What grows in tidal zones may be our best ally against climate change. How to preserve BC's 'blue carbon'?
In February of this year, scientists identified what may be the oldest living organisms on Earth: a gnarled mass of aquatic seagrass off the coast of Spain, thought to be 200,000 years old. About 8,000 kilometres away, in the estuary of the Squamish River, a gumbooted army of volunteers attempts to restore a once broad seagrass meadow, long ago destroyed by log booming.
What the two aquatic gardens a hemisphere apart share is the potential to store more carbon than the thickest swathe of Amazonian rainforest, nurturing as much life concentrated into a smaller footprint. And while forests hold carbon for centuries at best, the sediments below such aquatic meadows can store carbon for millennia.
Coastal marine environments like seagrass meadows, salt marshes and mangroves (known collectively as "blue carbon") are just beginning to attract attention for all the free services they provide to humanity, most notably a seemingly supernatural capacity to remove carbon from the atmosphere (see sidebar).
Yet as with many natural spaces on land, no widely accepted metric yet exists to place a value on the carbon-scrubbing services such blue carbon sinks provide. As their importance has gone unrecognized, human activity has destroyed as much as seven per cent of the globe's remaining blue carbon sinks, including those in B.C., in a single year. Their continuing losses expose coastlines to erosion, diminish biodiversity, and release enormous amounts of carbon into the atmosphere.
A BLUE CARBON PRIMER
The term "blue carbon" is used to refer to marine vegetated coastal habitats that can store enormous amounts of carbon over millennia.
Seagrass is a generic term for a rare group of flowing ocean plants (called "angiosperms") that thrive in submerged meadow ecosystems and range from cold polar waters to the tropics. A native seagrass in British Columbia is eelgrass (Zostera marina), which is by far our most abundant blue carbon stock.
Salt marshes and mangroves are intertidal systems, living between the rise and fall of the tides. Salt marshes generally hold more carbon by area than eelgrass in British Columbia, but much of our historical stock has been lost. Mangrove forests occur only in tropical and subtropical areas, where they are routinely cleared to farm shrimp for export to developed nations.
The maximum reported carbon-sink capacities of salt marsh, mangrove and sea grass ecosystems exceed that of undisturbed Amazonian forest by factors of 10, six and two respectively. Globally, blue carbon habitats are disappearing four times faster than tropical rainforests.
"Imagine what it would cost to construct a carbon sink to absorb all the emissions from the planet's entire transportation fleet," says Sierra Club of B.C. science advisor Colin Campbell. "You would be aghast at what that would cost right? But we already have it, with our blue carbon habitats, and all we have to do is stop wrecking them to make shrimp farms, marinas and boat ramps."
Campbell is currently championing a cartographic sweep of the province to map where blue carbon occurs and how it stores carbon so efficiently. Better understanding, he hopes, will discourage society from wiping that capability out.
The author of a pioneering report on the precarious state of B.C.'s blue carbon stocks, Campbell estimates that just 400 square kilometres of salt marsh and seagrass meadow are left in coastal B.C., an area just slightly larger than the city of Abbotsford that yet stores away as much carbon as B.C.'s entire forested share of the boreal ecozone, which covers nearly one-third of the province's total land base. And each year those neglected sea gardens lock away as much more carbon as 200,000 cars emit over that time.
Today, 85 per cent of this key environmental asset lacks all protection from the impacts of human development.
Trained as a palaeontologist, and later in ecology at the University of California at Berkeley, 66-year old Campbell says blue carbon suffers a "charisma gap." Unseen underwater environments are not as intriguing to the popular mind as tropical and temperate rainforests. Worse still, they inhabit places where humans love to build things. Think scenic coastal marinas built over B.C. salt marshes, or tropical mangrove forests razed to farm shrimp.
Carbon stored in coastal marine environments went almost entirely unstudied until 1996. But when they looked, scientists were astounded: blue carbon plants have the ability to bury carbon in the sediments in which they grow, where it can be held for millennia in ooze that accumulates to great depth over time.
