evidence: A mini ice age could hit the Earth in the 2030s, the first such event to occur since the early 1700s. New mathematical models of the Sun's solar cycle developed at Northumbria University suggest solar activity will see a "significant" drop, causing temperatures on Earth to plummet. The last mini ice age occurred between 1645 and 1715 and caused temperatures in northern Europe to fall dramatically, with London's River Thames freezing over during winter and sea ice extending for miles around the UK. The prolonged cold snap, known as the Maunder Minimum, has been linked to a reduction in the number of sunspots, as observed by scientists at the time.