From the UNIVERSITY OF LINCOLN, where they are trying to make the North Atlantic Oscillation bend to their will part of climate change.
Severe snowy weather in winter or extreme rains in summer in the UK might be influenced by warming trends in the Arctic, according to new findings.
Climate scientists from the UK and the US examined historic data of extreme weather events in the UK over the past decade and compared them with the position of the North Atlantic polar atmospheric jet steam using a measure called the North Atlantic Oscillation (NAO) index.
The NAO indicates the position of the jet stream – which is a giant current of air that broadly flows eastwards over mid-latitude regions around the globe – through a diagram which shows ‘negative’ and ‘positive’ spikes, similar to how a heart monitor looks.
The researchers highlight that the exceptionally wet UK summers of 2007 and 2012 had notably negative readings of the NAO, as did the cold, snowy winters of 2009/2010 and 2010/2011, while the exceptionally mild, wet, stormy winters experienced in 2013/2014 and 2015/2016 showed pronounced positive spikes.
The scientists also highlighted a correlation between the jet stream’s altered path over the past decade – so-called jet stream ‘waviness’ – and an increase during summer months in a phenomenon called Greenland high-pressure blocking, which represents areas of high pressure that remain nearly stationary over the Greenland region and distort the usual progression of storms across the North Atlantic.
Increased jet waviness is associated with a weakening of the jet stream, and the accompanying ‘blocking’ is linked to some of the most extreme UK seasonal weather events experienced over the past decade. The strength and path of the North Atlantic jet stream and the Greenland blocking phenomena appear to be influenced by increasing temperatures in the Arctic which have averaged at least twice the global warming rate over the past two decades, suggesting that those marked changes may be a key factor affecting extreme weather conditions over the UK, although an Arctic connection may not occur each year.
Edward Hanna, Professor of Climate Science and Meteorology at the University of Lincoln’s School of Geography, carried out the study with Dr Richard Hall, also from the University of Lincoln, and Professor James E Overland from the US National Oceanographic & Atmospheric Administration Pacific Marine Environmental Laboratory.
Professor Hanna said:
“Arctic warming may be driving recent North Atlantic atmospheric circulation changes that are linked to some of the most extreme weather events in the UK over the last decade.
“In winter, a positive North Atlantic Oscillation (NAO) is linked with a more northward, vigorous jet and mild, wet, stormy weather over the UK, while a negative NAO tends to be associated with a more southerly-positioned jet and relatively cold and dry but sometimes snowy conditions. In summer the jet stream is displaced further north, so a positive NAO is typically associated with warm dry weather, while a negative NAO often corresponds to wetter, cooler UK weather conditions.
“While part of the uneven seasonal North Atlantic Oscillation changes might be due to natural random fluctuations in atmospheric circulation, the statistically highly unusual clustering of extreme NAO values in early winter, as well as extreme high summer Greenland Blocking Index values since 2000, suggest a more sustained, systematic change in the North Atlantic atmospheric circulation that may be influenced by longer-term external factors. This includes possible influences from the tropical oceans and solar energy changes as well as the extreme warming that has recently occurred in the Arctic.
“Of course, weather is naturally chaotic, and extremes are a normal part of our highly variable UK climate, but globally there has recently been an increase in the incidence of high temperature and heavy precipitation extremes. The cold UK winter episodes we noted are not so intuitively linked to global climate change but reflect part of a long-term trend towards more variable North Atlantic atmospheric circulation from year to year during winter months, especially early winter.
“This trend has culminated in the last decade having several record negative and positive December values of the North Atlantic Oscillation, with lots of resulting disruption from extreme weather over the UK. On the other hand there has been no really notably dry, hot, sunny summer in the UK since 2006; summers overall have either been around average or exceptionally wet, and this appears to be linked with strong warming and more frequent high pressure over Greenland in the last decade.”
###
The study has been published in Weather, the magazine of the Royal Meteorological Society, where apparently “tantalising clues” is part of the science lexicon now.
Abstract
We explore a possible relation between the recent Arctic amplification of global warming and changes in North Atlantic jet stream circulation and UK extreme weather conditions over the last decade. Such a link is supported by some tantalising clues from recent North Atlantic atmospheric circulation changes in summer and winter, but due to multiple factors affecting jet stream variability, we need extended records over at least a further decade to more reliably attribute these changes to global warming.
