The Covid-19 pandemic, combined with ominous signs of global warming, made 2020 and 2021 years of widespread anxiety. Many for the first time confronted the possibility that humanity was doomed by short-termism and greed. It may still be. But a host of developments have helped move climate discussions into a more realistic space, somewhere between immobilizing dread and a misplaced optimism. At the heart of that adjustment is the combination of a deeper public (and corporate) awareness of global warming, an increasing willingness of consumers to hold elected officials and companies to some account, and more and better information about what can realistically be done.
Climate activists have long been averse to talking about the promise of technology, for fear of weakening pressure to cut CO2 emissions, which remains the first line of defense against global warming. But a dire and specific assessment by the Intergovernmental Panel on Climate Change (IPCC), the UN body that tracks scientific knowledge of climate change, seems to have helped boost interest in carbon capture, where previous reports have not.
In a 2022 report, the IPCC concluded that drastically reducing carbon emissions is no longer sufficient: the world has now reached the point where NETS (Negative Emissions Technologies) will be needed to keep global warming to within the critical two-degree Celsius threshold that was the focus of the 2015 Paris Accords. Accordingly, humans will need to remove billions of tons of carbon annually from the atmosphere by mid-century, to bridge the gap between pledged emission reductions and the ‘carbon budget’ – the amount of carbon remaining to be emitted before a breach of the 2 degree limit is inevitable.
Within the box of technological assists, carbon dioxide removal (CDR) is increasingly seen as the most promising space in which to make up the shortfall in the carbon budget. NETS technologies include those that grab carbon from the atmosphere (through Direct Air Capture, or DAC), or from the oceans, or speed up direct weathering of minerals, or promote growth of new carbon sinks. The basic technology behind DAC has been around for decades – ironically, pioneered by the fossil fuel industry to drive what is called “enhanced oil recovery” (EOR) from older wells: carbon-filled mixtures are re-injected into oil formations to help flush out harder-to-catch hydrocarbons.
Over the last decades, there have been formidable obstacles to a viable carbon capture strategy, including the absence of a developed market for captured carbon, the scarcity of investment for R&D, the lack of renewable energy sources capable of powering large negative emissions projects, and of course, partisan politics. But there’s been steady progress on most, if not all of these fronts.
Renewable power – including wind, solar, and geothermal – has become more broadly available; consumer pressures are moving companies towards “net zero” emissions planning; the up-take of ESG (Environment, Social and Governance) accounting means that companies are no longer able to support claims of carbon neutrality with hand-waving: offsets with uncertain capture (planting trees, for example) are harder to justify to the public and shareholders when emission streams are growing. Recently an environmental group sued Air France-KLM was recently sued for “misleading” public carbon neutrality claims, given the mismatch between the uncertain result of its carbon capture commitments and the relative certainty of the aviation’s growing carbon footprint. Experts think this legal action is just the beginning. And despite the fact that climate has been a staple issue for partisan warfare in the United States, carbon capture is one remedy where partisan chasm isn’t as deep: big oil understands that effective carbon capture can extend the economic lifespan of fossil fuels.
The IPCC report may have broken the dam in favor of NETS, but the combination of steady technical progress and the threat of huge near-term financial losses due to global warming laid the foundation for the the movement of billions of dollars into carbon capture tech in the last few months. Among the beneficiaries are a small but growing number of companies like Climeworks, the most visible CDR tech firm, runs a flagship direct air capture facility in Iceland, that removes about 5000 tons of carbon from the atmosphere per year. The company offers individuals the option to purchase carbon removal with their credit card. Running Tide, a Maine-based company, has been working since 2010 to develop a system for growing macro-algae (i.e., kelp forests, a carbon sink) and associated aquaculture across swathes of open ocean. The technologies are promising, but the biggest challenge remains scalability. At 5000 tons/year, the world would need hundreds of thousands of units to capture enough carbon to be meaningful.
Carbon capture advocates frequently cite the growth of photovoltaics (PV) to make that point that technology can advance quickly: solar cells have nearly doubled in efficiency between 2015 and 2020. Others note that the active constraint to effective carbon capture is not technology but political will and funding — a public private partnership between the government of Norway and Statoil resulted in the world’s first (heavily subsidized) point-source CDR project, “Sleipner,” which since 1996 has captured and re-injected into underground storage about a million tons/year of carbon from a natural gas drilling platform in the North Sea. Sleipner demonstrated that significant carbon capture and storage levels at emission source points (where the carbon concentration is highest) is possible.
Capture6, based in California and New Zealand, is perhaps the only carbon-capture firm that addressing the economics – and therefore scale – problem head-on. The firm marries existing technology and infrastructure practices to the rapidly growing market for “high quality” corporate carbon offsets (carbon that can be reliably measured and stored more or less permanently).
According to Capture6’s co-founder Ethan Cohen-Cole, “There’s a huge unmet demand for non-biological CDR by Fortune 500 companies, and even many governments with net-zero goals. Satisfying that present and growing demand means utilizing and reorganizing the technologies that industry already knows how to deploy at massive scale. Capture6 has looked at equipment and processes used in industries such as desalination and is reorganizing them for carbon capture.”
Capture6 uses salt-water and electrochemistry as a path to absorption of atmospheric carbon, which is incorporated into calcium carbonate – what sea-shells are made of — and then returned back to the ocean. At plant scale, the process removes as much carbon as Sleipner, but from the ambient air, not from the equivalent of a smokestack, and while improving the ocean’s chemistry. That, too, is an innovation, as other CDR technologies do one or the other. Capture6 believes its industrial-scale solutions can realistically capture millions of tons of carbon/ year by 2030, well before mid-century, when larger extractions will be needed.
While the development pathways for CDR and NETS remain unclear, there’s an increasing consensus within the scientific and industry community that these technologies are both necessary and here to stay, even if they do not provide a silver bullet to the climate crisis.