NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Back to Results
Fate of Water Pumped from Underground and Contributions to Sea Level RiseThe contributions from terrestrial water sources to sea-level rise, other than ice caps and glaciers, are highly uncertain and heavily debated1-5. Recent assessments indicate that groundwater depletion (GWD) may become the most important positive terrestrial contribution6-10 over the next 50 years, probably equal in magnitude to the current contributions from glaciers and ice caps6. However, the existing estimates assume that nearly 100% of groundwater extracted eventually ends up in the oceans. Owing to limited knowledge of the pathways and mechanisms governing the ultimate fate of pumped groundwater, the relative fraction of global GWD that contributes to sea-level rise remains unknown. Here, using a coupled climate-hydrological model11,12 simulation, we show that only 80% of GWDends up in the ocean. An increase in runo to the ocean accounts for roughly two-thirds, whereas the remainder results from the enhanced net flux of precipitation minus evaporation over the ocean, due to increased atmospheric vapour transport from the land to the ocean. The contribution of GWD to global sea-level rise amounted to 0.02 (+/- 0.004)mm yr(sup-1) in 1900 and increased to 0.27 (+/- 0.04)mm yr(sup-1) in 2000. This indicates that existing studies have substantially overestimated the contribution of GWD to global sea-level rise by a cumulative amount of at least 10 mm during the twentieth century and early twenty-first century. With other terrestrial water contributions included, we estimate the net terrestrial water contribution during the period 1993-2010 to be +0.12 +/-0.04)mm yr(sup-1), suggesting that the net terrestrialwater contribution reported in the IPCC Fifth Assessment Report report is probably overestimated by a factor of three.
Document ID
20160006711
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Wada, Yoshihide (NASA Goddard Inst. for Space Studies New York, NY, United States)
Lo, Min-Hui (National Taiwan Univ. Taipei, Taiwan, Province of China)
Yeh, Pat J.-F. (National Univ. of Singapore Singapore)
Reager, John T. (Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Famiglietti, James S. (Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Wu, Ren-Jie (National Taiwan Univ. Taipei, Taiwan, Province of China)
Tseng, Yu-Heng (National Center for Atmospheric Research Boulder, CO, United States)
Date Acquired
May 31, 2016
Publication Date
May 2, 2016
Publication Information
Publication: Nature Climate Change: Letters
Subject Category
Geosciences (General)
Report/Patent Number
GSFC-E-DAA-TN32038
Funding Number(s)
CONTRACT_GRANT: NNX14AB99A
Distribution Limits
Public
Copyright
Other
Keywords
water
ice
glaciers
ground water
oceans