Land-Use, Land-Use Change and Forestry - the IEA Bioenergy Task ...

S.Subak – Addressing COP6 Decisions on Agricultural Soil Carbon 9Addressing COP6 Decisions on Agricultural Soil CarbonAccumulationSusan SubakAmerican Association for the Advancement of Science FellowOffice of Atmospheric Programs, U.S. Environmental Protection AgencyABSTRACTThe Kyoto Protocol introduces the possibility that changes in carbon stock on agricultural and forest landand soils may be counted against countries’ commitments to reduce their greenhouse gas emissions.Including activities related to land use change and forestry in the international climate change agreementmay stimulate new incentives for soil-conservation practices domestically. However, a primary criteria fortheir inclusion relates to the level of accuracy and transparency with which carbon stock changes can beassessed. Parties will also be concerned with the wider environmental impact of different sequestrationpractices, and the impact of offsets on overall emissions targets. This paper examines these issues foragricultural soils, considering recent research in temperate regions. It is argued that incentives for carbonsequestration practices may need to be implemented independently of actual stock changes because farmlevelsoil monitoring would be very costly. Priority should be given to establishing incentives for covercrops and to expanding conservation tillage programs. These activities provide a range of ancillaryenvironmental benefits. In contrast, improvements in biomass yield tend to rely on higher fertilizer inputswith their related environmental costs. Carbon accumulated through any of these activities is easily lost if thepractices are discontinued, and so assessment procedures are needed that would avoid overestimatingsequestration. Annual accumulation in agricultural soils could be equivalent to about 10% of Annex I carbondioxide emissions, and therefore options for limiting sink credits from soils should be considered.