Climate change and interprovincial trade move grain production and environmental burdens northwards in China.

Understanding how the grain trade redistributes environmental burdens across regions is critical for designing equitable food security and environmental stewardship policies. Using grain production, trade and environmental data from 1980 to 2020, we quantify environmental spillovers embedded in China's interprovincial grain trade, identify their socio-economic and climatic drivers, project future scenarios and estimate ecological compensation schemes. Interprovincial grain trade increased more than fivefold (from 22 to 128 million tonnes), and production shifted northwards, generating a 196% increase in virtual cropland displacement, a 415% rise in virtual water consumption and more than a 217% increase in embodied nitrogen losses and greenhouse gas emissions in China. Irrigation, mechanization and urbanization were the key drivers of these shifts, outweighing climatic influences. Continued reliance on northern grain exports could escalate environmental costs, and climate-induced yield declines may shrink trade networks. Addressing these inequitable regional ecological burdens may require south-to-north transfers of up to US$12.5 billion by 2060 under Shared Socioeconomic Pathway 2-4.5.