Including Harvested Grain Related CO2 in Climate Accounting

Abstract The current international climate greenhouse gas accounting system excludes the CO₂ removed from the atmosphere and stored in harvested crops, and the CO₂ emissions that occur when crops are oxidized, viewing both fluxes as carbon-neutral activities. Despite being previously described by Searchinger et al. (2009) as a “critical flaw in climate accounting,” all parties within the United Nations Framework Convention on Climate Change continue to treat these CO₂ fluxes as carbon-neutral activities. A two-region trade model is used to show that when harvested-grain biomass as carbon-neutral there is an incentive for parties committed to reducing emissions under the Paris Agreement to develop policies that use grains to produce biofuels, with no offsetting policy incentive to produce the grains required to meet this additional demand. A solution to the flaw in accounting is to treat harvested grain CO₂ fluxes the same as fossil fuel CO₂ and expand National GHG Inventory accounts to include the CO₂ sequestered in harvested grains, and the CO₂ emissions that occur when grain is consumed. Including these two additional lines in National GHG Inventories would more accurately measure national emissions and would incentivize parties in the Paris agreement to increase net grain exports, thereby enhancing food security while reducing the market incentives for carbon intensive land use conversion in non-compliant countries. Applying this more comprehensive Net Ecosystem Exchange (NEE) accounting system to Canadian agricultural emissions over the past decade, demonstrates the simplicity of accounting, the magnitude of impacts, and the profound impact on policy incentives.