Scientists have long speculated that so-called "negative emissions" technologies like CO2 removal could not only slow the accumulation of carbon in the air, but even reverse it. The problem was that all that speculation was, well, largely speculative; nobody had convincingly demonstrated how to pull off negative emissions at scale. Previous estimates had pegged the cost of sucking carbon from the skies at $600 per ton — way too pricey to qualify as a viable cleanup solution. However, findings from Carbon Engineering point the way toward a future in which negative emissions are not only technically possible but financially feasible.
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This is big, significant, encouraging news. But it's not all blue skies and rainbows.
Carbon removal technologies, promising though they may be, are over-hyped, says David Keith, an applied physicist at Harvard and Carbon Engineering's founder. "And the over-hyping has become a political trick." That hype, he says, makes it easier for policymakers to avoid drafting near-term mitigation strategies and exceed their carbon budgets, in hopes that their debt will be repaid at some point in the future. What begets this trickery? Computer simulations. When the Intergovernmental Panel on Climate Change modeled more than a thousand scenarios in search of ways to limit a rise in global temperatures, the most propitious projections relied heavily on the assumption that CO2 removal would one day swoop in and save our collective asses: Of the 116 IPCC scenarios found to limit warming to below 2° Celsius, 101 relied on negative emissions. "It enables policymakers to claim that we're very close to keeping global temperatures below a 1.5 or 2 degree increase, while sweeping under the rug the hard work that remains to be done researching carbon dioxide removal," Keith says.
Carbon removal technologies, promising though they may be, are over-hyped, says David Keith, an applied physicist at Harvard and Carbon Engineering's founder. "And the over-hyping has become a political trick." That hype, he says, makes it easier for policymakers to avoid drafting near-term mitigation strategies and exceed their carbon budgets, in hopes that their debt will be repaid at some point in the future. What begets this trickery? Computer simulations. When the Intergovernmental Panel on Climate Change modeled more than a thousand scenarios in search of ways to limit a rise in global temperatures, the most propitious projections relied heavily on the assumption that CO2 removal would one day swoop in and save our collective asses: Of the 116 IPCC scenarios found to limit warming to below 2° Celsius, 101 relied on negative emissions. "It enables policymakers to claim that we're very close to keeping global temperatures below a 1.5 or 2 degree increase, while sweeping under the rug the hard work that remains to be done researching carbon dioxide removal," Keith says.
Many people share his concerns. As a collection of climate researchers noted in a 2014 commentary published in the journal Nature: Negative emissions' "credibility as a climate change mitigation option is unproven and its widespread deployment in climate stabilization scenarios might become a dangerous distraction." An essay by climate researchers Kevin Anderson and Glen Peters, published in Science in 2016, leveled even harsher criticism: "Negative-emission technologies are not an insurance policy, but rather an unjust and high-stakes gamble," they wrote. "The mitigation agenda should proceed on the premise that they will not work at scale. The implications of failing to do otherwise are a moral hazard par excellence."
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Carbon Engineering’s direct air capture equipment pulls carbon from the air at a test plant in Squamish, British Columbia.
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Granted, the argument could be made that negative emissions technologies ceased to be a moral hazard when they became a necessary condition. Carbon Engineering’s latest data was published in a world in which atmospheric CO2 levels are higher than at any point in human history, and rising. The company's method proposes to attenuate that rise by combining the carbon dioxide it captures with hydrogen to produce carbon-neutral liquid fuel. "That'll be the first application of our technology en masse—making a completely clean fuel," says CEO Steve Oldham. "And, if we need it to, we might one day use it to collect excess CO2 from the atmosphere.
And if the IPCC's models are any indication, we probably will need to. "The moral hazard discussion would have been great to have in 1980, when atmospheric carbon levels were lower, but it's too late now," says Klaus Lackner, director of the Center for Negative Carbon Emissions at Arizona State University. Lackner pioneered the concept of direct air capture of carbon dioxide, and was quick to counter Anderson and Peters' editorial in Science with a letter of his own. "Throwing a life-preserver to a drowning victim may not assure a successful rescue, but it is not a high-stakes gamble. Offering the life-preserver is preferable," he concluded. Anderson and Peters rebutted Lackner's rebuttal by extending his analogy; relying on negative emissions, they argued, would be akin to "letting someone jump into a raging torrent, and telling them that we may be able to save them with a technology that we have not yet developed."
Science squabbles notwithstanding, both sides of the moral hazard argument agree that negative emissions technologies like those in development at Carbon Engineering should be pursued with vigor. Peters reiterates his point that while relying on the future development of negative emission technologies is a high stakes gamble, "we need more research, development, and eventual deployment of negative emission technologies." Keith concurs. "As of today there is extraordinarily little research on it," he says. "The number of scientists funded to do work on carbon removal globally is seriously small." And that's a problem. Because the only thing worse than assuming that carbon removal will save the day is assuming it will save the day — and then not funding its development.