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« Deliberate distortions | Main | More gloom for renewables rentiers »
Wednesday
Apr302014

Wet, wet, wet

The Guardian is reporting claims that extreme rainfall events are becoming more likely in the UK:

Climate change caused by humans has made the likelihood of extreme rainfall similar to that seen in England this winter significantly higher, according to analysis seen by the Guardian.

Rainfall events that would previously have occurred only once in a century are now likely to be witnessed once every eighty years in the south of England, the Oxford University work shows.

This is a very frustrating article as there is no link to a paper. It's therefore hard to tell exactly what has been done to arrive at this conclusion. In fact it's not entirely clear whether there is a paper backing up these claims - it may be that there is only a press release.

But we should only note that the apparent contradiction with reports a few years ago that the drought risk in the south of England was similar to that in the Sahara.

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Reader Comments (48)

"Climate change caused by humans"

That sounds like a tacit (if unintentional) admission that there are other sorts. Perhaps the Grauniad would like to quantify the natural contribution..?

Apr 30, 2014 at 9:45 AM | Registered Commenterjamesp

Climate researchers seem to be rather like Lord Derby of whom David Lloyd George said:

Like a cushion he always bore the impress of the last man who had sat on him.

Climate researchers's prognostications for the years to come bear the impress of whatever the weather has been doing in recent months. A long, hot spell, and global warming will lead to more droughts; torrential rain, and climate change will cause more floods; a series of storms, and climate change will cause more storms.

Who needs complex models and expensive super-computers or even crystal balls? Anybody can make the same long term predictions using this methodology. Could any lurking, consensus-supporting climatologist possibly deny that this is the case?

Apr 30, 2014 at 9:59 AM | Unregistered CommenterRoy

"Climate change caused by humans"

This is a big improvement over the Orwellian "Climate Change". When the natural climate change is fully acknowledged, there will be no room for any AGW.

Apr 30, 2014 at 10:00 AM | Unregistered CommenterEdim

"Rainfall events that would previously have occurred only once in a century are now likely to be witnessed once every eighty years in the south of England"

What used to be expected as at most a once in a lifetime experience is now expected to be an at most a once in a lifetime experience, in the south of England.

As someone who lives in the south of England, should I be more afraid?

Apr 30, 2014 at 10:04 AM | Unregistered Commenterson of mulder

Most official bodies and the lefty MSM outlets are lying about this, e.g. http://notrickszone.com/2014/04/29/german-weather-service-employs-manipulative-statistical-sleights-of-hand-to-craft-warming-from-cooling/

This is the German Weather Service manipulating data to pretend that the German climate is still warming.

Apr 30, 2014 at 10:09 AM | Unregistered Commenterturnedoutnice

To carry out my research into historic reconstruction of the climate I sped a lot of time at the Met Office library. The overwhelming impression I get from reading the historic reports is that they had FAR more extreme events at times in the past than we do now. Heavy rain and monumental flooding are the most notable features, followed by extreme heat waves. Here is a short extract from consecutive years in the 13th century


1233 wet summer from 23 March with great inundations of rain through the whole summer destroying warrens and washed away the ponds and mills throughout almost all England. Water formed into lakes in middle of the crops where the fishes of the rivers were seen to great astonishment and mills were standing in various places they had never before been seen.

1233-1234 severe frost from Christmas 1233 to Feb 2 1234 destroying roots of trees to four foot down then rest of year very unseasonable

1234 third unseasonable year
Wet weather in autumn choked the seed and loosened it.

1236 great floods in Jan, Feb and part of March that no one had seen the like before. Bridges submerged, fords impassable, mills and ponds overwhelmed and sown land meadows and marshes covered. Thames flooded palace of Westminster so small boat could be navigated in the midst of the forecourt. And folk went to their bed chambers on horseback
Followed by dry summer with intolerable heat that all lasted four months. Deep pools and ponds were dried up and water mils useless.

1237 great rains in February, fords and roads impassable for 8 successive days
Turbulent year stormy and unsettled

1238 great floods in many parts December
Cloudy and rainy in beginning until spring had passed then the drought and heat were beyond measure and custom in two or more of the summer months. Great deluge of rain in the autumn that straw and grain became rotten and an unnatural autumn which is held to be a cold and dry season gave rise to various fatal diseases.

1239 very wet weather continually from Jan to March, it has continued for four months without intermission.

tonyb

Apr 30, 2014 at 10:13 AM | Unregistered Commentertonyb

I take anything the Guardian says about climate with a tonne of salt.

Apr 30, 2014 at 10:18 AM | Unregistered CommenterSchrodinger's Cat

Tonyb (Apr 30 2014 @10:10am), you should publish this record on a web site so that anyone who claims "unprecedented" could be pointed to it.

