Current research at the Centre for Climate Repair at Cambridge University tackles how we can reinvigorate the world’s largest potential carbon sinks: oceans.
The ocean is too powerful to omit in the climate conversation
With the world’s attention on COP26, it’s hard to ignore that ocean-based solutions have been largely ignored in today’s climate crisis conversations. Oceans cover most of our planet and trap around 93% of the excess heat caused by climate change. For years, global talks have framed the ocean as a victim of anthropogenic activities and climate change effects—phrases like ocean acidification, coral bleaching, habitat degradation, biodiversity loss, overfishing, and islands of floating plastic rule the day. These are inevitable challenges to face as the world works to recognize the power of Earth’s oceans in the race to reach drawdown as quickly, safely, and as equitably as possible. When it comes to ocean-based climate solutions, we need international cooperation, engagement of all stakeholders (especially coastal communities), ocean-smart financing, and successful enforcement.
Shifting the oceans dialogue from “victim” to “solution” is a game-changer. Stopping and reversing marine habitat degradation is a powerful tool for carbon sequestration, but it would also halt devastating biodiversity loss and provide climate change adaptation for marine organisms and coastal communities. Improving the ways we catch, produce, and consume seafood will not only reduce GHG emissions but also allow global fish populations to regrow, securing food for future generations while eliminating inequalities in the fishing industry. Oceans, therefore, offer cascading benefits that go far beyond the climate crisis.
The key instrument for the development of some ocean-based solutions is successful protection and restoration of ocean habitats, often achieved via Marine Protected Areas (MPAs). Coastal wetlands (mangroves, seagrasses, salt marshes) are already well-recognized champions in carbon removal, sequestering CO2 in their biomass and the soil below. Other marine habitats that have achieved less attention—but share a high potential for carbon removal—are macroalgae forests. Macroalgae, being one of the most productive organisms on Earth, sequesters large amounts of CO2 which is (in-part) naturally exported to the deep sea.
The fate of carbon stored at the seafloor depends on whether the seafloor remains untouched. Activities that degrade ocean seafloors such as bottom trawling and deep-sea mining should be prohibited in carbon-rich ocean areas. MPAs strategically designed for the protection and restoration of blue carbon habitats are therefore a must for achieving significant climate impact. Passive restoration should be incorporated with active restoration; even with today’s best global efforts to conserve these ecosystems, some continued decline due to climate change is likely inevitable.
Transforming the ways we exploit and produce seafood provides another set of powerful ocean-based solutions. Global fisheries are experiencing overcapitalization (for example, there are far too many vessels) and overfishing, mainly due to open-access fishing policies and harmful subsidies. By optimal management—such as fishing at “Maximum Sustainable Yield” and by promoting artisanal fishery over industrial fishery—a significant emissions reduction from fuel used by vessels is possible. In tandem, we would expect to see rebuilding fish stocks and greater carbon sequestration in fish biomass—a boon for oceans and human communities around the world.
Due to the continuous overexploitation of wild fish resources, the aquaculture sector has become a major seafood protein provider. Because of its rapid growth, aquaculture operates under serious ongoing sustainability concerns. The majority of GHG emissions are related to feed production (including wild fish oil extraction, terrestrial animal-based proteins, soy leading to deforestation, and more) and some systems are highly energy-intensive. Promoting alternative feed components such as insects, seaweeds, and lab-based proteins—all while ensuring that consumed energy is based partly on renewables—should be a key focus for global stakeholders.
Another way of transforming the seafood industry? Immediately expanding regenerative seaweed farming is a climate no-brainer. Scaling this farming would provide powerful carbon removal (via the same mechanism as wild macroalgae), and seaweed biomass is increasingly used in a number of applications including animal feed, bioplastics, and biofuel. By unlocking the potential for market growth and creating opportunities to reduce GHG emissions from other sectors (through practices like adding seaweed to livestock feed to reduce methane emissions from cattle), this oceans solution provides surprisingly powerful benefits. The potential for seaweed farming expansion is high, with many coalitions and NGO’s ensuring the sector’s long-term sustainability.
To guarantee the success of ocean-based solutions, management plans must be a) designed wisely, b) include all stakeholders, and c) ensure long-term application. All of this, of course, requires financing. Implementing MPAs can be challenging, especially when it hits nearby coastal communities (that rely on fishing for subsistence) the hardest. One way to deal with this issue is to exclude the most damaging activities—industrial fishing), and to favor small-scale fisheries that benefit locals, not only in the potential increase in catch but also from tourism profits. Redirecting harmful subsidies from capacity-enhancing to other types of subsidies (e.g., transforming fuel subsidies to direct income payments to fishers) could help achieve fishing effort reduction and stock rebuilding goals alongside the financial benefits to locals.
We have little time to fix our climate and without ambitious, sustainable oceans management, the potential of blue carbon habitats and ocean-based solutions weakens. Ocean-based solutions not only mitigate climate change—they play a large role in climate adaptation and add benefits core to successful Sustainable Development Goals that benefit people and the planet. When we think about climate solutions, we must never forget the power of Earth’s oceans.
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