"Blue carbon comprises half a per cent of the whole world's ocean surface and yet [it's] storing more than half of the carbon the ocean actually sequesters every year," says Campbell. "Because of that, our estuaries and eelgrass-rich intertidal zones in B.C. occupy the highest possible priority for conservation, restoration and enhancement."
While most of B.C.'s blue carbon stocks exist in the southwestern corner of the province, there are other significant fields found all along the central and north coast. A single patch of salt marsh at the end of Kingcome Strait on the central B.C. coast is believed to be absorbing as much C02 as 1,000 gas powered cars just shy of 3,000 tonnes of CO2 every year. And it's doing it for free.
Underwater offsets to protect blue carbon?
Researchers at Duke University's Nicholas Institute consider the ongoing destruction of blue carbon environments a "market failure" in desperate need of correction.
"Because markets do not easily capture the values of ecosystem services," they report, "those who control coastal resources often do not consider these values when choosing whether to clear habitat to produce goods that can be sold in the marketplace."
A partial answer, the Duke researchers suggest, is to give coastal ecosystems and the role they play in the global carbon and climate system a footprint in the financial world as well. In other words: measure the storage in blue carbon areas by the tonne, and sell it on the open market as offsets.
This is easier said than done: while it is now commonplace to protect standing forests by creating offsets based on estimates of the carbon stored there, scientific uncertainty continues to limit the prospects of creating carbon offsets from blue carbon.
Not a single blue carbon offset project yet exists anywhere in the world. James Tansey, CEO and co-founder of Offsetters Clean Technology Inc. believes it's a lack of knowledge that is holding us back.
Science lacks the foundational knowledge about mangrove, eelgrass and salt marshes that it has long possessed about forests, in large part because we have never commercially exploited these habitats. The extractive value of cut timber provided an incentive to continually improve our understanding of how forests grow and regenerate, Tansey notes; no comparable interest motivated acquiring any such knowledge about blue carbon.
As a result, every effort to quantify what's stored in blue carbon must start from close to scratch. In order to meet the expectations of international offset buyers, Tansey says, "You're going to have to do [each inventory] salt marsh by saltmarsh, get the data, and that's going to be a huge barrier to growing it quickly. I think forests are going to dominate [carbon offsetting] for a long time."
It starts with trees
Another hope is that blue carbon will eventually be bundled with other social and economic values into a sort of "value-added" carbon offset. A framework to do just that has existed since 2005.
The Climate Community and Biodiversity Alliance (CCBA) was created in 2003, back when voluntary carbon markets were new. International environmental groups allied to develop a way to consider more than just carbon when creating offset projects.
"CCBA is basically a stamp of high quality to show that a project is not only delivering carbon benefits, it's also delivering significant benefits to the local communities and for biodiversity," says the Alliance's standards coordinator Gareth Wishart from his base in Virginia.
Since the standard was completed and it was first launched in 2005, the CCBA has become a necessity for forestry offset projects hoping to tap the most lucrative voluntary carbon offset markets -- worth more than $420 million globally in 2010.
"Bundling the [offset] product is where everyone is headed," says Campbell, who attended the 2012 World Oceans Summit in Singapore, and participated there in discussions about "stacking" terrestrial forest and blue carbon offsets. "You bundle them to create this product," he explains, "and what buying it really means, is not ruining it for a century."
Compared to tropic archipelagos like Indonesia, B.C.'s carbon stocks are relative tiny. That suggests that even when the data are in, potential paydays from blue carbon could be humble here.
"B.C. might not be the most profitable place to be doing work on blue carbon," Campbell concedes. "But it's here, it's healthy, and there's a lot of estuaries that store carbon that have no protection whatsoever. From my point of view, there's something to do here."
Most of it has yet to be tackled. David Rokoss, director of Compliance Markets (where regulated entities buy offsets to meet legal requirements) for Vancouver offset developer ERA Restoration Associates, says stacking environmental values on top of carbon to enhance the value of assets is still largely a voluntary market phenomenon.
"But we hope carbon is the gateway into unlocking additional biological values inherent in the ecosystem," Rokoss says. "Nobody has ever really put a tangible value on water and salmon spawning grounds, and all these things that carbon helps promote. The million dollar question now is, does [CCBA] add additional tangible value to that project or that offset?"
