| Title | The Global Methane Budget 2000-2017 |
| Authors | Saunois, Marielle Stavert, Ann R. Poulter, Ben Bousquet, Philippe Canadell, Josep G. Jackson, Robert B. Raymond, Peter A. Dlugokencky, Edward J. Houweling, Sander Patra, Prabir K. Ciais, Philippe Arora, Vivek K. Bastviken, David Bergamaschi, Peter Blake, Donald R. Brailsford, Gordon Bruhwiler, Lori Carlson, Kimberly M. Carrol, Mark Castaldi, Simona Chandra, Naveen Crevoisier, Cyril Crill, Patrick M. Covey, Kristofer Curry, Charles L. Etiope, Giuseppe Frankenberg, Christian Gedney, Nicola Hegglin, Michaela, I Hoglund-Isaksson, Lena Hugelius, Gustaf Ishizawa, Misa Ito, Akihiko Janssens-Maenhout, Greet Jensen, Katherine M. Joos, Fortunat Kleinen, Thomas Krummel, Paul B. Langenfelds, Ray L. Laruelle, Goulven G. Liu, Licheng Machida, Toshinobu Maksyutov, Shamil McDonald, Kyle C. McNorton, Joe Miller, Paul A. Melton, Joe R. Morino, Isamu Muller, Jurek Murguia-Flores, Fabiola Naik, Vaishali Niwa, Yosuke Noce, Sergio Doherty, Simon O. Parker, Robert J. Peng, Changhui Peng, Shushi Peters, Glen P. Prigent, Catherine Prinn, Ronald Ramonet, Michel Regnier, Pierre Riley, William J. Rosentreter, Judith A. Segers, Arjo Simpson, Isobel J. Shi, Hao Smith, Steven J. Steele, L. Paul Thornton, Brett F. Tian, Hanqin Tohjima, Yasunori Tubiello, Francesco N. Tsuruta, Aki Viovy, Nicolas Voulgarakis, Apostolos Weber, Thomas S. van Weele, Michiel van der Werf, Guido R. Weiss, Ray F. Worthy, Doug Wunch, Debra Yin, Yi Yoshida, Yukio Zhang, Wenxin Zhang, Zhen Zhao, Yuanhong Zheng, Bo Zhu, Qing Zhu, Qiuan Zhuang, Qianlai |
| Affiliation | Univ Paris Saclay, Lab Sci Climat & Environm, LSCE IPSL CEA CNRS UVSQ, F-91191 Gif Sur Yvette, France CSIRO Oceans & Atmosphere, Global Carbon Project, Aspendale, Vic 3195, Australia CSIRO Oceans & Atmosphere, Global Carbon Project, Canberra, ACT 2601, Australia NASA, Biospher Sci Lab, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA Stanford Univ, Woods Inst Environm, Dept Earth Syst Sci, Stanford, CA 94305 USA Stanford Univ, Precourt Inst Energy, Stanford, CA 94305 USA Yale Univ, Yale Sch Environm, New Haven, CT 06511 USA NOAA, Global Monitoring Lab, 325 Broadway, Boulder, CO 80305 USA SRON Netherlands Inst Space Res, Sorbonnelaan 2, NL-3584 CA Utrecht, Netherlands Vrije Univ Amsterdam, Dept Earth Sci, VU Amsterdam, Earth & Climate Cluster, Amsterdam, Netherlands JAMSTEC, Res Inst Global Change, 3173-25 Showa Machi, Yokohama, Kanagawa 2360001, Japan Chiba Univ, Ctr Environm Remote Sensing, Chiba, Japan Environm & Climate Change Canada, Climate Res Div, Canadian Ctr Climate Modelling & Anal, Victoria, BC V8W 2Y2, Canada Linkoping Univ, Dept Themat Studies Environm Change, S-58183 Linkoping, Sweden European Commiss Joint Res Ctr, Via E Fermi 2749, I-21027 Ispra, VA, Italy Univ Calif Irvine, Dept Chem, 570 Rowland Hall, Irvine, CA 92697 USA Natl Inst Water & Atmospher Res, 301 Evans Bay Parade, Wellington, New Zealand NYU, Dept Environm Studies, New York, NY 10003 USA Univ Hawaii, Dept Nat Resources & Environm Management, Honolulu, HI 96822 USA Univ Campania Luigi Vanvitelli, Dipartimento Sci Ambientali Biol & Farmaceut, Via Vivaldi 43, I-81100 Caserta, Italy RUDN Univ, Dept Landscape Design & Sustainable Ecosyst, Moscow, Russia Ctr Euro Mediterraneo Cambiamenti Climat, Impacts Agr Forests & Ecosyst Serv Div, Via Augusto Imperatore 16, I-73100 Lecce, Italy Ecole Polytech, Lab Meteorol Dynam, LMD IPSL, F-91120 Palaiseau, France Stockholm Univ, Dept Geol Sci, Svante Arrhenius Vag 8, S-10691 Stockholm, Sweden Stockholm Univ, Bolin Ctr Climate Res, Svante Arrhenius Vag 8, S-10691 Stockholm, Sweden Skidmore Coll, Environm Studies & Sci Program, Saratoga Springs, NY 12866 USA Univ Victoria, Pacific Climate Impacts Consortium, House 1,POB 1700 STN CSC, Victoria, BC V8W 2Y2, Canada Ist Nazl Geofis & Vulcanol, Sez Roma 2, Via V Murata 605, I-00143 Rome, Italy Babes Bolyai Univ, Fac Environm Sci & Engn, Cluj Napoca, Romania CALTECH, Div Geol & Planetary Sci, Pasadena, CA 91125 USA CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA Met Off Hadley Ctr, Joint Ctr Hydrometeorol Res, Maclean Bldg, Wallingford OX10 8BB, Oxon, England Univ Reading, Dept Meteorol, Reading RG6 6BB, Berks, England Int Inst