Climate Change Projections of Aridity Conditions in the Iberian Peninsula

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.

Multi-Indices Diagnosis of the Conditions That Have Led to the Two 2017 Major Wildfires in Portugal

“…Overall, the implementation of a multi-index's methodology might be a highly relevant tool for Portugal, whose complex orography and land cover, along with the projected increase in temperatures and intensification in duration and frequency of drought conditions [70][71] will lead to an increase in conditions prone to the occurrence of EWE. A new forecast system can help ensuring the development of appropriate spatial preparedness plans, proactive responses by the civil protection regarding firefighter's management, suppression efforts, and alert communities in order to minimize the detrimental impacts of wildfires in Portugal.…”

Flood Hazards in Flat Coastal Areas of the Eastern Iberian Peninsula: A Case Study in Oliva (Valencia, Spain)

“…The "cold drop" phenomenon or DANA generates clouds that reach 10 km in height and produce great rainfalls. A reduction in precipitation is expected due to climate change, which will tend to amplify desertification [53,54], but an intensification of extreme precipitation events is also expected [55]. Both phenomena may be devastating to some areas, causing flooding and erosions of great potential damage.…”

Holocene climates of the Iberian Peninsula: pollen-based reconstructions of changes in the west–east gradient of temperature and moisture

“…The Iberian Peninsula is characterized by a steep west-east gradient in temperature and moisture today, reflecting the dominance of maritime influences along the Atlantic coast and more Mediterranean-type climate further east. Projections of future climate change suggest that the region will become both warmer and drier, but nevertheless show that this west-east differentiation is maintained (Andrade et al, 2021a). The changes in temperature are projected to be larger and the occurrence of extreme temperature episodes more frequent in the south-central and eastern parts of Iberia than in Atlantic coastal areas (Carvalho et al, 2021).…”