There are good reasons to believe that carbon dioxide reduction (CDR) technologies are viable, however, there are also legitimate concerns about such technologies. An EASAC report concluded that NETs are unlikely to remove even several GtCO2/year after 2050. “Negative emission technologies may have a useful role to play but, on the basis of current information, not at the levels required to compensate for inadequate mitigation measures,” the report stated. Low technological readiness, high costs, and negative effects on terrestrial and marine ecosystems are factors weighing against NETs, it said (EASAC, 2018).
Cost is often presented as an important consideration. However, as explained by Peter Wadhams, professor emeritus of ocean physics at Cambridge University, “initiatives to devise economically acceptable methods for carbon dioxide removal from the atmosphere should be the most important concern of science and technology. The success of these efforts will mean the difference between the prospect of a positive future for mankind and the certainty of descent towards climate-driven chaos” (Wadhams, 2016). Cost is also a commonly cited reason for resistance to climate action and this is certainly a factor for CDR technologies. However, these fears may be unfounded as a cost-benefit analysis indicates that climate action is associated with a sizable net economic benefit (Matthews, 2020). According to climate researcher Mark Jacobson, climate action will contribute to an annual $11 trillion savings which will offset the upfront $73 trillion cost. “There’s really no downside to making this transition,” (Jacobson, et al, 2019). The costs of climate action have declined dramatically, and those costs will continue to decline as they are scaled. As we will see this is also true for CDR.
The price of carbon capture has declined from $600 per tonne of CO2 to below $100 per tonne, which as explained by CDR pioneer Jan Wurzbacher, is the “magic number” (McGrath, 2017). Such numbers represent “real progress,” says climate scientist Chris Field (Service, 2018). Driving down the price of capturing CO2 is key to making CDR work and as Wurzbacher explained mass production will contribute to price declines (McGrath, 2017). Massively increasing production will cause costs to decline as will building more efficient plants and creating secondary markets for captured carbon (Rathi, 2017).
When considering costs, we should note that what we currently construe as too expensive may change over time. Klaus Lackner, director of the Center for Negative Carbon Emissions at Arizona State University said that these technologies become commercially important when they cost less than $100 a metric ton, “but” he added, “if things are really hurting, people are going to do it anyway, even if it is more expensive” (Ross, 2018). When we consider the costs of carbon capture, we must also factor the costs of failing to implement and scale such technologies.”
When estimating costs, we also need to understand that there are significant elements of risk and uncertainty. As explained by Stanford’s Field: “Many of the scenarios that come forward in the models that are cost-effective do exactly that: They say we’ll come up with this technology, based on incomplete information it will be cheap and effective, the land will be available, and people will embrace this. That might be right. But there’s almost no evidence confirming that it’s right” (Peters, 2017).
Nonetheless, we have made significant progress in our efforts to assess the scalability potential of CDR. Princeton’s Pacala, who is also the chair on the panel on carbon removal technologies for the NAS, believes we are in a better position to more accurately assess the scalability potential because we now have more data from functioning facilities (Service, 2018).
Massive scaling of CDR technologies is required to meaningfully contribute to climate action and as we reviewed above, scaling reduces cost. To appreciate the relationship between scaling and cost we need to understand the basic dynamics of economies of scale. To illustrate, consider how much the costs of solar cells have declined in the last couple of decades. Since 1977 the cost of photovoltaic solar panels has declined by a factor of 100 (McGrath, 2017). Like solar and wind power we can expect the costs of CDR technologies to fall rapidly once production is scaled up.
Although the scale of the challenge we face is daunting (Babiker et al, 2018), upsizing is also the key to reducing costs. As explained by Sen. Whitehouse, “We need to design and deploy technology to capture lots of carbon from our atmosphere at a pace never before seen,” (Welch, 2019). To get a sense for the scope of this undertaking consider what scaling would mean for the world’s first working carbon capture plant. The Climeworks plant can capture 900 tons of carbon dioxide in a year, according to the company’s own calculations 750,000 shipping container-sized units would be needed to capture 1% of global emissions. To capture 10 Gts of emissions, between 10 and 20 other carbon capture companies would have to build out similar operations (Peters, 2017).
The massive rollout required augurs questions about scalability because CDR technologies are still at an early stage of development (Peters, 2017). However, research is helping to shed light on the scalability of CDR technologies. An interactive geoengineering map, prepared by ETC Group and the Heinrich Boell Foundation, shows the locations of geoengineering projects all around the world including carbon capture (Etc Group, n.d.). Between 2012 and 2017 the number of geoengineering projects (including carbon capture) increased from 300 to 800 (Etc. Group, n.d.). While the number of CDR projects is growing, it is still very far from the required scale.
The prospects of scaling CDR have received mixed reviews. According to the National Academy of Science, the combination of currently available NETs could be ramped up to the 10 GtCO2 level by 2050 (NAS, 2019). However, others are less optimistic about their ability to scale. “There is a real risk they will be unable to deliver on the scale of their promise” (Anderson, 2016). Climate scientist Chris Field cautions that carbon removal technologies are not a “silver bullet” adding we don’t really know how quickly they can scale or whether they can remove atmospheric carbon in a meaningful way. “There is a long way to go to see whether it will have any large-scale impact,” Field said (Service, 2018).
Building out CDR infrastructure capable of meaningfully reducing atmospheric carbon is a massive undertaking and it will not be easy. In 2007, Richard Branson offered $25 million to anyone who develops a commercially viable technology capable of removing at least 1 billion tons of CO2 annually from the air for 10 years. The prize has yet to be claimed.