Sunspot decline could mean decades of cold UK winters

Ice-skating on the Thames to make a comeback?

British scientists have produced a new study suggesting that the Sun is coming to the end of a "grand solar maximum" – a long period of intense activity in the Sun – meaning that we in Blighty could be set for a long period of much colder winters, similar to those seen during the "little ice age" of the 17th and 18th centuries.

The new research from boffins led by Professor Mike Lockwood of Reading uni says that "solar activity during the current sunspot minimum has fallen to levels unknown since the start of the 20th century" and that there is a serious chance that the Sun may be headed into another so-called "Maunder Minimum", a long period with almost no sunspots like that which was recorded by astronomers from 1645 to 1715.

As NASA notes:

Although the observations were not as extensive as in later years, the Sun was in fact well observed during this time and this lack of sunspots is well documented. This period of solar inactivity also corresponds to a climatic period called the "Little Ice Age" when rivers that are normally ice-free froze and snow fields remained year-round at lower altitudes. There is evidence that the Sun has had similar periods of inactivity in the more distant past. The connection between solar activity and terrestrial climate is an area of on-going research.

In fact it used to be commonplace for people to go ice-skating on the Thames back then, something which has never happened in living memory.

American scientists at the US National Solar Observatory recently presented research which also pointed to a coming reprise of the Maunder Minimum, saying that the sunspot cycle could be entering "hibernation". However many professional climate scientists do not believe that variations in the Sun have any significant effect on the Earth's climate, and there is intense hostility to the idea from the green movement as it could de-emphasise the importance of human-driven carbon emissions.

However Professor Lockwood, while not keen on the term "little ice age", believes that solar variations can be correlated with changes in the weather, and that the UK may well be in for a long spell of much colder winters than we've been used to.

According to the new study, chances that the average winter temperature will fall below 2.5°C will be around 1 in 7, assuming that all other factors, including man-made effects and El Niño, remain constant.

Put in context, the average UK winter temperature for the last 20 years has been 5.04°C. The last three winters have averaged 3.50°C, 2.53°C and 3.13°C, with 2009-10 being the 14th coldest in the last 160 years.

Lockwood says that a full-on Maunder minimum is definitely possible, but obviously – remembering the historical background to the last one - this would not mean glaciers overrunning Europe.

"Our results show that over the next fifty years there is a 10 per cent chance that temperatures will return to Maunder minimum levels. Describing the Maunder minimum as a 'little ice age' is somewhat misleading however," says the prof.

"Cold winters were indeed more common during the Maunder minimum but there were also some very warm ones between them, summers were not colder, and the drop in average temperatures was not nearly as great, nor as global, as during a real ice age."

The study is published in Environmental Research Letters. ®

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