Bioenergy: counting on incentives.

The suggestion by T. D. Searchinger et al. (“Fixing a critical climate accounting error,” Policy Forum, 23 October 2009, p. [527][1]) to account for CO2 by “tracing the actual flows of carbon” appears to promote an approach to carbon accounting in which emissions and removals from a forest are determined on the basis of gross atmospheric fluxes between the forest, or forest products, and the atmosphere. This contrasts with the current “stock-change” approach, in which the annual removals or emissions from a country's forest are assumed to be equal to the net change in carbon stocks in biomass and soils of the forest estate. We share the concern of the authors that a “critical climate accounting error” exists within the Kyoto protocol and could undermine greenhouse gas (GHG) reduction goals. However, we feel that their solution would create new, unintended disincentives for the sustainable use of biomass. The practical problem in the current accounting framework is that some countries do not have commitments under the Kyoto Protocol, and they are therefore not obliged to account for emissions from loss of terrestrial carbon. Furthermore, some countries with commitments choose not to account for some sources of emissions (for example, conversion of natural to managed forest, conversion of grassland to cropland). Therefore, loss of carbon stock associated with the supply of biomass for bioenergy may not be accounted for. Applying the atmospheric-flow accounting approach would not solve this problem. The importing country would account only for the carbon contained in the biomass used for bioenergy, even though the carbon stock losses in the cleared forest, especially if growing on peatland, could be many times greater than the quantity of carbon contained in the imported biomass ([ 1 ][2]). Replacing the current stock-change accounting approach with the proposed atmospheric-flow–based accounting approach would also lead to unintended incentives. For instance, combustion of biomass may appear in national GHG accounting with higher CO2 emissions than coal combustion (because the energy content per unit of carbon is higher for coal than for biomass), even if biomass is harvested on a sustainable basis without reducing the biological carbon stock. This would make all imported bioenergy uncompetitive with fossil fuels. The negative impacts of the atmospheric-flow approach have been discussed in depth ([ 2 ][3]–[ 5 ][4]); the conclusions favoring a stock-change–based approach, which is applied in the existing GHG accounting framework, remain valid. Rather than abandoning the current approach and implementing the atmospheric-flow–based strategy that they advocate, we suggest retaining the existing stock-change–based accounting framework for biomass while extending the end-user's responsibility to include the terrestrial carbon stocks. The “end-user country” would be required to take full or partial responsibility for changes in the terrestrial carbon stocks in the “producer country. ” Quantifying the change in carbon stocks attributable to bioenergy is difficult, especially given that bioenergy is not the only driver of land-use change. (For example, the food industry is also a rapidly growing market for vegetable oils.) Development of feasible accounting rules is thus a challenging task. However, it is critical that policy measures do not create disincentives for bioenergy from sustainable sources. 1. [↵][5] 1. J. Fargione 2. et al . , Science 319, 1235 (2008). [OpenUrl][6][Abstract/FREE Full Text][7] 2. [↵][8] 1. B. Lim 2. et al . , Environ. Sci. Pol. 2, 207 (1999). [OpenUrl][9][CrossRef][10] 3. UNFCCC, “Estimating, reporting, and accounting of harvested wood products” (Technical Paper FCCC/TP/2003/7, 27 October 2003); . 4. 1. A. Cowie 2. et al . , Clim. Pol. 6, 161 (2006). [OpenUrl][11] 5. [↵][12] 1. M. Apps 2. et al . , “Accounting system considerations: CO2 emissions from forests, forest products, and land-use change—A statement from Edmonton” (1997); [www.ieabioenergy-task38.org/publications/publication1.htm][13]. 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