Assessing the climate change impacts on Coffee arabica cultivation regions in China

Coffea arabica, a vital cash crop in Yunnan Province’s plateaus(YN), comprises 98% of China’s total coffee output in both cultivation area and yield. In this study, the average annual temperature (Tyear), the average temperature of the coldest month(Tcoldest), annual precipitation (Ryear) and precipitation from February to March (R2–3) were used to assess the climatic suitability of Coffea arabica cultivation in YN, to understand the possible expansion of the crop in future scenarios The simulated outputs of the regional climate model RegCM4 driven by three global climate models (HadGEM2-ES, MPI-ESM-MR and NorESM1-M) were used, and the ensemble average method was applied to obtain the ensemble model results. The suitability of Coffea arabica cultivation in YN for the base period (1981–2010) and three future periods (2021–2030, 2031–2040, 2041–2050) under three emission scenarios (RCP2.6, RCP4.5, RCP8.5) was analyzed. The results showed that the suitable planting area of small-grain coffee in YN increased significantly under the three models and the aggregate model, it expanded to the north and east, and the unsuitable planting area decreased sharply. The optimum areas of the northern part of southwestern YN and of the western, eastern, and central parts of southeastern YN were enlarged, while the suitability grade of the southern part was improved. In most parts of southeastern YN in particular, the areas that were not suitable or were less suitable for small-grain coffee cultivation became suitable or even the most suitable, and the suitability grade improvement and area expansion were considerable. Among the three models, the largest increase was obtained with the MPI-ESM-MR model, the smallest increase with the HadGEM2-ES model, and the largest decrease with the MPI-ESM-MR model from 2041 to 2050 (55.2%) under the RCP8.5. The largest increases in the most suitable area were 65.5% and 64.5%, which were obtained under the RCP8.5 with the NorESM1-M and MPI-ESM-MR models, respectively, from 2041 to 2050. Under RCP2.6 and RCP4.5, the change is similar to that of RCP8.5, but the increase is lower than that of RCP8.5.