The hidden crisis beneath our feet

doi:10.1126/science.abh2867

GSTDTAP > 气候变化

DOI	10.1126/science.abh2867
	The hidden crisis beneath our feet
	James S. Famiglietti; Grant Ferguson
	2021-04-23
发表期刊	Science
出版年	2021
英文摘要	Most of the world's unfrozen freshwater is invisible to humanity. Ninety-six percent of it ([ 1 ][1]) is stored beneath the land surface as groundwater in soil and rock layers called aquifers. However, groundwater's unobtrusive nature belies its critical importance to global water and food security while simultaneously subjecting it to massive overexploitation. Groundwater is the primary water source for billions of people and for nearly half of irrigated agriculture, yet its inconspicuous presence has allowed groundwater to elude effective governance and management in countless regions around the world ([ 2 ][2], [ 3 ][3]). Consequently, more than half of the world's major aquifers are being depleted, some of them at an alarming pace ([ 4 ][4]). On page 418 of this issue, Jasechko and Perrone ([ 5 ][5]) show that millions of the wells that are used to pump the disappearing groundwater are at risk of running dry. Jasechko and Perrone assembled a dataset of nearly 39 million groundwater wells from 40 different countries and territories. The dataset, which includes the locations, depths, purposes, and construction dates of the wells, allowed the authors to reach two main conclusions. They found that up to 20% of the wells they analyzed are at risk of running dry because of long-term groundwater decline, seasonal variation in water levels, or both. In addition, they identified that new wells tend to be drilled to greater depths. However, the authors note that the deeper wells are not necessarily located in regions of substantial groundwater depletion ([ 6 ][6]), with the implication that many of the new wells are just as likely to run dry as the old wells. Jasechko and Perrone implicitly deliver a timely warning that universal access to groundwater is fundamentally at risk. As groundwater levels decline around the world, only the relatively wealthy will be able to afford the cost of drilling deeper wells and paying for the additional power required to pump groundwater from greater depths. Lower-income families, poorer communities, and smaller businesses, including smaller farms, will experience progressively more limited access in the many regions around the world where groundwater levels are in decline. This scenario is already playing out, for example, in California's heavily agricultural Central Valley, where deeper wells are drawing down groundwater levels such that farm workers' domestic wells are running dry. Without intervention, the gap between the water “haves” and “have nots” ([ 3 ][3]) will only widen further. Beyond dwindling access to groundwater, the consequences of millions of wells running dry, and perhaps millions more in the decades to come, would be severe and unparalleled at such a scale in human history. They include major threats to food production, the health and livelihoods of the millions to billions of people affected, and the environment. Disappearing groundwater resources may act as a trigger for violent conflicts and have the potential to generate waves of climate refugees. Avoiding such a scenario is clearly paramount to human security. This requires considerable discovery-driven and engaged research, combined with broad and inclusive stakeholder engagement, water diplomacy, and advocacy to federal governments and international bodies. ![Figure][7] Watching