Diverging hydrological drought traits over Europe with global warming

Abstract

Abstract. Climate change is anticipated to alter the demand and supply of water at the earth's surface. Since many societal impacts from a lack of water happen under drought conditions, it is important to understand how droughts may develop with climate change. This study shows how hydrological droughts will change across Europe with increasing global warming levels (GWLs of 1.5, 2, and 3 K above pre-industrial temperature). We employed a low-flow analysis based on river discharge simulations of the LISFLOOD (De Roo et al., 2000) spatially distributed physically based hydrological and water use model, which was forced with a large ensemble of regional climate model projections under high emissions (RCP8.5) and moderate mitigation (RCP4.5) Representative Concentration Pathways. Different traits of drought, including severity, duration, and frequency, were investigated using the threshold level method. The projected changes in these traits identify four main sub-regions in Europe that are characterized by somehow homogeneous and distinct behaviours with a clear south-west–north-east contrast. The Mediterranean and Boreal sub-regions (defined in Sect. 3.1.1) of Europe show strong but opposite changes at all three GWLs, with the former area mostly characterized by stronger droughts (with larger differences at 3 K), while the latter is expected to experience a reduction in all drought traits. In the Atlantic and Continental sub-regions, the changes are expected to be less marked and characterized by a larger uncertainty, especially at the 1.5 and 2 K GWLs. Combining the projections in drought hazard with population and agricultural information shows that with 3 K global warming an additional 11 million people and 4.5 ×106 ha of agricultural land are projected to be exposed to droughts every year, on average, with the most affected areas located in the Mediterranean and Atlantic regions of Europe.

Impacts of Global Climate Warming on Meteorological and Hydrological Droughts and Their Propagations

“…Besides, the stationary assumption is made within a given time window (typically 30 years) for the historical and future climate in most of the drought projection studies (Cammalleri et al, 2020;Gu, Chen, Yin, Sullivan, et al, 2020;Naumann et al, 2018). However, the stationarity assumption for the future period is challenged in the global warming context, especially when a long time period is selected Jehanzaib et al, 2020;Mukherjee et al, 2018).…”

“…They found that drought risks are projected to increase significantly for warming levels in the Mediterranean, central Europe, the Amazon, southern Africa, and Southern Australia relative to the present-day reference period . Cammalleri et al (2020) investigated the changes in hydrological droughts over Europe under 1.5, 2, and 3°C warming levels, and they found an opposite tendency in the Mediterranean and Boreal sub-regions of Europe in warmer climates. Specifically, the former region is projected to suffer an exacerbated drought condition with the temperature rising, while that in the latter region will be relieved.…”

“…They found that the historical 50-year droughts may double over half of the global surface land under 1.5°C warming level and the magnitude wound increase by about 9% for an additional 0.5°C. Since the approval of the Paris Agreement, especially after recognizing that the speed of global warming has not slowed down in the past few years, researchers have had to focus on what if the unprecedented global warming exceeding 2.0°C (Aadhar & Mishra, 2019;Cammalleri et al, 2020;Ji et al, 2020). For example, Cammalleri et al (2020) assessed the variation in hydrological droughts from aspects of drought severity, duration, and frequency over Europe under 1.5, 2.0, and 3.0°C warming levels.…”

“…Since the approval of the Paris Agreement, especially after recognizing that the speed of global warming has not slowed down in the past few years, researchers have had to focus on what if the unprecedented global warming exceeding 2.0°C (Aadhar & Mishra, 2019;Cammalleri et al, 2020;Ji et al, 2020). For example, Cammalleri et al (2020) assessed the variation in hydrological droughts from aspects of drought severity, duration, and frequency over Europe under 1.5, 2.0, and 3.0°C warming levels. They found that the changes in drought characteristics would be similar but more pronounced under warmer levels.…”

Directions and Extent of Flows Changes in Warta River Basin (Poland) in the Context of the Efficiency of Run-of-River Hydropower Plants and the Perspectives for Their Future Development

“…Increases in water consumption may even be of the same magnitude as the projected impact of climate change [35]. Meanwhile, according to Cammalleri et al [36], the projected increases in water demand may play a more critical role in the future than climate change in continental subregions of Europe. In the dry Mediterranean climate, projections indicate that flows are probably lower in all months of the year.…”