In addition to CCBA, two other initiatives are laying groundwork for the future monetization and protection of blue carbon environments. The American Carbon Registry, an organization that hosts a voluntary carbon credit registry, this year unveiled a wetlands program targeting the restoration of wetlands in the Mississippi Delta, designed to protect both carbon stores and coastlines from storm surges and flooding.
And by October of this year, a new set of rules for creating a broad range of wetland carbon offset projects -- including possibly mangroves and salt marshes -- will be finalized by the Verified Carbon Standard, a greenhouse gas accounting program used across the world to verify and issue carbon credits in voluntary markets.
An army in gumboots
Before British Columbians contemplate putting a price on blue carbon, there is upfront work to do.
Salt marshes in the intertidal zone -- the area exposed by low tides -- can be surveyed on foot, or better yet by helicopter or planes with video. Most seagrasses live below the low tide mark however; the scuba divers or boats and towed cameras needed to record them are slow and expensive.
Partly as a result, much of what we know about blue carbon in British Columbia has come from volunteers concentrated in the Lower Mainland and southern Gulf Islands -- known loosely in B.C. environmental circles as "the gumboot army."
Since 2002, an unlikely citizen's network of community conservation groups, government agencies, scientists and First Nations has working collaboratively to conserve seagrasses and map more than 12,000 hectares of eelgrass (Zostera marina) on B.C. coastlines. The Seagrass Conservation Working Group, as it is known, works hand in hand with a tiny nonprofit called SeaChange, which applies for grants to do the necessary mapping, as well as educational outreach and restoration.
The last of these will become more important as time goes on, says Nikki Wright, a jack-of-all-trades biologist, scuba diver and community organizer who also serves as both executive director of SeaChange and chair of the working group.
"We call eelgrass a plastic plant," she says, "because it's so flexible. It's one of those plants that has higher hopes for climate change, because it can adapt itself in a relatively short period of time."
Eelgrass has proven adaptable equally to the muddy shallows of the Salish Sea and the rocky pocket beaches and estuaries up along the central and northern B.C. coast. Even in the Squamish Estuary at Cattermole Slough, rinsed in turbid, freezing-cold glacial melt 11 months of the year, replanted eelgrass is taking root, Wright says.
Old fashioned preserves
Wright displays the simultaneous optimism and world-weariness typical of many volunteer stewards who sense they are fighting a losing battle as governments step back from protecting the environment. She worries how pending changes to the federal Fisheries Act may focus reduced stewardship on commercially valuable fish, neglecting their habitat.
"It's very exciting that [blue carbon] is finally starting to get on the radar," she says. "But where the resources are going to come [from] to actually do the research, monitoring and data gathering, is a real puzzle. Things are looking a little dark."
There is one glimmer of hope for B.C.'s blue carbon stocks. As of this writing, the provincial and federal governments are inching closer to creating a 1,400 square kilometre marine protected "reserve" in the southern Georgia Strait -- a region that is ground zero for blue carbon.
Last October, the governments agreed to boundaries that would extend from the southern tip of Gabriola Island to Saanich Inlet and Cordova Bay, just north of Victoria (see map). Since that time Parks Canada and the province of B.C. have been engaging 19 affected First Nations and additional local governments affected by the boundary. A spokesman for the B.C. Ministry of Environment said a decision on the reserve could come in 2013.
Protect and enhance
After nearly two decades immersed in mapping and restoring blue carbon, Wright has devised a prescription for ensuring that our blue carbon stocks continue to flourish in B.C.:
1. Map out exactly how much blue carbon we have.
2. Protect it.
3. Identify where more can be restored, and do it.
Campbell is focused on the first of those tasks. "We need to determine how much carbon our eelgrass holds in long-term storage, and how much more gets added every year," he says. After the carbon-rich sediments beneath coastal B.C. grass beds are mapped, they must still be drilled for cores that will reveal the quantity of carbon they store and how long it has been sequestered.
Only when all that is done, he and Wright agree, are we likely to give these habitats their full due in our other economic and development decisions.