Climategate: A Modern-Day Little Ice Age

22nd April 2010

Quieter activity on Sun may push Britain

into a Modern-Day Little Ice Age

Frozen Britain: Large parts of Britain and Central Europe were covered in snow during last winter, as

this Nasa satellite image from January 7 shows. Scientists think low solar activity could be the culprit

Horse racing on frozen rivers? Ice bowling? Activities last seen during Britain's Little Ice Age could once more be seen, researchers believe.

Having just emerged from a bitterly cold winter the experts are warning that Britain could return to the mini ice-age at the end of the 17th century. This is despite claims that global warming is causing Arctic ice to melt and temperatures to rise.

Back then the Thames played host to 'frost fairs' complete with puppet shows, horse races and ice bowling. Henry VIII is even said to have travelled all the way from central London to Greenwich by sleigh.

The prediction of a return to an annual deep freeze follows research linking solar flares and other activity on the surface of the Sun with the weather across northern Europe.

Scientists found that when the Sun is relatively calm, winters are harsh.

The Sun passes through high and low phases of activity during an 11-year cycle, which affects how much radiation and particles stream towards Earth.

Visible evidence of this cycle is provided by the dark sun spots on the Sun's surface.

If there are a large number of these spots, the Sun is experiencing a particularly high level of magnetic activity and therefore radiates very brightly. Which leads to warmer winters but now the opposite is true.

The cold winters are brought by the the freezing winds coming to northern and central Europe from Siberia.

These winds are normally stopped by the jet stream but scientists have found that this bends at times of low solar activity allowing the cold air through. The connection between the jet stream bending and solar activity is not fully understood.

A frost fair on the Thames River. Henry VIII is even said to have

travelled all the way from central London to Greenwich by sleigh

Scientists believe cold winds travel south towards Europe and mild west winds are blocked

due to a bend in a jet stream. The bend is thought to be caused by low solar activity

This bend also stops warm winds from the Atlantic reaching this part of Europe.

Professor Mike Lockwood started the investigation after he realised the past two cold British winters had coincided with a particularly quiet period in the Sun's activity.

He was helped in his research by colleagues at Reading University, along with scientists at the Rutherford Appleton Laboratory in Oxfordshire and the Max Planck Institute in Germany.

The team studied British weather records back to 1659. These were then compared with solar activity over the same period.

Solar activity is indicated by the strength of the solar magnetic field, which extends to Earth where it causes small fluctuations in the Earth's magnetic field.

Reliable measurements of the Sun’s magnetic field are only available from 1900 onwards, so researchers used computer simulations for further back in time.

The statistical comparisons clearly showed that after decades of high solar activity and comparably mild winters, low solar activity and severe winters had become more common in Europe again.

Professor Somi Solanki from the Max Planck Institute said this meant the recent cold weather did not contradict the theory that global warming is being caused by human activity.

'The connection between solar activity and cold winters in Europe only became apparent after we subtracted the superimposed trend towards global warming,' he said.

So don't throw away your thermals just yet.