Climate Change Impact on the Magnitude and Timing of Hydrological Extremes Across Great Britain

Abstract

Climate change could intensify hydrological extremes, changing not just the magnitude but also the timing of flood and drought events. Understanding these potential future changes to hydrological extremes at the national level is critical to guide policy decisions and ensure adequate adaptation measures are put in place. Here, climate change impact on the magnitude and timing of extreme flows is modelled across Great Britain (GB), using an ensemble of climate data from the latest UK Climate Projections product (UKCP18) and a national grid-based hydrological model. All ensemble members show large reductions in low flows, of around −90 to −25% for 10-year return period low flows by 2050–2080. The direction of change for high flows is uncertain, but increases in 10-year return period high flows of over 9% are possible across most of the country. Simultaneous worsening of both extremes (i.e., a reduction in low flows combined with an increase in high flows) are projected in the west. Changes to flow timing are also projected; with mostly earlier annual maximum flows across Scotland, later annual maximum flows across England and Wales, and later low flows across GB. However, these changes are generally not statistically significant due to the high interannual variability of annual maximum/minimum flow timing. These results highlight the need for adaptation strategies that can cope with a wide range of future changes in hydrological extremes, and consider changes in the timing as well as magnitude.

EURO-CORDEX: A Multi-Model Ensemble Fit for Assessing Future Hydrological Change?

“…Consequently, changes in climate will invariably lead to alterations of river flow regimes (Rahel and Olden, 2008;Arnell and Gosling, 2016). Recent research by the authors have investigated the impact of these changes on the river flow regime in terms of future flood and drought magnitude, duration, and frequency (Collet et al, 2017(Collet et al, , 2018Visser-Quinn et al, 2019aEllis et al, 2021), which is also corroborated by other authors (Kay, 2021;Lane and Kay, 2021). The work on changing extremes in the UK indicates the threats faced at a regional level, as well as more widely across Europe (Marx et al, 2018) are likely to intensify in the coming decades.…”

Climate change impacts on socio-hydrological spaces of the Brahmaputra floodplain in Assam, Northeast India: A review

“…Global warming and resultant climate change are altering the magnitude and timing of hydrological hazards (Lane and Kay, 2021), putting additional stress on agriculture. Therefore, disaster management should be considered an integral part of agricultural management strategies.…”

“…Global studies suggest that climate change could increase the risk of hydrological disasters in the future (Van Aalst, 2006;Lane and Kay, 2021). The fluvial processes of the Brahmaputra River and its tributaries continuously alter the floodplains, at times to an undesired magnitude (Sarma and Phukan, 2004;Kotoky et al, 2005Kotoky et al, , 2012Das et al, 2012;Lahiri and Sinha, 2012).…”

Differences in hydrological impacts using regional climate model and nested convection-permitting model data

“…Previous application of the UKCP18 RCM ensemble has suggested large decreases in summer and extreme low flows across Britain, but possible increases in winter and extreme high flows, especially in the north and west (Kay 2021;Lane & Kay 2021). The main reason for developing CPM projections in the UK was to enable investigation of potential future changes in extreme summer storms (Orr et al 2021).…”