Assessment of the Impacts of Climate Change on Mountain Hydrology
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Moving Forward The study met the objective of developing a methodology to assess the hydrological response to global climate change in tropical mountain basins, but data availability remains a challenge. Gathering the required data may require a large share of the resources demanded by this type of analysis. Calibration of the models should provide good to very good model performance indicators. Also, a thorough sensitivity analysis is strongly recommended. The study looked at the hydrological cycle from the supply side; only water availability and variability are considered. The work should be expanded to analyze the social and economic consequences associated with hydrological changes. In order to assess the economic consequence of climate change through water availability, the work should be complemented by an analysis of the economic consequences for the energy, agricultural and water supply sectors. Other socioeconomic impacts could also be explored.
Lessons Learned Need for criteria to assess the suitability of results from GCM. How to select among the many models available? Should an ensemble of GCMs be used? Which models should be incorporated in the ensemble? How to assess the ability of the models to reproduce climate observations? How to weigh the dierent models? For practical purposes, criteria by which to judge model suitability should be clearly defined. The criteria should respond to the problem at hand (a function of the results sought) and the socioeconomic sensitivity to changes in the selected criteria. A bag of tools instead of a single silver bullet. It may be be er to use complementary tools, and in some instances to mix methods that appear to be competing, in order to produce similar results. As indicated in the climate component, the various methods used complement and enrich the results, reduce uncertainty, allow risk analysis and provide the basis to conduct sensitivity analyses. Limitations when interpreting the results and the need for sensibility analysis. Good practice dictates that model limitations should be well understood by model users and should be an integral part of the analysis of results. It is recommended that a list of the limitations of the methodology/approach used and of each tool utilized be prepared. To cope with the uncertainties associated with these planning exercises, it is recommended that a thorough sensitivity analysis be conducted.
Conclusion On the basis of the results obtained, it seems that the combination of the climate and hydrology analysis can simulate current conditions at a regional and basin level and project future hydrological conditions. The methods employed could be of use to predict future impacts of climate change on hydrology for other mountain basins in the Andes.
Notes 1. The reference to hydraulic infrastructure highlights the fact the climate change is having and will have great impact on the design and operation of water related works. 2. It is recommended that high standards be maintained in the calibration and verification tasks for the results to capture the basic hydrological response to existing climate conditions.