利用未來統計降尺度氣候資料評估臺灣水稻生產潛勢

Abstract

本文利用IPCC AR5 統計降尺度(SDSM)RCP 4.5 及8.5 兩種氣候情境之未來氣候預測值，輸入本所研發之糧食生產評估系統，結合地理資訊系統，用以評估未來臺灣水稻生產潛勢。氣候預測值分析結果顯示，RCP 4.5情境下臺灣在未來最高溫度之趨勢，世紀末平均上升0.91℃，RCP 8.5 則上升1.75℃。溫度升高縮短水稻生育日數，若不考慮二氧化碳對水稻生長的影響，在基期(1986-2005 年)生育日數低於120d 之區域僅限於屏東、高雄及臺南等部分區域， 世紀末(2081-2100年)RCP 4.5 延伸至嘉義及雲林，RCP 8.5 則將涵蓋臺中市，東部則延伸至花蓮北端。而水稻產量呈現減產趨勢，在RCP 8.5 情況下(未來氣候環境最失控的狀態)，於世紀末水稻產量平均改變率約-13%，約減產約1,100 kg ha-1。若考慮二氧化碳及其與氣溫交感效應對水稻生長的影響，加入二氧化碳後水稻產量是增加的， 當二氧化碳濃度設定為850ppm，則水稻產量增加15%。 The future rice production potential in Taiwan was assessed by using the predicted values of future climate under the climatic conditions of IPCC AR5 statistical downscaling model (SDSM) RCP 4.5 and 8.5 as inputs into the grain production assessment system developed by Taiwan Agriculture Research Institute, combining with geographic information system. Results of climate prediction analysis showed that, the trend of the highest temperature of Taiwan in the future, under the RCP 4.5 scenario, would increase an average value of 0.91℃ at the end of the century. It will increase1.75℃ in the case of RCP 8.5 scenario. The rising temperature shortens rice growth period. Without the direct effect of CO2, in the base period (1986-2005), only rice grown in areas of Pingtung, Kaohsiung and Tainan had less than 120 d growing period. At the end of this century (2081-2100), RCP 4.5 scenario would extend to Yunlin and Chiayi, while RCP 8.5 would cover Taichung City and would extend to the northern part of Hualien in the east. The output of rice production showed a reducing trend under the condition of RCP 8.5, the most deleterious status in future climate environment. At such condition, the prospect for rice production at the end of the century would reduce about -13% in average island-wide, approximately 1,100 kg ha-1. Considering that the impact of CO2 and temperature interaction effect on rice growth, with combined effect increased rice production. When the CO2 concentration was 850 ppm, it would result in an increased rice production of 15%.