Turning the Tides on the Climate Crisis
The world's oceans will be a vital ally in combatting climate change.
The glaring omission from this picture is that the ocean has been a significant ally when it comes to emissions mitigation and climate regulation since the industrial revolution. The global ocean soaks up nearly a third of carbon dioxide emitted from natural and human sources, contains about 50 times more carbon than the amount in the atmosphere, and absorbs 90% of excess heat resulting from climate change.
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The Planet’s Most Important Carbon Sink
Through observation and modelling, scientists have come to understand that the atmosphere and the ocean work like a pendulum to moderate the earth’s climate. Oceanic currents are responsible for both moderating atmospheric temperatures by absorbing thermal energy and anthropogenic carbon output, and pushing our meteorological systems to the extremes through thermocline circulation.
This is as troubling as it is an opportunity. The IPCC AR6 report warns with grim confidence that on our business-as-usual trajectory of increasing emissions, the ocean will lose its effectiveness as a carbon sink. This process is perpetuated through a cascading array of consequences which are already taking place:
The ocean, while absorbing excess heat, has warmed substantially
Warming sea water circulates less, and settles into stratified layers
In the surface layer that interacts with the atmosphere, increased carbon absorption will increase acidity. Acidic and warm water has a lower capacity to absorb subsequent emissions.
Warmed, acidic water will only hold carbon in the short term. Rather than mixing with deep seawater where it would be stored for the long-term, it will seep back into the atmosphere.
These changes in seawater resulting from climate change do not support photosynthesising life. Living biological carbon pumps like phytoplankton, microalgae, coral reefs, and seaweeds will lose productivity at removing carbon and releasing oxygen.
Even if we achieve our most ambitious emission reduction pathways, increased levels of carbon and acidity in the ocean will need to be addressed. This is even more so concerning considering an aspect of carbon exchange often overlooked by reduction schemes – the levels of carbon in the ocean and atmosphere equilibrate. If atmospheric carbon concentrations reduce significantly, while levels in the surface ocean remain the same, the ocean would still respire excess CO2 back into the atmosphere. Prior to the industrial revolution, the ocean actually had a net release to the atmosphere of roughly two thirds of a gigaton annually, a process which reversed as anthropogenic emissions increased. If we only focus on emissions reduction, while levels of carbon dioxide entering the ocean might gradually decrease, the net flux of carbon from the ocean may ultimately return to the atmosphere, negating a portion of our GHG abatement.
The first and most critical step in reducing the scale and impacts of climate change has always been to evolve our societal behaviours to reduce emissions and live more harmoniously with the planet. Even so, the IPCC prescribes a removal of 2 to 20 gigatons of carbon from the atmosphere each year to limit warming to 1.5 degrees. Carbon dioxide removal (CDR) is an prescribed, unavoidable step in moving towards a healthier earth which supports the wellbeing of all species.
Regenerating the Global Ocean
Technologies and strategies which preserve and enhance the health of the ocean’s carbon cycling and storage capabilities play an integral role to reach beyond net-zero towards a carbon negative future. The most established pathways to enhance ocean’s CDR capabilities are:
Blue carbon solutions, typically the conservation and restoration of seagrasses, reefs, wetlands, and mangroves, that protect and enhance existing biological carbon sinks. Apple and Conservation International are working to preserve a 27,000-acre mangrove forest in Colombia, the first fully accounted carbon offset credit for a mangrove. These projects are often led by NGO and conservation agencies. The Delta Blue Carbon Project has protected and restored 350,000 hectares of tidal wetlands, and could see up to three million carbon credits traded with buyers including Carbon Growth Partners, Microsoft, Trafigura and Respira International.
Macroalgae cultivation, through the growing of seaweeds and kelp which photosynthesises carbon, and the long term storage of that biomass in both wild and engineered settings. Think Running Tide, Kelp Blue, Pull to Refresh, among others.
Microalgae cultivation, whether that be in closed systems such as photobioreactors or membranes, or in endemic, open conditions like the boundaries of continental deep sea upwelling. A standout in this area is Brilliant Planet.
