Global estimations of the inventory and mitigation potential of methane emissions from rice cultivation conducted using the 2006 IPCC guidelines

Abstract

While there have been many estimates of global CH 4 emissions from rice fields, none of them have been obtained using the IPCC guidelines. In this study, we used the Tier 1 method described in the 2006 IPCC guidelines to estimate the global CH 4 emissions from rice fields. To accomplish this, we used countryspecific statistical data regarding rice harvest areas and expert estimates of relevant agricultural activities. The estimated global emission for 2000 was 25.4 Tg/yr, which is at the lower end of earlier estimates and close to the total emission summarized by individual national communications. Monte Carlo simulation revealed a 95% uncertainty range of 14.8 to 41.5 Tg/yr. We estimated that, if all of the continuously flooded rice fields were drained at least once during the growing season, the CH 4 emissions would be reduced by 4.1 Tg/yr. Furthermore, we estimated that applying rice straw off-season wherever and whenever possible would result in a further reduction in emissions of 4.1 Tg/yr globally. Finally, if both of these mitigation options were adopted, the global CH 4 emission from rice paddies could be reduced by 7.6 Tg/yr.