CARBON CAPTURE -DAC

KATIE BRIGHAM • MAY 30, 2025   image-May-30-2025-07-23-24-7353-PM

Technology to suck carbon dioxide out of the air — a.k.a. direct air capture — has always had boosters who say it’s necessary to reach net zero, and detractors who view it as an expensive fig leaf for the fossil fuel industry. But when the typical venture capitalist looks at the tech, all they see is dollar signs. Because while the carbon removal market is still in its early stages, if you look decades down the line, a technology that can permanently remove residual emissions in a highly measurable fashion has got to be worth a whole lot, right? Right?  

Not so, says Tom Chi, founder of At One Ventures and co-founder of Google’s technological “moonshot factory,” X. Bucking the dominant attitude, he’s long vowed to stay away from DAC altogether. “If you’re trying to collect carbon dioxide in the air, it’s like trying to suck all the carbon dioxide through a tiny soda straw,” Chi told me. Given that the concentration of CO2 in the atmosphere sits at about 0.04%, “2,499 molecules out of 2,500 are not the one you’re trying to get,” Chi said. “These are deep, physical disadvantages to the approach.”   He’s obviously not the first to realize this. DAC companies and their scientists are aware of the challenges they face. But investors are generally comfortable taking on risk across a host of different technologies and industries on the premise that at least a few of their portfolio companies will hit it big.

As such, a nascent market and challenging physics are not inherent reasons to steer clear. DAC’s potential to secure cash-rich oil and gas industry buyers is pure upside.   Most prominent climate tech venture capital firms — including Lower carbon Capital, Breakthrough Energy Ventures, Prelude Ventures, and Khosla Ventures — have at least one DAC company in their portfolios. At One Ventures itself has backed everything from producing oxygen on the moon (while also decarbonizing steel) to indoor solar cells and thorium-powered nuclear reactors, a hobbyhorse of techno-optimist nuclear bros and former presidential candidate Andrew Yang. So the fact that Chi won’t touch DAC is no small deal.       His hesitation stems from a matter of scale.To capture that 0.04% of atmospheric carbon, many DAC companies use giant fans to pull in large volumes of air from the atmosphere, which then pass through either a solid filter or a liquid solution that chemically captures the carbon dioxide. Although some companies are pursuing alternate approaches that rely on passive air contact rather than energy-intensive fans, either way, the amount of air that reaches any DAC machine’s so-called “collection aperture” is minuscule “relative to the scale of planet Earth,” Chi told me.  

He views this as the core pitfall of the technology. “Half of the [operating expense] of the system is just trying to go after a technical disadvantage that you took on from day one,” Chi said. “By comparison, nature-based restorations have enormous apertures,” Chi told me. “Think about the aperture of all the forests on the planet. Think about the aperture of all the soils on the planet, all the wetlands on the planet, the ocean” … 

Published by Steve Martin

Steve is a passionate advocate for learning for sustainability and has spent nearly 40 years facilitating and supporting organisations and governments in ways they can contribute towards a more sustainable future. Over the past 15 years he has been a sustainability change consultant for some of the largest FTSE100 companies and Government Agencies such as the Environment Agency and the Learning and Skills Council. He was formerly Director of Learning at Forum for the Future and has served as a trustee for WWF(UK). He is an Honorary Professor at the University of Worcester and President of the sustainability charity Change Agents UK. He is currently a member of the Access Forum for the Peak District National Park and is supporting the local district council on its Climate emergency programme.

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