Electrochemical CDR, through both electrodialytic and electrolytic methods which utilises a similar technological paradigm to direct air capture but applied to seawater. Equatic is a spinout of UCLA’s Institute of Carbon Management tackling ocean CDR using electrodialysis.
Ocean alkalinity enhancement (OAE), which counteracts acidification using alkaline substances to change the chemistry of seawater, making it more conducive towards carbon sequestration and storage. Planetary Technologies and Vesta fall under this umbrella.
Emerging Pathways for Ocean Carbon Removal
Other approaches we’ve identified as potential pathways for ocean carbon removal include novel solutions such as a photochemical carbon removal, spearheaded by Seattle-based startup Banyu, genetically engineered phytoplankton, as is alluded to in this YCombinator request for startups, and artificial upwelling and downwelling technologies.
Challenges and Opportunities for Ocean Carbon Dioxide Removal:
Many of these technologies, while beautifully ambitious, remain in their nascent stages. Some, such as kelp and seaweed cultivation, have been the welcome recipients of press noise and well intentioned optimism. The opacity in the area of marine CDR is clearing up as the solutions become more mature; just last week, the US Department of Commerce and NOAA announced $24 million for projects that will tackle the climate crisis by researching marine carbon dioxide removal strategies. As peer-reviewed, proof-of-concept data emerges, and consensus forms around the best approaches to marine carbon removal, these are the challenges and opportunities we anticipate in the area:
Challenge: Unlocking CDR strategies which go beyond net-zero carbon removal to ecosystem restoration, circular economies, and net-positive paradigm change
Opportunity Space: Regenerative ocean carbon reduction will form positive feedback loops - restoring carbon sinks to their full capacity, rebalancing the slow and fast carbon cycles, creating new materials from waste rather than extraction, and speeding up the energy transition to renewables.
The climate crisis is not just a carbon crisis - it’s also a biodiversity crisis and a societal crisis. Addressing carbon dioxide is just one piece of the wider climate solutions puzzle, albeit a critical one. As investors looking to catapult regenerative technologies that heal at a systems-level, we see the greatest paradigm shifting potential in approaches that address ocean carbon reduction and most urgent threats to human and environmental health. CDR projects will need to meet the goals that communities have beyond climate restoration — like addressing environmental health, climate justice, ecosystem regeneration, and economic well-being.
Ideas in this realm that excite us include blue carbon approaches that enhance coastal resilience and support biodiversity; electrochemical CDR which produces blue hydrogen; carbon removal approaches which produce enough renewable energy needed to sustain its own operation and even return surplus energy to the local grid; CDR approaches which deliver an easily measurable, pure stream of usable CO2; OAE deployed locally to improve aquaculture systems and support healthy fisheries; artificial upwelling for microorganism cultivation could both improve photosynthetic productivity and mitigate the impacts of warming sea surface temperatures; phytoplankton engineered to sink into the deep water storage, returning carbon to slow carbon cycles; microalgae that treats wastewater and supports communities impacted by inequitable environmental hazards; software and MRV tools that catalyze market demand for blue carbon credits produced by smallholder and indigenous farmers; and so many other emerging dual-use solutions that go far beyond emissions reduction.
Challenge: Developing a holistic, systems-level understanding of the impact of CDR pathways on marine ecosystems, including their benefits, risks, and carbon flux.
Opportunity Space: The complexity of marine ecosystems cannot be overlooked when we turn to solutions which harness the inevitable opportunities related to it. Recently, researchers at University of Tasmania published an analysis showing that measurements of carbon flux on blue carbon projects fail to include the extended network of organisms supported by restoration projects. This means they may vastly underestimate the carbon released by the ecosystem as a whole. Any underestimation is far from benign; even ecosystems are carbon neutral, illusory gains in CO2 removal may well be traded as carbon credits and/or used to offset emissions. This risks the potential for buyers to emit more emissions than would have been released into the atmosphere to begin with.
At the core of their model, most CDR businesses will rely on the sale of carbon credits, and there is a lack of viable MRV systems for measuring the carbon sequestration of these projects effectively. We’d like to see companies innovating enabling technologies in the Measurement, Reporting, and Verification space. This would be impactful for the whole suite of ocean CDR methodologies, in order to facilitate demand for the high quality ocean carbon credits that underwrite their business models, and to ensure that carbon removal is accurately equivalent to the amount traded.
