Maintaining food security and environmental integrity over time requires a transition towards sustainable food systems. This paper analyzes different dimensions of national food supply sustainability on a global scale. By focusing on four food staples: wheat, rice, maize, and soybeans, the analysis identifies production regions that are more or less environmentally sustainable. It explores the dependence of different countries on calories supplied by these regions. These four staples' production requires 648 million hectares of cropland and about 559 cubic kilometers of irrigation water. It also leads to several environmental impacts, including potential soil loss and species loss. Yet, these impacts and pressures are spread unevenly across agricultural systems.

We find that over one-third of the global calorie intake originates from regions with a high per ton environmental impacts. Although most consumed calories are from domestic sources, traded calories mostly originate from environmentally suitable production regions, increasing importing countries' food supply sustainability. This analysis also reveals interregional tradeoffs, where food imports into one region (increased food provision) is associated with high environmental impact in production regions. Further, this typology allows identifying an elusive, often overlooked interregional connection. That is the potential loss of future ecosystem service flow from countries with the lower gross domestic product per capita and high biodiversity. To date, those countries rely primarily on domestic staple production, which puts pressure on vulnerable local ecosystems. Species loss in those regions reduces the potential future interregional flows of genetic material. Alternatively, conservation combined with food imports can maintain diversity and the potential flow of genetic material from those regions. The functional regions typology provides a complete assessment of the interregional connections that make up the global food system. Therefore, it is useful for informing policy analysts and policymakers of a broader collection of stakeholders regarding the local environment. It also provides essential information about the suitability of different policy mechanisms to govern interregional systems. Future research shall expand the functional regions' typology to include additional environmental and human-related (e.g., technological), to cover more crops, and to account for other food categories, such as meat.

随着时间的推移保持粮食安全和环境完整性，需要向可持续的粮食系统过渡。本文分析了全球范围内国家粮食供应可持续性的不同方面。通过重点关注四种粮食主食：小麦，大米，玉米和大豆，该分析确定了或多或少在环境上可持续的生产地区。它探讨了不同国家对这些地区提供的卡路里的依赖性。这四个主食的生产需要6.48亿公顷的农田和约559立方千米的灌溉水。它还会导致多种环境影响，包括潜在的土壤流失和物种流失。但是，这些影响和压力在农业系统中分布不均。

我们发现，全球卡路里摄入量的三分之一以上来自每吨环境影响较高的地区。尽管消耗的大部分卡路里来自国内，但交易的卡路里大部分来自环境适宜的生产地区，从而提高了进口国的粮食供应可持续性。该分析还揭示了区域间的权衡，其中一个区域的粮食进口（增加的粮食供应）与生产区域的高环境影响有关。此外，这种类型可以识别难以捉摸的，经常被忽视的区域间联系。这就是人均国内生产总值较低和生物多样性较高的国家未来生态系统服务流量的潜在损失。迄今为止，这些国家主要依靠国内主食生产，这给脆弱的当地生态系统带来了压力。这些区域的物种损失减少了未来遗传材料跨区域的潜在流动。另外，保护与粮食进口相结合可以保持多样性和来自这些地区的遗传物质的潜在流动。功能区域类型学对构成全球粮食系统的区域间联系提供了完整的评估。因此，这对于将更多有关当地环境的利益相关者告知政策分析人员和政策制定者很有用。它还提供了有关不同政策机制管理区域间系统的适用性的基本信息。未来的研究将扩大功能区域的类型，使其包括更多的环境和与人类相关的（例如技术），以覆盖更多的农作物，