Apr 30, 2014 at 10:29 AM | Unregistered CommenterIlma

Schrodinger's Cat ... I take anything the Guardian says about climate with a tonne of salt.

You old cynic! :-)

Apr 30, 2014 at 10:32 AM | Unregistered CommenterYertizz

I have watched several uk programs recently about their recent winter all hosted by met off geniuses, using met off personnel, and they have all 'suggested' that "climate change" was part of the winter weather. What they are doing is providing the media with an opportunity to promote the MOs AGW emmissive without the MO being directly implicated. All of their pronouncements are based on their FAILED models and they know they have failed.

Apr 30, 2014 at 10:33 AM | Unregistered Commenterstephen richards

How long does it take to accurately establish, with, say 20% error bars on either side, how often random roughly-once-per-century events occur?
Ooh, say, 1000 years of data?
How far back do we have accurate rainfall data for the UK? 25 years, 50 years?
I suggest we start taking this claim seriously if it still stands in the year 2964.

Apr 30, 2014 at 10:33 AM | Unregistered CommenterAlex

So, in a 1,000 years there should be 12-13 such events rather than 10. Maybe 10,000 years hence there will be 120-130 events validating that part of the claim with reasonable confidence. But who the hell knows what the British climate will be like then (or, indeed, who cares); or, indeed, whether there has been approximately 100 similar events since 8000 BC?

Apr 30, 2014 at 10:34 AM | Unregistered CommenterNeil McEvoy

@ Schrodinger's Cat

For the sake of your health you had better stop reading the Guardian. It must be terrible for your blood pressure!

Apr 30, 2014 at 10:35 AM | Unregistered CommenterRoy

A few years ago this was the 'official' line:

https://www.gov.uk/.../pb13274-uk-climate-projections-090617.pdf‎

They were then (2009) predicting hotter and drier summers, warmer and wetter winters. Strange that only 3 years later the wettest summer for 100 years (2012) was therefore 'proof' of climate change..........and the fact that since 2009 we've had some of the coldest winters for decades doesn't seem to cause any problems for the prediction either.

Apr 30, 2014 at 10:36 AM | Unregistered CommenterJim

Clearly man made CO2 is changing the climate so much that we can expect both droughts and floods in the same place and at the same time.

In fact, it's a hell of a gas...

Apr 30, 2014 at 10:36 AM | Unregistered CommenterJimmy Haigh

The guardian article says

The scientists who conducted the study warned that this estimate of the frequency of extreme rainfall was based solely on current levels of observed rainfall in the recent past, compared with historical levels and those predicted for the future under a wide variety of possible scenarios under climate change.

Then says

Under the programmes, the scientists used the spare capacity on home computers to compare tens of thousands of simulations of possible weather in our present-day climate with tens of thousands of simulations of a hypothetical world without the influence of past greenhouse gas emissions in the atmosphere, using the same climate model.

Unless there is an additional angle to the weather@home project that I have missed this does not involve real observations despite the earlier claim but, merely, simulating the present conditions and in parallel also simulating some different conditions and comparing the output. They are stretching the word 'observation' to its limits imo.

Expected results here

Results as they come in here

Apr 30, 2014 at 10:39 AM | Unregistered CommenterGareth

"Rainfall events that would previously have occurred only once in a century are now likely to be witnessed once every eighty years in the south of England, the Oxford University work shows."

That doesn't sound "significantly higher" to me, particularly as it doesn't mean such events would occur every 80 years but only every 80 years on average. There might be another one next year, even under existing odds.
As "son of mulder" says, the average person can expect to experience one such event in a lifetime, possibly.

OT but what is the general opinion on the CH4 documentary "Britain's Most Extreme Weather"?
It seemed to me to be marginally less alarmist in it's conclusions than usual, although that was not reflected in the footage.

Apr 30, 2014 at 10:46 AM | Unregistered CommenterQV

I have a 580 page pdf document entitled "A Chronological Listing of Early Weather Events! compiled by James A. Marusek. It is downloaded from www.breadandbutterscience.com.
It covers what it says on the cover from 6 AD Rome, through chronologies of England, Egypt, China, Japan, Germany etc. up to 1900

Well worth a read.
SimonJ

Apr 30, 2014 at 10:54 AM | Unregistered CommenterSimonJ

http://www.wmo.int/pages/meetings/documents/otto_IPCC14.pdf
"We do need to model the world that might have been "
WTF ?

Apr 30, 2014 at 10:58 AM | Unregistered Commentertoad

A few days ago the Guardian also linked global-warming to the sinking of the Titanic, so I wouldn't pay them too much attention.

