The gene that causes red hair is thought to be an evolutionary response to cloudy skies and allows inhabitants to get as much Vitamin D as possible.
But if predictions of rising temperatures and blazing sunshine turn out to be correct, it could spell doom for carrot tops within a few centuries.
Last year it was revealed that red-headed individuals are 100 times more susceptible to developing melanoma, the deadly skin cancer which claims more than 2,000 lives a year in the UK.
A gene mutation that colours red hair and gives pale skin leaves DNA in skin cells more prone to be damaged by sunlight.
Dr Alistair Moffat, managing director of Galashiels-based ScotlandsDNA, said of the hypothesis: "We think red hair in Scotland, Ireland and in the north of England is adaption to the climate.
"If the climate is changing and it is to become more cloudy or less cloudy then this will affect the gene. If it was to get less cloudy and there was more sun, then yes, there would be fewer people carrying the gene."
Only one or two per cent of the world's population has red hair, but in Scotland this figure is about 13 per cent, with 650,000 people believed to have ginger hair.