An assessment of the vulnerability of Scotland’s river catchments and coasts to the impacts of climate change: Work Package 2 Report

This report for the project ―An assessment of the vulnerability of Scotland’s river catchments and coasts to the impacts of climate change” covers Work Package 2. It presents a first idea of the additional flood risk under climate change for catchments across Scotland, based upon re-working and re-presenting Defra/EA FCERM project FD2020’s summary catchment-based results purely for those FD2020 catchments located in Scotland. Showing these results purely using Scottish catchments provides a much better summary of the potential range of impacts of climate change on flood flows in Scotland than is provided by the available FD2020 summaries, which use catchments across England, Wales and Scotland. The results use data from 16 x 4th Assessment Report Global Climate Models (GCMs) and 11 x UK Climate Projections 09 (UKCP09) Regional Climate Models (RCMs). As well as providing a first idea of the additional flood risk under climate change for catchments across Scotland, they show the variation in additional risk according to catchment type and location. Results are provided for the A1B (Medium) emissions scenario and the 2080s time-horizon. Although these results are presented in a quasi-probabilistic way, they are not truly probabilistic projections as their sample sizes are far too small. Work Package 1 of this project will use the truly probabilistic UKCP09 projections, along with the FD2020 key response patterns, to provide probabilistic estimates of impacts for the 10 UKCP09 river-basin regions in Scotland — North Highland, North-East Scotland, Tay, Forth, Tweed, Solway, Clyde, Argyll, West Highland, and Orkney and Shetland --- following the methodology of Defra/EA FCERM project FD2648. Work Package 1 will also present results for a range of time-horizons and emissions scenarios.