Bren School of Environmental Science & Management, University of California, Santa Barbara, Santa Barbara, CA, USA.
Department of Environmental Systems Sciences, ETH Zürich, Zürich, Switzerland.
Nature. 2024 Jan;625(7996):715-721. doi: 10.1038/s41586-023-06879-8. Epub 2024 Jan 24.
Groundwater resources are vital to ecosystems and livelihoods. Excessive groundwater withdrawals can cause groundwater levels to decline, resulting in seawater intrusion, land subsidence, streamflow depletion and wells running dry. However, the global pace and prevalence of local groundwater declines are poorly constrained, because in situ groundwater levels have not been synthesized at the global scale. Here we analyse in situ groundwater-level trends for 170,000 monitoring wells and 1,693 aquifer systems in countries that encompass approximately 75% of global groundwater withdrawals. We show that rapid groundwater-level declines (>0.5 m year) are widespread in the twenty-first century, especially in dry regions with extensive croplands. Critically, we also show that groundwater-level declines have accelerated over the past four decades in 30% of the world's regional aquifers. This widespread acceleration in groundwater-level deepening highlights an urgent need for more effective measures to address groundwater depletion. Our analysis also reveals specific cases in which depletion trends have reversed following policy changes, managed aquifer recharge and surface-water diversions, demonstrating the potential for depleted aquifer systems to recover.
地下水资源对生态系统和生计至关重要。过度开采地下水会导致地下水位下降，从而引发海水入侵、地面沉降、水流枯竭和水井干涸。然而，由于全球范围内尚未对原位地下水位进行综合分析，因此全球范围内地下水局部下降的速度和普遍性仍难以确定。在这里，我们分析了覆盖全球约 75%地下水开采量的国家的 17 万口监测井和 1693 个含水层系统的原位地下水位变化趋势。结果表明，在 21 世纪，地下水位迅速下降（>0.5 米/年）的现象非常普遍，特别是在干旱地区和广泛种植农作物的地区。至关重要的是，我们还发现，在过去四十年中，全球 30%的区域含水层的地下水位下降速度加快。这种广泛的地下水位加深加速，凸显了急需采取更有效的措施来应对地下水枯竭问题。我们的分析还揭示了一些具体案例，即在政策变化、含水层人工补给和地表水调水后，耗竭趋势发生了逆转，这表明耗竭的含水层系统有恢复的潜力。
