A seagrass meadow near Helford, Cornwall | Credit: Paul Naylor
First of their kind studies warn vast amounts of CO2 stored in UK seabed habitats are at risk of being disturbed by bottom trawler fishing and offshore development
Seabed habitats around the UK have been found to naturally store many hundreds of millions of tonnes of carbon, prompting calls for urgent action to prevent CO2 being released into the atmosphere from damaging activities such as bottom trawler fishing and offshore energy development.
In groundbreaking research published today, scientists for the first time sought to map the 'blue carbon' storage capacity of just the top 10cm of sediment on the sea floor around the UK, revealing potentially significant implications for both climate change and nature.
Dubbed the Blue Carbon Mapping Project, the joint initiative between WWF, The Wildlife Trusts, and RSPB estimates areas of the seabed hold 244 million tonnes of organic carbon in only the top 10cm, 98 per cent of which is stored in sediments such as mud and silt.
Moreover, the research contends that if stronger protections were put in place, these seabed habitats have the potential to naturally sequester even more carbon - potentially up to 13 million additional tonnes a year, which is almost three times more than the current carbon removal capacity of UK forests.
However, it also warns that physical disturbances to the seabed from human activity such as bottom trawling fishing boats, vessel mooring, and offshore developments pose a major threat to these habitats and could undermine their carbon storage capacity and impact the biodiversity they support.
Disturbing seabed habitats - which include biodiversity-rich seagrass meadows, kelp forests, intertidal seaweeds, and reefs, as well as mud and silt - can release large amounts of carbon into the atmosphere, potentially exacerbating climate change in the process, the report said.
As such, the environmental groups behind the study are calling on governments across the UK to strengthen protections for valuable blue carbon stores and seabed habitats, including in existing Marine Protected Areas (MPAs) where disruptive fishing activity is often still permitted. At present, MPAs cover less than half - 338,000 square kilometres - of UK seas, but most were not designed to prevent CO2 disturbances.
"These world-first reports reveal the enormous value of UK seas, while highlighting that many areas need far better protection," said Joan Edwards, director of marine policy for The Wildlife Trusts. "We need strategic decision-making from policymakers to recognise the value of blue carbon by minimising the impact of human activities on the seabed. Damaging activities such as bottom trawling and large development must not take place in protected areas. This research gives the UK an opportunity to lead the world in protecting blue carbon and marine biodiversity."
Blue carbon is primarily created by phytoplankton, which absorb CO2 drawn into seas from the atmosphere, and then drift to the bottom of the sea when they die and are added to seabed sediments.
These sediments are hundreds of metres thick and contain millennia's-worth of carbon, meaning UK seabeds are certain to store far more carbon than is estimated to be contained in the top 10cm analysed in today's study. The sediments also play a key role in supporting marine biodiversity.
Seas around the UK and Isle of Man cover almost 885,000 square kilometres, which is over three times the size of the country's land mass, underscoring the huge potential of better marine protection efforts to support climate and nature goals, according to green groups.
They are therefore calling for both carbon and biodiversity to be taken into account when designating any new MPAs, and for greater investment in the restoration of habitats such as seagrass beds, kelp forests and saltmarshes.
And, as the new government embarks its plans to rapidly scale up offshore wind development to meet its stretching 2030 clean power goal, they are also calling for fresh efforts to limit the impact on the seabed of new energy development plans.
Kirsten Carter, head of UK marine policy at the RSPB, said the study findings could prove critical in aiding understanding of the huge contribution UK seas can make towards meeting national net zero and nature targets.
"Accelerating efforts on land to tackle the nature and climate emergency is critical, but we must not underestimate the role of UK seas," she said.
"This report is a gamechanger for our knowledge of the marine environment and a huge asset for decision-makers. Now we need them to act on its findings. To meet net zero and stop biodiversity decline we must work with nature, not against it. This means restoring habitats, properly planning offshore development, and investing in protected areas to safeguard wildlife and keep blue carbon locked up."
In its general election manifesto earlier this year, Labour promised to take action to meet national Environment Act targets, including the overarching goals to halt the decline of British species by 2030 and protect 30 per cent of land and seas by the same date. It is also currently reviewing and updating the existing Environmental Improvement Plan to ensure it is fit for purpose in meeting statutory nature goals, and has promised to ratify the Global Oceans Treaty.
Earlier this month, Environment Secretary Steve Read also stated his ambition to ensure Labour leads "the most nature-positive government this nation has ever had".
Responding to today's research findings, the Department for the Environment, Food and Rural Affairs (Defra) said in a statement that "protecting our oceans, and the precious species that depend on them, is fundamental to a healthy and thriving environment".
"We will ratify a new Global Oceans Treaty to protect marine life, enforce bottom trawling restrictions in our Marine Protected Areas and ensure all catch limits are set sustainably," it added.
You can now sign up to attend the fifth annual Net Zero Festival, which will be hosted by BusinessGreen on October 22-23 at the Business Design Centre in London.
