Humans have persistent food needs that triggered considerable greenhouse gas emissions, varying significantly by region. However, the greenhouse gas footprint and inequality in food system are not well assessed within countries. Prof. DENG Xiangzheng's team at the Institute of Geographic Sciences and Natural Resources Research of the Chinese Academy of Sciences, quantified China’s national and sub-national food greenhouse gas footprints from 2007 to 2017, revealing a decline in both national and provincial per capita footprints. Further studies showed that despite notable inequalities among households both between and within provincial-level regions (hereafter provinces), China has experienced a reduction in inequality alongside economic development. This work was published in Cell Reports Sustainability.

They first compiled a greenhouse gas (GHG) emission inventory covering dozens of economic sectors, then estimated the food GHG footprints of provincial-level households across ten income groups in China from 2007 to 2017 using a multiregional input-output model, and finally assessed regional and inter-household inequality using the Gini coefficient. By adopting a comprehensive assessment framework, the study identifies GHG emission contributions at different life-cycle stages of the food system and realizes the assessment of food GHG footprints and inequality at the sub-national level.

In addition, they observed a decline in the national per capita food footprints from 0.66 to 0.53 tCO₂-equivalent, with a similar declining pattern observed across the majority of provinces. The findings also underscore substantial variances in food GHG footprints among households, both within and between provinces. Notably, regions with higher levels of affluence exhibit lower levels of inequality compared to economically disadvantaged areas. The national food GHG footprint Gini coefficient declined from 0.356 to 0.339 with economic development, while almost all provinces, except for Shaanxi, experienced declining Gini coefficients. These findings highlight changes in inequality of China’s household food GHG footprints along with economic development, showing the differences among various income groups and national improvement in food GHG footprint inequality.

This research offers an important foundation for the equitable allocation of responsibilities in emission reduction within the food system, aligning perfectly with the overarching goal of achieving a net-zero emission target. Furthermore, this study emphasizes the pivotal role that economic development plays in mitigating emissions inequality, presenting a promising strategy for addressing societal inequality, while simultaneously combating climate change, which aligns seamlessly with UN Sustainable Development Goals 10 and 13.

This work was financially supported by the National Natural Science Foundation of China (Grant No. 72221002) and the Strategic Priority Research Program of the Chinese Academy of Sciences (Grant No. XDA23070400).

Figure 1: The assessment framework of food greenhouse gas footprints (Image by Prof. DENG Xiangzheng’s team)

Figure 2: The relationship between household food greenhouse gas footprint inequality and per capita GDP. (Image by Prof. DENG Xiangzheng’s team)