Synergizing climate change adaptation and mitigation in agriculture through crop switching: A sustainable pathway to ensure China's food security by the 2050s

Climate-Smart Agriculture (CSA) has become a vital approach to adapting to and mitigating climate change while safeguarding food security. Future climate change is projected to shift suitable cropping areas northward in China. Guided by the CSA framework, this study establishes a refined spatial linear optimization model for multi-cropping at national and provincial scales to explore the potential of crop switching in synergizing climate change adaptation and mitigation under the RCP4.5 and RCP6.0 scenarios in the 2050s. Results indicate that under national planning compared to the future baseline scenario without spatial crop reallocation, an adaptation optimization strategy increases crop production by 24.1% to 24.6% and achieves staple crop self-sufficiency (wheat, maize, rice, and soybean) by the 2050s under RCP4.5 and RCP6.0, but at the cost of a 19.2% to 23.3% increase in greenhouse gas (GHG) emissions. Alternatively, the mitigation optimization strategy can reduce direct cropland GHG emissions(CH 4 and N 2 O) by 30.8%(86.0% from CH4)to 52.0% (79.9% from CH4) while maintaining crop production. While trade-offs exist, specific weighting regions of the Pareto front reveal co-benefits, including crop production (+4.0% to +21.4%), economic profits (+13% to +28.3%), reduced GHG emissions (-52% to -16.2%), and irrigation water savings (-12.8% to -0.7%). Acknowledging implementation constraints alongside modeling uncertainties, these optimal outcomes indicate that, carefully designed crop-switching strategies such as expanding soybean cultivation in North China and replacing rice with wheat, maize, and soybean in the Yangtze River Plain could both enhance climate adaptation and mitigation and help meet China’s food demand in the 2050s without cropland expansion. • Develop an optimal crop switching model with the scenarios of climate adaptation, mitigation, and the synergy between them. • The adaptation optimization strategy increased the crop production by 24.1% to 24.6%, but at the cost of a 19.2% to 23.3% increase in GHG emissions. • The mitigation optimization strategy reduced the GHG emissions by 30.8% to 52.0% without compromising crop production. • Under synergistic optimization strategies, crop switching can bring co-benefits with +4.0% to +21.4% crop production, +13% to +28.3% economic profits, -52% to -16.2% GHG emissions, and -12.8% to -0.7% irrigation water use.