―win-win‖ projects are ineligible under most domestic and international payment-based mitigation programs, this suggests that the agricultural sector should feature prominently under policy regimes that encourage payments for mitigation efforts. As we discuss later, this is not the case.

As the agricultural chapter of the IPCC report makes clear, the consensus estimate of 1.6 GtCO2e in mitigation potential is based on models in which the agricultural sector is narrowly defined, focusing on onfarm activities primarily involving crops and livestock and the handling of animal wastes (Smith et al., 2007). As a consequence, additional opportunities linked to the use of organic agricultural wastes, such as bagasse or rice husks, as a renewable fuel are not counted toward reported mitigation potentials in agriculture, but are attributed to sectors in which the fuel-switching takes place. Top-down studies referenced in the report suggest that this class of opportunities for mitigation is nearly as large as agriculture‘s on-farm potential, with mitigation estimates ranging from 0.7 to 1.26 gtCO2e per year by 2030 at costs of US$20 or below.

The mitigation potential from changing how agricultural land is used is included in the IPCC estimates. However, as Smith et al. (2008) emphasize, measuring the mitigation potential for agricultural land-use is complex because a single activity can initiate a chain of emission outcomes among a portfolio of greenhouse gasses that also depend on local soils and local climate conditions. As an example, the authors cite evidence presented in Paustian et al. (2004) showing that composting manure can suppress methane emissions while simultaneously accelerating emissions of another greenhouse gas, nitrous oxide. Similarly, soil restoration can encourage carbon uptake in plants and soils, while stimulating the release of carbon through the decomposition of organic matter.

After accounting for interrelated effects, the authors provide a further breakdown of the mitigation potential for a set of agricultural activities under a range of carbon prices, shown in figure 6. Keeping in mind that mitigation activities linked to agricultural biomass are excluded, the reported literature suggests that most mitigation opportunities are related to soil and land management practices that generate net sequestration gains. At low carbon prices (less than US$20), cropland management practices are key sources of mitigation, along with other land management practices, including the restoration of organic soils, degraded lands and improved management of grazing.

It is worth emphasizing that the types of mitigation activities identified are those often undertaken to enhance agricultural productivity or better manage agricultural resources even when mitigation incentives are absent. In particular the report notes that improved agronomic practices designed to improve yields, such as expanding crop rotations or adding nutrients when they are deficient, can lead to greater carbon sequestration in soils. Utilizing vegetative cover between rows of trees or vines both protects against erosion and enhances carbon storage. The authors also note that improved nutrient management on crop and grazing land can sequester carbon while holding down production costs. Adding organic matter or controlling erosion in order to restoring degraded lands increases the stock of land usable for agriculture and while stockpiling carbon in the soils. Smaller but important mitigation opportunities are tied to efforts designed to reduce methane emissions from wetland rice, livestock and manure.

The IPCC report provides estimates of the full set of technically feasible mitigation potential from agriculture by region, but does not further distinguish among the projects by cost. The mean estimates for selected regions are given in figure 7. For ECA, the mean estimated technical potential mitigation is about 781million tonsCO2 equivalent (MtCO2e) per year by 2030, which works out to more than 13 percent of the estimated mitigation potential of agriculture world-wide.

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