groundwater depletion from the sky Changes in total water storage are shown for regions within several mid-latitude aquifer systems from the NASA Gravity Recovery and Climate Experiment (GRACE) and follow-on (GRACE-FO) satellite missions. Vertical dashed lines indicate the data gap between the GRACE and GRACE-FO missions. Monthly storage changes are reported as anomalies for the period from March 2002 to June 2020 with 24-month smoothing. GRAPHIC: DAVID FERRIS, UNIVERSITY OF SASKATCHEWAN, ADAPTED BY N. DESAI/ SCIENCE Maintaining water levels above the intake portions, called well screens, is a critical measure of whether groundwater is being developed sustainably but often has been ignored in favor of recharge rates and residence times ([ 7 ][8]). Predicting changes in water levels remains a key challenge in hydrology owing to the difficulty in characterizing the hydraulic properties of the subsurface ([ 8 ][9]). Breakthroughs in characterization and monitoring of groundwater systems and new modeling approaches are required to understand where and when wells might go dry. Satellites like NASA's Gravity Recovery and Climate Experiment (GRACE) mission can identify large-scale (>150,000 km2) trends in groundwater storage changes ([ 4 ][4]–[ 6 ][6]), which are important for understanding aquifer-scale behavior and identifying excessive rates of decline (see the figure). However, satellites cannot peer beneath Earth's surface to measure water-table heights and fluctuations. National and international collaborative efforts are required to systematically explore and characterize Earth's hydrogeology ([ 3 ][3]), comprehensively monitor groundwater levels and groundwater quality ([ 9 ][10]), develop and test large-scale groundwater models and coupled land surface-groundwater models ([ 10 ][11]), and openly share the data ([ 9 ][10]). To ensure that groundwater remains a reliable component of water supplies, several other formidable challenges must be addressed. Inclusive governance ([ 2 ][2], [ 11 ][12]), effective management ([ 12 ][13]), and an agreed-upon definition of groundwater sustainability ([ 7 ][8]) are all essential elements of what must be a multifaceted strategy. Few aquifer systems around the world are managed within such an ideal framework, and the capacity to do so does not typically exist. New institutions and networks must be fostered to raise awareness of these urgent needs, encourage and coordinate stakeholder participation, and help governments build the political will to protect groundwater as a key element of water security. Because most large groundwater systems are regional and transboundary, regional collaboration is essential, as is a water diplomacy strategy that treats groundwater as a vehicle for cooperation rather than conflict. A global coordinating body may well be required to share knowledge, tools, and best practices across regions and raise the profile of groundwater within the United Nations Sustainable Development Goals (SDGs), in particular, in SDG6, ensuring the availability and sustainable management of water and sanitation for all. Jasechko and Perrone have helped make the invisible visible. The authors have demonstrated that millions of groundwater wells are at risk of running dry, illuminating that climate resilience is at considerable risk. Digging deeper wells is a supply-side solution that only exacerbates the problems described. The time is now for key research and exploration and for science-informed governance and policy that address the demand for groundwater and eliminate its overexploitation. 