Letter | Published:

Terrestrial water fluxes dominated by transpiration

Nature volume 496, pages 347350 (18 April 2013) | Download Citation


Renewable fresh water over continents has input from precipitation and losses to the atmosphere through evaporation and transpiration. Global-scale estimates of transpiration from climate models are poorly constrained owing to large uncertainties in stomatal conductance and the lack of catchment-scale measurements required for model calibration, resulting in a range of predictions spanning 20 to 65 per cent of total terrestrial evapotranspiration (14,000 to 41,000 km3 per year) (refs 1, 2, 3, 4, 5). Here we use the distinct isotope effects of transpiration and evaporation to show that transpiration is by far the largest water flux from Earth’s continents, representing 80 to 90 per cent of terrestrial evapotranspiration. On the basis of our analysis of a global data set of large lakes and rivers, we conclude that transpiration recycles 62,000 ± 8,000 km3 of water per year to the atmosphere, using half of all solar energy absorbed by land surfaces in the process. We also calculate CO2 uptake by terrestrial vegetation by connecting transpiration losses to carbon assimilation using water-use efficiency ratios of plants, and show the global gross primary productivity to be 129 ± 32 gigatonnes of carbon per year, which agrees, within the uncertainty, with previous estimates6. The dominance of transpiration water fluxes in continental evapotranspiration suggests that, from the point of view of water resource forecasting, climate model development should prioritize improvements in simulations of biological fluxes rather than physical (evaporation) fluxes.

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  1. 1.

    , , & Partitioning of evaporation into transpiration, soil evaporation, and canopy evaporation in a GCM: impacts on land-atmosphere interaction. J. Hydrometeorol. 8, 862–880 (2007)

  2. 2.

    , , & Simulations of global evapotranspiration using semiempirical and mechanistic schemes of plant hydrology. Glob. Biogeochem. Cycles 23, GB4023 (2009)

  3. 3.

    , , , & Importance of carbon dioxide physiological forcing to future climate change. Proc. Natl Acad. Sci. USA 107, 9513–9518 (2010)

  4. 4.

    & Water-use efficiency of the terrestrial biosphere: a model analysis focusing on interactions between the global carbon and water cycles. J. Hydrometeorol. 13, 681–694 (2012)

  5. 5.

    et al. Contemporary “green” water flows: simulations with a dynamic global vegetation and water balance model. Phys. Chem. Earth 30, 334–338 (2005)

  6. 6.

    et al. Terrestrial gross carbon dioxide uptake: global distribution and covariation with climate. Science 329, 834–838 (2010)

  7. 7.

    & Estimates of freshwater discharge from continents: latitudinal and seasonal variations. J. Hydrometeorol. 3, 660–687 (2002)

  8. 8.

    & Fluxes of CO2 and water between terrestrial vegetation and the atmosphere estimated from isotope measurements. Nature 380, 515–517 (1996)

  9. 9.

    et al. Evapotranspiration components determined by stable isotope, sap flow and eddy covariance techniques. Agric. For. Meteorol. 125, 241–258 (2004)

  10. 10.

    Determining water use by trees and forests from isotopic, energy balance and transpiration analyses: the roles of tree size and hydraulic lift. Tree Physiol. 16, 263–272 (1996)

  11. 11.

    et al. δ18O of water vapor, evapotranspiration and the sites of leaf water evaporation in a soybean canopy. Plant Cell Environ. 31, 1214–1228 (2008)

  12. 12.

    , & in Climate Change in Continental Isotopic Records (eds et al.) 1–36 (Am. Geophys. Union, 1993)

  13. 13.

    & Liquid-vapour fractionation of oxygen and hydrogen isotopes of water from the freezing to the critical temperature. Geochim. Cosmochim. Acta 58, 3425–3437 (1994)

  14. 14.

    & in Stable Isotopes in Oceanographic Studies and Paleotemperatures (ed. ) 9–130 (Lab. Geol. Nucl., 1965)

  15. 15.

    & Interpolating the isotopic composition of modern meteoric precipitation. Wat. Resour. Res. 39, 1299 (2003)

  16. 16.

