In the first phase of the GICC-Rhône project, the global climate change liable to take place in the Rhône region under the 2 x CO2 scenario was estimated with the help of outputs from several general atmospheric circulation models. These indications were disaggregated using the perturbation method to the more detailed scales needed for hydrological modelling.

In the second phase, the climatic indications obtained were applied to several hydrological models of the French side of the Rhône catchment and of tributaries of particular interest.

The authors deduced from the hydrological modelling some indications on how climate change affects the major physical variables of the hydrosystems studied. They also attempted to assess its impacts on various physical, biological and socio-economic aspects, in particular:

• The general hydrology of rivers (high water, median discharge, low water);
• The interactions with groundwater;
• The expected trends in water temperatures;
• The quantitiative and qualitative trends of the natural vegetation ;
• The altered relationships between the water resource and irrigated crop systems;
• The response of fish communities to an altered water regime.

Building on these findings, they quantified the uncertainties contained in current knowledge on the subject.

The outputs of the second phase are:

• A set of time series of river discharges under various climate change scenarios, consultable by the other participants in the GICC programme;
• A set of sectoral reports on the consequences of climate change;
• A general report summarizing the main findings of the two phases of the GICC-Rhône project and giving a preliminary synthesis of uncertainties.

Website

http://cnrm.meteo.fr/mc2