climate Article Climate Change Projections of Dry and Wet Events in Iberia Based on the WASP-Index Cristina Andrade 1,2, * , Joana Contente 1 and João A. Santos 2   Citation: Andrade, C.; Contente, J.; Santos, J.A. Climate Change Projections of Dry and Wet Events in Iberia Based on the WASP-Index. Climate 2021, 9, 94. https://doi.org/ 10.3390/cli9060094 Academic Editor: Steven McNulty Received: 20 April 2021 Accepted: 8 June 2021 Published: 10 June 2021 Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affil- iations. Copyright: © 2021 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). 1 Natural Hazards Research Center (NHRC.ipt), Instituto Politécnico de Tomar, Quinta do Contador, Estrada da Serra, 2300-313 Tomar, Portugal; joana.contente@ipt.pt 2 Centre for the Research and Technology of Agro-Environmental and Biological Sciences (CITAB), University of Trás-os-Montes e Alto Douro, P.O. Box 1013, 5001-801 Vila Real, Portugal; jsantos@utad.pt * Correspondence: c.andrade@ipt.pt; Tel.: +351-249-328-100 Abstract: The Weighted Anomaly of Standardized Precipitation Index (WASP-Index) was computed over Iberia for three monthly timescales (3-month, 6-month and 12-month) in 1961–2020, based on an observational gridded precipitation dataset (E-OBS), and between 2021 and 2070, based on bias- corrected precipitation generated by a six-member climate model ensemble from EURO-CORDEX, under two Representative Concentration Pathways (RCPs), RCP4.5 and RCP8.5. The area-mean values revealed an upward trend in the frequency of occurrence of intermediate-to-severe dry events over Iberia, which will be strengthened in the future, particularly for the 12-month WASP (12m- WASP) intermediate dry events under RCP8.5. Besides, the number of 3-month WASP (3m-WASP) intermediate-to-severe wet events is projected to increase (mostly the severest events under RCP4.5) but no evidence was found for an increase in the number of more persistent 12m-WASP wet events under both RCPs. Despite important spatial heterogeneities, an increase/decrease of the intensity, duration and frequency of occurrence of the 12m-WASP intermediate-to-severe dry/wet events was found under both scenarios, mainly in the southernmost regions of Iberia (mainly Comunidad Valenciana, Región de Murcia, Andalucía in Spain, Alentejo, and Algarve in Portugal), thus becoming more exposed to prolonged and severe droughts in the future. This finding corroborates the results of previous studies. Keywords: WASP-Index; climate change; projections; extreme precipitation; Iberian Peninsula 1. Introduction It is commonly accepted that climate change has a direct link to the increasing fre- quency and intensity of extreme events [1]. Projected increases in temperature [2–4] and alterations in precipitation patterns will be accompanied by more frequent and intense droughts, as well as floods [5]. These extreme events can have a deep impact on the econ- omy [6–8], agriculture [9,10] and the environment [11]. Therefore, a better understanding of their future projections in regions more vulnerable to climatic shifts is of utmost relevance. Drought can be defined as a prolonged absence of precipitation leading to a deficit in natural water availability [12]. However, four different types of droughts can be defined in an increasing severity grade: meteorological, agricultural, hydrological and socioeconomic. Meteorological drought is caused by a precipitation deficit with respect to the climatological average of a region; agricultural drought occurs when the soil moisture is too scarce to sustain crop production, and hydrological drought is caused by weak stream flows leading to low water levels in rivers, lakes and reservoirs. Lastly, socioeconomic drought can be defined as the consequence of the above-mentioned drought types, resulting in a lack of water supply to produce or sustain an economic good or service [13,14]. Floods are one of the most recurrent natural hazards in the world [15] and can be defined, to a certain extent, as the opposite of droughts as an excess of precipitation relative to the climatological average in a given region, promoting a rise of water levels in rivers, lakes and reservoirs. Climate 2021, 9, 94. https://doi.org/10.3390/cli9060094 https://www.mdpi.com/journal/climate