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Behind a steak served in China, there is often a soybean cultivation in Brazil. A new study, published in Nature Food, a snapshot of an increasingly interconnected and fragile food system.

The research shows that China's growing demand for meat and other animal proteins considerably depends on Brazilian agricultural resources, with direct effects on land use, water resources and deforestation.

Between 2004 and 2020, soybean imported to China rose from 6 million to 60 million tons, recording a peak at 68 million in 2018, marking a more than ten-fold increase. In 2020, this required 17.8 million hectares of land, an area the size of Uruguay, and over 86 km³ of rainwater, in addition to 0.29 km³ of irrigation water.

These soybeans—largely intended for feeding pigs, poultry and farmed fish—support almost a third of the animal protein consumed in China, accounting for 29% of animal protein and 10% of the total protein content of the national diet.

The research was authored by Camilla Govoni and Maria Cristina Rulli of the Department of Civil and Environmental Engineering at Politecnico di Milano, together with La Zhuo of Northwest Agriculture & Forestry University (China), the Chinese Academy of Sciences, and Dirce Lobo Marchioni of the Universidade de São Paulo (Brazil).

"Understanding that a significant part of the nutritional intake of a population of over a billion depends on agricultural resources located on the other side of the world prompts us to question the future of our food systems," says Govoni, lead author of the study. "If we want to make these food systems resilient, we need to focus not only on the protein supply, but also on their sustainable and equitable distribution, reducing pressure on ecosystems while safeguarding global food security."

The work focuses on water resources, and on the environmental impact of agricultural expansion.

"Brazil is historically a country with few critical water issues, but deforestation, land use changes, agricultural over-exploitation and climate change could induce pressure, leading to stress and water scarcity," says Rulli. "Agricultural expansion linked to soya does not only impact land-related ecosystems. It also involves a global redistribution of water resources in the form of virtually exported water."

Although the Moratorium on Soya has limited direct deforestation, indirect soil conversion remains, especially in the Cerrado savannahs and brownfield pastures.

The study is also an example of a multidisciplinary approach converging expertise in hydrology, environmental sciences and human nutrition. "Only the integration of different skills and collaboration with colleagues from Brazil and China allowed us to fully grasp the complexity of the problem," added the authors.

In conclusion, the results highlight the importance of global governance strategies to reduce the environmental impact of protein production and international trade. As Govoni concludes, "Agricultural and food choices can no longer be considered only at the local or national level. They are part of a global balance that invisibly binds countries, ecosystems and populations. Governing this balance responsibly is the actual challenge to ensure a resilient and sustainable food system."