In the Hengduan Mountain region, soil erosion is the most serious ecological environmental problem. Understanding the impact mechanism of water yield and soil erosion is essential to optimize ecosystem management and improve ecosystem services. This study used the Integrated Valuation of Ecosystem Services and Tradeoffs (InVEST) and Revised Universal Soil Loss Equation (RUSLE) models to separate the relative contributions of land use and climate change to water yield and soil erosion. The results revealed that: (1) Although soil and water conservation has been strengthened in the past 25 years, both water yield and soil erosion increased from 2010 to 2015 due to the conversion of woodland to grassland, which indicates that continuous benefits after the implementation of ecological restoration projects were not obtained; (2) Climate change played a decisive role in water yield and soil erosion changes in the Hengduan Mountain region from 1990 to 2015, and soil erosion was not only related to the amount of precipitation but also closely related to precipitation intensity; (3) The contribution of land use and climate change to water yield was 26.94% and 73.06%, while for soil erosion, the contribution of land use and climate change was 16.23% and 83.77%, respectively.

The Fifth Assessment Report of the Intergovernmental Panel on Climate change (IPCC) shows that climate change poses severe risks to the Belt and Road region and could cut future crop production. Identifying the positions and features of hotspots, which refer to regions with severe yield loss at 1.5 °C global warming, is the key to developing proper mitigation and adaptation policies to ensure regional food security. This study examined yield loss hotspots of four crops (maize, rice, soybean and wheat) at 1.5 °C global warming under RCP8.5. Yield data were derived from simulations of multiple climate-crop model ensembles from the Inter-Sectoral Impact Model Intercomparison Project (ISI-MIP). Hotspots were identified by setting a threshold of the 10th percentile of crop yields during the reference period (1986–2005). To quantify the likelihood of crop yield loss hotspots within multi-model ensembles, the agreement of model combinations for hotspots was calculated for each crop at the grid scale with 0.5° × 0.5° spatial resolution. Results revealed spatial heterogeneity of cultivation structure and hotspot likelihood for four crops. The four crops’ production of SA (South Asia) and SEA (Southeast Asia) accounts for more than 40% of the total production in the Belt and Road region, roughly four times the amount produced in CEE (Central and Eastern Europe) and NEA (Northeast Asia). Besides, the hotspots likelihood of maize, rice and soybean is generally larger in SA/SEA than that in CEE/NEA which means the risk of yield reduction is higher in the current main agricultural area. According to IPCC’s classification rules for likelihood, four crops’ hotspot patterns were displayed under the 1.5 °C global warming. As the highest-yielding crop, maize shows the largest proportion of “likely” hotspots (hotspot likelihood > 66%), which is about 6.48%, accounting for more than four times that of the other three crops. In addition, four crops’ hotspots are mainly distributed in SEA and SA. Overall, SEA and SA are vulnerable subregions and maize is the vulnerable crop of the Belt and Road region. Our results could provide information on target areas where mitigation or adaptations are needed to reduce the adverse influence of climate change in the agricultural system.

According to the Fifth IPCC Assessment Report, climate change poses severe risks to the Belt and Road region. To promote regional food security, this study examined yield risks in four staple crops (rice, wheat, maize, and soybeans) under 1.5°C and 2°C global warming scenarios. Yield data was derived from simulations of multiple climate-crop model ensembles from the Inter-Sectoral Impact Model Intercomparison Project. A threshold was defined as the 10th percentile of the reference period distribution (1986–2005) of crop yields. Then, adverse consequences on yield were assumed to arise once future crop yields were lower than the threshold. To quantify the likelihood of crop yield loss, the agreement of model combinations at which the threshold was crossed was calculated for each crop on a grid scale. Conclusions about crop loss and its risks were as follows: (1) Impacts of warming on yields differ between crop types and regions. The likelihood of yield loss in low-latitude regions was higher than that in mid-latitude regions for maize, rice, and soybeans. (2) Under a higher warming scenario, the mean yield loss likelihood would increase 0.16%–3.06% at low-latitude subregions but dropped by no more than 2% for subregions with higher latitudes. (3) Under 1.5°C global warming, the “risk zone” accounted for 37%, 35%, 25%, and 13% of growing areas for maize, wheat, rice, and soybeans, respectively. (4) The higher the warming, the larger the “risk zone”. When warming increased from 1.5°C to 2°C, the four crops’ calculated “newly added risk zones” would increase by 1.8%–3.5%. This study revealed patterns of yield loss risks for major crops in the Belt and Road in different warming scenarios and subregions and could provide some references for regional responses or adaptions to climate change in the agricultural system.