Reversing Emissions

Carbon dioxide removal (CDR) is an activity that consists in removing carbon dioxide (CO2) from the atmosphere to durably store it in geological, terrestrial, or ocean reservoirs or in products (IPCC, 2022). The process of drawing down the CO2 from the atmosphere, like photosynthesis does, is referred by the term “sink” while the final storage of the CO2 is referred as a “reservoir” when it is not a product. Therefore, while some methods of CDR aim at directly sucking the CO2 out of the atmosphere through technological means, other aim at reinforcing existing natural sinks so as to make them more efficient in removing CO2. In other words, CDR does not only include planting trees on a large scale but many other methods, intervening at various steps of the carbon cycle, on land or at sea.

“All Global Modelled Pathways involve…CDR”

While CDR has been studied for several decades, the publication of the IPCC Mitigation Report in 2022 has led to an intensification of attention given to CDR, with a particular emphasis on emphasizing its key role in climate mitigation.

The report indicates that, in addition to significant reductions in CO2 emissions, the world will need the use of CDR to compensate residual emissions (ie., emissions from sectors who cannot reach carbon neutrality by emission reductions alone, so called hard-to-abate-sectors), or to reverse an overshoot (ie., removing the surplus of CO2 in the atmosphere to bring back the temperature to 1.5°C after it has exceeded 1.5°C). A third scenario on how to deploy CDR, not mentioned by the IPCC, could also be to compensate what is commonly referred to as “business as usual emissions”. In that scenario, CDR would compensate emissions that are not necessarily “hard to abate” but from sectors that would see more benefits in compensating their carbon footprint through CDR rather than cutting their emissions. This position is unsurprisingly left out by the IPCC as it provides a dangerous incentive to rely on CDR to mitigate climate change instead of reducing emissions. Since CDR does not come without environmental risks it should be kept to a minimum and only serve as a last resort option to reach the target of the Paris Agreement. Emission reductions which are, in environmental terms, purely beneficial, should thus be the preferred option in climate mitigation strategies, keeping CDR as a last resort option.

The “Tech-Fix” Caveat

This legitimate fear of seeing the existence of CDR as an incentive to delay emission reduction applies particularly to the third scenario but it also affects the discussions on the two previous options as well. On the one hand, resorting to CDR to compensate “hard to abate” emissions places a heavy burden on the definition of “hard to abate” as the width of the definition will influence the degree of CDR deemed necessary. On the other hand, using CDR to reverse an overshoot in the planet’s temperature or in CO2 atmospheric concentration may imply that there is only a minor risk in the short term, since the situation can be “fixed” later. Both scenarios thus present caveats in terms of providing wrong incentives regarding climate action which has pushed some to reject CDR entirely. Yet, it would be too naive to assume that the world can now effectively reach the target of the Paris Agreement without any form of CDR given that all the pathways predicted by the IPCC limiting global warming to even 2°C by the end of the century include the deployment of CDR.

Ultimately, CDR remains a controversial area still under research. But as time is running out, the pressure for setting effective regulations has increased as more startups require permits to test or deploy their technologies. Although there is currently no global regulatory framework in place to govern CDR activity, two international legal regimes have directed their attention towards the latter, with a particular focus on marine-based CDR, given the potential for transboundary effects associated with this particular type of activity.

CDR in International Regimes

The Convention on Biological Diversity (CBD) is the largest of these two international legal regimes and regroups 196 Parties. With a mandate focusing on protecting biodiversity, the CBD has mostly looked at CDR with worried eyes. Through its Conference of Parties (COP), it has therefore repeatedly since 2008 warned through resolutions of the danger of “geoengineering”, emphasizing that, in the absence of a robust scientific background and in the absence of regulatory mechanisms, no activity of “geoengineering” should take place with the exception of small scale scientific experiments.

The second initiative was taken by the COP of the 1972 London Convention on the Prevention of Marine Pollution by Dumping of Wastes and Other Matter (London Convention, LC) and its 1996 London Protocol (LP). Within that smaller framework (87 and 54 Parties respectively) concerned with the dumping of materials and waste at sea, the question of “marine geoengineering” suddenly surfaced in 2008 after the private company Planktos revealed plans to drop iron dust in the Pacific, a process dubbed ocean fertilization, in order to sell carbon offsets. Since then, the COP to the LC/LP has adopted resolutions on fertilization notably echoing the worries of the CBD Secretariat on the need to prioritize scientific research and to postpone deployment. However, the LC/LP-COP went even further by adopting  a first assessment framework on ocean fertilization research activities in 2010 and most importantly, by taking the first step towards a regulatory framework on marine geoengineering in the form of an amendment to the London Protocol in 2013. These developments have therefore placed the London Convention (and particularly its London Protocol) at the centre of any discussion on the regulation of marine geoengineering or marine CDR, even though it mostly remains an attempt rather than an accomplishment. Indeed, since this amendment has been proposed in 2013, only six states (the UK, Finland, Estonia, Norway, the Netherlands, Germany) have ratified it, with Denmark and Australia nearing their accession. Thus, the amendment is falling short of the 36 ratifications (two-third of the London Protocol parties) necessary for the entry into force of the amendment. Besides, the amendment only establishes a frame that needs to be filled with content, as is typical for framework agreements. And, at the moment, only ocean fertilization research activities would be concerned. Considering that more than 10 years have passed since the adoption of the amendment, discussions are therefore open on whether this amendment has a future. While the LC/LP-COP has started to consider adding new CDR methods to the amendment, thus amending the amendment before it has even entered into force, some states have instead emphasized that this may be a waste of time and resources. Instead, the LC/LP-COP should rather focus on promoting ratification or evaluate the application of the existing frameworks to marine geoengineering.

