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Met Office criticises 'misleading' Mail article predicting 'mini ice age'

  • 30 Jan 2012, 18:00
  • Christian Hunt and Verity Payne

Columnist David Rose's latest article for the Mail on Sunday - " Forget global warming - it's Cycle 25 we need to worry about (and if NASA scientists are right the Thames will be freezing over again)" - repeats what is becoming a common misconception in the tabloid press: that a drop in solar activity is about to cause a 'mini ice age'.

In the piece, Rose so badly misrepresents the Met Office's work that they have taken the unusual step of responding to it on their blog, describing his article as containing

"numerous errors in the reporting of published peer reviewed science undertaken by the Met Office Hadley Centre."

Rose has a poor track record on accurately portraying climate science. This latest effort doesn't improve matters.

The sun and climate change - the story so far

The sun's energy fluctuates, rising and falling on an 11-year cycle. This has an effect on the planet's climate. The graph below shows how solar activity has changed over time:

NASA ssn

Source: NASA

You can see that during a 70 year period in the late 17th to early 18th Century, the sun went through a period of particularly low energy - known as the 'Maunder Minimum'. (There's another period of low activity at the start of the 19th Century called the 'Dalton Minimum'.)

The Maunder Minimum overlapped with part of what is called the 'Little Ice Age' - a 300 year long period of cooling which affected areas of the planet. People sometimes link the Little Ice Age and the Maunder Minimum, but there isn't a clear link, and research is still going on into what actually caused the Little Ice Age.

Scientists have been speculating for some time that the next solar minimum (called 'cycle 25') could be a particularly low one - perhaps even another Maunder-style minimum.

But because of the extent to which man-made greenhouse gases are affecting the Earth's climate, this probably won't have much of an effect on global warming.

In 2010, scientists modelling the possibility of another Maunder-minimum style event found that it will cool global temperatures by a only small amount - not enough to counteract the projected future warming due to human activity.

Now new research by Professor Mike Lockwood of the University of Reading and colleagues at the Met Office (not yet published, but available online) essentially echoes this finding. A less active sun would have a small cooling effect, if man-made greenhouse gases weren't having a much bigger warming one.

How does Rose report this new research?

The new Lockwood paper features heavily in Rose's article for the Mail. Remember, the Lockwood paper argues that a decline in the Sun's activity will not lead to significant cooling of the planet. Rose uses this as a hook to write a piece suggesting that a decline in the Sun's activity is going to lead to a 'mini ice age'.

How is this possible? Simple - Rose reports that the paper says we're heading for a solar minimum, and then says that the findings of the paper that this won't lead to significant cooling are 'fiercely disputed by other solar experts'. By this, Rose means 'climate skeptics', and he then quotes several who suggest that the sun's behaviour means that global warming has stopped.

So... this means global warming has stopped, right?

No. Other work from Professor Lockwood suggests that a big drop in the Sun's activity changes atmospheric patterns giving cold UK and European winters - but Lockwood stresses that this is a regional affect, and is balanced out by warmer Greenland winters. So this will cause little change in global temperatures overall.

This wasn't the answer Rose appears to have been after. In the Mail article, he promotes his personal belief that global warming has stopped in the article's opening lines, with reference to another piece of Met Office research:

"THE supposed 'consensus' on man-made global warming is facing an inconvenient challenge after the release of new temperature data showing the planet has not warmed for the past 15 years.
The figures suggest that we could even be heading for a mini ice age to rival the 70-year temperature drop … in the 17th century.
The data was issued last week without fanfare by the Met Office and the University of East Anglia Climatic Research Unit. It confirms that the rising trend in world temperatures ended in 1997."

Just in case you were wondering whether this was right, the Met Office responded:

"This article includes numerous errors in the reporting of published peer reviewed science undertaken by the Met Office Hadley Centre and for Mr. Rose to suggest that the latest global temperatures available show no warming in the last 15 years is entirely misleading.
Despite the Met Office having spoken to David Rose ahead of the publication of the story, he has chosen to not fully include the answers we gave him to questions around decadal projections produced by the Met Office or his belief that we have seen no warming since 1997."

So here's what happened. The Met Office were approached by Rose. They told him what they thought about global temperatures. Rose then presented their research in what they call a 'misleading' way, and included only a fraction of their response, so this wouldn't be obvious.

The full Met Office response - which they provide on their blog - reads:

"However, what is absolutely clear is that we have continued to see a trend of warming, with the decade of 2000-2009 being clearly the warmest in the instrumental record going back to 1850."

Compare this with the headline of the article, which begins:

"Forget global warming..."

The Met Office tried to explain this was wrong to Rose before publication - and he appears to have ignored them.

Coda: The perils of only reading the press release?

One line in the article suggests that Rose may not have actually read the Lockwood paper. We don't know that he didn't, but it is our guess.

Rose says that the Lockwood paper shows a very high chance of a very low solar minimum in the near future:

"According to a paper issued last week by the Met Office, there is a 92 per cent chance that both Cycle 25 and those taking place in the following decades will be as weak as, or weaker than, the 'Dalton minimum' of 1790 to 1830."

Where does this 92 per cent figure come from? It's not in the paper itself, of the press release, which quotes Professor Lockwood:

"The most likely scenario is that we'll see an overall reduction of the Sun's activity compared to the 20th Century, such that solar outputs drop to the values of the Dalton Minimum (around 1820). The probability of activity dropping as low as the Maunder Minimum - or indeed returning to the high activity of the 20th Century - is about 8%. The findings rely on the assumption that the Sun's past behaviour is a reasonable guide for future solar activity changes."

The 8 per cent suggests that Rose has made a fairly basic mistake and assumed that he could just reverse the number from the press release.

We checked with Professor Lockwood, who said that his research has shown there's actually around a 50 per cent probability of a Dalton-style solar minimum over the next forty years, almost a 10 per cent chance of solar activity dropping to Maunder Minimum levels, and about a 10 per cent chance that solar activity will hardly drop at all.

So the 92 per cent figure is way off, and this would have been clear from reading the paper - or checking with the scientists. 

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