1. [↵][14]1. P. H. Gleick 1. I. Shiklomanov , in Water in Crisis: A Guide to the World's Fresh Water Resources, P. H. Gleick, Ed. (Oxford Univ. Press, 1993). 2. [↵][15]1. K. G. Villhoth et al 1. K. G, Villholth, 2. K. I. Conti , in Advances in Groundwater Governance, K. G. Villhoth et al., Eds. (CRC Press, 2018). 3. [↵][16]1. J. S. Famiglietti , Nat. Clim. Chang. 4, 945 (2014). [OpenUrl][17] 4. [↵][18]1. A. S. Richey et al ., Water Resour. Res. 51, 5127 (2015). [OpenUrl][19] 5. [↵][20]1. S. Jasechko, 2. D. Perrone , Science 372, 418 (2021). [OpenUrl][21][Abstract/FREE Full Text][22] 6. [↵][23]1. M. Rodell et al ., Nature 557, 651 (2018). [OpenUrl][24][CrossRef][25][PubMed][26] 7. [↵][27]1. T. Gleeson, 2. M. Cuthbert, 3. G. Ferguson, 4. D. Perrone , Annu. Rev. Earth Planet. Sci. 48, 431 (2020). [OpenUrl][28][CrossRef][29] 8. [↵][30]1. S. M. Gorelick, 2. C. Zheng , Water Resour. Res. 51, 3031 (2015). [OpenUrl][31] 9. [↵][32]International Groundwater Resources Assessment Centre,; [www.un-igrac.org/][33]. 10. [↵][34]1. L. E. Condon, 2. R. M. Maxwell , Sci. Adv. 5, eaav4574 (2019). [OpenUrl][35][FREE Full Text][36] 11. [↵][37]1. J. Hoogesteger, 2. P. Wester , Environ. Sci. Policy 51, 117 (2015). [OpenUrl][38] 12. [↵][39]1. J. J. Butler Jr., 2. D. O. Whittemore, 3. B. B. Wilson, 4. G. C. Bohling , Geophys. Res. Lett. 43, 2004 (2016). [OpenUrl][40][CrossRef][41] [1]: #ref-1 [2]: #ref-2 [3]: #ref-3 [4]: #ref-4 [5]: #ref-5 [6]: #ref-6 [7]: pending:yes [8]: #ref-7 [9]: #ref-8 [10]: #ref-9 [11]: #ref-10 [12]: #ref-11 [13]: #ref-12 [14]: #xref-ref-1-1 "View reference 1 in text" [15]: #xref-ref-2-1 "View reference 2 in text" [16]: #xref-ref-3-1 "View reference 3 in text" [17]: {openurl}?query=rft.jtitle%253DNat.%2BClim.%2BChang.%26rft.volume%253D4%26rft.spage%253D945%26rft.genre%253Darticle%26rft_val_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Ajournal%26ctx_ver%253DZ39.88-2004%26url_ver%253DZ39.88-2004%26url_ctx_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Actx [18]: #xref-ref-4-1 "View reference 4 in text" [19]: {openurl}?query=rft.jtitle%253DWater%2BResour.%2BRes.%26rft.volume%253D51%26rft.spage%253D5127%26rft.genre%253Darticle%26rft_val_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Ajournal%26ctx_ver%253DZ39.88-2004%26url_ver%253DZ39.88-2004%26url_ctx_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Actx [20]: #xref-ref-5-1 "View reference 5 in text" [21]: {openurl}?query=rft.jtitle%253DScience%26rft.stitle%253DScience%26rft.aulast%253DJasechko%26rft.auinit1%253DS.%26rft.volume%253D372%26rft.issue%253D6540%26rft.spage%253D418%26rft.epage%253D421%26rft.atitle%253DGlobal%2Bgroundwater%2Bwells%2Bat%2Brisk%2Bof%2Brunning%2Bdry%26rft_id%253Dinfo%253Adoi%252F10.1126%252Fscience.abc2755%26rft.genre%253Darticle%26rft_val_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Ajournal%26ctx_ver%253DZ39.88-2004%26url_ver%253DZ39.88-2004%26url_ctx_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Actx [22]: /lookup/ijlink/YTozOntzOjQ6InBhdGgiO3M6MTQ6Ii9sb29rdXAvaWpsaW5rIjtzOjU6InF1ZXJ5IjthOjQ6e3M6ODoibGlua1R5cGUiO3M6NDoiQUJTVCI7czoxMToiam91cm5hbENvZGUiO3M6Mzoic2NpIjtzOjU6InJlc2lkIjtzOjEyOiIzNzIvNjU0MC80MTgiO3M6NDoiYXRvbSI7czoyMjoiL3NjaS8zNzIvNjU0MC8zNDQuYXRvbSI7fXM6ODoiZnJhZ21lbnQiO3M6MDoiIjt9 [23]: #xref-ref-6-1 "View reference 6 in text" [24]: {openurl}?query=rft.jtitle%253DNature%26rft.volume%253D557%26rft.spage%253D651%26rft_id%253Dinfo%253Adoi%252F10.1038%252Fs41586-018-0123-1%26rft_id%253Dinfo%253Apmid%252F29769728%26rft.genre%253Darticle%26rft_val_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Ajournal%26ctx_ver%253DZ39.88-2004%26url_ver%253DZ39.88-2004%26url_ctx_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Actx [25]: /lookup/external-ref?access_num=10.1038/s41586-018-0123-1&link_type=DOI [26]: /lookup/external-ref?access_num=29769728&link_type=MED&atom=%2Fsci%2F372%2F6540%2F344.atom [27]: #xref-ref-7-1 "View reference 7 in text" [28]: {openurl}?query=rft.jtitle%253DAnnu.