What Happened to Carbon Air Capture?

Last Friday, the Paris Agreement, a momentous climate change accord ratified by 109 sovereign members of the U.N. Framework Convention on Climate Change, entered into force. With that came an obligation by signatories to cooperate on reducing greenhouse gas emissions, with a goal of keeping global warming to within 2C of pre-industrial levels. But amidst the optimism came sobering news from the U.N. itself: all the pledges put forth by member nations would still amount to a 3C rise in temperatures.

Carbon Air Capture, or Direct Air Capture (DAC), offers civilization one of the only conceivable means of going beyond carbon-neutral, into carbon-negative altogether, and achieving the goals set out by the Paris Agreement. By drawing and storing carbon dioxide directly from the air, we can directly counteract past and present emissions, while acquiring CO2 for industrial and agricultural use.

The intricacies are complex, but the idea is simple. Air full of CO2 is sucked in, a sorbent pulls the CO2 out, and clean air is output. Given atmospheric CO2’s propensity to disperse across roughly longitudinal lines, a DAC system in Miami could very well help compensate for emissions in Delhi.

So much of the doom-and-gloom surrounding climate change follows the assumption that its effects — to marine ecosystems, weather patterns, coastal communities, and more — are irreversible. That the Arctic and Antarctic ice sheets will slowly break apart. That generations to come will be cursed with hotter summers and deadlier weather. That we will never again have the vibrant, colorful Great Barrier Reef of ’90s coffee table books. DAC offers a way out, and patented methods for it have been around for nearly a decade now.

So what’s the problem?

With all that in mind, one would expect DAC arrays to be ubiquitous by now, if not worldwide then at least in developed, Western economies. But it isn’t, and there are two factors at play that may explain why.

Moral Hazard

A subset of climate scientists believe negative-emissions tech will risk disincentivizing traditional carbon reduction methods, which may backfire if DAC doesn’t live up to the hype.

The concern isn’t entirely baseless. Researchers Kevin Anderson and Glen Peters pointed out last month that relying entirely on DAC and other negative-emissions systems to control climate change could lock us into a “high-temperature pathway” if DAC proves ineffective or is not properly deployed. Yet Anderson and Peters assume policymakers are already being misled by the potential of carbon-negative technologies, and that turning their attention back to reduction methods is the only way to remain within the 2C threshold. Unfortunately, this is not the case.

As Tim Flannery of the Australian Climate Change Commission pointed out last year, “because energy systems take time to change, and greenhouse gases warm the Earth for decades or centuries after they’re released, we’re headed for 2C of warming pretty much no matter what we achieve in Paris, or in the two decades afterwards.”

Insofar as we as a global community are trying to meet that goal of sub-2C warming, we have already failed. From 2000 to 2014, over $90 billion were invested in emissions reduction, while virtually nothing was spent on carbon-negative technology. The true moral hazard would be to hope that our current emissions policies will work better than expected — a strategy that evidently has not worked so far — while decrying and discouraging investment into an area that is beginning to show promise.

As long as governments and environmental NGOs are cognizant of the stage carbon-negative technology is at, and keep their estimates conservative until that tech is ready, we can only benefit from further investment into DAC and other carbon-negative approaches.


Of course, once we get past the question of whether DAC investment is morally justifiable, we need to consider whether or not it is economically appropriate. It’s not just a matter of finding a working system and building enough of it to capture so many billions of tons of CO2 per year. It’s also a matter of making that system financially palatable to governments and, more importantly, business interests.

The demand side is pretty much covered here. The Center for Carbon Renewal recently presented on the biggest markets for captured CO2:

  • Biofertilizers — $900m/yr
  • Industrial Gases — $20B/yr
  • Food & Beverage — $5B/yr
  • Construction — $1.5B/yr
  • Synthetic Fuels — $500m/yr
  • Desalination — $100m/yr

What is more challenging is actually justifying the price of drawing CO2 out of the air. Even the most liberal estimates have placed the cost of DAC at anywhere between $27/ton and $136/ton captured, astronomically higher than the $13/ton market price of CO2 today. Nor can we expect any government with sane economists to subsidize carbon capture by as much as ten times the purchase price, at the scale needed to make a meaningful difference in global greenhouse gas accumulation.

And although the purchase price of CO2 may see upward pressure as the markets for captured CO2 grow, if DAC does achieve widespread success, that will do little to compensate for the billions of tons of CO2 flooding the market of its own accord. The tech must be ready for economies of scale to kick in, lest carbon capture entrepreneurs price themselves out of the market.

It is hard to overstate how great a barrier this may be. Our atmospheric concentration of CO2 currently sits at around 390 parts per million by volume (ppm), compared to the pre-industrial levels of 280 ppm. Deforestation and fossil fuel burning release around 34 gigatons of CO2, or 4.35 ppm, into the atmosphere annually, after accounting for traditional emissions reduction technology. To become carbon-neutral, we would need to capture 34 billion tons of CO2 each year. If we want to reduce CO2 levels back to pre-industrial levels outright, within 100 years, that number jumps to 50 billion.

If there is no feasible way to sell or permanently store 34 to 50 billion tons of CO2 each year, there is a strong chance that DAC will be DOA.

What’s Next?

We can only speculate on what the future holds for Direct Air Capture. While the moral hazard argument is flimsy, it is still on the minds of climatologists and others involved in the space, and entrepreneurs and business leaders with any plans for DAC tech will need to work to dispel these concerns. At the same time, it will be difficult to justify large-scale DAC deployment until both the tech and the markets are ready for it.

Other carbon capture technologies also exist, with the ability to capture CO2 released by automobiles, aircraft, and livestock that we are otherwise unable to effectively control. The possibility remains that some of other options, such as reforestation and Biochar, may prove more viable in the long-run. In any case, it’s about time the global environmental community begins giving carbon-negative technology the attention and consideration it needs, while we still have a choice.

Marcello Miranda is an entrepreneur currently building the Florida-based VR startup HubVR, with the goal of helping virtual reality reach the mass market. Follow him on Medium and Twitter, and hit that if you enjoyed this content!