livestocks long shadow

Table 3.1
Past and current concentration of important
greenhouse gases
Gas Pre-industrial Current Global
concentration tropospheric warming
(1 750) concentration potential*
Carbon dioxide (CO2) 277 ppm 382 ppm 1
Methane (CH4) 600 ppb 1 728 ppb 23
Nitrous oxide (N2O) 270–290 ppb 318 ppb 296
Note: ppm = parts per million; ppb = parts per billion; ppt

Livestock numbers (2002) and estimated carbon dioxide emissions from respiration
Species World total Biomass Carbon dioxide emissions
(million head) (million tonnes liveweight) (million tonnes CO2)
Cattle and buffaloes 1 496 501 1 906
Small ruminants 1 784 47.3 514
Camels 19 5.3 18
Horses 55 18.6 71
Pigs 933 92.8 590
Poultry1 17 437 33.0 61
Total2 699 3 161