Potential future impact of climate change on recharge in the Sierra de las Nieves (southern Spain) high-relief karst aquifer using regional climate models and statistical corrections

The Sierra de las Nieves high-relief karst aquifer, which is located in the natural park and UNESCO biosphere reserve of the same name, is an area of great interest due to its geological, geomorphological (both at the surface and underground), hydrogeological, and ecological value. The aquifer is not influenced by pumping and is considered to be a natural laboratory for karst research because of how well developed the main karst characteristics are at both the surface (karst depressions and karst springs) and underground (with a large network of caves). The hydrological cycle is sustained by relatively high precipitation (annual mean precipitation of approximately 1000 mm) and moderate temperatures (annual mean temperature of approximately 16 °C). However, these climate parameters are susceptible to significant disruption because of ongoing anthropogenic-driven climate change induced by increased CO₂ in the atmosphere. This paper offers an analysis and discussion of the impact that these potential future changes, estimated from the temperature and precipitation projections from regional climate models, may have on this karst aquifer, particularly on its recharge. The projections have been corrected using several techniques based on two hypotheses, bias correction and delta change approaches. We have focus on the future assessment for the horizon 2071–2100 under the most pessimistic emission scenario (RCP 8.5) contemplated within the last published IPCC report (IPCC, Contribution of working group II to the fifth assessment report of the intergovernmental panel on climate change. Cambridge University Press, Cambridge, UK and New York, NY, USA, 2014). It is expected that there will be, on average, a 27% reduction in precipitation and a 19% increase in temperature. This is a dangerous combination that will dramatically decrease recharge and will require new local adaptation measures, in addition to global mitigation measures, to prevent the area’s resources, biodiversity, and geodiversity from being drastically diminished.