The Climate Tech Investor Who Won’t Touch DAC

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 well 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 Lowercarbon 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.” His preferred methods of carbon removal are all nature-based. “In addition, their sequestration tends to be photosynthesis-powered, which means we’re not burning natural gas or using grid electricity in order to go make that thing work.”

Nature-based solutions often raise eyebrows in the carbon removal and reduction space, though, bringing to mind highly questionable carbon offsets such as those earned via “avoided deforestation.” The inherent counterfactual — would these trees really have been cut down if we didn’t buy these credits? — is difficult to measure with any certainty, and a 2023 investigation by The Guardian found that the majority of these types of credits are essentially bogus.

This same essential question around measurability plagues everything from afforestation and reforestation to soil carbon sequestration, biochar application, and wetland restoration. It’s extremely difficult to measure how much carbon is stored — and for how long — within complex, open ecosystems. On the other hand, engineered solutions such as direct air capture or bioenergy with carbon capture and storage are simple to quantify and promise permanent storage, making them attractive to large corporate buyers and easy to incentivize via mechanisms such as the federal carbon sequestration tax credit.

When I put all this to Chi, his response was simple. “It’s not an advantage to be able to measure something that can’t solve the problem,” he told me. For a moment, it seemed as if we had hit an intellectual dead end. For now, carbon removals and reductions are mainly driven by the voluntary carbon market, where prices are based on the exact tonnage of carbon removed. Reputable buyers don’t want to be burned again by investing in difficult to quantify offsets, and the current administration certainly doesn’t seem likely to step in with nature-based removal mandates or purchasing commitments anytime soon.

Chi’s answer to this conundrum is “financial enclosure,” essentially a fancy way of saying we need to monetize the value of nature-based systems. In many cases, he admitted, we don’t quite yet know how to do that, at least in a way that benefits the common good. “We figured out how to financially enclose a forest, clear cut it in order to go make board feed and paper and pulp,” he explained. But we don’t know how to financially enclose the benefit of preserving said forest, nor many other ecosystems such as wetlands that serve as highly effective carbon sinks.

At One Ventures has backed companies that work with a variety of buyers — from national governments to mining companies and farmers — that have a financial stake in (or are legally required to care about) ecosystem preservation and restoration. “Sometimes people break nature hard enough that it becomes that obvious. And then they have to go fix it,” Chi told me. “We’re going to invest in the companies that make it possible to go do that at incredibly low cost structures.”

One portfolio company, Dendra Systems, uses robots, drones, and other automated methods to do large scale ecosystem restoration, such as replanting mangroves in parts of the world such as Myanmar and Abu Dhabi where they’ve been cleared for property development or industrial use. The governments of both countries are paying Dendra to do this after realizing that removing mangroves had catastrophic consequences —- destroying subsistence fishing, wrecking erosion breaks — that would cost more to ameliorate than simply replanting the trees.

Then there’s Dalan Animal Health, which is developing vaccines for honeybees as hives become more vulnerable to disease. While not directly focused on carbon removal, the company has successfully “financially enclosed” pollination, as industrial farmers whose crops depend on pollinators will pay for the vaccine. This helps restore healthy ecosystems that can ultimately draw down more carbon. Chi told me that insurance companies have also shown a willingness to pay for nature-based solutions that can help lessen the impact of disasters such as floods or hurricanes.

While the carbon benefits of these companies are simply a bonus, the firm has invested in one pure play removal company, Gigablue. This startup releases engineered particles into the ocean that attract carbon-absorbing phytoplankton. As the particles accumulate more plankton, they sink to the ocean floor, where the carbon is then stored. Using onsite sampling and other advanced techniques, Chi told me that this tech is “very measurable” while also having an “aperture [that] is as wide as the ocean area that we’ve sprinkled things onto.”

Though Chi dislikes the illogical nature of the voluntary carbon market — he would much prefer a “polluter pays” system where money is directed towards nature-based sequestration — he knows that with the markets we have, precise measurability is paramount. So At One Ventures is throwing money at this, too. Portfolio company Chloris Geospatial combines satellite data and machine learning to measure biomass from space and track changes over time, helping legitimize forest-based removals. And Miraterra is focused on novel sensing tech and advanced modeling that allows farmers to calculate the amount of carbon in their soil.

But even if the carbon stored in natural ecosystems never becomes quite as measurable as engineered carbon removals, Chi thinks investors, companies, or governments should still be going all in. “When your volume is so much larger, then you can even throw big error bars around your measurability and still be miles ahead,” he told me.

Many investors say they want it all. You’ll see them funding nature-based and engineered carbon removal companies alike in an effort to take a “portfolio approach” to carbon removal. Chi, unsurprisingly, thinks that’s hogwash. “It’s weasel words to be like, it’s an important part of this portfolio,” he told me. The United Nations Intergovernmental Panel on Climate Change also advocates for a diversified approach, without saying DAC itself is strictly necessary. DAC is “not going to do 1%, and it’s going to be massively more expensive than your other 99%,” Chi said. “At some point you’re going to be like, why is this in the portfolio?”

It’s certainly a more blunt assessment of the industry’s viability (or lack thereof) than I’ve heard any investor hazard before. But there may be more folks starting to come around to Chi’s perspective. With government support for DAC in question and the utility of carbon capture tax credits — which only benefit engineered removals — deeply threatened, venture funding for DAC is down over 60% from this time last year, Bloomberg reported.

Rajesh Swaminathan, a climate tech investor at Khosla Ventures told the publication that while many investors have taken bets on direct air capture, “Now, people are stepping back and saying, ‘Why didn’t I look at the economics there?’” Khosla itself is an investor in the DAC company Spiritus.

So what’s a longterm skeptic like Chi to do in this moment of doubt? As he told me, “I’m just going to keep on giving talks on it, and I know that physics is on my side.”