Changes in Climate, Snow and Water Resources in the Spanish Pyrenees: Observations and Projections in a Warming Climate

Abstract

The Pyrenees constitute one of the greatest sources of freshwater in the Spanish territory, but, like many other mountain systems in the world, they are subject to environmental changes that ultimately affect the availability of water resources in areas downstream. In this study, we offer an assessment of hydrological changes in the Pyrenees, from a warming climate perspective, including climate and snow cover trends, changes in the timing of river flows, and future changes under climate change scenarios. Overall, we found that increasing temperatures are responsible for a lesser accumulation of snow over time, although with spatial differences. As a consequence, the occurrence of spring flows (that largely depend on snowmelt) on the studied rivers, has shifted earlier by approximately one month (from mid-June to mid-May). Future projections, which are made by coupling regional climate models outputs and hydrological modelling, indicate that observed decrease in snow accumulation and shifts in streamflow timing will exacerbate in a warmer short-term future (2050). The amount of water yields will not change significantly, only will suffer a slight decrease due to increased evapotranspiration. Observed and projected hydrological changes must be considered by water managers and environmental technicians if a sustainable management of the water resource and the mountain territory is to be done.

Long‐term trends (1958–2017) in snow cover duration and depth in the Pyrenees

“…However, the temperature trends after 1980 have been weaker or non‐existent (López‐Moreno et al ., 2019). This explains why some studies using snow data for the Spanish Pyrenees since 1986 have found no trends in the snowpack (Buisan et al ., 2015; Morán‐Tejeda et al ., 2017); for this specific part of the Pyrenees this finding is reinforced by the relatively high frequency of winters having negative NAOi values (Añel et al ., 2014; Buisan et al ., 2016), which is associated with frequent humid conditions in the massifs located southwards.…”

Detecting snow-related signals in radial growth of Pinus uncinata mountain forests

“…Reduced snowpack depth and duration have been reported in the main mid-latitude mountain ranges (López-Moreno, 2005;Marty, 2008;McCabe and Wolock, 2009;Beniston, 2012;Morán-Tejeda et al, 2013a) including Mediterranean (drought-prone) areas such as the Pyrenees (Morán-Tejeda et al, 2017).…”

Projected hydrologic changes over the north of the Iberian Peninsula using a Euro-CORDEX multi-model ensemble

“…The latter implies a decrease of snow accumulation in winter and an earlier snowmelt presence during spring, therefore affecting the amount and timing of the streamflow (Morán-Tejeda et al, 2010. This downward tendency driven by a warmer climate has being previously identified for the mountainous areas in Spain (López-Moreno et al, 2009;Morán-Tejeda et al, 2017;Collados-Lara et al, 2019) and other parts of the world (e.g. Bhatti et al, 2016;Majone et al, 2016;Coppola et al, 2018;Ishida et al, 2018Ishida et al, , 2019Liu et al, 2018), thus suggesting a critical role of the snowmelt component for the future management of mountain water resources (Viviroli et al, 2011;Mankin et al, 2015).…”