By IANS,
Panaji : A study by a leading central government funded marine research institute has debunked a claim by a Brazilian agency that Indian freshwater reservoirs, especially those of dams, were sources of methane.
Scientists of the National Institute of Oceanography (NIO), who conducted studies at eight reservoirs in the country – including the Selaulim reservoir in Goa and the Tillari reservoir in Maharashtra – found that methane produced by these reservoirs was minimal to the point of being insignificant.
The team, led by scientist Gayatree Narvekar, concluded that most of the methane produced in Indian reservoirs is converted to carbon dioxide by methane oxidizing microorganisms and that methane emission to the atmosphere from the Indian dam-reservoirs has been greatly overestimated.
“Although most of these reservoirs were found to turn anaerobic during the summer, measured dissolved methane concentrations are substantially lower than assumed. Moreover, accumulation of methane generally occurred below the depths of water intake for power generation and irrigation,” the NIO said in a statement Wednesday.
A study by Ivan Lima and his colleagues from Brazil’s National Institute for Space Research, published in a peer-reviewed journal, concluded that annual methane emissions from dam-reservoirs in India alone were estimated to be around 33.5 million tonnes.
That figure, if true, would amount to about 19 percent of the country’s global warming emissions from all sources and 28 percent of methane emission from all large dams of the world.
“These figures raised a great deal of alarm in the media and among policy makers,” the NIO statement said.
The NIO scientists made extensive measurements of methane in eight dams-reservoirs across India from the Western Ghats (Selaulim, Supa, Tillari, Koyna and Markandeya) to the central Indo-Gangetic Plain (Rihand) and the foothills of the Himalayas (Bhakra Nangal).
“Although most of these reservoirs were found to turn anaerobic during the summer, measured dissolved methane concentrations are substantially lower than assumed in the above-mentioned study,” the NIO said.
“These results demonstrate that the hydroelectric power in the country appears to be quite green,” the NIO said.