Clearing coastal wetlands for agriculture and other land uses is releasing 'centuries' of stored CO2, but a new report says protecting these ecosystems and promoting development need not be mutually exclusive.
The rate of mangrove loss is up to four times that of forests on land
The numbers paint a grim picture.
From beds of Indonesian seagrass to deltas in Northern Europe, the world is losing its wetlands at a startling pace.
They are disappearing up to four times faster than forests on land, and their loss can be expected to have a similar impact on our climate, according to a new report by the World Bank and the International Union for the Conservation of Nature (IUCN).
Long regarded as wasted space, marshes and mangroves have been cleared to make way for everything from farms to industry to luxurious sea-side housing.
Wetlands serve as crucial habitats for wildlife
The report says that between 1980 and 2005, the world lost 20 percent of its wetlands, an area roughly four times the size of metropolitan New York City, thanks to various forms of development.
Yet far from just taking up space, wetlands provide a habitat for rare species and help buffer us from storms and flooding. They also sequester large quantities of greenhouse gas emissions, with disturbing implications for our efforts to curb climate change.
"The carbon that has been accumulating for years and years is now being released into the atmosphere," Dorothée Herr, one of the report's authors, told Deutsche Welle.
Of the 15 coastal deltas around the world studied for the report, seven were found to have released more than 500 million tons of carbon dioxide through drainage over the last century - a rate roughly equal to Mexico's annual greenhouse gas emissions for the year 2007.
In the Sacramento-San Joaquin Delta in California, for instance, the drainage of hundreds of square kilometers of wetlands has resulted in the release of nearly one billion tons of carbon dioxide.
Development versus nature
The report highlights a dramatic scale of wetland destruction.
About a third of Indonesia's seagrass beds have been lost. More than 5,000 square kilometers of wetlands have been destroyed in northern Europe. In China, some 22,000 square kilometers of mangroves and salt marshes have been dammed over a period of about four decades.
The trend doesn't appear to be wavering, either.
As cities in Southeast Asia and West Africa continue to swell due to growing populations, wetland destruction is expected to continue.
"Often, it's associated with the idea that we have land that's not being put to a huge amount of use," said Carl Gustaf Lundin, head of IUCN's global marine program.
"There's a perception that you can create more land and get away with it."
For a country like China - where there are laws against converting farmland for other uses - coastal wetlands are seen less as carbon sinks than acreage ripe for development, resulting in massive changes to the country's coastline.
Meanwhile, campaigns to save wetlands have failed to garner the public's enthusiasm, perhaps because they are not considered especially scenic. "They're often characterized as mosquito-infested swamps," Lundin said.
In reality, generations have depended on these so-called "swamps" for their livelihoods over the years - but with no formal ownership, they have been briskly swept aside in favor of more profitable investment opportunities.
Herr says wetlands destruction is a global problem
The carbon conundrum
Coastal wetlands often make prime real estate - but they are also prime storage space for CO2.
"They are huge carbon sinks…and what's more, they are huge potential sources of carbon dioxide emissions," said World Bank marine specialist Marea Hatziolos.
Preserving their function as carbon sinks means keeping wetlands intact, not draining them to make use of the land.
The issue is "green growth," and Hatziolos said it comes down to one basic question: "How do you promote sustainable development and growth without jeopardizing natural capital and the future of the planet?"
There are no easy answers, but Hatziolos said there are ways to develop the land without destroying it.
She said ideas like environmentally friendly tourism, sustainable aquaculture and exploiting wetlands as a nursery for fish species, all serve as ways to balance development and environmental protection.
Most countries, however, have a shaky track record on that front.
Efforts to dam rivers upstream have changed the conditions of the waters downstream, in coastal deltas - and underscore governments' lack of understanding about how wetland ecosystems really function.
Hatziolos said one of the main motivations behind the report was to help policymakers understand the true value of wetland resources.
One-fifth of the world's mangroves vanished between 1980 and 2005
Just the beginning
Meanwhile, scientists still have a lot of work ahead of them to quantify exactly how much CO2 coastal wetlands are capable of storing.
That knowledge could help expand climate protection efforts on the international level, and specific wetland areas could eventually be incorporated into carbon offset schemes in a way similar to proposals for forests.
"There's been a very large focus on land versus sea," said the IUCN's Carl Gustaf Lundin. "There's a wider story beyond the trees that needs to be told."
Ultimately, Hatziolos said coastal wetlands should be declared "critical habitats."
"Countries are supposed to be protecting their mangroves - there aren't that many left," she said.
Author: Amanda Price
Editor: Nathan Witkop