Climate change projections for UK viticulture to 2040: a focus on improving suitability for Pinot noir

Between 1981-2000 and 1999-2018, growing season average temperatures (GST) in the main UK viticulture regions have warmed similar to 1.0 degrees C and are now more reliably > 14.0 degrees C GST. This warming has underpinned the rapid expansion of the UK viticulture sector and its current focus on growing grape varieties for sparkling wine. Near-term (2021-2040) climate change may condition opportunities for further variety and/or wine style changes. Using the latest high -resolution (5 km) ensemble (x 12) of downscaled climate change models for the UK (UK Climate Projections; UKCP18) under Representative Concentration Pathway (RCP) 8.5, we calculate near-term trends and variability in bioclimatic indices (BCIs). We simulate the projected repetition of the UK's highest yielding season-2018-and use an analogue approach to model the 1999-2018 mean growing season temperatures from Pinot noir producing areas of Champagne (France), Burgundy (France) and Baden (Germany) over the UK during 2021-2040. We also project, across the UK for the 2021-2040 period, BCI values of recent high-quality vintage years from Champagne and Burgundy. GST are projected to increase from a 1999-2018 spatial range of 13.0 (minimum threshold)-15.7 degrees C to a future (2021-2040) range of 13.0-17.0 degrees C, and Growing Degree Days (GDD) from 850 (minimum threshold)-1267 to 850-1515. Growing season precipitation (GSP) is projected to decline in some UK viticulture areas but is not modelled as a limiting viticulture factor. High inter-annual weather variability is simulated to remain a feature of the UK viticulture climate and early season frost risk is likely to occur earlier. Large areas of the UK are projected to have > 50 % of years within the bioclimatic ranges experienced during the 2018 growing season, indicating potential higher yields in the future. The 1999-2018 mean Champagne, Burgundy and Baden GST and GDD are projected for much of England and some areas in the far south and south-east of Wales during 2021- 2040, with significant areas projected to have > 25 % of years within the BCI ranges of top Champagne vintages. These results indicate greater potential for Pinot noir for sparkling wines and shifting suitability to still red wine production. Accounting for changes in variety suitability and wine styles will be essential to maximise opportunities and build resilience within this rapidly expanding wine region.