Estimate of CH4 Emissions from Year-Round Flooded Rice Fields During Rice Growing Season in China

A special kind of rice field exists in China that is flooded year-round. These rice have substantially large CH4 emissions during the rice-growing and emit CH4 in the non-rice growing season. CH4 emission factors were used to estimate the CH4 emissions from flooded rice during the rice-growing in China. The CH4 emissions for the flooded rice in China for the rice growing over a total area of 2.66 Mha were estimated to be 2.44 Tg CH4 year-1. The uncertainties of these estimations are discussed as well. However, the emissions during the non-rice growing could not be estimated because of limited available data. Nevertheless, methane emissions from rice that were flooded could be several times higher than those from the rice drained in the non-rice-growing season. Thus, the classification of continuously flooded rice fields in the IPCC (International Panel on Climate Change) Guidelines for National Greenhouse Gas Inventories is suggested to be revised and divided into continuously flooded rice during the rice growing season and year-round flooded rice fields.