The fate of the Patagonian rivers: fluvial captures and climate trends.

Patagonia and Tierra del Fuego are the only places to analyse climate changes at high latitudes in the Southern (Oceanic) Hemisphere. This region is totally dominated by westerly winds, although the altitude of the Andes Cordillera —transverse to these winds— modifies their effects. According to short meteorological records, air temperature is increasing slightly while precipitations are diminishing. Hydrologic records are longer; their trends are biased by geomorphological changes in the watersheds by fluvial andglacier captures. The discharges of the Negro, Chubut, Senguerr, Deseado, Santa Cruz and Gallegos rivers have decrease although some of them are not significantly modified by dams. The Santa Cruz River is the only example that is increasing the discharges due to significant variations at the upper watershed.