Impacts of climate change on European hydrology at 1.5, 2 and 3 degrees mean global warming above preindustrial level

Abstract

Impacts of climate change at 1.5, 2 and 3°C mean global warming above preindustrial level are investigated and compared for runoff, discharge and snowpack in Europe. Ensembles of climate projections representing each of the warming levels were assembled to describe the hydro-meteorological climate at 1.5, 2 and 3°C. These ensembles were then used to force an ensemble of five hydrological models and changes to hydrological indicators were calculated. It is seen that there are clear changes in local impacts on evapotranspiration, mean, low and high runoff and snow water equivalent between a 1.5, 2 and 3°C degree warmer world. In a warmer world, the hydrological impacts of climate change are more intense and spatially more extensive. Robust increases in runoff affect the Scandinavian mountains at 1.5°C, but at 3°C extend over most of Norway, Sweden and northern Poland. At 3°C, Norway is affected by robust changes in all indicators. Decreases in mean annual runoff are seen only in Portugal at 1.5°C warming, but at 3°C warming, decreases to runoff are seen around the entire Iberian coast, the Balkan Coast and parts of the French coast. In affected parts of Europe, there is a distinct increase in the changes to mean, low and high runoff at 2°C compared to 1.5°C, strengthening the case for mitigation to lower levels of global warming. Between 2 and 3°C, the changes in low and high runoff levels continue to increase, but the Climatic Change (2017) 143: 13-26 DOI 10.100713-26 DOI 10. /s10584-017-1971 Electronic supplementary material The online version of this article (doi:10.1007/s10584-017-1971-7) contains supplementary material, which is available to authorized users.

Climate change alters low flows in Europe under global warming of 1.5, 2, and 3 °C

“…Our study shows contrasting results for the Mediterranean region compared to Donnelly et al (2017) under different levels of warming. At global warming of 3 K, large decreases of up to −35 % and high robustness (very likely) are observed here, whereas no projected changes in absolute gridspecific runoff values with little robustness was reported by Donnelly et al (2017).…”

“…At global warming of 3 K, large decreases of up to −35 % and high robustness (very likely) are observed here, whereas no projected changes in absolute gridspecific runoff values with little robustness was reported by Donnelly et al (2017). These differences can be explained through methodological choices of low-flow indices used between the two studies.…”

“…This holds especially true in drier regions, which are characterized by very small Q90 runoff values. From a practitioner point of view, our study highlights the need for adaptation to climate-induced low flows in these regions, which would not be concluded based on the metrics reported in Donnelly et al (2017).…”

“…the difference between the 25th and 75th percentile). It has been shown in recent literature that both GCMs and HMs contribute to the uncertainty in projected changes Donnelly et al, 2017;Hattermann et al, 2017). In this study, the sequential sampling approach of Samaniego et al (2017a), following Schewe et al (2014), is applied.…”

European climate change at global mean temperature increases of 1.5 and 2 °C above pre-industrial conditions as simulated by the EURO-CORDEX regional climate models

“…Vautard et al 2014;Maule et al 2017) and in impact studies (e.g. Alfieri et al 2015;Donnelly et al 2017). However, previous studies have either been based on earlier RCM ensembles or only on smaller subsets of the full EURO-CORDEX set of RCM simulations.…”