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The authors make several references to high pressure over Greenland.
*sigh*
That used to be called the Icelandic Blocking High. It was a near permanent fixture on the weather maps from late spring through early fall, every year in the 1960s and early 1970s. The jet stream did indeed get “pinned” in place and had a big loop going down to the southern US and then coming up the eastern seaboard.
New England weather was hot and dry in the summer, with a major multi-year drought in the late 1960s. This was also the tail end of the cooling from the late 1930s to ~1975.
Then the PDO shifted, and led to what has been described as “the great climate shift”.
If only they has studied weather history going further back than 1988 and The Great Global Warming Alarm.
I suppose if you oppose this type of hypothesis. you have to first consider two issues.
1) Is the weather in the UK somewhat more severe in some ways than it has been in the last 50 years, Are there more weather ‘events’?
2) If the answer is yes, which seems reasonable, we have to ask, why is this happening?
It’s easy to shout down hypotheses you don’t like. But much harder to come up with alternate ideas that can be considered. So lets hear what posters consider to be more valid reasons for our one in a hundred year events occurring every couple of years.
Of course you can always retreat to the idea that nothing is happening and all is normal which is unlikely if you live in the UK.
British weather has been pretty much the same for the 50 years I have lived here. 8 months of winter followed by 4 months of sh1t weather. If you come to visit make sure you bring something warm and waterproof whatever time of year it is.
There is more reporting of “weather events”, 24/7, and hyped to the max. Because pounding the “global warming” alarm bell doesn’t cut it. “Extreme weather” has become the fave proxie for the CAGW ideology. It’s such an easy bandwagon to jump onto.
Scientists: Don’t make “extreme cold” centerpiece of global warming argument
WaPo
February 20, 2014
It’s an intriguing theory – that recently has gotten legs: the melting Arctic – spurred by global warming – is causing the weather’s steering flow, the jet stream, to become more extreme. This extreme jet stream – rather than zipping around the world in a straight circle (right below) – is more frequently meandering off course (left below) and getting stuck in place, sending bitter, prolonged blasts of cold southward and conversely, see-sawing strong heat domes northward. It’s a fascinating paradox: global warming as the culprit for bone-chilling cold.
But more and more scientists are expressing reservations about this hypothesis, first proposed by Rutgers climate scientist Jennifer Francis and collaborators.
“It’s an interesting idea, but alternative observational analyses and simulations with climate models have not confirmed the hypothesis, and we do not view the theoretical arguments underlying it as compelling,” write five preeminent climate scientists (John Wallace, Isaac Held, David Thompson, Kevin Trenberth, and John Walsh) in a recent letter published in Science Magazine.
===========
2. DYNAMICS OF CLIMATIC AND GEOPHYSICAL INDICES
[…]
Meridional (C) circulation dominated in 1890-1920 and 1950-1980. The combined, “zonal” (W+E) circulation epochs dominated in 1920-1950 and 1980-1990. Current “latitudinal”(WE) epoch of 1970-1990s is not completed yet, but it is coming into its final stage, and so the “meridional” epoch (C-circulation) is now in its initial stage. […]
It was found that “zonal” epochs correspond to the periods of global warming and the meridional ones correspond to the periods of global cooling.
-U.N. Fisheries & Aquaculture Org
http://www.fao.org/docrep/005/y2787e/y2787e03.htm
======================
Answer to Question 1 is ‘No’ therefore question 2 is irrelevant. Just because the global warming obsessed UK Met Office decides to give a name to every puff of wind that comes off the Atlantic to make it seem as if the British Isles are subject to more and more extreme weather events, doesn’t actually make it so. The UK has always been subject to bouts of extreme weather, albeit much less extreme than many other areas of the planet. And there has been nothing unusual or unprecedented going on with the UK climate in recent years. In the past, these events all used to be called ‘Gale’. By the way, just because there is a ‘1 in a 100 year’ event, whatever the cause, it doesn’t actually mean that these events occur only once every century. The more able statisticians who frequent this site can problably bore you to death ad nauseum with a detailed explanation as to why.
