The environmental costs and benefits of high-yield farming
The environmental costs and benefits of high-yield farming
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DOI：
10.1038/s41893-018-0138-5
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发表时间：
2018-09-01
影响因子：
27.6
通讯作者：
Eisner, Rowan
中科院分区：
文献类型：
--
作者：
Balmford, Andrew;Amano, Tatsuya;Eisner, Rowan
我们如何管理农业和粮食系统以满足不断增长的需求对生物多样性的未来至关重要。大量的实地数据表明，通过提高现有农田的产量，以节省剩余的自然栖息地，将大大减少对野生种群的影响。高产农业引起了其他关切，因为按单位面积计算，它可能产生大量的外部因素，如温室气体排放和养分损失。然而，这些指标低估了低产系统的总体影响。在这里，我们开发了一个框架，而不是比较外部性和土地成本每单位生产。我们将这个框架应用于不同的数据集，描述了四个主要的农业部门的外部性，并揭示，而不是涉及权衡，替代生产系统的外部性和土地成本可以协变积极：每单位产量，土地效率的系统往往产生较低的外部性。对于温室气体排放，一旦将放弃的固碳包括在内，这些关联就变得更加积极。我们的结论是有限的：很少有研究报告在产量的同时还报告了外部因素;许多重要的外部因素和耕作制度没有得到充分的衡量;要实现高产制度的环境效益，通常需要采取额外措施限制农田扩张。然而，我们的研究结果表明，关键成本指标之间的权衡并不像有时认为的那样普遍存在。
How we manage farming and food systems to meet rising demand is pivotal to the future of biodiversity. Extensive field data suggest that impacts on wild populations would be greatly reduced through boosting yields on existing farmland so as to spare remaining natural habitats. High-yield farming raises other concerns because expressed per unit area it can generate high levels of externalities such as greenhouse gas emissions and nutrient losses. However, such metrics underestimate the overall impacts of lower-yield systems. Here we develop a framework that instead compares externality and land costs per unit production. We apply this framework to diverse data sets that describe the externalities of four major farm sectors and reveal that, rather than involving trade-offs, the externality and land costs of alternative production systems can covary positively: per unit production, land-efficient systems often produce lower externalities. For greenhouse gas emissions, these associations become more strongly positive once forgone sequestration is included. Our conclusions are limited: remarkably few studies report externalities alongside yields; many important externalities and farming systems are inadequately measured; and realizing the environmental benefits of high-yield systems typically requires additional measures to limit farmland expansion. Nevertheless, our results suggest that trade-offs among key cost metrics are not as ubiquitous as sometimes perceived.