Solar Science Bipolar Disorder
Guest post by Steven Goddard
About once every 11 years, the sun’s magnetic poles reverse. However some high profile solar scientists reverse their own polarity more frequently.
The BBC reported Wednesday that Mike Lockwood at the University of Reading has established a statistical link between cold weather and low solar activity.
The UK and continental Europe could be gripped by more frequent cold winters in the future as a result of low solar activity, say researchers.
“By recent standards, we have just had what could be called a very cold winter and I wanted to see if this was just another coincidence or statistically robust,” said lead author Mike Lockwood, professor of space environment physics at the University of Reading, UK.
To examine whether there was a link, Professor Lockwood and his co-authors compared past levels of solar activity with the Central England Temperature (CET) record, which is the world’s longest continuous instrumental record of such data.
The researchers used the 351-year CET record because it provided data that went back to the beginning of the Maunder Minimum, a prolonged period of very low activity on the Sun that lasted about half a century.
“Frost fayres” were held on the Thames during the Maunder Minimum
The Maunder Minimum occurred in the latter half of the 17th Century – a period when Europe experienced a series of harsh winters, which has been dubbed by some as the Little Ice Age. Following this, there was a gradual increase in solar activity that lasted 300 years.
Professor Lockwood explained that studies of activity on the Sun, which provides data stretching back over 9,000 years, showed that it tended to “ramp up quite slowly over about a 300-year period, then drop quite quickly over about a 100-year period”.
He said the present decline started in 1985 and was currently about “half way back to a Maunder Minimum condition”. More at the BBC
His study was basically a rehash of what many others have done previously over the past few centuries, but he has the BBC’s ear – because in 2007 he prominently claimed just the opposite.
No Sun link’ to climate change
Tuesday, 10 July 2007
“This should settle the debate,” said Mike Lockwood
Similarly, in 2006 David Hathaway at NASA reported that the Sun’s conveyor belt had “slowed to a record low.”
May 10, 2006: The Sun’s Great Conveyor Belt has slowed to a record-low crawl, according to research by NASA solar physicist David Hathaway. “It’s off the bottom of the charts,” he says. “This has important repercussions for future solar activity.”
Then on March 12, 2010 he reported the exact opposite:
March 12, 2010: In today’s issue of Science, NASA solar physicist David Hathaway reports that the top of the sun’s Great Conveyor Belt has been running at record-high speeds for the past five years.
In 1810, the great English astronomer William Herschel established a link between sunspot activity and the price of grain in Europe - a proxy for climate. As far as we know, he never reversed polarity on that belief. Modern solar science is just coming around to what Herschel hypothesized 200 years ago.
UPDATE: Full Lockwood et al paper at Environmental Research Letters here
Abstract. Solar activity during the current sunspot minimum has fallen to levels unknown since the start of the 20th century. The Maunder minimum (about 1650–1700) was a prolonged episode of low solar activity which coincided with more severe winters in the United Kingdom and continental Europe. Motivated by recent relatively cold winters in the UK, we investigate the possible connection with solar activity. We identify regionally anomalous cold winters by detrending the Central England temperature (CET) record using reconstructions of the northern hemisphere mean temperature. We show that cold winter excursions from the hemispheric trend occur more commonly in the UK during low solar activity, consistent with the solar influence on the occurrence of persistent blocking events in the eastern Atlantic. We stress that this is a regional and seasonal effect relating to European winters and not a global effect. Average solar activity has declined rapidly since 1985 and cosmogenic isotopes suggest an 8% chance of a return to Maunder minimum conditions within the next 50 years (Lockwood 2010 Proc. R. Soc. A 466 303–29): the results presented here indicate that, despite hemispheric warming, the UK and Europe could experience more cold winters than during recent decades.
Figure 2 from the paper: