Projected changes in the Iberian Peninsula drought characteristics

Area of Science:

• Climate Science
• Environmental Science
• Hydrology

Background:

• Droughts pose a significant threat to the Iberian Peninsula (IP).
• Understanding future drought characteristics is crucial for adaptation strategies.
• Previous projections often lack high spatial resolution.

Purpose of the Study:

• To project high spatial resolution drought characteristics for the Iberian Peninsula.
• To analyze changes in drought duration, frequency, and severity under different climate scenarios.
• To compare the performance of two drought indices in capturing these changes.

Main Methods:

• Utilized the Weather Research and Forecasting (WRF) model for regional climate simulations.
• Drove WRF with two Global Climate Models (CCSM4 and MPI-ESM-LR).
• Analyzed drought using Standardized Precipitation Evapotranspiration Index (SPEI) and Standardized Precipitation Index (SPI) at 3- and 12-month time scales under RCP4.5 and RCP8.5 scenarios for near (2021-2050) and far (2071-2100) futures.

Main Results:

• The Iberian Peninsula is projected to experience significantly longer and more severe droughts.
• Substantial changes in drought frequency, duration, and severity are expected across most of the IP by the end of the century, particularly under RCP8.5.
• The SPEI indicated more severe drought increases than the SPI, especially under high-emission scenarios, with a notable risk of megadroughts ( >15 years) by 2100.

Conclusions:

• Climate change will likely intensify drought conditions in the Iberian Peninsula.
• The choice of drought index (SPEI vs. SPI) influences the projected severity and risk, with SPEI showing more extreme outcomes.
• Urgent mitigation and adaptation measures are needed to address the escalating risk of severe and prolonged droughts, including potential megadroughts.