WSL > Research units > Mountain Hydrology > Group Hydr. Forecasts > Projects > Impact of the CH2014 climate scenarios on water resources

Research Units Mountain Hydrology Staff Projects Dossiers Group Hydr. Forecasts Projects CH2014-Impacts Publications Hyv News Group Torrents Group Snow Hydrology Group Mass Movements Alptal (SZ) Walenstadt (SG) Illgraben (VS) Sperbel- Rappengraben Open Master Thesis Downloads

Impact of the CH2014 climate scenarios on water resources - an estimate for Switzerland

The projected climate change might have significant impacts on snow cover and glaciers, and thus on Alpine water resources. Within the study CCHydro (BAFU) we realized high temporal and spatial resolution scenarios of the water cycle and the discharges for the different climates and elevations of Switzerland. To reflect the estimated local climate change in a large basin, the climate scenarios of the ENSEMBLES project were calculated, using the delta change method on a daily basis, based on the A1B emission scenario for temperature and precipitation.

For the periods 2021-2050 and 2070-2099 were simulated the local meteorological changes and the resulting changes in the glaciation, the snowpack and runoff in comparison with the control period 1980-2009.

These studies have been extended by the use of the CH2014 scenarios by MeteoSwiss. These are based on a probabilistic method, representing the model uncertainty and the decadal variability. In contrast to the delta change approach, the projected climate data are available for five regions of Switzerland only. In addition to the A1B scenario two further emission scenarios are provided: RCP3PD (moderate) and A2 (“worst case”).

Looking at the expected changes, primarily the ice melt part of the total runoff will decline (-22%) in the first half of this century, which is expected to level off by the end of this century. However, the snow melt fraction of the total runoff is expected in the near future by about 15% and decrease in the second period by up to 40%. If we compare the A1B-based CCHydro results with the optimistic scenario RCP3PD, we can clearly demonstrate that a reduction of greenhouse gases will have a positive effect by the end of the century. In contrast, the A2 results are comparable with the A1B values, with stronger anomalies by the end of the century.

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Luzi Bernhard

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