Appl Syst Anal IIASA, Air Qual & Greenhouse Gases Program AIR, A-2361 Laxenburg, Austria Stockholm Univ, Dept Phys Geog, S-10691 Stockholm, Sweden Natl Inst Environm Studies NIES, Ctr Global Environm Res, Onogawa 16-2, Tsukuba, Ibaraki 3058506, Japan CUNY City Coll, Dept Earth & Atmospher Sci, New York, NY 10031 USA Univ Bern, Phys Inst, Climate & Environm Phys, Sidlerstr 5, CH-3012 Bern, Switzerland Univ Bern, Oeschger Ctr Climate Change Res, Sidlerstr 5, CH-3012 Bern, Switzerland Max Planck Inst Meteorol, Bundesstr 53, D-20146 Hamburg, Germany CSIRO Oceans & Atmosphere, Climate Sci Ctr, Aspendale, Vic 3195, Australia Univ Libre Bruxelles, Dept Geosci Environm & Soc, B-1050 Brussels, Belgium Purdue Univ, Dept Earth, Dept Agron, W Lafayette, IN 47907 USA European Ctr Medium Range Weather Forecasts, Res Dept, Reading, Berks, England Lund Univ, Dept Phys Geog & Ecosyst Sci, Solvegatan 12, S-22362 Lund, Sweden Environm & Climate Change Canada, Climate Res Div, Victoria, BC V8W 2Y2, Canada Univ Bristol, Sch Geog Sci, Bristol BS8 1SS, Avon, England NOAA, Geophys Fluid Dynam Lab GFDL, Princeton, NJ 08540 USA Meteorol Res Inst MRI, Nagamine 1-1, Tsukuba, Ibaraki 3050052, Japan Univ Bristol, Sch Chem, Bristol BS8 1TS, Avon, England Univ Leicester, Natl Ctr Earth Observat, Leicester LE1 7RH, Leics, England Univ Quebec Montreal, Inst Environm Sci, Dept Biol Sci, Montreal, PQ H3C 3P8, Canada Peking Univ, Coll Urban & Environm Sci, Sino French Inst Earth Syst Sci, Beijing 100871, Peoples R China CICERO Ctr Int Climate Res, Pb 1129 Blindern, N-0318 Oslo, Norway Sorbonne Univ, LERMA, CNRS, Observ Paris,Univ PSL, Paris, France MIT, Dept Earth Atmospher & Planetary Sci, Bldg 54-1312, Cambridge, MA 02139 USA Lawrence Berkeley Natl Lab, Climate & Ecosyst Sci Div, 1 Cyclotron Rd, Berkeley, CA 94720 USA Southern Cross Univ, Ctr Coastal Biogeochem, Sch Environm Sci & Engn, Lismore, NSW 2480, Australia TNO, Dep Climate Air & Sustainabil, POB 80015, NL-3508 TA Utrecht, Netherlands Auburn Univ, Int Ctr Climate & Global Change Res, Sch Forestry & Wildlife Sci, 602 Duncan Dr, Auburn, AL 36849 USA Pacific Northwest Natl Lab, Joint Global Change Res Inst, College Pk, MD 20740 USA Univ Maryland, Dept Atmospher & Ocean Sci, College Pk, MD 20740 USA UN FAO, Stat Div, Food & Agr Org, Viale Terme di Caracalla, I-00153 Rome, Italy Finnish Meteorol Inst, POB 503, Helsinki 00101, Finland Imperial Coll London, Dept Phys, London SW7 2AZ, England Tech Univ Crete, Sch Environm Engn, Khania, Greece Univ Rochester, Dept Earth & Environm Sci, Rochester, NY 14627 USA KNMI, POB 201, NL-3730 AE De Bilt, Netherlands Univ Calif San Diego, Scripps Inst Oceanog, La Jolla, CA 92093 USA Environm & Climate Change Canada, 4905 Rue Dufferin, Toronto, ON, Canada Univ Toronto, Dept Phys, 60 St George St, Toronto, ON, Canada Univ Maryland, Dept Geog Sci, College Pk, MD 20740 USA Hohai Univ, Coll Hydrol & Water Resources, Nanjing 210098, Peoples R China NASA, Goddard Space Flight Ctr, Computat & Informat Sci & Technol Off, Greenbelt, MD 20771 USA Univ Victoria, Sch Earth & Ocean Sci, POB 1700 STN CSC, Victoria, BC V8W 2Y2, Canada Natl Inst Environm Studies NIES, Ctr Environm Measurement & Anal, Onogawa16-2, Tsukuba, Ibaraki 3058506, Japan |
| Keywords | GREENHOUSE-GAS EMISSIONS BIOMASS BURNING EMISSIONS PROCESS-BASED MODEL GOSAT SWIR XCO2 TM 4D-VAR V1.0 ATMOSPHERIC METHANE NATURAL-GAS CARBON-DIOXIDE CH4 EMISSIONS TRACE GASES |
| Issue Date | 15-Jul-2020 |
| Publisher | EARTH SYSTEM SCIENCE DATA |
| Abstract | Understanding and quantifying the global methane (CH4) budget is important for assessing realistic pathways to mitigate climate change. Atmospheric emissions and concentrations of CH4 continue to increase, making CH4 the second most important human-influenced greenhouse gas in terms of climate forcing, after carbon dioxide (CO2). The relative importance of CH4 compared to CO2 depends on its shorter atmospheric lifetime, stronger warming potential, and variations in atmospheric growth rate over the past decade, the causes of which are still debated. Two major challenges in reducing uncertainties in the atmospheric growth rate arise from the variety of geographically overlapping CH4 sources and from the destruction