edu.ucar.opensky::articles:19312 UCAR/NCAR - Library OpenSky Support PO Box 3000 Boulder CO 80307-3000 opensky@ucar.edu http://opensky.ucar.edu/ homepage pointOfContact 2025-12-26T02:38:26.680998 ISO 19115-2 Geographic Information - Metadata - Part 2: Extensions for Imagery and Gridded Data ISO 19115-2:2009(E) https://n2t.org/ark:/85065/d7v126jn https://doi.org/10.3334/CDIAC/GLOBAL_METHANE_BUDGET_2016_V1.1 https Related Dataset #1 Global Methane Budget 2000-2012 (V.1.0, issued June 2016 and V.1.1, issued December 2016) The global methane budget 2000-2012 2016-12-12T00:00:00Z publication https://n2t.org/ark:/85065/d7v126jn https://doi.org/10.5194/essd-8-697-2016 Saunois, M. author Bousquet, P. author Poulter, B. author Peregon, A. author Ciais, P. author Canadell, J. G. author Dlugokencky, E. J. author Etiope, G. author Bastviken, D. author Houweling, S. author Janssens-Maenhout, G. author Tubiello, F. N. author Castaldi, S. author Jackson, R. B. author Alexe, M. author Arora, V. K. author Beerling, D. J. author Bergamaschi, P. author Blake, D. R. author Brailsford, G. author Brovkin, V. author Bruhwiler, L. author Crevoisier, C. author Crill, P. author Covey, K. author Curry, C. author Frankenberg, C. author Gedney, N. author Höglund-Isaksson, L. author Ishizawa, M. author Ito, A. author Joos, F. author Kim, H. author Kleinen, T. author Krummel, P. author Lamarque, Jean-François author Langenfelds, R. author Locatelli, R. author Machida, T. author Maksyutov, S. author McDonald, K. C. author Marshall, J. author Melton, J. R. author Morino, I. author Naik, V. author O'Doherty, S. author Parmentier, F. W. author Patra, P. K. author Peng, C. author Peng, S. author Peters, G. P. author Pison, I. author Prigent, C. author Prinn, R. author Ramonet, M. author Riley, W. J. author Saito, M. author Santini, M. author Schroeder, R. author Simpson, I. J. author Spahni, R. author Steele, P. author Takizawa, A. author Thornton, B. F. author Tian, H. author Tohjima, Y. author Viovy, N. author Voulgarakis, A. author Van Weele, M. author van der Werf, G. R. author Weiss, R. author Wiedinmyer, Christine author Wilton, D. J. author Wiltshire, A. author Worthy, D. author Wunch, D. author Xu, X. author Yoshida, Y. author Zhang, B. author Zhang, Z. author Zhu, Q. author UCAR/NCAR - Library publisher The global methane (CH4) budget is becoming an increasingly important component for managing realistic pathways to mitigate climate change. This relevance, due to a shorter atmospheric lifetime and a stronger warming potential than carbon dioxide, is challenged by the still unexplained changes of atmospheric CH4 over the past decade. Emissions and concentrations of CH4 are continuing to increase, making CH4 the second most important human-induced greenhouse gas after carbon dioxide. Two major difficulties in reducing uncertainties come from the large variety of diffusive CH4 sources that overlap geographically, and from the destruction of CH4 by the very short-lived hydroxyl radical (OH). To address these difficulties, we have established a consortium of multi-disciplinary scientists under the umbrella of the Global Carbon Project to synthesize and stimulate research on the methane cycle, and producing regular (biennial) updates of the global methane budget. This consortium includes atmospheric physicists and chemists, biogeochemists of surface and marine emissions, and socio-economists who study anthropogenic emissions. Following Kirschke et al. (2013), we propose here the first version of a living review paper that integrates results of top-down studies (exploiting atmospheric observations within an atmospheric inverse-modelling framework) and bottom-up models, inventories and data-driven approaches (including process-based models for estimating land surface emissions and atmospheric chemistry, and inventories for anthropogenic emissions, data-driven extrapolations). For the 2003-2012 decade, global methane emissions are estimated by top-down inversions at 558 Tg CH4 yr−1, range 540-568. About 60 % of global emissions are anthropogenic (range 50-65 %). Since 2010, the bottom-up global emission inventories have been closer to methane emissions in the most carbon-intensive Representative Concentrations Pathway (RCP8.5) and higher than all other RCP scenarios. Bottom-up approaches suggest larger global emissions (736 Tg CH4 yr−1, range 596-884) mostly because of larger natural emissions from individual sources such as inland waters, natural wetlands and geological sources. Considering the atmospheric constraints on the top-down budget, it is likely that some of the individual emissions reported by the bottom-up approaches are overestimated, leading to too large global emissions. Latitudinal data from top-down emissions indicate a predominance of tropical emissions (~64 % of the global budget, < 30° N) as compared to mid (~32 %, 30-60° N) and high northern latitudes (~4 %, 60-90° N). Top-down inversions consistently infer lower emissions in China (∼ 58 Tg CH4 yr-1, range 51-72, -14 %) and higher emissions in Africa (86 Tg CH4 yr-1, range 73-108, +19 %) than bottom-up values used as prior estimates. Overall, uncertainties for anthropogenic emissions appear smaller than those from natural sources, and the uncertainties on source categories appear larger for top-down inversions than for bottom-up inventories and models. The most important source of uncertainty on the methane budget is attributable to emissions from wetland and other inland waters. We show that the wetland extent could contribute 30–40 % on the estimated range for wetland emissions. Other priorities for improving the methane budget include the following: (i) the development of process-based models for inland-water emissions, (ii) the intensification of methane observations at local scale (flux measurements) to constrain bottom-up land surface models, and at regional scale (surface networks and satellites) to constrain top-down inversions, (iii) improvements in the estimation of atmospheric loss by OH, and (iv) improvements of the transport models integrated in top-down inversions. The data presented here can be downloaded from the Carbon Dioxide Information Analysis Center (http://dx.doi.org/10.3334/CDIAC/GLOBAL_METHANE_BUDGET_2016_V1.1) and the Global Carbon Project. UCAR/NCAR - Library OpenSky Support PO Box 3000 Boulder CO 80307-3000 opensky@ucar.edu http://opensky.ucar.edu/ homepage pointOfContact PDF Text theme Resource Type 2016-01-01T00:00:00Z publication Copyright Author(s) 2016. This work is distributed under the Creative Commons Attribution 3.0 License None eng geoscientificInformation