Table 7

Comparison of the estimates of agricultural GHG mitigation potential (Mt CO2-eq. yr−1) by 2030 with previous global and regional estimates, for combinations of practices, gases considered and different marginal costs assumed.

studyregion—practicegas consideredprice of CO2previous mitigation potential estimate (Mt CO2-eq. yr−1)equivalent mitigation potential estimate from this study (Mt CO2-eq. yr−1)
IPCC (1996; TAR)aglobe—soil sequestrationCO2 onlybiophysical potential1400–29001370–3880
Lal (2003, 2004a)aglobe—soil sequestrationCO2 onlybiophysical potential3300±11001370–3880
IPCC (2000; SR-LULUCF)bglobe—soil sequestrationCO2 onlybiophysical potential14701370–1470
Manne & Richels (2004),cglobe—soil sequestrationCO2 onlyUS$ 27 t CO2-eq.−117001370–1470
IPCC (2001; TAR)dglobe—all measuresCO2, CH4 and N2OUS$ 27 t CO2-eq.−11300–27501540–1640
Caldeira et al. (2004),eglobe—all measuresCO2, CH4 and N2Obiophysical potential45104300–5950
Lal & Bruce (1999),fglobe—croplands onlyCO2 onlybiophysical potential1580–20901980–2140
Conant et al. (2001),gglobe—permanent pastures onlyCO2 onlybiophysical potential68601360–1560
Squires et al. (1995),hglobe—desertification control onlyCO2 onlybiophysical potential3670approximately 650
Lal (2001),hglobe—desertification control onlyCO2 onlybiophysical potential730–1470approximately 650
US-EPA (2006),iglobe—soil N2O onlyN2O onlyUS$ 100 t CO2-eq.−1200120
US-EPA (2006),iglobe—rice CH4 onlyCH4 onlyUS$ 100 t CO2-eq.−1230230
US-EPA (2006),iglobe—livestock CH4 onlyCH4 onlyUS$ 100 t CO2-eq.−1200–300210
US-EPA (2006),iUS—livestock CH4 onlyCH4 onlyUS$ 20 t CO2-eq.−14032
US-EPA (2006),iChina—livestock CH4 onlyCH4 onlyUS$ 50 t CO2-eq.−14542
US-EPA (2006),iIndia—livestock CH4 onlyCH4 onlyUS$ 10 t CO2-eq.−11712
US-EPA (2006),iBrazil—livestock CH4 onlyCH4 onlyUS$ 30 t CO2-eq.−12346 (for all South America)
Smith et al. (2000),jEurope (excluding Russia)CO2 onlylimited by suitability205120, 160, 240
Lal et al. (2003),kUS—croplands onlyCO2 onlybiophysical potential165–360140
Lal et al. (2003),kUS—grasslands onlyCO2 onlybiophysical potential48–25760
Lal et al. (2003),kUS—land conversion onlyCO2 onlybiophysical potential77–282
Lal et al. (2003),kUS—land restoration onlyCO2 onlybiophysical potential92–22030
Sperow et al. (2003),kUS—croplands onlyCO2 onlybiophysical potential220–257140
Boehm et al. (2004),lCanada—all agricultureCO2 onlybiophysical potential16.5–29.9
Boehm et al. (2004),lCanada—all agricultureCO2, CH4 and N2Obiophysical potential4–15.6
Lal (2004c),mChinaCO2 onlybiophysical potential436–829425
Lal (2004d),lCentral AsiaCO2 onlybiophysical potentialapprox. 60±30
Lal (2004e),nIndiaCO2 onlybiophysical potentialapprox. 160±18330 (for all South Asia)
Lal (2005),oBrazilCO2 onlybiophysical potential400570 (for all South America)
  • a Economic potentials estimated here at up to 20 US$ t CO2-eq.−1 of approximately 1300–1400 Mt CO2-eq. yr−1 rising to 2200–2400 and 3600–3900 Mt CO2-eq. yr−1 at up to 50 and up to 100 US$ t CO2-eq.−1, respectively.

  • b IPCC LULUCF (2000) estimate is based on C stock change in croplands, grazing lands, agroforestry, rice paddies and urban lands. Compared to estimates here at 0–20 US$ t CO2-eq.−1.

  • c Manne & Richels (2004) estimates for 2010 assuming a marginal cost of US$ 100 t C −1 (equivalent to US$ 27 t CO2-eq.−1); figures from this study are from closest comparable price range of 0–20 US$ t CO2-eq.−1.

  • d IPCC TAR (2001) estimates for 2020 assuming a marginal cost of US$ 100 t C –1 (equivalent to US$ 27 t CO2-eq.−1); figures from this study are from closest comparable price range of 0–20 US$ t CO2-eq.−1.

  • e Caldeira et al. (2004) estimates are for all gases for practices: enteric fermentation, rice cultivation, biomass burning, animal waste treatment and agricultural soils over a 0–20 year time horizon; estimates here are between the estimates at 0–100 US$ t CO2-eq.−1 and total biophysical potential (up to 6000 Mt CO2-eq. yr−1).

  • f Estimate for croplands only; comparable figure is for the biophysical potential of cropland management, plus restoration of degraded croplands.

  • g The Conant et al. (2001) estimate for permanent pasture only is much larger than many estimates for all agricultural mitigation measures combined; as such, it may be unrealistically high.

  • h Comparable estimates for this study are for restoration of degraded lands.

  • i All US-EPA (2006) estimates are for 2020. Global estimates are for prices of 100 US$ t CO2-eq.−1. US-EPA (2006) estimate for Brazil should be equivalent to approximately 60% the estimate from this study for South America. Rice figures are taken directly from US-EPA (2006).

  • j Comparable figures for this study are quoted for prices of up to 20, up to 50, up to 100 US$ t CO2-eq.−1, respectively. Other studies from individual countries are not included as there is no comparable area in the present study.

  • k From this study, biophysical potentials used for all North America (US plus Canada) from cropland management, grassland management and restoration of degraded lands.

  • l No comparable area in the present study.

  • m Estimate in this study for East Asia.

  • n Estimate in this study for South Asia; covers a larger area than just India.

  • o Lal (2005) estimates that 180 Mt CO2 yr−1 could be sequestered in the soils of Brazil, plus a further 220 Mt CO2 yr−1 mitigated by erosion prevention; estimate from this study from South America; covers a larger area than just Brazil.