Dietary improvement not only benefits human health conditions, but also offers the potential to reduce the human food system's environmental impact. With the world's largest population and people's bourgeoning lifestyle, China's food system is set to impose increasing pressures on the environment. We evaluated the minimum environmental footprints, including carbon footprint (CF), water footprint (WF) and ecological footprint (EF), of China's food systems into 2100. The minimum footprints of healthy eating are informative to policymakers when setting the environmental constraints for food systems. The results demonstrate that the minimum CF, WF and EF all increase in the near future and peak around 2030 to 2035, under different population scenarios. After the peak, population decline and aging result in decreasing trends of all environmental footprints until 2100. Considering age-gender specific nutritional needs, the food demands of teenagers in the 14-17 year group require the largest environmental footprints across the three indicators. Moreover, men's nutritional needs also lead to larger environmental footprints than women's across all age groups. By 2100, the minimum CF, WF and EF associated with China's food systems range from 616 to 899 million tons, 654 to 953 km3 and 6513 to 9500 billion gm2 respectively under different population scenarios. This study builds a bridge between demography and the environmental footprints of diet and demonstrates that the minimum environmental footprints of diet could vary by up to 46% in 2100 under different demographic scenarios. The results suggest to policymakers that setting the environmental constraints of food systems should be integrated with the planning of a future demographic path.
Keywords: carbon footprint; demographic scenarios; ecological footprint; food consumption; healthy diet; water footprint.