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

摘要

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 country-specific 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.