Friday, June 17, 2011

The new Ice Age: Climate change could slow as sun simmers down - 17th June 2011

The last time the sun went to sleep, there were frost fairs on the Thames and ice extended for miles into the North Sea.

Now scientists have unearthed evidence that the sun is poised to enter its first period of ‘hibernation’ since the Little Ice Age of the early 1700s.

If they are right – and it’s a big if – it means global warming caused by greenhouse gases could be less severe over the next few decades than predicted.

The sun goes through a regular cycle of activity that peaks every 11 years.

During its most frenzied periods, huge magnetic storms erupt from the sun while vast sunspots appear on its surface. But during the quiet part of the cycle – the solar minimum – eruptions and sunspots are rarer.

Astronomers say the sun should now be building up to its next maximum and that sunspots should be appearing on its surface. But three separate studies reported at an astronomy conference in America this week have found clues that the sun is not waking up on schedule.

Dr Frank Hill, of America’s National Solar Observatory, showed that a regular jet-stream current within the sun – which was due in 2008 and 2009 – has failed to start up again.

Meanwhile, Dr Richard Altrock, of Sacramento Peak Observatory – who has been studying the sun’s ‘atmosphere’, the corona, for 40 years – found that a tell-tale march of magnetic activity towards the poles that heralds the start of the solar maximum has failed to materialise.

And Matthew Penn, also of the National Solar Observatory, has shown that the strength of the magnetic field inside sunspots has been much weaker than expected and is in steady decline.

If this continues, the sun will have lost its spots completely by 2022.

The last time the sun went quiet was during the ‘Maunder Minimum’ from 1645 to 1715, when Europe and America suffered a succession of bitterly cold winters called the Little Ice Age. Read More