Table S2 CH4 emission rates (Tg CH4 yr-1) from different wetlands located within different regions of China Region Wetland type Flooding condition Season Flux References Qinghai-Tibetan Peatland Continuous flooding Growing season 8.30 ± 7.66 1-3 Seasonal flooding Growing season 7.83 ± 8.87 1,2 Seasonal flooding during Non-growing season 0.56 1 Plateau the growing season Northeast China Peatland Seasonal flooding Growing season 3.27 Freshwater Continuous flooding Growing season 11.24 Non-growing season 0.68 Growing season 5.08 Non-growing season 0.24 ± 1.96 ± 5.72 4,5 2,6-8 marshes Seasonal flooding Other regions 9 ± 4.93 6,8 9 ± 1.10 10 Swamp Seasonal flooding Growing season 0.61 Freshwater Continuous flooding Growing season 9.76 7 Continuous flooding Non-growing season 3.29 11 marshes during the growing season Salt marshes Tidal flooding Annual 2.89 ± 3.97 12-14 Swamp Tidal flooding Annual 0.06 ± 0.07 15 (mangrove) References 1 Chen H, Yao S P, Wu N, Wang Y F, Luo P, Tian J P,Gao Y H (2008). Determinants influencing seasonal variations of methane emissions from alpine wetlands in Zoige Plateau and their implications. Journal of Geophysical Research, 113,D12303, 10.1029/2006JD008072. 2 Ding W, Cai Z,Wang D (2004). Preliminary budget of methane emissions from natural wetlands in China. Atmospheric Environment, 38, 751-759. 3 Hirota M, Tang Y, Hu Q et al. (2004). Methane emissions from different vegetation zones in a Qinghai-Tibetan Plateau wetland。 Soil Biology and Biochemistry, 36, 737-748. 4 Mu C, Shi L,X. S (2009). Fluxes and controls of CO 2, CH4 and N2O in a marsh wetland of Xiaoxing'an mountains, Northeastern China Chinese Journal of Plant Ecology, 33, 617-623, in Chinese with an English abstract. 5 Yu J B, Liu J S, sun Z G, Sun W D, Wang J D, Wang G P,Chen X B ( 2009). The fluxes and controlling factors of N2O and CH4 emissions from freshwater marsh in northeast China. Science in China Series D: Earth Sciences, 39, 177 -187, in Chinese with an English abstract. 6 Song C, Yan B, Wang Y, Wang Y, Y. L,Zhao Z (2003). Fluxes of carbon dioxide and methane from swamp and impact factors in Sanjiang Plain, China. Chinese Science Bulletin, 48, 2749-2753. 7 Wang Z P, Han X G, Li L H, Chen Q S, Duan Y,Cheng W X (2005). Methane emission from small wetlands and implications for semiarid region budgets. Jounal of Geophysical Research, 110, D13304, doi:10.1029/2004JD005548. 8 Zhou W M, Wang J D,Liu J S (2006). Study on the relation of plant biomass and CH4 , N2O emission in the wetland of Sanjiang Plain. Journal of the Graduate School of the Chinese Academy of Sciences, 23, 736-743, in Chinese with an English abstract. 9 Zhang J, Song C,Yang W (2005). Cold season CH4, CO2 and N2O fluxes from freshwater marshes in northeast China. Chemosphere, 59, 1703-1705. 10 Sun X, Mu C, Shi L, Cheng W, Liu X, Wu Y,Feng D (2009). Methane emission from forested swamps in Xiaoxing'an mountains, Northeastern China Chinese Journal of Plant Ecology, 33, 535-545, in Chinese with an English abstract. 11 Wang Z P,Han X G (2005). Diurnal variation in methane emissions in relation to plants and environmental variables in the Inner Mongolia marshes. Atmospheric Environment, 39, 6295-6305. 12 Chang T C,Yan S S (2003). Methane emission from wetlands in Taiwan. Atmospheric Environment, 37, 4551-4558. 13 Tong C, Zeng C S, Wang W Q, Yan Z,Yang H (2009). Main factors influencing CH 4 flux from a Phragm ites australis wetland in the Min River estuary. Acta Scientiae Circumstantiae, 29, 207-216, in Chinese with an English abstract. 14 Wang D, Chen Z,Xu S (2009). Methane emission from Yangtze estuarine wetland, China. Jounal of Geophysical Research, 114, G02011 doi:10.1029/2008JG000857. 15 Ye Y, Lu C,Lin P (2000). Seasonal and spatial xhanges of methane emissions from mangrove wetlands in Hainan island and Xiamen. Chinese Journal of Atmospheric Sciences, 24, 152-156, in Chinese with an English abstract.