Just from a physics perspective, a dollar invested into substituting coal burning is likely to be many orders of magnitude more effective than first burning the coal to CO2, diluting it to 400 parts per million in the atmosphere, concentrating that CO2 back to some high percentage, maybe turn it CO2 to some higher density form of carbon again etc.

Every step requires a lot of effort, capital and energy.

The best way to store carbon is coal. And it's already there, in the ground.

I'm surprised that people keep trying to direct-air-capture. I was under the impression that the carbon content (as carbonates) in seawater was much higher than in the atmosphere.

I believe the navy has had some initial success in transforming marine carbonates in to petroleum products, which they will probably use as fuel, but I can't wait for the day when we have reverse oil wells pumping carbon back in to the ground..

> Other approaches to geoengineering to counteract the effects of climate change could have potential as well.

What safeguards does YC have in place to help a company do this without starting unintended consequences and maybe accidentally making the problem worse? A large body of evidence suggests that humans and businesses, overall, do not get a good grasp on how their actions will cascade 20-30-100 years into the future.

Does YC have a plan or opinion at least on how to reduce the likelihood of your startups wreaking uncertain havoc on the other side of the world while engaging in geoengineering?

Edit: I'm not allowed to reply on HN any more I guess, but here is my response to the comment below.

My comment was specifically not about carbon removal, but the "Other approaches to geoengineering to counteract the effects of climate change could have potential as well", specifically not talking about carbon removal.

Index of startups and technologies for mining carbon from the air: http://airminers.org

We built Air Miners to catalog what exists so hackers can find the gaps in carbon removal and build new solutions :)

  - Any interest in funding commercial permaculture setups?

  - Any interest in small-scale mushroom farmers?

  - Any interest in aquaculture/closed-loop systems that focuses on reducing, reusing, and recycling nutrients and other resources (carbon obvious included)?

  - Interest in non-profits that reclaim abandoned warehouses in urban areas, rehab and function as sustainable greenhouses and employ the "non-employable"?

  - What is the position on marijuana and cannabis cultivation?
    + if the focus is on epigentics?
    + if the focus is on DNA fingerprinting / identification?
    + non-sales, research only, mapping the genetics to cannabinoid expressions?
    + if 100% of profits (minus investor cuts) are funneled back into YC projects?

  - I've already submitted my application but my answers weren't catered to the RFS.  Should I bother editing it to draw focus on the fact that my company addresses the RFS or should I leave the answers a bit more generic? e.g. "How far along are you?" yielded a response focused on business operations, not the technology and its associated R&D which relates to the RFS

It's heartening because carbon removal has to happen. It's surprising because, unlike afforestation or biochar, which produce useful products, there is a very small market for CO2. There is in fact no market for CO2 separated using direct air capture (DAC) because it costs an order of magnitude more to separate CO2 (>$300/T) than its value on the market ($15/T). (Ironically, the biggest market for CO2 is for enhanced oil recovery, which is exactly what it sounds like: it allows more oil to be extracted from oil wells.) So, the real question is, who is going to pay for it?

The companies currently operating in this space (e.g. Climeworks, Carbon Engineering) are doing so at a massive loss. In the case of Climeworks, they are pumping the CO2 to a greenhouse. On the face of it, this seems great because the CO2 is being used, but the problem is that the plants would remove the same amount of CO2 from the atmosphere whether they were grown with captured CO2 or not (they might just grow a bit faster in the greenhouse). In fact, the energy required for the carbon capture process means that the carbon footprint of the plants grown in the greenhouse using captured CO2 is likely higher than if they were grown outdoors!

For direct air capture to be economically and environmentally sound, there has to be a second step in the process where the CO2 is converted into a marketable product (so that the product displaces emissions). This means something like converting CO2 to plastic or fuel that would otherwise be produced using petrochemicals. Carbon Engineering recently announced that they are pursuing this. Of course, in addition to the technical challenge, they’ll have to get those fuels to be cost-competitive with current fossil fuels.

The other thing to keep in mind is that CO2 emissions from man-made sources total 60 GT per year. To put this into perspective, the amount of oil produced globally per year is about 5 GT. Which industries are big enough to handle all of that matter?

What is YC’s angle here? Is YC also considering carbon utilization companies? I personally feel like pursuing standalone direct air capture companies is a bit like putting the cart before the horse.