Climate Change Impact on Rice Yield and Adaptation Response of Local Farmers in Sumedang District, West Java, Indonesia

Abstract

Despite the well-documented model-simulated adverse climate change impact on rice yields reported elsewhere, interventions to address the issue seems still limited, particularly at local level. This links to the uncertainty that entails to climate projection and its likely future impact, which varies across regions and climate models. The study analyzes climate change-induced yield reduction and the adequacy of current adaptations to cope with the large range of impact under various climate models. Seventeen General Circulation Models (GCMs) under Representative Concentration Pathways (RCPs) climate change scenarios of RCP8.5 and RCP4.5, combined with CROPWAT model were used for near-future (2011-2040) and far-future (2041-2070) projections. The output confirms yield reduction to occur in the near-future, to the extent variable across the GCMs. At the highest estimation, rice yield decreases by 32.00% and 31.81%, in comparison to baseline, for near-future under RCP8.5 and RCP4.5, respectively. The reduction extends, with a slightly higher degree, to the far-future. The reduction is sensitive to variation in farming practices of the local farmers, in particular that in planting time and irrigation scheduling. The shifting of planting time to better match rainfall pattern and improved irrigation reduced the yield reduction by 16.16% and 15.18%, respectively. The combined impact of the two, however, still leaves un-tapped a reduction of 5.86%, suggesting that planned interventions are still required to improve the current farm management. The findings provide valuable inputs for relevant authorities to understand the whole continuum of climate change-induced rice yield reduction, based on which sets of planned interventions locally specific for the areas could be developed, accordingly.