Evidence of increasing drought severity caused by temperature rise in southern Europe

Abstract

We use high quality climate data from ground meteorological stations in the Iberian Peninsula (IP) and robust drought indices to confirm that drought severity has increased in the past five decades, as a consequence of greater atmospheric evaporative demand resulting from temperature rise. Increased drought severity is independent of the model used to quantify the reference evapotranspiration. We have also focused on drought impacts to drought-sensitive systems, such as river discharge, by analyzing streamflow data for 287 rivers in the IP, and found that hydrological drought frequency and severity have also increased in the past five decades in natural, regulated and highly regulated basins. Recent positive trend in the atmospheric water demand has had a direct influence on the temporal evolution of streamflows, clearly identified during the warm season, in which higher evapotranspiration rates are recorded. This pattern of increase in evaporative demand and greater drought severity is probably applicable to other semiarid regions of the world, including other Mediterranean areas, the Sahel, southern Australia and South Africa, and can be expected to increasingly compromise water supplies and cause political, social and economic tensions among regions in the near future.

Drought Trends in the Iberian Peninsula over the Last 112 Years

“…In the last decades, the severity of droughts in the IP has increased, together with an increased tendency for dryness and decrease of vegetation cover, due to the higher atmospheric evaporative demand [28,37]. These agree with the findings of Greve et al [38] that identified the Southwest of the IP as one hot spot of the pattern "dry gets drier."…”

“…Different sources of data have been used to compute drought indicators including observations from meteorological stations [26][27][28], gridded datasets [22,29], and reanalysis datasets [30]. Several authors have provided evidences of an increasing number of droughts forced by higher temperatures and enhanced dry conditions [28,31,32].…”

Adaptation Strategy to Mitigate the Impact of Climate Change on Water Resources in Arid and Semi-Arid Regions: a Case Study

“…A high number of meteorological drought indices with different intricacy have been utilised in various climatic conditions . Latest drought trend studies (Sheffield et al 2012;Vicente-Serrano et al 2014) and drought scenarios under possible climate change predictions (e.g., Cook et al 2014) depend on indices that take into consideration evapotranspiration and precipitation such as the reconnaissance drought index (RDI), which is considered in this study.…”

Improving water use efficiency of vineyards in semi-arid regions. A review

“…In dry areas, water use by irrigation scheduling can be a compromise for environmental sustainability of the crop and sometimes be a competition with other critical human uses ). Moreover, evaporative demand is expected to increase as a consequence of increased global air temperature (Vicente-Serrano et al 2014) and intensity of climatic anomalies, such as droughts and heat waves (IPCC 2013;Jones and Vaughan 2010). These effects could only be alleviated with higher transpiration rates to lower leaf temperature.…”