A pathway of global food supply adaptation in a world with increasingly constrained groundwater.
A pathway of global food supply adaptation in a world with increasingly constrained groundwater.
复制标题
在地下水日益紧张的世界中，全球粮食供应适应的途径。
DOI：
10.1016/j.scitotenv.2019.04.070
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发表时间：
2019
期刊：
影响因子：
--
通讯作者：
Son H Kim
中科院分区：
文献类型：
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作者：
S. Turner;M. Hejazi;K. Calvin;P. Kyle;Son H Kim
世界上许多主要的淡水含水层正在被不可持续地开采，其中一些预计将在世纪达到对环境不安全的水位下降极限。鉴于含水层枯竭往往发生在重要的作物产区，干涸的前景对全球粮食安全构成重大威胁。在这里，我们使用全球变化评估模型（GCAM），探讨土地利用和农业部门对全球水资源严重限制的反应。我们模拟的情况下，一些重要的地下水含水层成为枯竭的地步，进一步取水是不可行的，无论是由于过度的提取成本或环境限制正在达到。结果，然后基准对一个方案，忽略了限制取水。我们发现，地下水枯竭和相关的水价上涨推动了农业部门的两种不同反应：雨养农业的扩张，以及灌溉作物生产向水资源更便宜的地区转移。作物生产的损失在水资源紧张的地区最为明显，这些地区的地下水正在不可持续地枯竭，以满足灌溉需求，即印度西北部、巴基斯坦、中东、美国西部、墨西哥和中亚。虽然这些结果突出了受影响区域农业经济的重大风险，但我们表明，在一个无摩擦贸易的世界中，灌溉和作物生长地点的适度变化可以确保在严重的水资源限制下满足全球粮食需求。
Many of the world's major freshwater aquifers are being exploited unsustainably, with some projected to approach environmentally unsafe drawdown limits within the 21st century. Given that aquifer depletion tends to occur in important crop producing regions, the prospect of running dry poses a significant threat to global food security. Here we use the Global Change Assessment Model (GCAM) to explore the response of land use and agriculture sectors to severe constraints on global water resources. We simulate a scenario in which a number of important groundwater aquifers become depleted to the point where further water withdrawal is unviable, either due to excessive extraction costs or environmental limits being reached. Results are then benchmarked against a scenario that neglects constraints on water withdrawals. We find that groundwater depletion and associated water price increases drive two distinct responses in the agriculture sector: an expansion of rain fed agriculture, and a shift in irrigated crop production toward regions with cheaper water resources. Losses in crop production are most pronounced in water stressed regions where groundwater is being depleted unsustainably to meet irrigation demands—namely northwest India, Pakistan, the Middle East, western United States, Mexico, and Central Asia. While these results highlight substantial risks for the affected regional agricultural economies, we show that modest changes in irrigation and location of crop growth, in a world with frictionless trade, could ensure global food demands are met despite severe water constraints.