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

Abstract

Changes in tropical wetland, ruminant or rice emissions are thought to have played a role in recent variations in atmospheric methane (CH4) 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 CH4 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 CH4 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.

Very Strong Atmospheric Methane Growth in the 4 Years 2014–2017: Implications for the Paris Agreement

“…Thus, it is probable that both wetlands and cows are contributing to current growth in tropical emissions. However, it should be noted that in India, the nation with by far the world's highest cattle population, atmospheric observations suggest there has been little or no growth in methane emissions between 2010 and 2015 (Ganesan et al, ). In other nations with very large ruminant populations (Brazil, China, United States, Ethiopia, Argentina, S. Sudan) this may not have been the case.…”

Estimating Methane Emissions From Underground Coal and Natural Gas Production in Southwestern Pennsylvania

“…As CH 4 emanates from numerous reported and unreported sources (Turner et al, 2017), atmospheric studies have played a significant role in evaluating CH 4 emissions (Cui et al, 2017;Ganesan et al, 2017; 10.1029/2019GL082131 Ren et al, 2018;Schwietzke et al, 2016). In comparison to site-level data collected from various anthropogenic sources, atmospheric measurements integrate emissions across large areas, from both natural and man-made sources, allowing for detection and quantification of sources that may be missed or underrepresented in bottom-up inventories (Levin et al, 2010).…”

History of chemically and radiatively important atmospheric gases from the Advanced Global Atmospheric Gases Experiment (AGAGE)

“…For the determination of the regional sources of trace gases, beginning with Chen and Prinn (2006) we now frequently merge measurements from the AGAGE and NOAA/ESRL/GMD stations and also aircraft and satellites whenever appropriate (e.g., Ganesan et al, 2017). Because source and sink estimation is very sensitive to errors in time and space gradients, we ensure intercalibration among instruments of the same type and intercomparison between different instruments measuring the same quantity.…”

“…Saunoir et al (2016Saunoir et al ( , 2017 used multi-network data and alternative models to elucidate the 2000-2012 methane budget and its multiyear variability. Finally, Rigby et al (2017) used AGAGE and GMD data for the estimation of OH concentrations and CH 4 emissions, and Ganesan et al (2017) used GOSAT satellite, CARIBIC aircraft, and AGAGE-calibrated surface measurements to estimate Indian subcontinent CH 4 emissions. Monthly means and standard deviations of the data with and without these events are included.…”