為探討臺灣水稻田溫室氣體排放情形，甲烷和氧化亞氮排放量以本土實地測定值和IPCC準則推估。以本土間歇性灌溉實地測定值推估，1990年至2010年臺灣第一期水稻田種植面積介於134,038-242,298公頃，甲烷年排放介於7,459-14,980公噸；第二期水稻田種植面積介於92,341-211,968公頃，甲烷年排放介於10,709-35,208公噸。如以IPCC連續浸水栽培準則推估，1990年至2010年臺灣第一期水稻田甲烷年排放量介於27,067-55,729公噸，第二期水稻田甲烷年排放量介於18,966-61,471公噸。以本土實地測定值推估，1990年至2010年臺灣第一期水稻田氧化亞氮排放量介於371-728公噸，第二期水稻田氧化亞氮排放量介於147-365公噸。臺灣水稻田以間歇性灌溉時第一期作、第二期作及全年甲烷排放量分別為IPCC連續浸水栽培準則及插秧期平均溫度推估值之26.72-28.92%、55.65-57.32%和41.19-43.10%。其值分別為IPCC單一通氣栽培準則及插秧期平均溫度推估值之53.44-57.84%、111.29-114.55%和82.38-86.20%。其值分別為IPCC多次通氣栽培準則及插秧期平均溫度推估值之133.60-144.61%、282.56-286.62%和205.96-215.49%。水稻田以間歇性灌溉栽培可以顯著降低甲烷排放量，水稻田適量施用氮肥和灌水亦可有效降低氧化亞氮排放量。

To investigate the greenhouse gas emissions from paddy fields, methane and nitrous oxide emissions were estimated with the local measurement and the IPCC method during 1990 to 2010 in Taiwan. Annual methane emissions ranged from 7,459 to 14,980 ton in the first crop season for 134,038 to 242,298 ha of paddy fields, and they were between 10,709 and 35,208 ton for 92,341 to 211,968 ha in the second crop season with the local measurement for intermittent irrigation. The values ranged from 27,067 to 55,729 ton of methane emissions in the first crop season, and they were between 18,966 and 61,471 ton in the second crop season with the IPCC guideline for continuous flooding. Annual nitrous oxide emissions from paddy fields were between 371 and 728 ton in the first crop season, and the values ranged from 147 to 365 ton in the second crop season with the local measurement. Methane emissions from paddy fields in Taiwan for intermittent irrigation were only 26.72-28.92%, 55.65-57.32% and 41.19-43.10% with the IPCC guidelines for continuous flooding and means temperature of transplanting stage in the first crop, the second crop and total paddy fields, respectively. The values were 53.44-57.84%, 111.29-114.55% and 82.38-86.20% with the IPCC guidelines for single aeration and mean temperature of transplanting stage, respectively; and the values were 133.60-144.61%, 282.56-286.62% and 205.96-215.49% with the IPCC guidelines for multiple aerations and mean temperature of transplanting stage, respectively. Intermittent irrigation in paddy fields reduces methane emission significantly; appropriate application of nitrogen fertilizer and irrigation in paddy fields also decreases nitrous oxide emission.