‘Dangerous blindspot’: why overlooking blue carbon could sink us | Coastlines

When the bold plan to permit sea water to flood over the Steart peninsula in Somerset was accomplished in 2014, critics referred to as it a waste of cash. Floods had not too long ago blighted the close by space, and a few native individuals argued the £20m spent on creating a brand new 250-hectare (617-acre) salt marsh would have been higher spent on different flood-prevention tasks.

Seven years in the past, the idea of “blue carbon” – how marine ecosystems retailer carbon – was in its infancy. Some analysis had checked out how mangrove forests soak up carbon, however little was recognized about how efficient seagrass and salt marshes additionally have been at absorbing greenhouse fuel emissions.

The two teams behind the salt marsh – the Environment Agency and the Wildfowl & Wetlands Trust (WWT) – barely talked about the local weather. They stated the aim of the marsh was to guard the coast from erosion and create a brand new priceless habitat for birdlife. Ian Liddell-Grainger, MP for Bridgwater and West Somerset, referred to as the marsh an “extravagant, ridiculous scheme” that put birds forward of people.

Less than eight years later, nonetheless, every little thing has modified. Blue carbon is on the forefront of the combat in opposition to the local weather disaster – and as world leaders collect at Cop26, proof has emerged that the Steart marsh could be a extra highly effective carbon sink than anyone imagined.

Scientists at Manchester Metropolitan University discovered that Steart marshes absorbed 19 tonnes of natural carbon a hectare yearly, or 18,000 tonnes in four years – the equal of eliminating the greenhouse fuel emissions of 32,900 automobiles. Their work is a part of a rising physique of analysis suggesting blue carbon is an order of magnitude extra environment friendly than its terrestrial equal.

Heron reflected in water
A heron at Steart marshes. Restoring and conserving wetland habitats, equivalent to marshes, is significant to spice up carbon sequestration. Photograph: WWT

“The carbon storage at Steart is phenomenal,” says Tim McGrath, head of venture improvement at WWT, which manages the salt marsh. “These exceptional findings could indicate that the carbon storage potential of restoring salt marsh around the UK coast has been underestimated.”

It would take 100 years for a woodland to sequester and retailer as a lot carbon as Steart can retailer in six years, McGrath says. “Trees and peat can take us so far, but blue carbon ecosystems, such as salt marshes, can take us further. It’s time governments seized this opportunity.”


But as world leaders at Cop26 earlier pledge to finish deforestation by 2030, campaigners and marine conservationists say the highly effective carbon sinks within the ocean are being missed. Only 43 out of 113 countries to submit greenhouse gas inventories, or nationally decided contributions (NDCs), have included blue carbon ecosystems as a part of their mitigation measures. The UK, regardless of being a coastal nation with huge reserves of potential blue carbon, is a kind of to failing to take action.

“If we are not protecting and counting the blue carbon in our seas, this leaves a dangerous blindspot” for UK coverage, says Ailsa McLellan, coordinator for Our Seas, a coalition of Scottish companies, communities and environmental teams. “It’s time we counted blue carbon, reinstated a limit on damaging methods of fishing, and put future generations first.”

map showing location of Steart Marshes

One research suggests backside trawling could launch as a lot carbon as world aviation emissions. Our Seas is asking on Kwasi Kwarteng, the enterprise secretary, to determine an accounting system for blue carbon, in order that marine and coastal ecosystems, together with salt marshes, could be protected as a part of the UK’s efforts to satisfy its local weather targets.

“Blue carbon habitats are some of the most effective carbon sequestration habitats, area for area, on the planet,” says Bill Austin, professor in ocean science at St Andrews University and chair of the Scottish authorities’s blue carbon discussion board. He is engaged on a government-funded “salt marsh code” that could permit firms to spend money on restoration schemes.


For now, blue carbon stays a little bit of an outlier in terms of carbon credit. Out of the large three coastal wetlands, says Austin, mangroves are one of the best studied, adopted by salt marshes after which seagrass. “There is definitely scope for us to raise our ambition” by together with blue carbon within the UK’s NDCs, he says.

Coastal marshes near the Steart peninsula, Somerset.
Coastal marshes close to the Steart peninsula. The idea of blue carbon is comparatively new however analysis is starting to point out the significance of the ocean and coastal habitats in mitigating local weather emissions. Photograph: James Osmond/Alamy

The Department for Environment, Food and Rural Affairs says the UK recognises the essential position blue carbon habitats can play in carbon sequestration, in addition to stopping biodiversity loss and constructing resilience to local weather crises: “The ocean plays a vital role in climate mitigation, and we continue to build the evidence base on blue carbon habitats as we strive towards net zero.”

That is a coded means of claiming that the science of blue carbon is comparatively younger. The time period was coined in 2009. Recent analysis estimates that conserving and restoring blue carbon ecosystems could remove the equivalent of 3% of annual global greenhouse emissions.

Salt marshes as proportion of ecosystems compared with temperate forests…
Salt marshes as carbon stores compared with temperate forests

But the longer term is one other nation – and one main professional predicts that, over time, the ocean’s contribution in the direction of mitigating local weather emissions could soar.

Carlos Duarte, a professor of marine science at King Abdullah University of Science and Technology in Saudi Arabia and one of many paper’s authors, says 3% was a “conservative estimate” as a result of the scope for restoration of some ecosystems could be bigger than beforehand believed.

“It is very well understood for mangroves, not well understood for salt marshes and very poorly understood for seagrass,” says Duarte. “We have huge gaps in our knowledge of the amount of seagrass in the ocean. The scope for restoring seagrass could be as much as five or 10 times larger than what we thought.”

The contribution of blue carbon to mitigating local weather emissions could be as excessive as 10% to fifteen%, he predicts, if “all blue carbon strategies are activated”, together with as but unexplored prospects equivalent to extra seaweed farming, avoiding disturbing sediments on continental cabinets, restoring kelp forests and defending whales.

Other scientists warning that uncertainty in some areas, equivalent to seaweed farms and kelp – neither of that are included within the Intergovernmental Panel on Climate Change’s greenhouse fuel emission stock – makes correct predictions troublesome.

That’s why Duarte needs to check these areas. He is working with Oceans 2050, an organisation run by Alexandra Cousteau, the granddaughter of the oceanographer Jacques, to pattern sediments from seaweed farms in 12 international locations to learn the way a lot carbon they actually take in.

chart showing equivalents of how much carbon is stored in the marshes

“I would be hard-pressed to find a climate-mitigation solution that has been proven to be as effective as blue carbon,” says Duarte. “Some people worry that 3% is too little to worry about. To these people in search of solutions that are going to magically deliver many betagrammes of emission, I tell them there are no low-hanging betagrammes.”

There isn’t any time to waste arguing over precisely how a lot blue carbon may help us reduce emissions; all choices have to be pursued, Duarte says. Blue carbon ecosystems don’t simply cut back emissions: they assist combat the opposite disaster, equivalent to biodiversity loss and stopping pure disasters.

Blue carbon, he says, has been missed for too lengthy. “By the time we find these solutions that can deliver 5% of the job, we will be in 2050 – and we will be burning.”


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