In recent years, the growing environmental pressures from increasing global meat consumption have become increasingly prominent. Livestock farming currently provides about a quarter of global human protein intake, occupies over 30% of land resources, and contributes substantially to greenhouse gas emissions and water pollution. In many regions—especially where intensive livestock farming is concentrated—nitrate concentrations in groundwater have significantly exceeded natural levels, threatening drinking water safety and posing a serious challenge to the achievement of the Sustainable Development Goals (SDGs).

A research team led by Associate Professor Zhilin Guo from the School of Environmental Science and Engineering at the Southern University of Science and Technology (SUSTech) has systematically revealed the long-term impact of conventional meat production on groundwater pollution. Their study suggests that moderate adjustments in dietary protein sources could significantly improve groundwater quality, providing a new pathway for achieving the SDGs.

Their paper, titled “Changes in meat consumption can improve groundwater quality”, has been published in Nature Food.

Using the United States (U.S.) as a case study, the researchers assessed the relationship between meat consumption and groundwater nitrate pollution from 1985 to 2020. Their analysis showed that the impact of livestock farming on groundwater pollution has been steadily increasing and, in some years, has surpassed that of traditional crop agriculture. With the continued expansion of the livestock industry, its influence on groundwater quality is projected to become even more pronounced.

In scenario modeling, the team simulated a 10% reduction in conventional meat intake, with the protein gap filled by alternatives such as plant-based proteins (e.g., legumes), novel animal sources (e.g., insects), and biotech innovations (e.g., cultured meat or fungal proteins). The results indicated that such a substitution strategy could reduce nitrogen fertilizer use by 3.4%, manure production by 10.7%, and water usage by 4.5%. More notably, it could lower the risk of groundwater nitrate exceedance (nitrate concentration >10 mg/L) by nearly 20%. Despite the modest substitution rate, the environmental benefits are substantial—demonstrating a “small change, big impact” potential in pollution mitigation.

Figure 1. Impacts of protein source transition on (a) nitrogen fertilizer, manure, and water footprint, and (b) groundwater nitrate levels

The study also highlights the spatial heterogeneity of these benefits. In the U.S., states like Texas and Iowa account for roughly one-third of the national livestock inventory. Implementing reductions in these high-density farming regions could yield disproportionately large environmental improvements, with positive benefits extending to feed production areas and beyond. For countries such as China and India—where meat demand is rising rapidly, livestock density is high, and nitrogen use efficiency in agriculture remains low—these findings are particularly relevant.

The team’s findings demonstrate that guiding dietary transitions in a scientifically informed and regionally adaptive manner can meet nutritional needs while significantly reducing agricultural pressures on groundwater systems. This offers valuable support for agricultural green transformation, high-quality water environment development, and the coordinated realization of multiple sustainability targets—including clean water, climate action, and biodiversity conservation.

Dr. Yang Zhan is the first author of the paper. Associate Professor Zhilin Guo is the corresponding author, with SUSTech serving as the first affiliated institution. Other co-authors include Dr. Joel Podgorski from the Swiss Federal Institute of Aquatic Science and Technology (Eawag); Associate Professor Peng Xu from Tianjin University; Liqing Peng from the World Resources Institute; Professor Vladan Babovic from the National University of Singapore; and Chair Professor Chunmiao Zheng from SUSTech.

Paper link: https://www.nature.com/articles/s43016-025-01188-x

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