Mack, Last December various walls and structures across Anglesey that had been in place since mediaeval times were severely damaged due to sudden unexpected floods. The main road to the bridge crossing over to the mainland was washed away for the first time since it was built 300 years ago. York, Carlisle, the West of England as well as many more have suffered similar fates over the last 10 years. These flooding events are becoming more frequent. I t appears that the overall rainfall is not increasing as such, but it seems that it falls all at once much more commonly. These are definite and recorded changes in climate. The house insurance company are well aware of the problem. You can say that it did not happen and my house is fine, but there are many observation and discussions on this site that you can refer to.
Much of the flooding had been caused by flash floods. The more built up a area becomes, the less surface area the water has to be soaked into the ground. The water has no where to go so follows contours in the urban surface that place larger volumes of water in specific areas that would had not happened if there was no concrete around. Regular unblocking of drains helps too and this had not even been done either, especially initially. It also doesn’t help building on well know flood plains around the UK. The rainfall rates in recent years have happened before in different areas of the UK at some time or another.
Why does it seem reasonable?
Weather records go back a lot further that the few decades that you insist on focusing on.
as mack says the answer to 1 is no,so the rest of your post is not worth reading.
Maybe it is worth you casting a glance over the news occasionally? Type in “Floods in the UK” The highly Conservative Daily Telegraph is a surprisingly useful source for this information on floods. If you still don’t believe there has been an increase in severe flooding, check out house insurance prices in vulnerable areas.
i live in the uk gareth. i spend more time outside on the coast than i spend in my own home. i see the met office get 90% of forecasts wrong for my coast in the winter. i neither need to listen to or read anymore crap from delusional fools with crap degrees in the soft sciences to know when someone is talking bollocks.
“Gareth January 5, 2018 at 1:26 am
If you still don’t believe there has been an increase in severe flooding, check out house insurance prices in vulnerable areas.”
As evidence of what? Where I lived in the UK, the bottom of the valley was undeveloped. Now, where a flood plain was stands a small housing estate, and it floods regularly! Who’s at fault there?
From the abstract:
….”tantalising clues”…”we need extended records over at least a further decade to more reliably attribute these changes to global warming.”
============
So, if after another decade of records, you still have no “reliable” attribute to global warming, what ya gonna do ?
Tell your children and their children, that they should look for other funding sources.
“The researchers highlight that the exceptionally wet UK summers of 2007 and 2012 had notably negative readings of the NAO, as did the cold, snowy winters of 2009/2010 and 2010/2011, while the exceptionally mild, wet, stormy winters experienced in 2013/2014 and 2015/2016 showed pronounced positive spikes.”
The -NAO is low solar, the +NAO in winter 2013/2014 was down to the ‘warm blob’ blocking.
“Arctic warming may be driving recent North Atlantic atmospheric circulation changes that are linked to some of the most extreme weather events in the UK over the last decade.”
-NAO drives the Arctic warming, the tail doesn’t wag the dog. The NAO can experience one extreme to the other irrespective of Arctic temperatures.
“On the other hand there has been no really notably dry, hot, sunny summer in the UK since 2006; summers overall have either been around average or exceptionally wet..”
July 2013 was one of the warmest.
https://www.metoffice.gov.uk/climate/uk/summaries/actualmonthly
‘…summers overall have either been around average or exceptionally wet..”
Lamb would recognise that as a regional cooling signal.
Well, it is all happening on the same planet so why not conveniently connect the dots? The weather in the UK is “influencing” the weather in the Arctic too, if you want it to. And Russian meddling too.
Jeez! The ‘university’ is younger than satellites. HH Lamb was writing books for longer.
HH Lamb new a lot more about weather and climate then many of these charlatans nowadays.
