Jennifer Francis & Arctic Sea Ice

By Paul Homewood

 

 

Yesterday, I mentioned the interview that Dr David Whitehouse did with Dr Jennifer Francis, regarding extreme weather. Her claims that global warming was making hurricanes worse showed a total lack of understanding of how the AMO works.

She also made references to the decline of Arctic ice, which she suggested had lead to a meridional jet stream, which in turn brought blocking weather patterns and cold winters. The Guardian published a detailed report on Francis’ work last year.

It is, therefore, perhaps worthwhile reprinting in full the post I ran at the time, dealing with her claims.

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Notalotofpeopleknowthat – Sep 28, 2012

 

 

 

Just in case we get a cold winter this year, the Guardian thought it advisable to warn us that this would no doubt be because of global warming.

The record loss of Arctic sea ice this summer may mean a cold winter for the UK and northern Europe. The region has been prone to bad winters after summers with very low sea ice, such as 2011 and 2007, said Jennifer Francis, a researcher at Rutgers University

Well yes, Jennifer. It has also been prone to mild winters recently. It was also prone to cold winters when the Arctic had more summer ice, and also mild winters in other years at the time. It is actually called “weather”.

Jennifer helpfully explains

"The jet stream is clearly weaker," said Francis. That means weather systems, be it rain or dry conditions, are slow to move on and last longer. Ultimately this can result in "blocking" events, such as the conditions that produced the terrible heatwave in western Russia during the summer of 2010, she said.

What Jennifer is referring to is what meteorologists call a “meridional jet stream”. Meteorologist Jeff Haby explains this phenomenon in layman terms below.

http://www.theweatherprediction.com/habyhints/159/

Are you keeping up so far, Jennifer? Good. Let’s go onto stage two then.

Hubert Lamb is one of the best known climate scientists of all time, and founded the Climate Research Unit at the UEA. In his book, “Climate: Past, Present & Future”, he talks about the climate during the 1960’s and early 70’s when the Arctic was getting colder and sea ice expanding. He identifies one of the effects of this Arctic shift as

“changes over middle latitudes, where the most significant feature has been the very awkward type of variability from year to year, associated with the behaviour of blocking systems and meridional circulation patterns.” which led to “the extremes of cold and warmth, drought and flood associated with the occurrences of blocking in middle latitudes.”

Scientists at the time even identified the mechanism involved

“The slight drop in temperature produces large numbers of pressure centres in the upper atmosphere. These break up the smooth flow of westerly winds over temperate areas.The stagnant air produced in this way causes an increase in extremes of local weather such as droughts, floods, extended dry spells, long freezes, delayed monsoons and even local temperature increases.”

Of course Lamb and his colleagues might have been wrong. But, if so, perhaps Jennifer might like to explain the UK’s Big Freeze of 1963, which lasted three months and was caused, according to the Met Office, by a high pressure system stuck for most of the winter to the north-east?

http://en.wikipedia.org/wiki/Winter_of_1962%E2%80%931963_in_the_United_Kingdom

Meanwhile, whether this winter is mild, cold, wet, dry, snowy, windy, or just plain normal, the hacks at the Guardian will have the answer. Global Warming!

 

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Met Office Report – March 2013

As a follow up to some of these issues that I raised, the Met Office published a report in March this year,  “Why was the start to spring 2013 so cold?, comparing the cold Spring this year, with that of 1962.

 

https://notalotofpeopleknowthat.wordpress.com/2013/06/27/jet-stream-weirding-1962-style/

 

It concluded:

 

It is informative to consider whether there are similarities in the global climate system in 1962(Figure 6) to this year’s situation (Figure 3). Comparison with the equivalent figures for 2013 shows a remarkable resemblance.

The hemispheric pattern of the surface air temperature anomalies is almost identical, as is the hemispheric pattern of mean sea level pressure anomalies. Again the negative phase of the NAO dominated the Euro-Atlantic sector in 1962, with the same southwards shift in the jet stream taking the weather systems into southern Europe and the Mediterranean.