Reducing environmental footprints of food consumption in urban and rural China: A scenario-based optimization towards sustainable diets.

Urban and rural residents differ markedly in the resource use and pollution emissions associated with their food consumption, particularly in rapidly urbanizing China. Based on environmental footprint theory, we developed a framework that accounts for four footprint types: water, carbon, nitrogen, and phosphorus, and we conducted a scenario analysis. Using panel data from 31 provinces spanning 2015 to 2023, we characterized the spatiotemporal evolution of the environmental footprints of urban and rural food consumption. We then established three scenarios for 2030: a baseline scenario (S0), a developing dietary pattern scenario (S1), and a multi-objective optimization scenario (S2). These scenarios project how environmental footprints of urban residents would change under different dietary patterns. Urban water, carbon, nitrogen, and phosphorus footprints continued to increase, with the highest values observed along the southeastern coast. In rural areas, total food consumption declined, whereas the nitrogen and phosphorus footprints showed a decline then rise pattern, with high value zones shifting to the Chengdu-Chongqing region and the middle-lower Yangtze River. Under the developing dietary pattern scenario, rural footprints increased at a much faster rate than their urban counterparts. Under the multi-objective optimization scenario, reducing livestock meat consumption to the lower bound of the dietary guidelines substantially reduced all four footprints relative to the baseline. The benefit of dietary optimization for controlling nitrogen and phosphorus nonpoint source pollution was four to six times greater than that for carbon reduction. Our scenario projections, which rely on nationally averaged footprint coefficients, are subject to data uncertainties. Uncertainty analysis using Monte Carlo simulation with a truncated normal distribution shows that, although the absolute estimates carry substantial uncertainty, the relative ranking of urban-rural comparisons and scenarios is insensitive to coefficient variation. Guiding urban and rural residents toward the dietary pattern recommended by the Chinese Dietary Guidelines, in particular substantially reducing livestock meat consumption, is an effective way to alleviate resource pressure, lower carbon emissions, and achieve coordinated nitrogen and phosphorus mitigation.