Quantification of the Effects of Droughts on Daily Mortality in Spain at Different Timescales at Regional and National Levels: A Meta-Analysis.

Coral Salvador,Julio Díaz,Cristina Linares,Luis Gimeno,Raquel Nieto

doi:10.3390/ijerph17176114

Abstract

A performance assessment of two different indices (the Standardized Precipitation Index (SPI) and the Standardized Precipitation Evapotranspiration Index (SPEI)) for monitoring short-term and short–medium-term drought impacts on daily specific-cause mortality in Spain was conducted. To achieve a comprehensive, nationwide view, a meta-analysis was performed using a combination of provincial relative risks (RRs). Moreover, the subdivisions of Spain based on administrative, climatic, and demographic criteria to obtain the measures of combined risks were also taken into account. The results of the SPEI and SPI calculated at the same timescale were similar. Both showed that longer drought events produced greater RR values, for respiratory mortality. However, at the local administrative level, Galicia, Castilla-y-Leon, and Extremadura showed the greatest risk of daily mortality associated with drought episodes, with Andalucía, País Vasco, and other communities being notably impacted. Based on climatic regionalization, Northwest, Central, and Southern Spain were the regions most affected by different drought conditions for all analyzed causes of daily mortality, while the Mediterranean coastal region was less affected. Demographically, the regions with the highest proportion of people aged 65 years of age and over reflected the greatest risk of daily natural, circulatory, and respiratory mortality associated with drought episodes.

Highlights

Drought is a complex phenomenon that occurs due to a deficiency of precipitation over an extended period of time
Mortality is represented by the number of deaths in the capital city and towns with over 10,000 inhabitants, and it was provided by the National Institute of Statistics (INE) of
The results obtained using both indices at the same timescale were generally very similar; differences in the magnitude of daily mortality risks associated with the use of the different timescales for Standardized Precipitation Evapotranspiration Index (SPEI) and Standardized Precipitation Index (SPI) were found, the differences were not significant

Summary

Introduction

Drought is a complex phenomenon that occurs due to a deficiency of precipitation over an extended period of time It can be promoted by an increase in evapotranspiration associated with the incidence of high temperatures, strong winds, or low humidity, causing a significant hydrological imbalance [1,2]. The response of environmental systems to the occurrence of this hydrologically extreme phenomenon can vary according to the time period in which it is measured For this reason, evaluating the performance of different types of drought indices and the sensitivity of the response to different timescales is important for predicting and quantifying drought impacts on a specific system or sector, such as human health. Drought effects can be typically classified as direct, commonly referred to as the reduction of water quantity and quality, reduced crop and

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