Table 1.

Annual CH4 emissions by source type for 1984–2003 from the electronic supplementary material in Bousquet et al. [5] in the middle column and for a range of years from 1997 to 2006 from Forster et al. [11] (Intergovernmental Panel on Climate Change (IPCC)); chemical sinks are scaled to total emissions based on Lelieveld et al. [12]. Units are Tg CH4 yr−1, where 1 Tg= 1012 g. Isotopic values are from a range of sources.

sourceBousquet (Tg yr−1)IPCC (Tg yr−1)δ13C (‰)δD (‰)
anthropogenic
energy110±1374–106−175±10
 coal and industry47±10−35±3
 gas63±9
North Sea−34±3
Siberia−50±3
enteric fermentationa90±1476–92−305±9
 C4 diet−49±4
 C3 diet−70±4
rice agriculture31±531–112−62±3−323±18
biomass burningb50±814–88−210±16
 C4 vegetation−17±3
 C3 vegetation−26±3
waste55±1135–69−293±20
 landfills−53±2
 domestic sewage−57±3
 animal waste−58±3
natural
wetlands147±15100–231
 swamps104±12−55±3
 bogs and tundra43±8−65±5
termites23±420–29
oceans19±64–15
total525±8503–610−52.9−283±13
sinksBousquet (Tg yr−1)IPCC (Tg yr−1)
troposphere448±1428–511
stratosphere37±130–45
soil21±326–34
totalc506492–581
  • aContains a small amount of natural emissions from wild ruminants.

  • bBiomass burning includes biofuels and wild fires.

  • cFor a burden of 4900 Tg CH4 in 2003, implies τ≈9.4 yr.