%2BRev.%2BEarth%2BPlanet.%2BSci.%26rft.volume%253D48%26rft.spage%253D431%26rft_id%253Dinfo%253Adoi%252F10.1146%252Fannurev-earth-071719-055251%26rft.genre%253Darticle%26rft_val_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Ajournal%26ctx_ver%253DZ39.88-2004%26url_ver%253DZ39.88-2004%26url_ctx_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Actx [29]: /lookup/external-ref?access_num=10.1146/annurev-earth-071719-055251&link_type=DOI [30]: #xref-ref-8-1 "View reference 8 in text" [31]: {openurl}?query=rft.jtitle%253DWater%2BResour.%2BRes.%26rft.volume%253D51%26rft.spage%253D3031%26rft.genre%253Darticle%26rft_val_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Ajournal%26ctx_ver%253DZ39.88-2004%26url_ver%253DZ39.88-2004%26url_ctx_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Actx [32]: #xref-ref-9-1 "View reference 9 in text" [33]: http://www.un-igrac.org/ [34]: #xref-ref-10-1 "View reference 10 in text" [35]: {openurl}?query=rft.jtitle%253DScience%2BAdvances%26rft.stitle%253DSci%2BAdv%26rft.aulast%253DCondon%26rft.auinit1%253DL.%2BE.%26rft.volume%253D5%26rft.issue%253D6%26rft.spage%253Deaav4574%26rft.epage%253Deaav4574%26rft.atitle%253DSimulating%2Bthe%2Bsensitivity%2Bof%2Bevapotranspiration%2Band%2Bstreamflow%2Bto%2Blarge-scale%2Bgroundwater%2Bdepletion%26rft_id%253Dinfo%253Adoi%252F10.1126%252Fsciadv.aav4574%26rft.genre%253Darticle%26rft_val_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Ajournal%26ctx_ver%253DZ39.88-2004%26url_ver%253DZ39.88-2004%26url_ctx_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Actx [36]: /lookup/ijlink/YTozOntzOjQ6InBhdGgiO3M6MTQ6Ii9sb29rdXAvaWpsaW5rIjtzOjU6InF1ZXJ5IjthOjQ6e3M6ODoibGlua1R5cGUiO3M6MzoiUERGIjtzOjExOiJqb3VybmFsQ29kZSI7czo4OiJhZHZhbmNlcyI7czo1OiJyZXNpZCI7czoxMjoiNS82L2VhYXY0NTc0IjtzOjQ6ImF0b20iO3M6MjI6Ii9zY2kvMzcyLzY1NDAvMzQ0LmF0b20iO31zOjg6ImZyYWdtZW50IjtzOjA6IiI7fQ== [37]: #xref-ref-11-1 "View reference 11 in text" [38]: {openurl}?query=rft.jtitle%253DEnviron.%2BSci.%2BPolicy%26rft.volume%253D51%26rft.spage%253D117%26rft.genre%253Darticle%26rft_val_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Ajournal%26ctx_ver%253DZ39.88-2004%26url_ver%253DZ39.88-2004%26url_ctx_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Actx [39]: #xref-ref-12-1 "View reference 12 in text" [40]: {openurl}?query=rft.jtitle%253DGeophys.%2BRes.%2BLett.%26rft.volume%253D43%26rft.spage%253D2004%26rft_id%253Dinfo%253Adoi%252F10.1002%252F2016GL067879%26rft.genre%253Darticle%26rft_val_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Ajournal%26ctx_ver%253DZ39.88-2004%26url_ver%253DZ39.88-2004%26url_ctx_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Actx [41]: /lookup/external-ref?access_num=10.1002/2016GL067879&link_type=DOI
领域	气候变化 ; 资源环境
URL	查看原文
引用统计
文献类型	期刊论文
条目标识符	http://119.78.100.173/C666/handle/2XK7JSWQ/324067
专题	气候变化资源环境科学
推荐引用方式 GB/T 7714	James S. Famiglietti,Grant Ferguson. The hidden crisis beneath our feet[J]. Science,2021.
APA	James S. Famiglietti,&Grant Ferguson.(2021).The hidden crisis beneath our feet.Science.
MLA	James S. Famiglietti,et al."The hidden crisis beneath our feet".Science (2021).