Changes in population exposure to drought in the Iberian Peninsula under 1.5 and 2 GWLs

In the context of escalating temperatures under climate change conditions, drought events are growing globally, particularly affecting Mediterranean Europe, a recognized climate change 'hotspot'. Consequently, the vulnerability of ecosystems and human populations is increasingly pronounced in areas such as the Iberian Peninsula (IP).This study delves into the repercussions of 1.5 and 2C Global Warming Levels (GWL) by the end of the 21st century on drought occurrences and population exposure in the IP. Utilizing EURO-CORDEX experiments, incorporating 13 simulations as a weighted multi-variable multi-model ensemble, spanning historical periods, 1.5 and 2C GWL years, and projections for the end of the century, this research employs the Standardized Precipitation Index (SPI) and the Standardized Precipitation-Evapotranspiration Index (SPEI) to assess droughts. Three greenhouse gas emission scenarios are considered alongside demographic projections up to 2100 for Portugal and Spain (RCP2.6, RCP4.5 and RCP8.5).Under the RCP8.5 scenario, a significant increase in moderate, severe, and extreme droughts is anticipated, with SPI and SPEI projections indicating a substantial rise in drought occurrences due to additional warming. Population exposure to extreme droughts is projected to be higher under the 2C scenario, emphasizing the impact of rising temperatures in the IP. By the end of the century, population exposure to extreme droughts could surge by varying percentages, particularly under RCPs 4.5 and 8.5. The study highlights a projected surge in population exposure to droughts across the IP, primarily driven by climate change. These findings stress the critical need for regional authorities, policymakers, and society to prioritize adaptation planning and enhance understanding of vulnerabilities to tackle challenges posed by dry extreme events.This work was funded by the Portuguese Fundao para a Cincia e a Tecnologia (FCT) I.P./MCTES through national funds (PIDDAC) UIDB/50019/2020 (https://doi.org/10.54499/UIDB/50019/2020), UIDP/50019/2020 (https://doi.org/10.54499/UIDP/50019/2020) and LA/P/0068/2020 (https://doi.org/10.54499/LA/P/0068/2020). This work was performed under the scope of projecthttps://doi.org/10.54499/2022.09185.PTDC(DHEFEUS) and supported by national funds through FCT. DL and AR acknowledge FCT I.P./MCTES (Fundao para a Cincia e a Tecnologia) for the FCT, 2022.03183.CEECIND/CP1715/CT0004 (https://doi.org/10.54499/2022.03183.CEECIND/CP1715/CT0004) and (https://doi.org/10.54499/2022.01167.CEECIND/CP1722/CT0006(Complex), respectively.