There was an interesting paper in the Journal of Climate (AmMet Soc) in 2015 which advises caution in drawing conclusions from relatively rare events such as extreme weather :
Need for Caution in Interpreting Extreme Weather Statistics
PRASHANT D. SARDESHMUKH AND GILBERT P. COMPO
CIRES, University of Colorado, and NOAA/Earth System Research Laboratory, Boulder, Colorado
CÉCILE PENLAND
NOAA/Earth System Research Laboratory, Boulder, Colorado
(Manuscript received 2 January 2015, in final form 1 June 2015)
ABSTRACT
Given the reality of anthropogenic global warming, it is tempting to seek an anthropogenic component in
any recent change in the statistics of extreme weather. This paper cautions that such efforts may, however,
lead to wrong conclusions if the distinctively skewed and heavy-tailed aspects of the probability distributions
of daily weather anomalies are ignored or misrepresented. Departures of several standard deviations from the mean, although rare, are far more common in such a distinctively non-Gaussian world than they are in a
Gaussian world. This further complicates the problem of detecting changes in tail probabilities from historical records of limited length and accuracy.
The abstract , introduction and bulk of the paper then goes on to analyse the reliability of statistics in connection with possible global warming .
Too advanced for me I fear , but others may benefit.
Sorry forgot the link:
http://journals.ametsoc.org/doi/abs/10.1175/JCLI-D-15-0020.1
I have studied UK weather and extreme events back to the 11 th century.
There is nothing remotely extreme or unusual about our weather at present. In fact compared to some of the events of the past it is rather benign.
You can not base a paper such as this on merely a decades worth of data. Natural variability works on short and extremely long cycles.
Tonyb
“There is nothing remotely extreme or unusual about our weather at present. In fact compared to some of the events of the past it is rather benign.”
Exactly!
Here in the US, we had a drought in California that lasted a few years that was called unprecedented from human caused climate change.
Never mind this:
https://www.mercurynews.com/2014/01/25/california-drought-past-dry-periods-have-lasted-more-than-200-years-scientists-say/
We had a minimal hurricane, Sandy that merged with a mid latitude upper level low and stalled in a high population area along the East Coast that was called an unprecedented Super Storm from human caused climate change.
Never mind this(during global cooling):
https://en.wikipedia.org/wiki/Hurricane_Hazel
We had a severe, widespread drought in the US Midwest during the Summer of 2012 from human caused climate change. Never mind that we had set the record for consecutive years WITHOUT a widespread drought. 24 years of the best crop growing conditions since the previous widespread severe drought in 1988.
We had the stalled remnants of a hurricane(Harvey) this past Summer dump record rains in TX because it moved so slow. Unprecedented from human caused climate change.
Never mind this:
http://www.chron.com/news/houston-texas/texas/article/After-35-years-Alvin-still-holds-U-S-record-for-5644837.php
We had several very powerful hurricanes making the news this past hurricane season…………after the US had the good fortune to avoid being a target for over a decade. The news featured all sorts of unprecedented and human caused climate change assertions.
Never mind the realities:
It was a top 5 season in several categories with a few isolated records or near records. Since when is the weather expected to stay inside of a narrow range of, let’s say 95% of what humans have recorded during the last century?
If we were able to expand the time frame to 2,000 years for instance(still a tiny fraction of weather history) almost every record we have right now would be much more extreme.
Warm up the coldest places during the coldest times of year on this planet and yes, it can effect the weather patterns. However, the meridional temperature gradient is reduced and you decrease some types of extreme weather. Weaker jet streams, less violent tornadoes. Less severe thunderstorms…………on average. The atmosphere does not need to work as hard to balance the heat disparity between hot tropics and the colder air as you go pole ward.
But the average can be misleading with weather because extremes are an EXPECTED part of the natural climate. It would be much more extraordinary if we were NOT breaking 130 year old records at some to many locations at different times for different weather events each year.
Hotter or wetter or drier than at any time that a 80 year old man can remember living in the same town……….must be human caused climate change (-:
I guess you would have to be even older than that to remember the 1930’s and the Dust Bowl:
https://www.epa.gov/climate-indicators/climate-change-indicators-high-and-low-temperatures
Good thing that we have accurate weather records, even if they only go back just over a century. They show that the 1930’s featured the most extreme weather in recorded history. Not just in the US but on the planet.
https://en.wikipedia.org/wiki/U.S._state_temperature_extremes
Today’s interpretation of extreme weather is distorted because it does give authentic weighting to past extreme weather events and/or to take into account the short time frame.
:
“Today’s interpretation of extreme weather is distorted because it does give authentic weighting to past extreme weather events and/or to take into account the short time frame. ”
does NOT give authentic weighting to past extreme weather events
The effects of so called extreme weather in the UK can nearly all be put down to human activity.