    , , , & Global canopy interception from satellite observations. J. Geophys. Res. 115, D16122 (2010)

  17. 17.

    , , & A high-resolution data set of surface climate over global land areas. Clim. Res. 21, 1–25 (2002)

  18. 18.

    , , & Historical isotope simulation using reanalysis atmospheric data. J. Geophys. Res. 113, D19108 (2008)

  19. 19.

    , & Effects of long-term rainfall variability on evapotranspiration and soil water distribution in the Chihuahuan desert: a modeling analysis. Plant Ecol. 150, 145–159 (2000)

  20. 20.

    et al. The global abundance and size distribution of lakes, ponds, and impoundments. Limnol. Oceanogr. 51, 2388–2397 (2006)

  21. 21.

    , & Earth’s global energy budget. Bull. Am. Meteorol. Soc. 90, 311–323 (2009)

  22. 22.

    , , , & Mean annual GPP of Europe derived from its water balance. Geophys. Res. Lett. 34, L05401 (2007)

  23. 23.

    , & Carbon isotope discrimination and photosynthesis. Annu. Rev. Plant Physiol. Plant Mol. Biol. 40, 503–537 (1989)

  24. 24.

    et al. Recent decline in the global land evapotranspiration trend due to limited moisture supply. Nature 467, 951–954 (2010)

  25. 25.

    , & Ocean salinities reveal strong global water cycle intensification during 1950 to 2000. Science 336, 455–458 (2012)

  26. 26.

    , & Global prediction of δA and δ2H-δ18O evaporation slopes for lakes and soil water accounting for seasonality. Glob. Biogeochem. Cycles 22, GB2031 (2008)

  27. 27.

    in Handbook of Environmental Isotope Geochemistry Vol. 2: The Terrestrial Environment (eds & ) 113–163 (Elsevier, 1986)

  28. 28.

    New equations for computing vapour pressure and enhancement factor. J. Appl. Meteorol. 20, 1527–1532 (1981)

  29. 29.

    , , , & Very high resolution interpolated climate surfaces for global land areas. Int. J. Climatol. 25, 1965–1978 (2005)

  30. 30.

    Global Energy and Water Cycle Experiment. International Satellite Land-Surface Climatology Project. (2012)

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We thank T. W. D. Edwards, T. Gleeson and M. C. Molles Jr for comments on the manuscript, and are grateful to O. Kwiecien, D. G. Miralles, B. K. Nyarko, K. Yoshimura and F. Yuan for providing access to isotope and gridded data sets. Support for this work was provided by a graduate fellowship awarded to S.J. by the Caswell Silver Foundation through the University of New Mexico.

Author information


  1. Department of Earth and Planetary Sciences, University of New Mexico, Albuquerque, New Mexico 87131, USA

    • Scott Jasechko
    • , Zachary D. Sharp
    •  & Peter J. Fawcett
  2. Alberta Innovates – Technology Futures, Vancouver Island Technology Park, Victoria, British Columbia V8Z 7X8, Canada

    • John J. Gibson
    • , S. Jean Birks
    •  & Yi Yi
  3. Department of Geography, University of Victoria, Victoria, British Columbia V8W 3R4, Canada

    • John J. Gibson
    •  & Yi Yi
  4. Department of Earth and Environmental Sciences, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada

    • S. Jean Birks


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S.J. designed the study, compiled each data set, did the geographic information system and remote sensing work, developed the equations, did the water balance and carbon flux calculations, and wrote the paper. Z.D.S., J.J.G., S.J.B., Y.Y. and P.J.F. discussed the results, commented on the manuscript and contributed to text.

Competing interests

The authors declare no competing financial interests.

Corresponding author

Correspondence to Scott Jasechko.

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    Supplementary Information

    This file contains Supplementary Text, Supplementary Figures 1-6 Supplementary Tables 1-6 and Supplementary References.

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    Supplementary Data

    This file contains a tabulated dataset of δ18O and δ2H values (V-SMOW standard reference) for large lakes.

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