Abstract
The assessment of aridity conditions is a key factor for water management and the implementation of mitigation and adaptation policies in agroforestry systems. Towards this aim, three aridity indices were computed for the Iberian Peninsula (IP): the De Martonne Index (DMI), the Pinna Combinative Index (PCI), and the Erinç Aridity Index (EAI). These three indices were first computed for the baseline period 1961–1990, using gridded observational data (E-OBS), and subsequently, for the periods 2011–2040 (short range) and 2041–2070 (medium range), using an ensemble of six regional climate model (RCM) experiments generated by the EURO-CORDEX project. Two representative concentration pathways (RCPs) were analyzed, an intermediate anthropogenic radiative forcing scenario (RCP4.5) and a fossil-intensive emission scenario (RCP8.5). Overall, the three indices disclose a strengthening of aridity and dry conditions in central and southern Iberia until 2070, mainly under RCP8.5. Strong (weak) statistically significant correlations were found between these indices and the total mean precipitation (mean temperature) along with projected significant decreasing (increasing) trends for precipitation (temperature). The prevalence of years with arid conditions (above 70% for 2041–2070 under both RCPs) are projected to have major impacts in some regions, such as southern Portugal, Extremadura, Castilla-La Mancha, Comunidad de Madrid, Andalucía, Región de Murcia, Comunidad Valenciana, and certain regions within the Aragón province. The projected increase in both the intensity and persistence of aridity conditions in a broader southern half of Iberia will exacerbate the exposure and vulnerability of this region to climate change, while the risk of multi-level desertification should be thoroughly integrated into regional and national water management and planning.
Highlights
Climate variability and change may have significant impacts on the environment and in many important socio-economic sectors, such as agriculture, water availability, or energy production
Two scenarios were taken into consideration: RCP4.5 that corresponds to a stabilization of the additional anthropogenic radiative forcing relative to the pre-industrial levels, without overshoot pathway, at 4.5 W/m2 by the end of the 21st century; RCP8.5 that corresponds to an increase in radiative forcing of 8.5 W/m2 by the end of the 21st century
The results indicate a decrease in total annual precipitation, mainly over southern Iberia, for 2041–2070 and under RCP8.5, the severest scenario
Summary
Climate variability and change may have significant impacts on the environment and in many important socio-economic sectors, such as agriculture, water availability, or energy production. Decreases in precipitation, increasing trends in air temperature and evapotranspiration, and higher thermal contrasts associated with increases in air temperature ranges, occurring from the daily to the seasonal timescales, may have a deep impact on aridity conditions, when acting synergistically. In this case, several studies consistently referred to the Iberian Peninsula (IP) as a climate change “hotspot” within the Mediterranean region [2,3,4,5]. Assessing the potential impact of climate change on aridity conditions within this region is of the foremost relevance [6]. This will require systematic updates of the existing knowledge, as well as the integration into the decision-making processes of different perspectives provided by diverse methodologies, which will contribute to defining the uncertainty level of regional climate change projections
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