Friday 13 May 2011

Indian Sundarbans mangrove forest sequesters 2.79 million ton Carbon annually.

Carbon dioxide capture and storage (CCS) is an approach to mitigate climate change by capturing carbon dioxide from large point sources such as power plants and subsequently storing it away safely instead of releasing it into the atmosphere. Aforestation is one of the various possibilities for carbon dioxide sequestration. Tropical forests process about six times as much carbon as the anthropogenic emission. Changes in carbon dynamics in tropical forest with 50% contribution to global terrestrial gross primary production (GPP) could alter the pace of climate change. India’s forest cover (678,333km2) accounts for 20.6% of the total geographical area of the country, and tree cover accounts for 2.8% of India’s geographical area. Over the last two decades, progressive national forestry legislation and policies in India aimed at conservation and sustainable management of forests have reversed deforestation and transformed India’s forests into a significant net sink of carbon dioxide. The carbon stocks stored in our forests and trees are about 6662 million ton with annual increment of 38 million ton of carbon.  Mangrove forest accounts for about 2.4% of tropical forest. The Indian Sundarbans mangrove forest in the estuarine portion of the River Ganges covers an area of 9630 km2 out of which 4264 km2 is law protected forest.  It is the largest delta on the globe and covers about 2.84% of the global mangrove area (15x104 km2). Department of Marine Science, Calcutta University recently studied Sundarbans mangrove forest for its potentiality to sequester anthropogenic carbon dioxide under the National programme on carbon dioxide Sequestration research, funded by DST, Govt. of India. During this study annual net biosphere-atmosphere exchange of carbon dioxide has been quantified to 2.79 million ton  Carbon. The overall carbon storage in the Sundarbans mangrove forest reservoir is estimated to be 21.13 million ton Carbon and in the soil reservoir (30 cm) 5.49 million ton Carbon. It stores 0.41% of the total carbon storage in the Indian forest (6621 million tone Carbon) and uptakes 2.79 million ton Carbon annually which is 0.55 % of the annual fossil fuel emission (504.6 million ton Carbon per annum) from India. Carbon accrual to live biomass is greater by 35 – 48% in the Sundarban mangrove forest than in the Amazonia forest (2.59 -3.24 kilo ton Carbon per hector per annum). Live biomass is about 4 times lower in the Sundarbans than in the Amazonia forest (167 ± 7.1 kilo ton Carbon per hector, but by contrast it shows relatively rapid carbon accrual in live biomass at Sundarbans than at Amazon. This rapid carbon accrual in the Sundarbans results turn over much faster (10 years) than Amazon forest (~50 years), indicating the advantage of mangroves over terrestrial forests for rapid carbon sequestration. This work has been accepted for publication in peer reviewed  international Journal, Ray, R et al., Carbon sequestration and annual increase of carbon stock in a mangrove forest, Atmospheric Environment, Elsevier, 2011, doi:10.1011/j.atmosenv.2011.04.074).

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