of CH4 by short-lived hydroxyl radicals (OH). To address these challenges, we have established a consortium of multidisciplinary scientists under the umbrella of the Global Carbon Project to synthesize and stimulate new research aimed at improving and regularly updating the global methane budget. Following Saunois et al. (2016), we present here the second version of the living review paper dedicated to the decadal methane budget, integrating results of top-down studies (atmospheric observations within an atmospheric inverse-modelling framework) and bottom-up estimates (including process-based models for estimating land surface emissions and atmospheric chemistry, inventories of anthropogenic emissions, and data-driven extrapolations). For the 2008-2017 decade, global methane emissions are estimated by atmospheric inversions (a top-down approach) to be 576 Tg CH4 yr(-1) (range 550-594, corresponding to the minimum and maximum estimates of the model ensemble). Of this total, 359 Tg CH4 yr(-1) or similar to 60 % is attributed to anthropogenic sources, that is emissions caused by direct human activity (i.e. anthropogenic emissions; range 336-376 Tg CH4 yr(-1) or 50 %-65 %). The mean annual total emission for the new decade (2008-2017) is 29 Tg CH4 yr(-1) larger than our estimate for the previous decade (2000-2009), and 24 Tg CH4 yr(-1) larger than the one reported in the previous budget for 2003-2012 (Saunois et al., 2016). Since 2012, global CH4 emissions have been tracking the warmest scenarios assessed by the Intergovernmental Panel on Climate Change. Bottom-up methods suggest almost 30 % larger global emissions (737 Tg CH4 yr(-1), range 594-881) than top-down inversion methods. Indeed, bottom-up estimates for natural sources such as natural wetlands, other inland water systems, and geological sources are higher than top-down estimates. The atmospheric constraints on the top-down budget suggest that at least some of these bottom-up emissions are overestimated. The latitudinal distribution of atmospheric observation-based emissions indicates a predominance of tropical emissions (similar to 65 % of the global budget, < 30 degrees N) compared to mid-latitudes (similar to 30 %, 30-60 degrees N) and high northern latitudes (similar to 4 %, 60-90 degrees N). The most important source of uncertainty in the methane budget is attributable to natural emissions, especially those from wetlands and other inland waters. Some of our global source estimates are smaller than those in previously published budgets (Saunois et al., 2016; Kirschke et al., 2013). In particular wetland emissions are about 35 Tg CH4 yr(-1) lower due to improved partition wetlands and other inland waters. Emissions from geological sources and wild animals are also found to be smaller by 7 Tg CH4 yr(-1) by 8 Tg CH4 yr(-1), respectively. However, the overall discrepancy between bottomup and top-down estimates has been reduced by only 5 % compared to Saunois et al. (2016), due to a higher estimate of emissions from inland waters, highlighting the need for more detailed research on emissions factors. Priorities for improving the methane budget include (i) a global, high-resolution map of water-saturated soils and inundated areas emitting methane based on a robust classification of different types of emitting habitats; (ii) further development of process-based models for inland-water emissions; (iii) intensification of methane observations at local scales (e.g., FLUXNET-CH4 measurements) and urban-scale monitoring to constrain bottom-up land surface models, and at regional scales (surface networks and satellites) to constrain atmospheric inversions; (iv) improvements of transport models and the representation of photochemical sinks in top-down inversions; and (v) development of a 3D variational inversion system using isotopic and/or co-emitted species such as ethane to improve source partitioning. The data presented here can be downloaded from https://doi.org/10.18160/GCP-CH4-2019 (Saunois et al., 2020) and from the Global Carbon Project. |
| URI | http://hdl.handle.net/20.500.11897/590457 |
| ISSN | 1866-3508 |
| DOI | 10.5194/essd-12-1561-2020 |
| Indexed | SCI(E) |
| Appears in Collections: | 城市与环境学院 |
