How the trade barrier changes environmental costs of agricultural production: An implication derived from China's demand for soybean caused by the US-China trade war

International trade is always affected by the frequently occurring trade barriers arising across the world. One such instance is when the US-China trade war formally began on July 6, 2018. Soybean was viewed as an important weapon of the Chinese government to cope with the United States (US) in the trade war, given the huge quantity of soybean imported from the US to China. This study is interested in the possible global and domestic environmental costs of China's demand for soybean caused by the trade barrier and considers the different strategies China could implement. The results showed that a change in international soybean trade would lead to the obvious growth of global environmental costs in the short term due to the soybean surplus in the US and the increased food transportation mileage. If the problem of surplus soybean in the US could be resolved, global environmental costs would decrease in the long term due to the comparative advantages of Brazil and Argentina over the US in regard to some environmental indicators of soybean production. Increasing China's soybean self-sufficiency by replacing existing maize crops with soybean would be the best strategy for improving global and domestic environmental costs. This study provides a research basis for policy-making to replenish the Chinese soybean deficit while considering the effects on the environment, and the findings of this study reveal the following implications: (1) a trade barrier among nations normally increases the global environmental costs of agricultural production in the short term; and (2) a rational crop layout and a sustainable cropping system at the global level would improve the environmental performance of the global agricultural system. (C) 2019 Elsevier Ltd. All rights reserved.