They're only net carbon emitters if they're powered by fossil fuels. The Climeworks plant is powered by geothermal. Any renewable or nuclear power source would be fine.
It's expensive but it's scalable. There is a vast supply of suitable basalt formations. In terms of land area, it absorbs a thousand times as much CO2 as planting trees.
I have seen a lot of complaints about the sheer number of devices that would be required, but this is the sort of scale that civilization is accustomed to. We built enough hardware to put that CO2 in the air. We can build enough to take it out. The real question is whether it can be made cheap enough in mass production to make a difference. That will partly depend on clean energy costs, but they are dropping constantly.
It's certain that reducing emissions will be more cost-effective in most cases, but for some applications, like long-distance jet travel, we probably can't get away from hydrocarbon fuels for the foreseeable future.
From what I'm reading, the method they're using right now to store the CO2 requires around 25 tonnes of water per tonne of captured CO2, and requires clean water at that. They are apparently working on using saltwater instead, but don't have the tech yet.
So I'm not personally convinced it is actually scalable for now. I will admit that they seem more serious than others (in particular, more than the company in this article, which is using CO2 to push more oil out of the ground).
It's expensive but it's scalable. There is a vast supply of suitable basalt formations. In terms of land area, it absorbs a thousand times as much CO2 as planting trees.
I have seen a lot of complaints about the sheer number of devices that would be required, but this is the sort of scale that civilization is accustomed to. We built enough hardware to put that CO2 in the air. We can build enough to take it out. The real question is whether it can be made cheap enough in mass production to make a difference. That will partly depend on clean energy costs, but they are dropping constantly.
It's certain that reducing emissions will be more cost-effective in most cases, but for some applications, like long-distance jet travel, we probably can't get away from hydrocarbon fuels for the foreseeable future.