The impact of global warming on Ontario’s icewine industry

Ontario’s wine regions lie at the climatic margins of commercial viticulture owing to their cold winters and short cool growing season. The gradual warming of northern latitudes projected under a human-induced climate change scenario could bring mixed benefits to these wine regions. On the one hand, climate change could moderate the severity of winter temperatures and extend the growing season and on the other, it could be jeopardize the production of internationally renowned icewines for which Canada is famous. This paper examines the trends in winter temperatures over the last forty years for the Niagara Peninsula wine region in Ontario. The study analyzes the occurrences of temperatures ≤ -8o C in the months of November, December, January and February in which the frozen grapes are normally picked. The results of trend analysis showed a high degree of variability along with a weak declining trend in the number of picking days. Two major risks to icewine grapes are prolonged warm and wet conditions that could lead to rot and secondly, destruction of the crop by bird predators. The study also discussed the potential use of weather contracts to mitigate these risks.