Watching the Future of Water Resources

Urbanization, deforestation and desertification are affecting water resources and water availability as much as climate change is, according to results of a four-year international assesment of the hydrological cycle that relied on modelling techniques developed by ICTP scientists.

The Water and Global Change project (WATCH), funded by the European Union Framework Six Programme, supported an extensive analysis of climate change and land use impacts on the global hydrological cycle, as well as future water resources for the entire world. Results confirm that the hydrological cycle is indeed changing; the project recommends actions for policymakers and the general public to help in the successful management of water resources.

Laura Mariotti and Claudio Piani, climate scientists from ICTP's Earth System Physics section, contributed to the project in three key areas: climate feedbacks, the hydrological cycle of the 20th century and hydrological forecasts for the 21st century.

Laura Mariotti used regional climate modelling methods and ran simulations over sub-Saharan African regions. The results of these simulations supported one of the main project findings that land use changes affect water resources and availability as much as climate change.

Another crucial finding of the project was that water availability in sub-tropical catchment areas could decrease by up to 30%. In order to make such predictions and to ensure that the simulated results match the observational ones, climate models needed tweaking. ICTP's Claudio Piani developed and applied a bias correction methodology for climate models. "Bias correction was crucial if climate models were to be used together with hydrological models to make predictions about future water availability," he says. The bias correction was adopted by all of the WATCH modeling community and also used in other EU projects.