CDR at the Climate COPs

Turning to climate change governance, CDR remains, perhaps surprisingly, low on the agenda. While the concept of CDR can already be inferred from the text of the 1992 UN Framework Convention on Climate Change (UNFCCC), where Article 4.1(d) mentions the enhancement of sinks and reservoirs of all greenhouse gases, CDR has so far mostly been limited to  the forestry sector. In fact, even though afforestation and reforestation can technically be seen as land-based CDR methods, they are not usually referred to as such.

In its final decision, the Climate COP28 in 2023 mentioned for instance the “enhancement of forest carbon stocks” without using the term CDR. The 2nd Report on the State of CDR published by a group of scholars therefore differentiates between ‘conventional CDR methods’ (mostly forestry) and ‘novel methods’ which require a higher degree of technology, either in the research phase, in the deployment phase or both.

While discussions on CDR are nevertheless taking place at the COPs, they are limited to side events gathering experts from developed countries, stakeholders associations, and private companies with an interest in the activity, such as Microsoft, backed up by its former CEO, Bill Gates. Since the number of states interested in novel forms of CDR remains low, negotiations at the COP29 will most likely leave out the topic of CDR and instead focus on more pressing matters such as finance (for more on this topic see Toussaint/Martínez Blanco and Fajordo/Huffman/Zenteno Villa in this symposium).

Yet, developments on a global UN carbon trading system envisaged by Article 6.4 of the Paris Agreement would have repercussions on CDR.  Indeed, as CDR activities are similar to carbon offsets in the sense that they can be used to compensate emissions, their proponents will be interested in developments in carbon markets that affect the economic sustainability or even profitability of CDR. Thus, negotiations on the regulation of the UN carbon market and on the methodologies for accounting emissions and removals will be crucial for the emergence of a CDR sector.

Twisting the Narrative

Beyond the technicalities, Climate COPs are also a mean to advance agendas and narratives. In that context, it will also be the role of CDR experts to disentangle genuine or intentional confusions around what can be qualified as CDR and what cannot. The final document of the COP28 is particularly illustrative in that regard, when it recognizes the need to accelerate “removal technologies such as carbon capture utilization and storage, particularly [in] low-carbon hydrogen production.” While this statement uses the word “removal”, the technology aimed at here is not CDR but carbon capture utilization and storage (CCUS or CCS) which is fundamentally different than CDR (on CCS, see Østgaard in this Symposium. Indeed, while CDR removes CO2 from the atmosphere, thereby creating a net reduction of CO2, CCS simply captures the emissions of a point source (e.g., a powerplant) to prevent them from reaching the atmosphere. CCS is therefore, at best, neutral in emissions but certainly not negative (whereby the expression “low-carbon hydrogen production” implying residual emissions rather than removals). This confusion between “removals” and “capture” in the COP28 final document is crucial because the latter is based on the desire to maintain the use of fossil fuels while at the same time making this energy source carbon neutral. Consequently, CCS is naturally attractive to stakeholders interested in perpetuating a fossil fuel-based economic model. CDR on the other hand, despite its caveats discussed above, is unrelated to any economic model or energy policy and does not compete with the expansion of renewable energies. Independently of the scientific merits of both techniques, it is therefore crucial to distinguish the two to detach CDR discussions from fossil fuel controversies which can directly impact the public acceptance of the method or greenwash unsustainable CCS practices.

Setting the Stage for Integrity

In conclusion, the CDR field remains gatekept by its high cost in terms of scientific capacity, which prevents most countries from effectively participating in regulatory and policy discussions on the matter. Yet, the effective use of CDR will cross borders and ultimately require international governance. In this event, broader participation will be crucial to establish such a framework and efforts need to be made now to avoid lasting biases. While research is still ongoing, particular attention is given to establishing definitions to ensure the integrity of climate action.

In this context, even though the negotiations in Baku are unlikely to focus on CDR, wider discussions on methodologies, definitions or carbon markets will affect the sector of CDR. For instance, States could explicitly agree to differentiate between emission reductions and removals within their climate targets, allowing genuine reductions to be highlighted separately from removal activities, including through CDR. This point, which has been called for by some CDR experts, would also clearly separate CCS from CDR, since CCS would only fit within the reductions. With the next round of climate pledges (called nationally determined contributions, NDC) just around the corner in February 2025 and considering that these will run until the crucial year of 2030, a discussion on pledges would therefore be timely.