Climate projections and the increasing aridity in the Canary Islands

Abstract

Island regions are particularly susceptible to the impacts of climate change, which affect key sectors such as agriculture, water resources, and human activities. The observed trends of rising temperatures, decreasing precipitation, altered evapotranspiration patterns, and increasing pressure on water resources contribute to shifts in the aridity levels of various territories. This study focuses on the Canary Islands as a case study to assess the evolution of aridity index throughout the current century, calculated as the ratio of precipitation to reference evapotranspiration. The Fundación para la Investigación del Clima (FICLIMA) methodology is employed, incorporating statistical downscaling techniques to generate regional and local projections with high spatial resolution (100 × 100 m). The results indicate an overall increase in aridity by the end of the century across all the islands. The western islands show greater decreases in the aridity index, such as La Gomera, which shows reductions of between − 0.14 and − 0.25 in the index value. The eastern islands, characterized by their currently higher aridity, are projected to experience smaller decreases in the aridity index (− 0.02 to − 0.05). Nevertheless, they are expected to reach very low AI values by the end of the century (around 0.06), posing significant challenges for sectors such as agriculture. These findings suggest that, despite differing rates of change, all islands will face intensifying aridity by the end of the century, with particularly severe implications for water management in the already drier eastern islands. This underscores the urgent need for differentiated resilience and adaptation strategies tailored to each island’s specific vulnerabilities.

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