Climatic potential and risks for apple growing by 2040

Summary

The impact of climatic change in 1971–2040 on the potential production areas and risks to nine apple cultivars (Malus domestica Borkh.) was studied over continental Finland using agro-climatic indices and gridded daily mean (Tm) and minimum temperatures from the Rossby Centre regional atmospheric climate model (RCA3) with SRES A2. Point data on daily minimum temperatures from 14 weather stations and low and high warming scenarios were also used. From the 1970’s to the present day, the areas of successful maturing of fruits have strongly expanded northwards. It is predicted that in 2011–2040, the warming of climate will allow expansion of commercial production in the south-eastern lake area, and a wider selection of cultivars for home gardens up to latitudes 65–66°N. Risk of extremely low temperatures (Tm< -26 °C) has reduced from 1980’s to the present but may not reduce much more in 2011–2040. Risk to shoots from fluctuating temperatures in winter and spring is likely to increase under the high warming scenario, more in the south-west than in the south-east. Risk to trees from cold days (Tm< -15 °C) with a concurrent thin snow cover is not predicted to increase. In the western inland of the country, below latitude 63°N, and in the south-western coast areas the frost risk during flowering may increase, especially in the early flowering cultivars. In order to adapt to and gain from the climatic change, breeding and testing targets should be modified within five years and they should include reduced sensitivity to temperature fluctuation in winter, late flowering, and frost tolerance of flowers.