Atmospheric observations show accurate reporting and little growth in India’s methane emissions

• Published in: Nature communications Vol. 8; no. 1; pp. 836 - 7
• Main Authors: Ganesan, Anita L., Rigby, Matt, Lunt, Mark F., Parker, Robert J., Boesch, Hartmut, Goulding, N., Umezawa, Taku, Zahn, Andreas, Chatterjee, Abhijit, Prinn, Ronald G., Tiwari, Yogesh K., van der Schoot, Marcel, Krummel, Paul B.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 10.10.2017; Nature Publishing Group; Nature Portfolio
• Subjects: 704/106/35/824; 704/106/694; 704/172/169/824; Atmospheric models; Climate change; Computer simulation; Emission inventories; Emission measurements; Emissions; Fluxes; Fossil fuels; Global warming; Humanities and Social Sciences; Methane; multidisciplinary; Science; Science (multidisciplinary); China; India
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-017-00994-7

Changes in tropical wetland, ruminant or rice emissions are thought to have played a role in recent variations in atmospheric methane (CH 4 ) concentrations. India has the world’s largest ruminant population and produces ~ 20% of the world’s rice. Therefore, changes in these sources could have significant implications for global warming. Here, we infer India’s CH 4 emissions for the period 2010–2015 using a combination of satellite, surface and aircraft data. We apply a high-resolution atmospheric transport model to simulate data from these platforms to infer fluxes at sub-national scales and to quantify changes in rice emissions. We find that average emissions over this period are 22.0 (19.6–24.3) Tg yr −1 , which is consistent with the emissions reported by India to the United Framework Convention on Climate Change. Annual emissions have not changed significantly (0.2 ± 0.7 Tg yr −1 ) between 2010 and 2015, suggesting that major CH 4 sources did not change appreciably. These findings are in contrast to another major economy, China, which has shown significant growth in recent years due to increasing fossil fuel emissions. However, the trend in a global emission inventory has been overestimated for China due to incorrect rate of fossil fuel growth. Here, we find growth has been overestimated in India but likely due to ruminant and waste sectors. India’s methane emissions have been quantified using atmospheric measurements to provide an independent comparison with reported emissions. Here Ganesan et al. find that derived methane emissions are consistent with India’s reports and no significant trend has been observed between 2010–2015.