New publications from our group:
A new publication by Dominik Wisser et al. reveals that global reservoir capacity has already peaked in 2006, this as a result of the silting up of reservoirs. In a changing climate and under a growing population, decreasing reservoir capacity is a complicating factor if future water demands are to be met. See the publication at:
Wisser, D., S. Frolking, S. Hagen, and M. F. P. Bierkens (2013), Beyond peak reservoir storage? A global estimate of declining water storage capacity in large reservoirs, Water Resources Research 49, doi:10.1002/wrcr.20452.
Yoshihide Wada, Dominik Wisser et al. analysed a multi-model run (multiple global hydrological models and multiple CMIP5 GCM inputs) to assess the change of irrigation water demand until 2100 under various climate scenarios (RCPs as defined for the 5th IPCC report) and a single socio-economic scenario (SSP 2). They found that under RCP 8.5 (the most extreme climate scenario) irrigation water demand increased by 20% on average. An unexpected finding of this study is that the largest source of uncertainty in projecting future irrigation water demand comes from the global hydrological models and not from the climate models or scenarios used. This is both good and bad news. The good news is that Hydrology matters. The bad news is that a lot of work is needed to improve the reliability of hydrological climate change impacts. The work is part of the ISI-MIP project and published in Geophysical Research Letters:
Wada, Y. , D. Wisser, S. Eisner, M. Flörke, D. Gerten, I. Haddeland, N. Hanasaki, Y. Masaki, F. T. Portmann, T. Stacke, Z. Tessler and J. Schewe (2013), Multimodel projections and uncertainties of irrigation water demand under climate change, Geophysical Research Letters, 10 SEP 2013, DOI: 10.1002/grl.50686.
In a recent paper in Water Resources Research, Walter Immerzeel and scientists from ETH Zürich analyzed the uncertainty in glacio-hydrological modellling in the Himalaya. They found that the effect of parametric uncertainty often exceeds the impact of climate uncertainty and natural climate variability, especially in heavily glacierized subcatchments. This means that further research into processes and parameterization of Glaci-hydrological models is necessary if progress is to be made in projecting the fate of Himalayan glaciers. See:
Ragettli, S., F. Pellicciotti, R. Bordoy, and W. W. Immerzeel (2013), Sources of uncertainty in modeling the glaciohydrological response of a Karakoram watershed to climate change, Water Resources Research 49, doi:10.1002/wrcr.20450.
Arthur Lutz published a paper comparing climate change effects on the extent of Central Asian Glaciers (in the upstream parts of the Amu and Syr Darya, important for e.g. Aral Sea influx). Particular attention is paid to developing a dynamic glacier model that can be used in large-scale hydrological applications.
Lutz, A. F., W.W. Immerzeel, A. Gobiet, F. Pellicciotti, F. and M.F.P. Bierkens, 2013. Comparison of climate change signals in CMIP3 and CMIP5 multi-model ensembles and implications for Central Asian glaciers, Hydrology and Earth System Science 17, 3661-3677.