A mini ice age that would freeze major rivers could hit Britain in less than two decades, according to research from universities in the UK and Russia.
A mathematical model of the Sun's magnetic activity suggests temperatures could start dropping here from 2021, with the potential for winter skating on the River Thames by 2030.
A team led by maths professor Valentina Zharkova at Northumbria University built on work from Moscow to predict the movements of two magnetic waves produced by the Sun.
It predicts rapidly decreasing magnetic waves for three solar cycles beginning in 2021 and lasting 33 years.
Very low magnetic activity on the Sun correspond with historically documented cold periods on Earth.
Professor Zharkova claims 97% accuracy for the model which dovetails with previous mini ice ages, including the Maunder Minimum period from 1645 to 1715 when frost fairs were held on the frozen Thames.
But she cautions that her mathematical research cannot be used as proof that there will be a mini ice age this time around, not least because of global warming.
"I hope global warning will be overridden by this effect, giving humankind and the Earth 30 years to sort out our pollution," she said.
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But Professor Zharkova warned that any downward impact on global warming will last only until the Sun's two magnetic waves become active again in the 2050s.
"We have to be sorted by that time and prepare everything on Earth for the next big solar activity," she said.