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Harnessing the power of our ocean


Blue carbon and the climate crisis

Chris Tuckett, Director of Programmes at the Marine Conservation Society, urges the government to rewild the UK’s waters

It has never been more critical for the UK to deliver an ambitious strategy to tackle the climate crisis. With Glasgow hosting COP26 in November, the time is now for UK governments to heed environmentalists’ advice and look to nature for solutions to the climate crisis.

The Marine Conservation Society’s recent report, Blue carbon: Ocean-based solutions to fight the climate crisis, published in partnership with Rewilding Britain, explores the merits of ocean-based solutions to the climate crisis. The report outlines how vital ‘blue carbon’ solutions are an effective strategy for hitting net zero by 2050.

Marine ecosystems like seagrass meadows, saltmarshes and mangroves are blue carbon habitats. This means that they can capture and store carbon from the atmosphere just like plants and trees on land. Blue carbon can be stored: in marine plants like seaweed and seagrass; in seafloor sediment where plants are rooted; and in the animals who live in the water, including seabirds, fish and larger mammals, such as whales.

Alongside their blue carbon powers, these marine habitats also provide numerous other benefits to people and planet. When healthy, they generate oxygen, help protect coastal communities from rising sea levels and remove pollutants from the water. They act as nursery grounds for commercial fish and shellfish species, and as wildlife havens.

As we face interlinked climate, health and ecological emergencies, we must consider the numerous and varied benefits that the ocean and its habitats can provide.

In 2020, as part of the UK’s commitment to the Paris Climate Agreement and to keeping global temperature rises to below 1.5°C, the UK government laid out its plans to cut carbon emissions: a reduction of 68 per cent compared with 1990 levels over the next decade, and to meet net zero greenhouse gas emissions by 2050.

We cannot achieve these targets without considering nature-based solutions – and, crucially, ocean-based solutions.

The potential of blue carbon

Reducing net carbon emissions by increasing the quantity of carbon dioxide taken out of the atmosphere and stored in long-term natural solutions like marine ecosystems can also serve to protect these ecosystems and help them recover. Research on the scale of the potential of blue carbon has revealed the following:

  • Globally, saltmarshes and seagrass – blue carbon sinks – draw down and store between them 235–450 million tonnes of carbon a year; almost half the emissions from the entire global transport sector.
  • Scientists estimate that saltmarsh and seagrass habitats fix carbon at two to four times the rate of mature tropical forests. This means the UK’s saltmarshes and seagrass beds have the carbon storage potential of between 1,000 and 2,000 km2 of tropical forests.
  • The UK’s shelf seas cover some 500,000 km2 and are estimated to store 205 million tonnes of carbon in seabed sediments – approximately 50 million tonnes more than held within our entire stock of standing forests – along with coastal seagrass and saltmarsh habitats, UK marine ecosystems store about 220 million tonnes of carbon.

The significant role of the world’s forests in reducing carbon emissions has been formally recognised through numerous initiatives and reforesting projects intended to keep carbon locked into the world’s forests on land. Unfortunately, the equivalent solutions in the ocean are often overlooked. If the UK is to reach its goal of net zero by 2050, blue carbon solutions must be considered in tandem with those on land. That’s why, at the Marine Conservation Society, we’re calling on UK governments to #RewildOurWaters.

What marine rewilding means

Carrageen, a reddish seaweed used commercially in the food industry. Photo: Peter Bardsley / MCS

Rewilding Britain defines the concept of rewilding as: ‘The large-scale restoration of ecosystems to the point where nature is allowed to take care of itself. Rewilding seeks to reinstate natural processes and, where appropriate, missing species – allowing them to shape the land and sea and the habitats within.

‘Rewilding encourages a balance between people and the rest of nature so that we thrive together. It can provide opportunities for communities to diversify and create nature-based economies; for living systems to provide the ecological functions on which we all depend; and for people to reconnect with wild nature.’

Marine rewilding is the same idea applied to a marine environment. This could mean ceasing all harmful activity in badly affected areas – including the damaging commercial bottom trawling, aggregate extraction, dredging or oil or gas exploitation – and allowing the ecosystem to recover. In others, it may mean giving recovery a helping hand through active restoration: reseeding an area with seagrass or returning lost species such as oysters.

Over the next decade harmful fishing practices such as bottom trawling and other activities such as dredging disturb seabed sediments and have the potential to result in the loss of 13 million tonnes of carbon from vital blue carbon stores, including shellfish beds and kelp forests. Action must be taken to protect and recover these vital habitats.

The Marine Conservation Society has made a start by being involved in numerous restoration projects across the UK, including European oyster restoration in the Dornoch Firth, replanting and protecting seagrass meadows on the south coast of England, and protecting kelp forests off the Sussex coast, working with the local community to introduce byelaws.

Globally, the rewilding of key blue carbon securing marine and coastal ecosystems such as seagrass beds, saltmarshes and mangroves could deliver carbon dioxide mitigation amounting to 1.83 billion tonnes. This figure doesn’t include the enormous quantities of carbon stored in fish and other marine life; in marine ecosystems such as coral reefs, seaweeds and shellfish beds; or the vast stores of carbon in our seabed sediments.

Investment in protecting our marine ecosystems is vital for both biodiversity and blue carbon storage.

Nature-based solutions could provide a third of climate change mitigations required to address the climate crisis, but currently they attract less than 3 per cent of funds invested globally in addressing climate change.

Internationally, the UK is leading the way by committing to significantly increase its spending on nature-based solutions, including those offered by the ocean. This must be matched with equally ambitious actions at home.

Action areas

The report makes the case for the development of a four-nation Blue Carbon Strategy, focusing on three key action areas:

1. Scaling up marine rewilding for biodiversity and blue carbon benefits

  • By 2030, extractive activities such as damaging fishing methods, and other impacts should be minimised in at least 30 per cent of UK seas. No extractive or destructive activity should be allowed in 10 per cent of our seas. In addition, designating zones around the UK coastline which are free from bottom-towed fishing gear would also give blue carbon habitats a chance to recover and thrive.
  • Alongside protection, we want to see invest­ment in restoration projects including seagrass, saltmarsh, oyster reefs and kelp forests.

2. Integrating blue carbon protection and recovery into climate mitigation and environmental management policies

  • As part of a Blue Carbon Strategy, UK governments should commit to specific and ambitious blue carbon habitat recovery, restoration and protection targets within the UK’s next Nationally Determined Contribution to the Paris Climate Agreement. The UK must fully account for blue carbon in future carbon budgeting.
  • A comprehensive Ocean Charter should be developed which integrates nature recovery plans with climate change mitigation and adap­tation policies, including those for blue carbon.

3. Working with the private sector to develop and support sustainable and innovative low-carbon commercial fisheries and aquaculture

  • UK governments and the fisheries industry should commit to fully sustainable management of UK commercial fish and shellfish stocks, applying an ecosystem-based approach and halving fisheries-related carbon emissions by 2030 to deliver climate and nature-positive fishing.
  • There should be investment in development of innovative low-carbon aquaculture technologies and best practice, including processing and feed production, to halve UK aquaculture carbon emissions by 2030.
  • UK governments and business should support and invest in the development of UK markets for sustainable, low-carbon wild caught fish and innovative aquaculture products, with a roadmap for delivery produced by 2022/23.

By recognising and harnessing the power of our seas to fight the climate crisis, UK governments will be able to make huge strides towards achieving net-zero by 2050. At the Marine Conservation Society, we’re pushing for policy changes and working with industry to encourage innovation. Only through greater investment, modernisation and recognition of our ocean’s capabilities will humanity be able to tackle the climate crisis effectively.