Droughts are defined in this analysis as periods of low river flow. The PESETA II report investigates how incidence of drought is projected to change under future climate conditions, and how people and cropland would be affected.
Methodology
The streamflow droughts analysis is based on hydrological simulations performed with the LISFLOOD model driven by the A1B ensemble of 12 climate realisations. Annual minimum flows are extracted from the daily LISFLOOD simulations for all river cells across Europe (Forzieri et al., 2014). The changes in drought frequency and magnitude were evaluated between the 2080s and control period. Climate impact indicators are expressed as total area of cropland affected and people exposed to droughts, which are defined as years where river flow is below the current 20 year minimum. As droughts are probabilistic events, the results are presented as expected annual impacts.
Main results and findings
The EU cropland area affected by droughts is projected to increase substantially under the A1B Reference climate simulation, reaching 700 000 km2/year, from nearly 100 000 km2/year in the control period. The highest absolute increase would occur in Southern Europe (from 27 000 km2/year to 365 000 km2/year) and Central Europe South (from 31 000 km2/year to 242 000 km2/year). In the UK & Ireland region the relative change is similar (almost six times more surface affected). In contrast, Northern Europe and Central Europe North show a reduction and a relatively small augmentation, respectively, in impacts on croplands in the future scenario, with respect to the control period.
In terms of people affected by drought, the Reference simulation could see an increase from 22 million/year in the control simulation to 144 million/year. The largest absolute increase would also occur in the Southern Europe region, with an increase of almost 70 million people/year. The Central Europe South and the UK & Ireland regions would also see the affected population increase by over five times. Interestingly, Central Europe North will experience much greater increase in people affected by drought than cropland.
Change in total area affected by drought due to climate change (SRES A1B scenario) between baseline period and current (a), 2020s (b), 2050s (c) and 2080s (d). Ensemble-median results based on 12 RCM/GCM combinations
References
Forzieri G, Feyen L, Rojas R, Flörke M, Wimmer F, Bianchi A (2014).
Ensemble projections of future streamflow droughts in Europe. Hydrology and Earth System Sciences, 18, 85-108.