We’re in winter now, and some of us may be feeling the chill. But it could be worse. It has been worse. And it will be worse again…
Throughout Earth’s 4.5 billion years, there have been five big ice ages, some of which lasted hundreds of millions of years. The most recent major ice age occurred in the Pleistocene period, about 2.6 million years ago, and lasted until about 11,700 years ago. Researchers are still trying to understand how often these periods of deep winter happen and how soon we can expect another one.
Across various periods of time, a quarter of our planet’s history has been held in the grip of a major ice event.. In between these ice ages, there have also been many smaller ice ages called glacials, and therefore some warmer periods, called inter-glacials.
The last mini ice age, which scientists call the Maunder Minimum, plunged the northern hemisphere into a series of bitterly cold winters between 1645 and 1715. It was caused by incredibly low solar activity. During the Maunder Minimum, the River Thames froze solid. The ice was so thick that the people of London could walk or skate from one side to the other without needing a bridge (as depicted above). However, although the winters were much colder than average, they were not life-threatening as they would have been in a ‘big’ ice age; If the citizens of the Seventeenth and Early Eighteenth century could survive the extreme cold without any form of central heating, then the next mini ice age will not be deadly for the human race.
It is a steady, severe drop in levels of sunshine that brings on a mini ices age. Solar expert Piers Corbyn, of forecasting group WeatherAction, warned that the Earth faces another mini ice age. “We are now in a decline of solar activity… This can cause a shift in the jet-stream, making it move further south and as a result it turns very cold in temperate latitudes including Europe, Britain and North America. We are anticipating temperatures to drop leading to ocean water freezing and ice drifts washing up around the coasts in Europe – we expect the next mini ice age.”
Corbyn and his colleagues have predicted that between now and 2020, the decrease in sun spots will continue. This fall in temperature will trigger the next Solar Minimum, which scientists think could last approximately 15 years. Work by the UK’s Met Office goes on to report however, that the effect of this mini ice age will be offset by an increase in global warming. This means that, rather than being faced with rivers that are frozen from top to bottom, and harsh temperatures that will keep us huddled around the fire, we will merely have to face winters that are much colder than we have become used to- so don’t rush out and buy those ice skates just yet.
Dr Kathryn Bates is a graduate of archaeology and history. She has excavated across the world as an archaeologist, and tutored medieval history at Leicester University. She joined the administrative team at Oxford Open Learning twelve years ago. Alongside her distance learning work, Dr Bates is a bestselling novelist, and an itinerant creative writing tutor for primary school children.