UN conference hope for Sunderbans

TNN | Nov 24, 2011, 04.55AM IST

KOLKATA: Less than a week to go for the crucialUnited Nations climate change conference in Durban, South Africa, it is still uncertain whether world leaders will be able to successfully negotiate further commitments on emission cuts even as the Kyoto Protocol commitment period ends in 2012. But if negotiations succeed, it will pave the way for an incentive mechanism to preserve forests. And the Sunderbans, one of the biggest mangrove forests in this part of the globe, could benefit majorly.

"Reducing Emissions from Deforestation and Forest Degradation (REDD) is a set of steps designed to use market incentives to reduce emissions of greenhouse gases from deforestation and forest degradation. REDD+ is the incentive programme proposed to spur regeneration of forest. Apart from reducing green house gases, it delivers co-benefits like biodiversity conservation and poverty alleviation. In Durban, we will push for the mechanisms," said Union ministry of new and renewable energy joint secretary Shashi Shekhar.

And that is where the local community in the Sunderbans could benefit by devising projects that can leverage the mechanisms. A study by Calcutta University has quantified the carbon absorption capacity of Indian Sunderbans stretching across 2,118 sq km at 4.15 crore tonne of carbon dioxide a year. If the REDD mechanism is introduced, the carbon sink can be monetised into carbon credits worth over $25 billion or Rs 1,25,000 crore. The amount is derived from a project in Himachal Pradesh in which carbon credits were sold under the UN-mandated Clean Development Mechanism to World Bank at the rate of around $6 per tonne of carbon.

"Mangrove trees act as a natural tank for carbon dioxide storage and absorb carbon for their own requirement. The higher the concentration of biomass, more will be the amount of CO{-2} drawn from atmosphere. This in turn will control the rise of atmospheric temperature and subsequent climate change," explained Calcutta University marine science department head Abhijit Mitra. As a primary greenhouse gas, large-scale CO{-2} emission is responsible for global warming as temperature rise leads to melting of polar ice and sea levels rise. This, in turn, threatens to inundate coastal regions. The Sunderbans both in West Bengal and Bangladesh,

is among the most vulnerable. Two islands in the Indian part of the Sunderbans have already gone under water, forcing its inhabitants to become climate refugees.

If the new forest formula finds favour in Durban, a big chunk of Sunderbans' 42 lakh inhabitants can benefit through specially designed

carbon reduction projects through preservation and regeneration of mangroves. It is then that the study by Mitra and other scientists from CU will be invaluable.

Funded by the Union Earth Science ministry, the two-year study of the carbon sequestration efficiency of the mangroves revealed that forest areas in the Sunderbans trapped four times the amount of carbon dioxide sequestered by other forests. "Since the Sunderbans is a mangrove eco-system with roots that break the wave velocity and tidal surges, accelerating the process of sedimentation, carbon trapping is more efficient here than in other forests," Mitra explained.

To evaluate carbon stocks in the above-ground biomass of three dominant mangrove species (Sonneratia apetala, Avicennia alba and Excoecaria agallocha) in the Sunderbans, carbon content in stem, branch and leaf biomass was estimated using laser beams. Carbon content of the soil was also studied by scientists Saurov Sett, Kasturi Sengupta and Kakoli Banerjee. The paper has been published in Forest Ecology and Management 2011, a Japanese journal from the Elsevier publishing house.

The study focused on three mangrove species common in the Sunderbans - Sonneratia apetala (keora), Avicennia alba (genwa) and Excoecaria agallocha (bain) and found them capable of absorbing enormous amounts carbon from the atmosphere. Keora absorbed 15-73 tonne of carbon per hectare, genwa 6-9 tonne per hectare and bain 10-21 tonne per hectare. Soil sample studies showed carbon content ranging from 13.34 tonne per hectare to 20.86 tonne per hectare.

"We have studied western Sunderbans (Sagar Islands, Lothian Island, etc) and central Sunderbans (Matla, Jharkhali, etc). Next year, the carbon content of east Sunderbans will be studied with forest department. The latter is the core area which has witness least degredation due to human intervention. The central part of the Sunderbans is a poor carbon sink when compared to the western Sunderbans due to high salinity and lack of fresh water," Mitra said.

Pradeep Vyas, director, Sunderban Biosphere Reserve, said a programme on plantation along the embankment could be taken up if NGOs join hands with the forest department. "During cyclone Aila, more than 600 km embankment that protected the islands from sea water incursion

was washed away. Alongside the rebuilding of embankments, we have plans to take up mangrove plantation so that the trees act as a buffer to break down tidal surges during such calamities," he said, adding that the forest department was ready to collaborate with the likes of TERI, Winrock Foundation and WWF-India.