't a mountain, it's a mountain range. This is a HUGE industrial process that is going to be required, and the volume of material that will come out of that industrial scale sequestration facility is very hard to imagine.

It doesn't matter what form you choose to sink the carbon into. Carbon density per cubic foot just doesn't vary much, even if you go all the way up to exotic targets like diamond. Hundreds of gigatons maps to huge volumes, and always will.

Worse, most things you might choose to sink the carbon into are energetically favorable for burning that carbon back into CO2 should mankind ever realize it could turn that huge pile of whatever into a source of energy. That sets up a situation where even if we solve the problem "now", most approaches would have us creating an attractive nuisance that is very likely to get burned back into the atmosphere 500 or 1000 years from now if we ever forget why it exists. Such an enormous amount of available potential energy will be very valuable financially and VERY difficult for humanity to refrain from burning back into the antmosphere again.

[DougN7]

Honest question: are we burning mountain ranges of carbon every year? I’m trying to get a feel for the size of the problem compared to the solution. Or is there a reason for the size difference if not?

Assuming the answer is yes, do we see the ground level around oil wells sinking by a comparable amount where we pump the oil out? Seems like we’d have to, wouldn’t we?

[yodon]

We aren't burning mountain ranges per year, but we have burned a mountain range total

[toomuchtodo]

When sequestering, it is imperative that the carbon in scope is buried in a form that is both stable and non combustible to prevent future potential combustion.

From Climeworks:

> Once the CO₂ is released from the filters, storage partner Carbfix transports the CO₂ underground, where it reacts with basaltic rock through a natural process, which transforms into stone, and remains permanently stored.