Skip to main content

Thank you for visiting You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

  • Letter
  • Published:

Climate change enhances interannual variability of the Nile river flow


The human population living in the Nile basin countries is projected to double by 2050, approaching one billion1. The increase in water demand associated with this burgeoning population will put significant stress on the available water resources. Potential changes in the flow of the Nile River as a result of climate change may further strain this critical situation2,3. Here, we present empirical evidence from observations and consistent projections from climate model simulations suggesting that the standard deviation describing interannual variability of total Nile flow could increase by 50% (±35%) (multi-model ensemble mean ± 1 standard deviation) in the twenty-first century compared to the twentieth century. We attribute the relatively large change in interannual variability of the Nile flow to projected increases in future occurrences of El Niño and La Niña events4,5 and to observed teleconnection between the El Niño–Southern Oscillation and Nile River flow6,7. Adequacy of current water storage capacity and plans for additional storage capacity in the basin will need to be re-evaluated given the projected enhancement of interannual variability in the future flow of the Nile river.

This is a preview of subscription content, access via your institution

Access options

Buy this article

Prices may be subject to local taxes which are calculated during checkout

Figure 1: Topographic map of Eastern Africa and the Nile sub-basins.
Figure 2: Observed stream flows and rainfall, and moving averages for the mean and standard deviation for the Upper Blue Nile and Atbara basins.
Figure 3: Changes in moving averages for the mean and standard deviation, coefficient of variation, number of ENSO events and frequency distribution of flow over Eastern Nile basin using 18 CMIP5 GCMs.
Figure 4: Total current water storage in the Eastern Nile basin, and required changes in future storage to accommodate the effects of climate change.

Similar content being viewed by others


  1. World Population Prospects: The 2012 Revision, Highlights and Advance Tables Working Paper No. ESA/P/WP.228 (United Nations, Department of Economic and Social Affairs, Population Division, 2013).

  2. Christensen, J. H. et al. in Climate Change 2007: The Physical Science Basis (eds Solomon, S. et al.) 847–940 (IPCC, Cambridge Univ. Press, 2007).

    Google Scholar 

  3. Christensen, J. H. et al. in Climate Change 2013: The Physical Science Basis (eds Stocker, T. F. et al.) 1217–1308 (IPCC, Cambridge Univ. Press, 2013).

    Google Scholar 

  4. Cai, W. et al. Increasing frequency of extreme El Niño events due to greenhouse warming. Nat. Clim. Change 4, 111–116 (2014).

    Article  CAS  Google Scholar 

  5. Cai, W. et al. Increased frequency of extreme La Nina events under greenhouse warming. Nat. Clim. Change 5, 132–137 (2015).

    Article  Google Scholar 

  6. Eltahir, E. A. B. El Niño and the natural variability in the flow of the Nile River. Wat. Resour. Res. 32, 131–137 (1996).

    Article  Google Scholar 

  7. Siam, M. S., Wang, G., Demory, M. E. & Eltahir, E. A. B. Role of the Indian Ocean sea surface temperature in shaping the natural variability in the flow of Nile River. Clim. Dynam. 43, 1011–1023 (2014).

    Article  Google Scholar 

  8. Baecher, G., Anderson, R., Britton, B., Brooks, K. & Gaudet, J. The Nile Basin: Environmental Transboundary Opportunities and Constraints Analysis (United States Agency for International Development, 2015).

    Google Scholar 

  9. New Dimensions in Water Security: Water, Society and Ecosystem Services in the 21st century (Food and Agriculture Organization of the United Nations, 2000).

  10. Kim, U. & Kaluarachchi, J. J. Climate change impacts on water resources in the Upper Blue Nile River Basin, Ethiopia. J. Am. Wat. Resour. Assoc. 45, 1361–1378 (2009).

    Article  Google Scholar 

  11. Elshamy, M. E. Impacts of climate change on Blue Nile flows using bias corrected GCM scenarios. Hydrol. Earth Syst. Sci. 13, 551–565 (2009).

    Article  Google Scholar 

  12. Beyene, T., Lettenmaier, D. P. & Kabat, P. Hydrologic impacts of climate change on the Nile River Basin: implications of the 2007 IPCC scenarios. Climatic Change 100, 433–461 (2009).

    Article  Google Scholar 

  13. Yates, D. N. & Strzepek, K. M. An assessment of integrated climate change impacts on the agricultural economy of Egypt. Climatic Change 38, 261–287 (1998).

    Article  Google Scholar 

  14. Gebre, S. L. & Ludwig, F. Hydrological response to climate change of the upper Blue Nile River Basin: based on IPCC Fifth Assessment Report (AR5). J. Climatol. Weath. Forecast. 3, 121 (2015).

