World coastlines can act as 'carbon sink'

Ellalyn B. De Vera Manila Bulletin 6 Dec 10;

MANILA, Philippines – Just as scientists search for better and immediate solutions to counter the impacts of climate change, international experts bared that the world's coastlines, which include mangroves, sea grasses, and tidal salt marshes, could potentially act as a major "carbon sink" in storing massive quantities of carbon for a long period of time.

It pointed out that mangroves, sea grasses, and tidal salt marshes could serve as immediate and cost-effective tool to offset the impact of climate change.

Conservation International (CI) and the International Union of Conservation Scientists (IUCN) explained that total carbon deposits per square kilometer in these coastal systems can be up to five times the carbon stored in tropical forests, resulting from their ability to sequester carbon at rates up to 50 times those of tropical forests.

"What we've seen is that these three main systems – mangroves, seagrasses, and salt marshes – are phenomenally efficient at storing carbon below ground in the sediment for centuries at a time," Dr. Emily Pidgeon, Marine Climate Change Program Director for CI, said.

"So it seems natural to us that oceans should be part of the climate change solution. It's been a bit puzzling to me as to why they haven't so far," she added.

Scientific analysis show that coastal systems globally are being lost at an alarming rate, with approximately two percent removed or degraded each year, which is four times the estimates of annual tropical forest loss.

Likewise, the analysis show that 29 percent of the world's seagrasses, and 35 percent of the world's mangroves have been either lost or degraded.

It also noted that 35,000 square kilometers of mangroves were removed globally between 1980 and 2005 or an area the size of Taiwan.

"The loss of mangroves is like a one-two punch to our planet: first, it results in the rapid emission of carbon stores that in many cases have built up over centuries and the lost opportunity of future carbon sequestration from these areas, and second, it destroys habitats that are critical for fisheries around the world," Pidgeon said.

In a related development, a new international consortium of scientists led by CI called the Blue Carbon Initiative, whose members include CI, IUCN, the World Conservation Monitoring Center of the United Nations Environment Program (WCMC-UNEP), the Intergovernmental Oceanographic Commission (UNESCO), and Restoring America's Estuaries have joined together to study the mitigation possibilities and economic value of coastal marine ecosystems.

"This is because they potentially give us one of the few low-cost options for actually removing carbon dioxide from the atmosphere, right now," Pidgeon said.