Climate change impact assessment on grape growth and wine production in the Okanagan Valley (Canada)

This study assesses the impacts of observed (1970–2019) and projected (2011–2100) climate change on key indicators and critical thresholds for grape growth (viticulture) and wine production (oenology) in the Okanagan Valley of British Columbia (Canada). Observational data was retrieved from the Kelowna weather station located in the centre of the valley. Indicators and thresholds associated with climate risks and climatic suitability were identified from among previous impact assessments on grape and wine within cool climate viticultural areas. Climate change projections from Global Climate Models were retrieved from the Climate Model Intercomparison Project 5, including both medium (RCP4.5) and high (RCP8.5) Representative Concentration Pathways. Two different statistical downscaling techniques were employed, evaluated, and selected, based on their ability to reproduce historical climate conditions. Scenarios from the Statistical Down-Scaling Model were used for temperature projections while scenarios from the Pacific Climate Impacts Consortium were used for precipitation projections. All the temperature variables considered demonstrated statistically significant warming trends during the historical period with continued warming projected over the course of the 21st century. Precipitation trends were less conclusive, with a wetter climate projected despite some evidence of historical drying. The results of this study demonstrate that the Okanagan Valley has already transitioned from cool to intermediate climate viticulture and may shift further into warm climate viticultural classifications. This means greater climate risks associated with heat stress but less risk due to freeze damage and frost potential. Effective climate change adaptation is of critical importance to the grape and wine industry in this region. Such planning and management strategies can ensure climate risks are minimised while capitalising on new opportunities associated with improved climatic suitability for growing more Europeans grape varieties, capable of producing higher quality wines, which often sell for greater market prices