The great swathes of caravans packed with holiday-makers and sun-seekers heading south on the A303 and M5 each summer provide a fairly strong indication of the warmer weather that Cornwall enjoys compared to most of the country. In fact, since 2000, a warming climate means that parts of the county have found themselves experiencing temperatures in excess of 10°C for more then seven months in a year, which qualifies them ‘subtropical’ status, compared to the ‘temperate’ zone the majority of the UK finds itself in.

The impacts of this new climate stretch far beyond simply more money going through the cash registers of B&Bs in Newquay and St Ives. New research conducted by the University of Exeter's Environment and Sustainability Institute in Penryn has enabled them to identify particularly mild parts of the landscape that would be most suitable for growing unusual crops normally associated with far warmer climates. Examples of such crops include quinoa and Japanese persimmon, both of which require warmer optimum growing conditions that the low temperatures which Cornwall would historically have been able to offer.

Could quinoa plantations start appearing in subtropical Cornwall? (Image: Marisa Estivill)

Using new techniques for modelling local microclimates, analysing the effects of terrain, sea temperatures, altitude and soil properties to predict local temperatures, researchers located sheltered coastal valleys (protected from the coldest temperatures by the more stable sea temperatures) and south-facing slopes as being significantly warmer than the surrounding landscape. As Cornwall has become both sunnier and warmer, these spots have warmed the fastest, making them prime locations for local horticulturalists to consider for diversifying Cornwall's agriculture.

‘While sub-tropical conditions may create opportunities to grow exotic crops, the lower frequency of frosts is also making Cornwall more susceptible to invasive species,’ warns Dr Ilya Maclean, a Senior Lecturer in Natural Environment, who led the research. ‘As the temperatures continue to warm, we need to ensure we manage the risks carefully as well as capitalising on the opportunities. This will require scientists to continue to work hand-in-hand with the horticultural sector.’