We get a big gale and down come the trees. Most of the town ones that do damage have a tree preservation order on them thus keeping them there long after they should be logged. There are 3.8 billion trees in the UK and some get blown over. Big deal. If none fell over that would be unusual.
A few old roofs blow off..Badly maintained. A few new ones blow off…Jerry built junk. Cars get drowned…their stupid owners park them in known flooding areas. We build houses on Flood Plains then let the ditches silt up and overgrow. We put rivers through pipes then act surprised when they flood around the debris that we let float down the riverbed.
Sea walls collapse because they have not had one iota of maintenance since they were built by the Victorians 150 years ago. Lots of flashy glass houses built by the rich gits appear but nobody is paid to clear the road drains outside.
We have the appearance of drought only because we have not built any new reservoirs and the population has increased by 20 million. We cut down all the farm hedges,and then get soil erosion and mudslides. When it snows we grind to a halt because the Council has no snow ploughs and no road salt because the warmys said we would never need them again, The litany of stupid goes on and on. Nothing to do with CO2 and we rely on fossil fueled fire trucks, dredgers, tow trucks, chain saws, floodlights etc to get us out of the mess.
I have been here 70 years now and the weather is no better and no worse than it ever was.
The effects of so called extreme weather in the UK can nearly all be put down to human activity.
We get a big gale and down come the trees. Most of the town ones that do damage have a tree preservation order on them thus keeping them there long after they should be logged. There are 3.8 billion trees in the UK and some get blown over. Big deal. If none fell over that would be unusual.
A few old roofs blow off..Badly maintained. A few new ones blow off…Jerry built junk. Cars get drowned…their stupid owners park them in known flooding areas. We build houses on Flood Plains then let the ditches silt up and overgrow. We put rivers through pipes then act surprised when they flood around the debris that we let float down the riverbed.
Sea walls collapse because they have not had one iota of maintenance since they were built by the Victorians 150 years ago. Lots of flashy glass houses built by the rich gits appear but nobody is paid to clear the road drains outside.
We have the appearance of drought only because we have not built any new reservoirs and the population has increased by 20 million. We cut down all the farm hedges,and then get soil erosion and mudslides. When it snows we grind to a halt because the Council has no snow ploughs and no road salt because the warmys said we would never need them again, The litany of stupid goes on and on. Nothing to do with CO2 and we rely on fossil fueled fire trucks, dredgers, tow trucks, chain saws, floodlights etc to get us out of the mess.
I have been here 70 years now and the weather is no better and no worse than it ever was.
They think average Joe is stupid. They think average Joe is like a particularly slow goldfish with severe amnesia. They truly think no one will even recall their alarmed trilling of a few short years ago about the leetle children not knowing what snow was anymore.
They think everyone is too dull to notice that what they said with utmost conviction a few years ago is in antiphase with what they are saying now with utmost conviction. They furrow their brows and stroke their chins in frank amazement that no one takes them seriously and climate alarmism features about 20 points lower on average Joe’s scale of importance than what colour to paint the bathroom.
The thing about weather , is but its is weather.
Weather we like cold or hot.
The weather is fickle,expect it to rain,it does not.
Effect and affect are are juxtapose.
What the weather will be like next week.
Who really knows?
I am sick to the teeth of reading the words “may” and “might” !!!
The alarmists argue that when we reasonable skeptics point out things like the 10 year pause in temperature and the humps in the raw data graphs, that you cant just look at a ten year period. Of course that is our skeptic argument all along. However if they are pointing to 1 overriding factor such as CO2 then if the data changes to less warming or more cooling for a short period then obviously the ONE overiding factor of increased CO2 is not as much overriding AS THEY SAY. You cant have it both ways. If they argue CO2 trumps everything then to be a valid theory there should be no pause in temperature increase and no humps in other graphs. To argue otherwise is to say that CO2 doesn’t trump everything and other factors are much more important in the short term. The whole climate argument then boils down to which is more important in the long term. I argue that CO2 cannot be more important in the long term because the earth has had extremely high levels of CO2 in the distant past with ice ages. I cant understand how certain intelligent people cannot grasp this logic. Is there any hope for the human race?
