Impact of climate change on droughts and their propagation in an alpine-semiarid basin in Granada, Spain. Does the snow component help to anticipate adaptation strategies?

Abstract

Study region: Alto Genil Basin, Granada, Spain Study focus: This study assesses past and projected climate change impacts on meteorological, agricultural, hydrological, and operational droughts in the Alto Genil Basin—an alpine Mediterranean region in southern Spain. A key focus is the role of snow in early adaptation, underscoring alpine vulnerability to global warming. The methodology involves: (1) generating future climate scenarios (2071–2100) to project temperature and precipitation; (2) applying a model chain including a rainfall-runoff model (Témez), a snowmelt model, CROPWAT for agricultural demand, and Aquatool for the Demand Satisfaction Index; and (3) evaluating droughts using the Standardised Precipitation Index (SPI) approach, applied respectively to precipitation, soil moisture, streamflow, and the Demand Satisfaction Index to assess meteorological, agricultural, hydrological, and operational droughts. Cluster analysis identified homogeneous hydroclimatic areas to explore drought propagation. New hydrological insights for the region: Results show a 27 % decrease in precipitation and a 6.6°C temperature rise. Agricultural water demand may increase by 23 %, intensifying pressure on resources. Droughts are expected to become more frequent, severe, and prolonged, especially in snow-reliant subbasins. The weakening link between meteorological and operational droughts suggests more erratic system responses. Reduced snowpack and a shift from snowfall to rainfall are likely to disrupt seasonal water availability, compromising the basin’s regulatory function. These findings highlight the urgent need for adaptive strategies in snow-dependent Mediterranean alpine basins.