Global Change and its Impact on Water Resources: the Role of UNESCO’s International Hydrological Programme - Siegfried Demuth and Biljana Radojevic page 6

  • The need to develop and understand the vulnerability, resilience and adaptability of different water management institutions and structures in stimulating and dealing with a changing environment. Water resources infrastructure development and management has historically required significant public funding by national and international agents. How can one understand the interaction between local and global actors in determining the future vulnerability and resilience of these systems and their local management to adapt to changing conditions?
  • The non-stationary behaviour of many other factors influenced by global change must be recognised. For example, the impact of soil compaction, land management changes, etc. on floods. Soil erosion in the U.S. has been reduced by ca. 40% between the early 1980s and late 1990s due to improved land management. These changes would also impact surface runoff and floods. The impacts of climate change on floods could therefore be underestimated. Increased flooding is likely to reflect increased soil compaction and reduced channel and floodplain storage as well as climate change.


One important recommendation on the adaptation of global change impacts on water resources is to develop a change assessment and prediction initiative in conjunction with a policy framework initiative to better develop the policy sciences for global hydrologic change adaptation. The recommendation is to pursue one or more case studies in a large river basin focused on global to local action. The criteria for the selection of such a site should be that it is:
  • An area with very high vulnerability;
  • An area where the water situation or hazard impacts are likely to be severe in the near to mid-term;
  • Collective action and learning on different aspects and solutions is feasible;
  • It is possible to clarify hierarchy of relations of water from local to regional to global levels;
  • It provides new ways to think about global or local solutions;
  • It provides a basis for an integrated project that draws leading global researchers from all relevant disciplines to a specific region to develop and demonstrate an end to end research and adaptation strategy.

There is a need for improved monitoring:


  • Even rainfall and runoff data can be inadequate, but the deficiencies increase greatly when groundwater and soil moisture are considered;
  • The need for leverage to increase monitoring activity or at least to stop the decline in monitoring activity;

  • Network decline and/or absence of networks (especially in the underdeveloped world and in the former Soviet Union), and cost issues in developed countries have created pressure for network erosion;
  • What are the appropriate network design criteria for hydrologic observations in the context of global change?
  • What is and can be the role of new observing methods (e.g. remote sensing)?
  • There are particular recommendations concerning the adaptation and management approaches;
  • The science can adopt a global perspective but adaptation and management require a regional or local approach;
  • Tools are needed to disentangle effects of land cover, climate change, and water management on hydro-hazards, particularly given their high natural variability;
  • Most glaciers globally appear to have negative mass balances. However, a sound predictive basis for assessing implications of these changes on stream flow regionally or globally (as contrasted with modelling of single glaciers) are lacking.

Finally the overall question is whether an IPCC like “Hydrological Change Initiative” can be built on top of the existing structure of these programs, including and bringing together all aspects of global change regionally and globally to better understand the drivers and their impacts on the water resources. To a certain extent the Global Water Systems Project (GWSP) intends to address many of the issues enumerated above through its global catchment initiative and other thrusts, such as the Global Water Atlas. FRIEND and HELP with their networks are also going in the same direction. The three programs have to be linked in order to avoid duplication and to benefit from each others strengths. All these previously mentioned initiatives may provide the foundation for a new “Hydrological Change Initiative” leading as input for the upcoming IPCC Reports.




The authors gratefully acknowledge the contributions from the numerous colleagues from the Division of Water Sciences at UNESCO who have provided directly or indirectly input for the paper. The paper very much benefited from the comments made by Shahbaz Khan, Sarantuyaa Zandaryaa and Anil Mishra from the Division of Water Sciences. Bozena Blix provided editorial support. The authors would also like to thank the participants from a workshop held at UNESCO in 2008 on adapting to the impacts of global changes on river basin and aquifer systems for their contributions.