Micky Mann’s Meandering Jetstream
By Paul Homewood
One of the “scientists” who demonstrated conclusively that global warming was an unnatural event with the famous “hockey stick” graph is now warning that giant jetstreams which circle the planet are being altered by climate change.
Professor Michael Mann said extreme weather events – such as the “unprecedented” drought in California last year, the flooding in Pakistan in 2010 and the heatwave in Europe in 2003 – were happening more often than they should do, even taking the warming climate into account.
This, he said, meant there had to be an additional factor.
Jetstreams are influenced by the difference in temperatures between the Arctic and the equator.
But the Arctic has been warming much faster than tropical climates – the island of Svalbard, for example was 6.5 degrees celsius warmer last year compared to the average between 1961 and 1990. The land has also been warming faster than the sea.
Both of those factors were changing the flow of these major air currents to create “extreme meanders” which were helping to cause “extreme weather events”, Professor Mann said.
Junk scientist Micky Mann has now come with a new wheeze. Unfortunately his new study is as bent as his hockey stick.
He, along with some Dutch researcher called Dim and some other grant addicts, now claims to have proved that a “warmer Arctic” has led to more extreme weather, all caused by a meandering jet stream.
As the video explains, this can bring cold weather to one region and much warmer weather to another next door. When these meanders get stuck, we end up with weather blocking, and a few days of warm, cold, wet or dry can turn into weeks.
All sounds plausible?
Well, maybe not. After all, we have been here before.
This is what HH Lamb wrote in 1982:
ANOTHER TURNING POINT
Over the years since the 1940’s, it has become apparent that many of the tendencies in world climate which marked the previous 50 to 80 years or more have either ceased or changed…. It was only after the Second World War that the benign trend of the climate towards general warming over those previous decades really came in for much scientific discussion and began to attract public notice.
Such worldwide surveys as have been attempted seem to confirm the increase of variability of temperature and rainfall [since 1950].’’
In Europe, there is a curious change in the pattern of variability: from some time between 1940 and 1960 onwards, the occurrence of extreme seasons – both as regards temperature and rainfall has notably increased.
A worldwide list of the extreme seasons reported since 1960 makes impressive reading. Among the items included:
This shortened list omits most of the notable events reported in the southern hemisphere and other parts of the world where instrument records do not extend so far back. Cases affecting the intermediate seasons, the springs and autumns, have also been omitted.
These variations, perhaps more than any underlying trend to a warmer or colder climate, create difficulties for the planning age in which we live. They may be associated with the increased meridionality of the general wind circulation, the greater frequency of blocking, of stationary high and low pressure systems, giving prolonged northerly winds in one longitude and southerly winds in another longitude sector in middle latitudes.
Over both hemispheres there has been more blocking in these years… The most remarkable feature seems to be the an intensification of the cyclonic activity in high latitudes near 70-90N, all around the northern polar region. And this presumably has to do with the almost equally remarkable cooling of the Arctic since the 1950’s, which has meant an increase in the thermal gradient between high and middle latitudes.
HH Lamb: Climate, History and the Modern World – pp 267-270
And it was not only Lamb.
In 1975, CC Wallen, Head of the Special Environmental Applications Division of the World Meteorological Organization, had this to say about the consequences of the cooling trend since 1940:
The principal weather change likely to accompany the cooling trend is increased variability-alternating extremes of temperature and precipitation in any given area-which would almost certainly lower average crop yields.
During cooler climatic periods the high-altitude winds are broken up into irregular cells by weaker and more plentiful pressure centers, causing formation of a “meridional circulation” pattern. These small, weak cells may stagnate over vast areas for many months, bringing unseasonably cold weather on one side and unseasonably warm weather on the other. Droughts and floods become more frequent and may alternate season to season, as they did last year in India. Thus, while the hemisphere as a whole is cooler, individual areas may alternately break temperature and precipitation records at both extremes.
And he even gave us these diagrams.
Mann will be arguing that black is white next, and the gullible readers of the failed Independent will no doubt believe him!