Trees falling as fragile forests become cropland is a visual shorthand for the environmental costs exporting countries pay to meet lucrative global demands for food. Yet a new study reveals a counterintuitive truth: Importing food also damages homeland ecology.

In this week’s Proceedings of the National Academy of Sciences, researchers at Michigan State University (MSU) and their colleagues show that the decisions domestic farmers must make as imported food changes the crop market can damage the environment.

“What is obvious is not always the whole truth,” said Jianguo “Jack” Liu director of MSU’s Center for Systems Integration and Sustainability and senior author of the paper. “Unless a world is examined in a systemic, holistic way, environmental costs will be overlooked.”

The researchers examine the global trade of soybeans — a demand which has exploded in China as its population becomes more prosperous. To meet the demand for soybeans as animal feed and food products, China’s market gobbled up more than 60 percent of the world’s exported soybeans, much of that from Brazil- and at a price Chinese farmers can’t match.

Brazil’s massive conversion of rainforest and Cerrado to cropland has received much attention, and policies have been enacted to mitigate the environmental damage there. The widely held conclusion has been that importing countries gain environmental benefits and displace environmental costs to the source of food. This paper shows that the shift is actually just an exchange

“This research demonstrates a surprising environmental impact of global agricultural trade,” says Betsy Von Holle, a director of the National Science Foundation’s Dynamics of Coupled Natural and Human Systems program, which funded the study. “If the importing country switches from a more sustainable crop, such as soybeans, to one that needs more water and nutrients, such as corn, the nitrogen pollution that results can harm the environment of the importing country.”

Read more at Michigan State University