Improved quantifi cation of diverse CH 4 sources at the urban scale is needed to guide local GHG mitigation strategies in the Anthropocene. Herein, we focus on landfi ll CH 4 emissions in California, challenging the current IPCC methodology which focuses on a climate dependency for landfi ll CH 4 generation (methanogen-esis), but does not explicitly consider climate or soil dependencies for emissions. Relying on a comprehensive California landfi ll database, a fi eld-validated process-based model for landfi ll CH 4 emissions (CALMIM), and select fi eld measurements at 10 California sites with a variety of methods, we support the contrary position: Limited climate dependency for methanogenesis, but strong climate dependency for landfi ll CH 4 emissions. Contrary to the historic IPCC empirical model for methanogenesis with kinetic constants related to climate, we demonstrate a simpler and more robust linear empirical relationship (r 2 = 0.85; n=128) between waste mass and landfi ll biogas recovery [126 × 10-6 Nm 3 CH 4 hr-1 Mg waste-1 ]. More interestingly, there are no statistically signifi cant relationships with climate, site age, or status (open/closed) for landfi ll biogas recovery. Th e current IPCC methodology does not consider soil or climate drivers for gaseous transport or seasonal methanotrophy in diff erent cover soils. On the other hand, we illustrate strong climate and soil dependencies for landfi ll emissions-e.g., average intermediate cover emissions below 20 g CH 4 m-2 d-1 when the site's mean annual precipitation is >500 mm y-1. Th ereby, for the California landfi ll CH 4 inventory, the highest-emitting sites shift from landfi lls containing the largest mass of waste to sites dominated by intermediate cover types having a reduced rate of soil CH 4 oxidation during the annual cycle. Th ese diff erences have profound implications for developing more realistic, science-based urban and regional scale GHG inventories for landfi ll CH 4 while reducing uncertainties for this important anthropogenic source.