What this could look like: improved software and hardware stacks for measuring and collecting data on carbon flux, marine life and behaviours and/or aquaculture systems under difficult environmental conditions; applying machine learning, advanced modelling and AI algorithms to data collected about these projects; B2B marketplace creation which integrates improved MRV across the value chain to demand creation and B2B sales of high-quality credits.
Challenge: Identifying the Ocean CDR approaches that optimise the maximum carbon removal while minimising their embedded carbon emissions across the value chain.
Opportunity Space: While technologies to process seawater for electrochemical CDR, or mining for alkaline materials to deploy OAE may be reliable and mature, they remain incredibly resource intensive, particularly given their energy consumption. We need to weigh the opportunity cost of utilising a significant amount of renewable energy to power these technologies against the benefits of allocating this power towards the grid.
CDR pathways such as kelp and microalgae have a variety of promising co-benefits and byproducts that may be derived from their biomass. However, only 10% of the carbon sequestration potential is realised when seaweed is farmed for the production of consumer goods, rather than being sunk in deep ocean storage. We need to determine what the optimal allocation of this biomass would look like; and additionally, to solidify our understanding of the most impactful use for the approach. In order to underwrite an investment into a CDR approach that farms kelp, it’s critical to determine whether the organism would have the most carbon impact by providing ecosystem services, alternative plastics to replace petrochemical-based materials, low-carbon food sources – versus when these organisms would provide the most value in by being farmed explicitly for carbon abatement, and then sunk in deep, long term carbon storage. Moreover, companies deploying biological pathways for ocean CDR who explore revenues in both carbon markets simultaneously to other use-cases de-risk their business model from depending solely on volatile carbon markets, and have the flexibility to allocate the resource for different use cases as our knowledge deepens, ultimately optimising planetary benefit.
Challenge: Propelling the solutions with the potential to scale at the rate and magnitude needed to match the urgency of the climate crisis.
Opportunity Space: Global carbon dioxide emissions from fossil fuels and industry were over 36.8 billion tons (GtCO₂) in 2022 - their highest ever level. This makes it all the more critical to concentrate our support on not only the most efficient technologies, but also those with the regulatory space, capital intensiveness, and readiness-for deployment that will allow them to make an impact on the fastest time horizon, at the scale mandated by the latest science.
The CDR Primer, a formative document in the area, identifies indecision as a key friction in the deployment of carbon removal technologies. The constant search for a best answer may overlook the urgent need to test and explore more than one strategy for carbon removal. Benchmarking technologies which have the potential to scale rapidly by their relatively low resource needs -– particularly land, energy, and human capital — can help us move from decision point to rapid deployment. Climate change and carbon emissions are incredibly time sensitive, and irreversible tipping points will be surpassed if CDR technologies are not removing adequate levels of CO2 by 2050.
Finally, companies relying on carbon markets for their primary revenue stream should demonstrate their ability to attract buyers for their credits, and to lower costs of capital over time. Traction with customers seeking long term agreements for high quality carbon removal credits is critical to bringing permanent, engineered solutions competitive with mature solutions, such as reforestation. The Microsoft-Heirloom carbon capture deal for example, will significantly lower cost of capital for Direct Air Capture companies that are seeking to finance infrastructure projects, such as future carbon dioxide removal facilities. Oceans CDR solutions will need to seek similar partnerships and uptake from the private sector buyers to reach the magnitude needed for significant impact.
The global ocean is an incredibly important carbon sink that supports millions of species and coastal communities. It will play a critical role in determining how our carbon emissions ultimately impact the climate. We find ourselves at a crossroads where we can seize the opportunity to consider the co-benefits and utilisation of carbon removal outputs as opportunities to create a circular, regenerative system that goes beyond net-zero emissions, aiming for carbon-negative goods and leaving a positive impact.
At ReGen, we’re confident that solutions which harness the potential of oceanic systems to mitigate climate change have the potential to catalyse profound impact at the planetary scale. If you share our passion for regenerating the ocean, drop me a line at firstname.lastname@example.org!
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