    Google Scholar 

  15. Taye, M. T., Ntegeka, V., Ogiramoi, N. P. & Willems, P. Assessment of climate change impact on hydrological extremes in two source regions of the Nile River Basin. Hydrol. Earth Syst. Sci. 15, 209–222 (2011).

    Article  Google Scholar 

  16. Adaptation to Climate-change Induced Water Stress in the Nile Basin: A Vulnerability Assessment Report. Division of Early Warning and Assessment (DEWA) (United Nations Environment Programme, 2013).

  17. Conway, D. & Schipper, E. L. F. Adaptation to climate change in Africa: challenges and opportunities identified from Ethiopia. Glob. Environ. Change 21, 227–237 (2011).

    Article  Google Scholar 

  18. Conway, D. From headwater tributaries to international river: observing and adapting to climate variability and change in the Nile basin. Glob. Environ. Change 15, 99–114 (2005).

    Article  Google Scholar 

  19. Conway, D. & Hulme, M. Recent fluctuations in precipitation and runoff over the Nile subbasins and their impact on Main Nile discharge. Climatic Change 25, 127–151 (1993).

    Article  Google Scholar 

  20. Siam, M. S. & Eltahir, E. A. B. Explaining and forecasting interannual variability in the flow of the Nile River. Hydrol. Earth Syst. Sci. 19, 1181–1192 (2015).

    Article  Google Scholar 

  21. Wang, G. & Eltahir, E. A. B. Use of ENSO information in medium and long range forecasting of the Nile floods. J. Clim. 12, 1726–1737 (1999).

    Article  Google Scholar 

  22. ElDaw, A., Salas, J. D. & Garcia, L. A. Long range forecasting of the Nile river flows using climate forcing. J. Appl. Meteorol. 42, 890–904 (2003).

    Article  Google Scholar 

  23. Kim, S. T. et al. Response of El Niño sea surface temperature variability to greenhouse warming. Nat. Clim. Change 4, 786–790 (2014).

    Article  Google Scholar 

  24. Hurst, H. E., Black, R. P. & Simaika, Y. M. Long-term storage: an experimental study. J. Roy. Stat. Soc. A 129, 591–593 (1966).

    Google Scholar 

  25. Hurst, H. E. Long term storage capacity of reservoirs. Trans. Am. Soc. Civ. Eng. 116, 770–779 (1951).

    Google Scholar 

  26. Cervigni, R., Liden, R., Neumann, J. E. & Strzepek, K. M. (eds) Enhancing the Climate Resilience of Africa’s Infrastructure: The Power and Water Sectors (World Bank Publications, 2015).

  27. King, A. & Block, P. An assessment of reservoir filling policies for the Grand Ethiopian Renaissance Dam. J. Wat. Clim. Change 5, 233–243 (2014).

    Article  Google Scholar 

  28. Yamana, T. K. Mechanistic Modelling of the Links between Environment, Mosquitoes and Malaria Transmission in the Current and Future Climates of West Africa (Doctoral dissertation, Massachusetts Institute of Technology, 2015).

  29. Rayner, N. A. et al. Global analyses of sea surface temperature, sea ice, and night marine air temperature since the late nineteenth century. J. Geophys. Res. 108, 4407 (2003).

    Article  Google Scholar 

  30. Vorosmarty, C. J., Fekete, B. M. & Tucker, B. A. Global River Discharge 1807–1991 Version. 1.1 (RivDIS). Data set. (Oak Ridge National Laboratory Distributed Active Archive Center, 1998);

  31. Vose, R. S. et al. Global Historical Climatology Network 1753–1990 (ORNL DAAC, 2016);

  32. Taylor, K. E., Stouffer, R. J. & Meehl, G. A. An overview of CMIP5 and the experiment design. Bull. Am. Meteorol. Soc. 93, 485–498 (2015).

    Article  Google Scholar 

Download references

Author information

Authors and Affiliations



E.A.B.E. conceived the study, and supervised the design and implementation of research. M.S.S. performed the analyses of observational data and climate models. E.A.B.E. supervised interpretation of results. M.S.S. wrote the paper, with input from E.A.B.E. Both authors contributed to revisions of the manuscript.

Corresponding author

Correspondence to Mohamed S. Siam.

Ethics declarations

Competing interests

The authors declare no competing financial interests.

Supplementary information

Supplementary Information

Supplementary Information (PDF 4356 kb)

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Siam, M., Eltahir, E. Climate change enhances interannual variability of the Nile river flow. Nature Clim Change 7, 350–354 (2017).

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI:

This article is cited by


Quick links

Nature Briefing Anthropocene

Sign up for the Nature Briefing: Anthropocene newsletter — what matters in anthropocene research, free to your inbox weekly.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing: Anthropocene