New research reveals the extent of shifting trends in floods and droughts across Europe over a period of seven decades. On average, climate change and variability contributed to a 0.5% rise in flood magnitude and a 6.6% drop in drought magnitude across Europe. However, these continental averages mask significant local variations driven by socio-economic factors.
The study, co-authored by the JRC, the Potsdam Institute for Climate Impact Research (PIK), the University of Szczecin and the University of Bologna, disentangles the individual impacts of climate, land use, reservoirs construction, and water use on Europe’s water extremes between 1951 and 2020. The results can support plans to improve resilience to floods and droughts, a key pillar of the European Water Resilience Strategy.
Regional climate dynamics
Since the 1950s, changing climate has created distinct regional hydrological trajectories across Europe:
- currently, Europe’s continental and Atlantic regions are experiencing a ‘wetting’ trend, marked by increased flood severity and reduced drought severity;
- the Mediterranean region is suffering a ‘drying’ trend, leading to intensified and prolonged droughts;
- the Alpine, mountainous regions are facing hydrological ‘acceleration’, where shifting snowpack and precipitation patterns increase the severity of both floods and droughts;
- in the Baltics and Scandinavia however, the trends show a slowdown of the intensity of droughts and floods.
How human activity reshapes local hazards
Socio-economic developments since 1950s have impacted the severity of floods and droughts locally, currently affecting 35% of the European river network.
Land use and urbanisation, expanding cities and sealed surfaces prevent water infiltration, accelerating runoff and worsening local flood peaks. Simultaneously, reforestation increases overall forest water uptake, which can lower river flows during dry spells.
The construction of hundreds of dams and reservoirs has affected 13% of the European river network. They act as stabilisers by reducing the severity of both floods and droughts. However, increased surface evaporation from large reservoirs reduces the total overall river volume.
Rising water demand also has an impact. Expanding water consumption, especially for domestic use, has intensified drought conditions in 10% of the river network. Domestic demand has steadily increased, becoming the largest water-use sector by 2020.
Background
The European Water Resilience Strategy aims to restore and protect the water cycle, including resilience against floods, droughts and water scarcity, improve water efficiency and secure clean and affordable water for all. By separating the influence of climate from that of land use, reservoirs and water consumption, this study shows where local pressures shape flood and drought hazards, helping authorities target measures where they will have the most effect.
The JRC also analyses climate change and its impact within the PESETA programme. The objective is to understand and assess a wide range of climate risks in Europe, among them risks to agriculture, energy, and water resources, and the associated socio-economic impact.
The PESETA programme has run since 2006 in support of European policymaking on climate mitigation and adaptation.
O artigo foi publicado originalmente em JRC.
