Environmental impacts of food trade via resource use and greenhouse gas emissions

Agriculture will need to significantly intensify in the next decades to continue providing essential nutritive food to a growing global population. However, it can have harmful environmental impacts, due to the use of natural and synthetic resources and the emission of greenhouse gases, which alter the water, carbon and nitrogen cycles, and threaten the fertility, health and biodiversity of landscapes. Because of the spatial heterogeneity of resource productivity, farming practices, climate, and land and water availability, the environmental impact of producing food is highly dependent on its origin. For this reason, food trade can either increase or reduce the overall environmental impacts of agriculture, depending on whether or not the impact is greater in the exporting region. Here, we review current scientific understanding of the environmental impacts of food trade, focusing on water and land use, pollution and greenhouse gas emissions. In the case of water, these impacts are mainly beneficial. However, in the cases of pollution and greenhouse gas emissions, this conclusion is not as clear. Overall, there is an urgent need for a more comprehensive, integrated approach to estimate the global impacts of food trade on the environment. Second, research is needed to improve the evaluation of some key aspects of the relative value of each resource depending on the local and regional biophysical and socio-economic context. Finally, to enhance the impact of such evaluations and their applicability in decision-making, scenario analyses and accounting of key issues like deforestation and groundwater exhaustion will be required.

在未来几十年，农业需要大幅集约化，以便继续为不断增长的全球人口提供必需的营养食物。然而，由于使用天然和合成资源以及排放温室气体，农业可能会对环境产生有害影响，这些影响改变了水、碳和氮循环，并威胁到土地的肥力、健康和生物多样性。由于资源生产力、耕作方式、气候以及土地和水资源可利用性的空间异质性，粮食生产对环境的影响在很大程度上取决于其产地。因此，粮食贸易可能会增加或减少农业对环境的总体影响，这取决于出口地区的影响是否更大。在此，我们回顾当前对粮食贸易环境影响的科学认识，重点关注水和土地利用、污染以及温室气体排放。就水而言，这些影响主要是有益的。然而，就污染和温室气体排放而言，这一结论并不那么明确。总体而言，迫切需要一种更全面、综合的方法来评估粮食贸易对环境的全球影响。其次，需要开展研究，以根据当地和区域的生物物理及社会经济背景，改进对每种资源相对价值的一些关键方面的评估。最后，为了增强此类评估的影响及其在决策中的适用性，将需要对森林砍伐和地下水枯竭等关键问题进行情景分析和核算。