Hydrological change--climate change impact simulations for Sweden

Area of Science:

• Environmental science
• Hydrology
• Climate science

Background:

• The enhanced greenhouse effect is projected to alter global hydrological systems.
• Hydrological changes will exhibit significant regional variations, necessitating local and regional impact assessments.
• Understanding these impacts is crucial for effective climate change adaptation strategies.

Purpose of the Study:

• To assess the hydrological impacts of climate change across various Swedish river basins.
• To compare different methods for translating climate model outputs to hydrological models.
• To analyze the influence of climate model choice and emissions scenarios on projected hydrological changes.

Main Methods:

• Utilized regional climate model (RCM) scenarios from the Swedish Regional Climate Modelling Programme (SWECLIM).
• Employed multiple methods for downscaling climate change signals from global climate models (GCMs) to RCMs.
• Conducted hydrological model simulations using the downscaled climate data for Swedish basins.

Main Results:

• Projected hydrological changes in Swedish basins show considerable subregional variations, particularly between northern and southern Sweden.
• The choice of GCM significantly influences RCM boundary conditions and, consequently, projected hydrological impacts.
• The selection of anthropogenic emissions scenarios also plays a critical role in determining the magnitude of hydrological change.

Conclusions:

• Subregional hydrological impacts of climate change in Sweden are highly variable.
• Projected river flow alterations are sensitive to both the GCM used for boundary conditions and the chosen emissions scenario.
• Future hydrological assessments must account for uncertainties associated with climate model selection and emissions pathways.