University of Reading researchers say a big drop in solar activity could confine the spectacular aurora borealis to the Arctic Circle within decades.
Study author Dr Mathew Owens said: “The magnetic activity of the sun ebbs and flows in predictable cycles, but there is also evidence that it is due to plummet, possibly by the largest amount for 300 years.
“If so, the Northern Lights phenomenon would become a natural show exclusive to the polar regions, due to a lack of solar wind forces that often make it visible at lower latitudes.”
Auroras are caused when energetic particles from the sun collide with molecules in Earth’s magnetic fields with the energy channelled towards the poles.
Strong solar winds enable the aurora to be visible at lower latitudes.
The Northern Lights – which encompass all sorts of colours from greens to purples and reds – can frequently be seen across large parts of the UK. Last year they were spotted as far south as Devon.
But the scientists now believe a marked reduction in the number of sunspots will lead to a decline in the solar activity which causes auroras.
A drop in the number of sunspots in the 17th century coincided with what is now known as the Maunder Minimum – or the ‘little ice age’.
During that period temperatures fell so much that the River Thames regularly froze over. Although global warming makes that scenario unlikely in future, a drop in the number of sunspots could suggest a coming fall in temperatures.
Study co-author Professor Mike Lockwood, also from the University of Reading, said: “If the decline in sunspots continues at this rate, and data from the past suggests that it will, we could see these changes occurring as early as the next few decades.”
The scientists, who published their research in the journal Scientific Reports, have also warned of damage to electrical equipment because the heliosphere – which acts as a bubble shielding Earth from the harmful effects of radiation from outer space – has shrunk significantly.
They claim the consequence is that although mass ejections of material from the sun’s surface may become less frequent, when they do happen they may cause more damage on Earth.