India's methane emissions have seen little growth over the last few years, according to a study published today which found that the levels of the greenhouse gas are consistent with the country's reports to the UN's international environmental treaty.
Methane is the second most powerful greenhouse gas whose concentrations are rising in the atmosphere but India received praise for accurate reporting of the country's emissions, researchers said.
The study, published in the journal Nature Communications, found that India's total methane emissions are about 10 times larger than the UK's but are smaller per person.
"As found through measurements from the atmosphere rather than through the cataloguing done by countries, we showed that emission levels are consistent with India's reports to the UNFCCC (United Framework Convention on Climate Change) and that between 2010-2015 methane emissions did not show any significant growth," said Anita Ganesan from Bristol University in the UK.
"This information is very valuable to know - both for providing this independent check but also for learning how to improve the accounting process," said Ganesan, lead author of the study.
The aim of the study was to quantify India's methane emissions using observations of methane concentration in the country's atmosphere, the first time this has been done for India at this scale.
"Methane emissions in inventories are highly uncertain due to the complexity of the sources that emit it. It is not uncommon for countries to report methane emissions with an uncertainty that is as large as the emissions themselves. By using a variety of approaches, we can narrow that uncertainty," Ganesan said.
A combination of observations were used - from the surface, from an aircraft and from a satellite that is measuring methane concentrations globally from space.
The study was also carried out to provide an independent assessment of emissions to what has been reported by India to the UNFCCC and to demonstrate the value of this independent check.
The study showed that methane emissions are enhanced each year between June and September over emissions that are being released continuously this signal is due to rice, which is predominantly grown during this season, and can clearly be observed.
"National monitoring of greenhouse gases needs to become a standard process that is done alongside current reporting practices," said Professor Ron Prinn of the Massachusetts Institute of Technology (MIT) in the US.
"This is the only way we can ensure transparency and accuracy of the reports that are submitted to the UN," said Prinn, co-author of the study.
The team now plans to use the techniques developed in this study to examine other tropical regions, whose methane emissions are poorly understood.
