Impact assessment of climate change on rice productivity in the Indochinese Peninsula using a regional‐scale crop model

ABSTRACT In order to assess the impact of climate change on rice yields for the Indochina peninsula region, a regional rice model was forced with climate variables from CORDEX ‐East Asia climate models. The future climate's impact on rice yield varies between countries, and it is dependent on both current climate conditions and the projected future climate. Climate change alone would lead to a 3.5–23.2% and 5.8–27.2% reduction in rice yield for the 2020s and 2040s, respectively, in the Indochinese peninsula, with the largest decreases in Cambodia. The negative impacts of climate change on rice can be partly offset by the positive effect of CO 2 fertilization. For the Indochinese peninsula regions, changes in rice yield are quite sensitive to increases in temperature, and each one‐degree increase in temperature can cause about a 10.26% reduction in rice yields. The uncertainty in the predicted temperature from the regional climate models used contributed to approximately 59.7% of the uncertainty in rice yield projections. This result implies that the uncertainty in the projected temperatures from climate models could be one of the major sources of uncertainty in impact assessments. In this study, adaptation strategies, including changes in planting dates and use of irrigation and heat tolerant varieties, were tested. The use of tolerant varieties and shifting planting date are simple management responses that may offset a small part of the negative impact of climate change. For all the countries in the Indochinese peninsula, the CO 2 fertilization effect and irrigation can offset most of the negative impacts caused by climate change by 2050, and irrigation is an effective adaptation method.