Impact of climate change on the streamflow in northern Patagonia

Abstract

Streamflow simulations from the Inter-Sectoral Impact Model Intercomparison Project phase 2b (ISIMIP2b) were analyzed to evaluate futurechanges in surface water resources over northern Patagonia, a region that contributes significantly to the total hydropower production ofArgentina. Ten global hydrological models (GHMs), forced by four general circulation models, effectively capture the winter streamflow maxi-mum in the Negro river basin. However, most of them face challenges in simulating the late-spring pulse due to a misrepresentation oftemperature over the higher elevations of the Andes. We quantified the future streamflow evolution using a multi-model ensemble froma subset of the best-performing GHMs under the RCP2.6 and RCP6.0 emission scenarios for two temporal horizons. According to themulti-model ensemble, there is a projected decrease in the annual streamflow of the analyzed rivers, which is more important consideringthe RCP6.0 scenario during the late 21st century, reaching up to 40% relative to the 1979–2005 reference period. This reduction is attributedto the projected precipitation decline in the headwaters of the Negro river basin in response to changes in the surface pressure patterns.These results have implications for regional water authorities for the development of adaptation plans considering future demandprojections.