preprints.org > environmental and earth sciences > environmental science > doi: 10.20944/preprints201912.0092.v2

Preprint Article Version 2 Preserved in Portico This version is not peer-reviewed

Version 1 : Received: 6 December 2019 / Approved: 7 December 2019 / Online: 7 December 2019 (12:22:44 CET)
Version 2 : Received: 15 January 2020 / Approved: 16 January 2020 / Online: 16 January 2020 (02:56:30 CET)

The outcomes of the 2015 Paris Agreement triggered a number of climate impact assessments, such as for floods and droughts, to focus on future time frames corresponding to the years of reaching specific levels of global warming. Yet, the links between the timing of the warming levels and the corresponding greenhouse gas concentration pathways to reach them, remain poorly understood. To address this gap, we compare projected changes of annual mean, extreme high and extreme low river discharges in Europe at 1.5°C and 2°C under scenarios RCP8.5 and RCP4.5 from an ensemble of Regional Climate Model (RCM) simulations. The statistical significance of the difference between the two scenarios for both warming levels is then evaluated. Results show that in the majority of Europe (>95% of the surface area for the annual mean discharge, >98% for high and low extremes), the changes projected in the two pathways are statistically indistinguishable. These results suggest that in studies of changes at specific warming levels the projections of the two pathways can be merged into a single ensemble without major loss of information. With regard to the uncertainty of the unified ensemble, findings show that the projected changes of annual mean, extreme high and extreme low river discharge are statistically significant in large portions of Europe.

climate change; warming levels; river runoff; extremes; emission pathway; LISFLOOD; Europe; PESETA project; climate adaptation

Environmental and Earth Sciences, Environmental Science

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