April 4, 2011

Mangrove Destruction Accounts For 10% Of CO2 Emissions

According to a study released on Sunday, mangroves are in important bulkhead against climate change.

The study found that destruction of these tropical coastal woodlands accounts for about 10 percent of carbon dioxide emissions from deforestation, which is the second largest source of CO2 after fossil fuel combustion.

Fewer trees would lead to less CO2 being absorbed from the air and would also release carbon stocks that have been accumulating in shallow-water sediment over millennia.

Mangroves offer many benefits to humans and the environment.

The brackish tidal waters that the trees thrive in are a natural nursery for dozens of species of fish and shrimp that are essential to commercial fisheries around the world.

Another major "ecosystem service" is protection from hurricanes and storm.

According to experts, the 2008 Cyclone Nargis would have been less deadly if half of Myanmar's mangroves had not been ripped up for wood or to make way for shrimp farms.  The cyclone killed 138,000 people in the country.

Daniel Donato of the U.S. Department of Agriculture's Forest Service in Hilo, along with colleagues, studied the carbon content in 25 mangroves scattered across the Indo-Pacific region.

The team found that the trees stored atmospheric CO2 just as well as land-based tropical forests.  The trees were more efficient below the water line.

"Mangroves are among the most carbon-rich forests in the tropics," Donato and his colleagues said in the study, published in Nature Geoscience.

"Our data show that discussion of the key role of tropical wetland forests in climate change could be broadened significantly to include mangroves."

Steven Bouillon from the Katholieke Universiteit Leuven in Belgium wrote in a commentary on the study that the carbon inventory uncovered by the research "provides a strong incentive to consider mangrove ecosystems as priority areas for conservation."


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