They are not just trying to blame the NAO on climate change, but also the AO. The fact being they once stated that global warming will cause the NAO to become increasingly positive.
The NAO was negative more often during previous decades when we had more frequent colder winters.
http://frontierscientists.com/wp-content/uploads/2013/06/JetStream_ArcticOscillation.jpg
The AO was negative more often during previous decades, when we had more frequent colder winters.
These traits reflect a planet that is cooling not warming.
A negative NAO or AO always cause colder air to move southwards in the Northern Hemisphere and warm the Arctic circle with warmer air replacing it. This has always happened and never been any different. Having virtually no data in the Arctic over many decades previously don’t half show up the bad science that they claim, was suppose to be much colder before when mid-latitudes had colder frequent winters. The truth is that have been lying and the Arctic circle would have been warmer with cold air moving south more often then recent years.
The reason why Arctic ice extent was high during the late 1970’s was because the Beaufort Gyre had recently gone in the opposite direction and pushed fresh water and ice into more southern locations cooling these areas. Scientists are recently concerned that the Beaufort Gyre has not reversed in flow for many years and has instead increased in flow. The reason being when it does eventually reverse it will push out more fresh water and ice further south then the event in the 1970’s making it even colder than then around sub-Arctic regions.
Nope, don’t need to read the article. There hasn’t been any extreme weather yet here in Central England.
It useful to read data in context. If you get 4 inches of rain in one day which causes catastrophic flooding, then the rest of the month has no rain, what is the average rainfall for that month? Overall stats sometime can be very misleading. If look in the climate records for the catastrophic floods last year and over the last few years you will find very little sign.
what i find odd is that they forget something important:: the real cold is not in the arctic but over the landmasses around the arctic ocean. The arctic cold an refreezes are always triggered by them
A decade is what, ten years?
Asked the “Climate scientists”.
Climate alchemy is the new science.
Usual BS that looks at statistics in order to try explaining processes.
“Increased jet waviness is associated with a weakening of the jet stream” is beyond stupid and can be debunked by looking at seasonal jet stream changes: jets are strong AND yet wavy in winter since they simply reflect the southward penetration of cold, high pressure polar air masses and much weaker wavy or not in summer. Thus according to their theory, if a weaker jet stream causes their polar vortex excursions, we should expect cold waves… in boreal summer.
Back in the early 18th Century when Ice Festivals were being held on the Thames, it must have been downright tropical at the North Pole. Santa and his elves drowned while Londoners played on the ice. So sad.
“North Atlantic polar atmospheric jet steam”
Or perhaps “jet stream”?
except this happens at low solar activity, solar influence on the jet stream is significant. Piers Corbyn has been successfully using solar influence in his forecasting for 30 years
Also a recent paper shows high correlation between quiet sun and blocking over Greenland.
These “scientists” are just quite literally just making sh&* up
What is seen in this paper is a actual a strength of climate ‘science’ in it through the liberal application of ‘maybe’ ‘could’ ‘ etc. . this allows them to make claims and never be wrong because they never said it ‘would or is’.
Therefore even if they make the ‘mistake’ of making short term forecast , where they are still around to asked why they got it wrong rather than long term ones , say 100 years , when there is no chance of that. They are ‘right ‘
And in very ‘green way’ they can recycle them using virtual the same data but making the opposite claim, given that reality makes their first one out as BS, and apply the same ‘could ‘ maybe ‘ etc. safety line .
Think religion and forget science , and you can understand the game they are playing.
All the snow in the US right now is being reported as, well being over-reported, and as unusual here in Aus. I recall New York in 2003 as being as cold and snowy…2ft deep snowy footpaths on Long Island…I actually got lost in near whiteout conditions and had to stop by a hardware store to ask for directions to the rail station and points on rail tracks had “oil” baths on fire to keep them warm to function. That concept seems odd, and reported in MSM in Aus. And the approaching w/e scorcher here, in the middle of an Aussie summer. 45c tipped for inner west Sydney, Penrith. It’s far enough away from the coast to negate coastal cooling. It’s why Sydney is cooler than Penrith.
Well, there were predictions of a 40+c day on Dec 25th in Sydney, and it wasn’t. 28c at best, ie, usual.