Fig. 1: Past and future trends in temperature and precipitation in the Rio Santa and Vilcanota-Urubamba basins.

a The three WRF model domains (D1-D3) used for the 1980 to 2018 hindcast. The outer domain, D1, covers all of Peru at 12 km resolution. D2 and D3 show the inner domains at 4 km resolution, covering the Rio Santa basin and the Vilcanota-Urubamba basin, respectively. The two river basins are outlined in black, with the upper Rio Santa and 30 km boundary from which station data were used are outlined in blue. The terrain height is shown as filled contours, the ocean and other water bodies are shown in blue, and all stations used in the bias-correction are shown as blue dots. b The 1980-2018 annual trends in temperature (top; °C year⁻¹) and precipitation (bottom; mm year⁻¹) from the bias-corrected WRF hindcast, shown spatially for the upper Rio Santa (referred to as ‘Rio Santa’ in the text and hereafter) (left) and Vilcanota-Urubamba (right), with stippling indicating areas of significant trend and black contours showing elevation in 500 m intervals. The location of the Cordillera Blanca is shown with brown arrows, and the Cordilleras Urubamba and Vilcanota are marked by brown boxes. The outlines of the glaciers are shown in blue. c Timeseries of the basin-averaged recent past (1980-2018) and future (2019–2100) annual-averaged minimum and maximum daily temperature (top; °C) and precipitation (bottom; mm) are shown for the Rio Santa (left) and Vilcanota-Urubamba (right). Black lines show the basin-averaged values from the bias-corrected WRF hindcast. Blue lines show the mean of all statistically downscaled CMIP5 models for the RCP8.5 scenario, and green lines show the RCP4.5 scenario. Shading indicates one standard deviation from the mean (across the 30 statistically downscaled CMIP5 models).