In a study done by researchers at University of Calcutta, the mangrove forests of Sundarbans, which have an area of 2118 sq. km, store around 4.15 crore tonnes of CO2, This is valued at US$ 79 billion in the international carbon trading markets. The two year study has been funded by the Union Ministry of Earth Science to analyze the carbon sequestration efficiency of the Mangrove Forests. Above ground biomass was estimated for carbon content using laser beams. The study excluded below ground biomass.