Revisiting the recent European droughts from a long-term perspective

Abstract

Early 21st-century droughts in Europe have been broadly regarded as exceptionally severe, substantially affecting a wide range of socio-economic sectors. These extreme events were linked mainly to increases in temperature and record-breaking heatwaves that have been influencing Europe since 2000, in combination with a lack of precipitation during the summer months. Drought propagated through all respective compartments of the hydrological cycle, involving low runoff and prolonged soil moisture deficits. What if these recent droughts are not as extreme as previously thought? Using reconstructed droughts over the last 250 years, we show that although the 2003 and 2015 droughts may be regarded as the most extreme droughts driven by precipitation deficits during the vegetation period, their spatial extent and severity at a long-term European scale are less uncommon. This conclusion is evident in our concurrent investigation of three major drought types – meteorological (precipitation), agricultural (soil moisture) and hydrological (grid-scale runoff) droughts. Additionally, unprecedented drying trends for soil moisture and corresponding increases in the frequency of agricultural droughts are also observed, reflecting the recurring periods of high temperatures. Since intense and extended meteorological droughts may reemerge in the future, our study highlights concerns regarding the impacts of such extreme events when combined with persistent decrease in European soil moisture.

North Atlantic Multidecadal Variability Enhancing Decadal Extratropical Extremes in Boreal Late Summer in the Early Twenty-First Century

“…As for eastern Europe, highfrequency extremes mainly appear in 1972-84 and 1996-2015, exhibiting a decadal variation. After 2000, there is an increasing trend of droughts, similar to the suggestion of Hanel et al (2018). Figure 1 also marks selected extremes in six regions, with higher than mean frequency after 2000.…”

A 250‐Year European Drought Inventory Derived From Ensemble Hydrologic Modeling

“…The same event has also been identified by Hanel et al (2018) as one of the most extreme drought events in the last 250 years. Considering these facts, droughts affecting large areas are likely to develop as both runoff and soil moisture droughts (dashed line-bordered boxes; Figures S5 and S6).…”

“…However, there are also some dry years in which drought is initiated without a significant deficit in precipitation. This is the case with the intense 1953–1954 drought in the Mediterranean, which similarly to the 1921–1922 event, has been regarded as one of the most severe droughts of the twentieth century (Hanel et al, ; Spinoni et al, ). It can be seen that even though more than half of the ensemble members are above the 90th quantile for runoff and soil moisture, the precipitation lies between the 50th and 90th quantiles (Figures S5 and S6, lower panel).…”

“…In particular, the application of these techniques will help improve our comprehension of complex, multivariate climate phenomena. Future studies should account for the modeling uncertainty dealing with drought reconstructions, including the effect of the two input data sets (Casty et al, ; Harris et al, ) in the original study (Hanel et al, ). Despite the underlying uncertainties, the developed drought inventory provides valuable information on long‐term historical changes in mean hydroclimate and its variability (major drought events) across Europe.…”

Moving beyond the catchment scale: Value and opportunities in large‐scale hydrology to understand our changing world

“…This is reflected by the aforementioned difficulty of separating human influence from natural drivers of hydrological drought (Van Loon et al, , ). For such reasons, endeavours such as large‐scale hydrological data rescue (e.g., Le Gros et al, ), reconstructing long‐term and large‐scale high‐resolution climate datasets (Devers, Vidal, Lauvernet, Graff, & Vannier, ) and corresponding near‐natural hydrological datasets (e.g., Hanel et al, ; Moravec, Markonis, Rakovec, Kumar, & Hanel, ) are central in understanding the large temporal and spatial variations of hydrology. Compatibility between, or merging of, national‐scale datasets (e.g., Caillouet, Vidal, Sauquet, Graff, & Soubeyroux, ; Keller et al, ) would be a further advance, as would improved quality assessment of large repositories such as the Global Runoff Data Centre under the auspices of the World Meteorological Organisation.…”