(Representative image)

BENGALURU: India may be home to 15% of the global livestock population, but its contribution to the global methane emissions by the domesticated animals is only 10.63%, a study by the National Institute of Animal Nutrition and Physiology (NIANP) has revealed.

Cows, buffaloes, sheep and goats are the huge contributors to methane emissions. Methane, released primarily by livestock, paddy cultivation, decay of organic waste in landfill sites and handling of fossil fuels, is estimated to be 25 times more harmful for environment over 100 years than carbon dioxide, the primary greenhouse gas responsible for global warming.

After 10 years of research, scientists from NIANP and the National Institute of Veterinary Epidemiology and Disease Informatics have prepared a national census that not only records each state's contribution to methane emission by livestock but has also identified hotspots of emissions and amelioration strategies to combat emission.

Dr Raghavendra Bhatta , director of Indian Council of Agricultural Research (ICAR)-NIANP, and the lead researcher on the project when it was first started, said lacuna in the database available then, as well as the need to refute the West's claim of India being a huge emitter of enteric methane was the catalyst behind preparing such a national inventory. “There were several issues with the way the data was computed earlier, including adoption of the countrywide default value of the intergovernmental panel for climate change ( IPCC ). Various agencies have computed our emission at 12 teragram or 12 million tonnes per year but this is inaccurate as it does not consider the variations of feed, diet and environment within countries and instead chooses to assign a single figure to the whole country,“ Dr Bhatta said.

The national census of 2012 has put India's livestock population at 512 million. The study used the 19th livestock census as well as feeding patterns from an existing national project to analyse 1,500 feed samples and diet combinations for their methane production potential from across India. “Our enteric methane emission is closer to 9.56tg per year,“ said Dr Bhatta.

The project titled `Outreach methane project on estimation of methane emission under different feeding systems and development of mitigation strategies' has identified certain changes that can be made in the diet to minimize the emission.

'Emission can't be stopped fully'

According to Dr Pradeep Kumar Malik, senior scientist at NIANP, the emission can't be stopped completely because it is an inherent process to dispose of fermentative gases; the goal then is to find the balance. The belching out of methane is essential as the accumulation of gases like carbon dioxide and hydrogen could be fatal for the animal. When these two gases are reduced together in the rumen (the first compartment in the animal's stomach) through methanogenesis, methane is produced. The production results in a 6-12% energy loss for the animal as well.

“We know that we can inhibit 25 30% of the emission without affecting the health of the animal.Through extensive in-vitro and invivo trials, we have identified four agents which, if added to the feed in certain proportions, will help tackle methane emission to an extent,“ he said.

Biotechnologist Dr Atul Kolte investigates the correlaton between rumen microbes and methanogenesis.

Using the assistance of Dr K P Suresh, a principal scientist and biostatistician working at the National Institute of Veterinary Epidemiology and Disease Informatics, the team has also been able to identify eight hotspots in the country where the methane emission is the highest.

“Using the animal body weight and dry matter intake from the 2012 census, we were able to calculate the methane emission of each animal.They are organized into different categories on the basis of age, species etc and we had to write programs in R, a computer language, which took the data and produced results right down to the village level. While the IPCC used approximations to come up with their figures, it is important to exercise granularity by starting from the bottom down and going from village to taluk to district,“ he said.

