Only 1 to 2 percent of people in the world have red hair — and that number could continue to decrease due to climate change, scientists warn.

In Scotland, 13 percent of the population has red hair, which is believed to be an evolutionary response to the lack of sun. If temperatures continue to rise and the sun isn't blocked as often by clouds, the gene responsible for red hair could regress.

"We think red hair in Scotland, Ireland, and in the north of England is adaption to the climate," Dr. Alistair Moffat, managing director of ScotlandsDNA, tells Britain's The Independent. "I think the reason for light skin and red hair is that we do not get enough sun and we have to get all the vitamin D we can."

Moffat is worried that with climate change, the number of cloudy days will decrease. "If there was more sun, then yes, there would be fewer people carrying the gene," he said.

Another scientist who asked to remain anonymous agreed that the gene is slowly dying out, but suggested it will take several hundred years for that to happen. "Red hair and blue eyes are not adapted to a warm climate," the scientist said. "It is just a theory, but the recessive gene may likely be lost. The recessive gene could be in danger." Catherine Garcia