Climate records studied by East Malling Research indicate that the amount of winter chill across the UK has fallen since 1913. In the south east it has been most dramatic. Winter chill a prolonged period when the temperature stays above freezing but below 7C is vital to the success of crops such as apples, pears and blackcurrants.
"Climate scenarios of the future suggest that, as concentrations of greenhouse gases continue to rise and global temperatures increase, the amount of chill the UK receives will decline further," said EMR head of science Chris Atkinson.
Fewer winter chill days would result in a change in the fruit varieties that could thrive in the south east, said Atkinson. "As the south east fails to deliver the period of chill and dormancy required for maximising the yield of commercial perennial crops, the traditional varieties will likely be disappearing or migrating north to chillier or longer winters," he said.
Forty years ago sweet cherries would only grow in Kent and Cornwall but are now able to survive in the UK outside those areas.
Atkinson is urging producers to explore alternative fruit cultivars, or novel replacement crops with lower chill requirements.
"UK grape production is increasing and this crop generally has a much lower chilling requirement than traditional tree fruits, particularly apples."
Hardy kiwis also potentially had lower winter chill requirements, he added.