Table 2. A Priori Bottom-Up Inventories and a Priori Annual Total Emissions Source Category Reference Emission, Tg CH4/yr Coal mining IIASAa [Klaassen et al., 2004] 26.6 Oil and natural gas IIASAa [Klaassen et al., 2004] 50.6 Enteric fermentation IIASAa [Klaassen et al., 2004] 99.6 Rice GISS [Matthews et al., 1991] 59.7 Biomass burning [van der Werf et al., 2004] 23.6 Waste IIASAa [Klaassen et al., 2004] 69.7 Wetlands (1) as described in section 3.3 174.5 (2) [Walter et al., 2001a, 2001b] Wild animals [Houweling et al., 1999] 5.0 Termites [Sanderson, 1996] 19.2 Soil [Ridgwell et al., 1999] ­37.8 Ocean [Houweling et al., 1999] 17.0 aIIASA inventory has been spatially disaggregated on 1degrees x 1degrees [Dentener et al., 2005] using the EDGAR 3.2 database for year 1995 [Olivier and Berdowski, 2001].