Dispatch from Texel

mCDR - working together to go farther

At the start of November Ecomonitor had the privilege to be invited to attend and contribute to a two day Symposium on mCDR (marine Carbon Dioxide Removal), organised by the Sustainable Ocean Community, and hosted between NIOZ and Utrecht University. The Sustainable Ocean Community is dedicated to creating the solutions necessary to tackle the coming challenges to the global ocean, and does so by bringing together scholars and stakeholders across many disciplines. This commitment to interdisciplinary collaboration was well on display during the two days of talks and meetings, with representatives in attendance from the four broad categories of research: science, policy, industry, and future experts (i.e. students). A series of fantastic talks were given on day 1, kicked-off by an insightful keynote address. With day 2 allowing for a more focussed face-to-face discussion on what the near future of mCDR should look like, where the research is going, and what the expert opinion(s) about that is.

What is mCDR exactly?

For those that may not yet be in the know, or who would like a quick refresher, mCDR consists of six loosely connected philosophical approaches to removing excess carbon dioxide (CO2) from the global ocean. These can be loosely classified into three groups. Ecosystem based methods: ‘Ecosystem Recovery’ and ‘Seaweed Cultivation’. Methods more directly affecting biological processes in the ocean: ‘Ocean Nutrient Fertilisation’ and ‘Artificial Upwelling/Downwelling’. Or those focussing more on the chemistry of seawater itself: ‘Ocean Alkalinity Enhancement’ and ‘Electrochemical Processes’. No one method is a silver bullet, with all of them having a range of pros and cons (Figure 1), and some methods are favoured more than others. Ocean nutrient fertilisation, for example, was one of the first major mCDR methods to gain notoriety (ocean iron fertilisation), but has fallen out of favour over the past decade due to the range of unknown environmental impacts it may have, while only potentially providing dubious CDR benefits in return. Furthermore, artificial upwelling/downwelling, the process of strategically pushing ocean water up to the surface from depth (or down to the depths from the surface), is an interesting engineering challenge, but will very likely not be able to deliver anywhere near to its operational cost. Of the four methods still being broadly pursued by the marine community, the option with the lowest environmental risk, environmental recovery, also has the least capability to scale the potential for CO2 sequestration. It is therefore an accepted reality that if a viable technological option to help address the CO2 emitted by human civilisation is to emerge from the ocean, a certain amount of ecological risk must be accepted. While this may sound alarming, or perhaps defeatist, it is important to note that if we do nothing, the natural world will almost certainly face a much greater risk from the rapidly changing climate. How then to balance the two?

Figure 1: The six types of mCDR (marine Carbon Dioxide Removal), and the strengths and weaknesses of each from an operational perspective. Source: Additional Ventures; now Outlier Projects.

Why does mCDR matter?

This is why the study of mCDR, and the community building up around it, matter. Because the ocean, willingly or not, has been recruited by the research community into our self-made struggle against the anthropogenic forcing of the global climate system. The scale of this task is truly Herculean, and current efforts have only just begun to scratch the surface (Figure 2). With emissions from human civilisation now reaching ~40 billion tons of CO2 equivalent per year (40 GtCO2e/year), there is no serious actor in the space that thinks we can offset this entirely via technological means, no matter how vast the ocean may be. Indeed, even in the most generous scenarios, technological and natural solutions working in tandem can only offset a small portion of human emissions. It is therefore critical that we reduce emissions as rapidly as possible, while scaling up as many CDR methods as rapidly, and safely, as possible, in order to offset the hard/impossible to abate emissions from certain sectors (such as some forms of farming and construction). It is a grand challenge, or according to some, the grand challenge, of our collective society at this current moment. We must explore all avenues open to us, on air, land, and sea.

Figure 2: Barplot showing the magnitude of the difference in CDR from conventional methods (primarily afforestation/reforestation) and novel methods. With mCDR being grouped under the ‘Other novel CDR’ methods in this plot. NB: Annual human emissions are ~40 GtCO2/yr, meaning that all novel methods of CDR together currently contribute a removal of ~0.003%/year. Source: Smith et al. (2024).

Can mCDR bring us together?

It is therefore important to note that, due to the urgency of the situation, and the critically important need to begin to remove as much CO2 from the atmosphere and the oceans as quickly as possible, industry has begun to pull ahead of academic research. This is a positive sign that industry is ready and willing to participate, and even lead in, the fight against the changing climate. But it also causes concern for members of academia, and the public at large that some methods being pursued may cause more harm than good. As mentioned above, ocean nutrient fertilisation was one such victim of this concern. The general public is often given to expressing their concern over large scale experiments being performed in their backyards without their prior consent or understanding of the risk/benefit calculus. And rightly so. 

But these conversations, while difficult, must be had. We no longer have the luxury of waiting. We must act now, and we need to develop as deep of a consensus between parties as possible. It is on this point for which I was so happy to see that, while different sectors of society have their own reasons for coming to the table, everyone agrees that the dialogue and collaborative efforts forming around this space are a must. While we at Ecomonitor are pursuing methods most closely related to ecosystem recovery (due to our focus on biodiversity and co-benefits), we acknowledge that there is a need to pursue chemistry based solutions due to their potential to scale to gigaton potential (e.g. ocean alkalinity enhancement and electrochemical processes).

Is mCDR the answer?

Until only recently, this sort of language was considered to be unacceptable by a large portion of the research community. In some places, it still is. Specifically, I am talking about the acceptance of the need to use science/technology based methods to remove anthropogenic CO2 emissions from the natural world. The rationale in the past was that by allowing for these dialogues to take place, it would disincentivise actors from reducing their emissions, rather favouring a solution that may appear at some point in the future. As was pointed out by one of the speakers at the Symposium, this still very much remains a risk. However, even the IPCC now advises that the only possible pathway that can limit global warming to 2°C or lower (1.5°C is no longer realistic) will require rapid deployment and scaling of CDR options to offset ongoing emissions. Policy makers will require confident estimates on the risks and hazards of these options at large scales if they can govern in the best interest of the citizens they represent. Allowing for this moment in time to be an opportunity for the scale and speed of industry to provide the real-world basis for academic research to understand and better model what impacts these mCDR options may have. Industry likewise needs the support of academia in order to safely pursue options that will work best for them and the relationship they have with the general public. There are many different actors in this noisy space, but it is also an amazing opportunity for us to come together for the good of the planet.