It reminds me a bit of the "Wellington Bomber found on moon" or "Hitler found in Birmingham" headlines from the Sunday Sport or some similar publication. All of them made me chuckle.

Apr 30, 2014 at 11:08 AM | Unregistered Commentermichael hart

I have often wondered where the 1 in 100 figure came from, it seems more like a number plucked from the air rather than research of data, which posts above show, is obviously available. Once a lifetime; 1 in 70 seems a more reasonable start point for extreme weather events.

As I'm in my mid 60s I'm expecting another 62/63 winter in the UK sometime in the next 30 years. That would match my mother who was alive in both 1947 and 1962/63 the benchmark winters.

Apr 30, 2014 at 11:10 AM | Unregistered CommentersandyS

It is always claimed that increased heat will bring more severe and increased rainfall. This is not true. Climate/weather works on heat transfer from the tropics to the poles. When the climate warms the polar regions warm more than the tropics so heat transfer falls so reducing storm severity. ie. less rain over a larger area so reduced flooding. cool periods the poles cool faster increasing heat transfer so storms become more frequent and severe due to the extra energy. Locally formed convective storms are small in comparison to regional cyclones though they can drop a lot of water into a small area sometimes with flash flood formation but these events are rare in comparison to cyclonic storm derived floods.

Apr 30, 2014 at 11:28 AM | Unregistered CommenterJohn Marshall

A few comments up thread correctly raise the question of how long a time series would be required to demonstrate that this change is statistically significant. Yes, recently we have had two unusually wet periods, one over a spring and summer and one over the last winter, but the question is whether these are skewing the statistics or are actually representative of a change in weather / climate patterns.

Of course another consideration is whether the rainfall patterns are being changed by changes in land use - clearly the south east of England now has more hard and impermeable materials covering the land than at any time in the past (and with plans for even more building). This means any rain that falls has a greater chance of being evaporated and recirculating into the next rain event, rather than being taken up by the soil and plant life. So, possibly human-caused, but not (or only trivially) linked to warming and increased CO2 levels.

Apr 30, 2014 at 11:30 AM | Unregistered CommenterIan Blanchard

Ian Blanchard:
"This means any rain that falls has a greater chance of being evaporated and recirculating into the next rain event, rather than being taken up by the soil and plant life."
I agree about change in land use but I think it results in water flowing into drains and rivers more quickly resulting in a greater chance of flooding.

Apr 30, 2014 at 11:41 AM | Unregistered CommenterQV

As Grauniad circulation falls I expect it will ultimately be reduced to a single member of staff carrying a sandwich board saying "The end of the world is nigh".

Yet they can't see that coming.

Apr 30, 2014 at 11:54 AM | Unregistered Commenterssat

QV
You're right, but I don't think Ian Blanchard is necessarily wrong. Evaporation from tarmac surfaces in warm (and not so warm) weather is going to put water back into the cycle quicker. Exactly what effect that is likely to have I wouldn't know but it's a further suggestion that there is an anthropogenic element in climate but more to do with land use changes than with CO2 emissions.

Apr 30, 2014 at 12:53 PM | Registered CommenterMike Jackson

Welcome to the world’s largest climate modelling experiment....It must all be true.

Apr 30, 2014 at 1:16 PM | Unregistered CommenterMartyn

I emailed Otto to ask about this.

Results are here
http://www.climateprediction.net/weatherathome/weatherhome-2014/results/
(this IS now linked from the Guardian)

Oxford press release is here
http://www.ox.ac.uk/news/2014-04-30-global-warming-makes-very-wet-winters-more-likely

Note the press release says
"However, the researchers say that while their finding is statistically robust, the result depends on how man-made climate change is represented in the experiment. They used different climate models to estimate the pattern of global warming, which provided a range of possible changes in risk. In several cases, the models gave no change or even a reduction in risk"
Somehow, that bit didn't make it into Fiona Harvey's article.

There is no paper yet.

Apr 30, 2014 at 1:21 PM | Registered CommenterPaul Matthews

A good record of past extreme weather is The Elements Rage by Frank W Lane published in the 40's. It's also a good read. I recommend it if you can get hold of a copy.

I was loaned a copy by my science teacher 50 years ago. It made such an impression I have never forgotten it and only recently tracked down a copy to re-read. It's still as good.

Apr 30, 2014 at 1:45 PM | Unregistered Commenterclovis marcus

QV

Don't entirely disagree -- it will depend a bit on how fast the rain falls as to whether there is a lot of water sitting on impermeable surfaces (e.g for lighter rain) or a lot flowing through drains and into surface run-off (heavier or more prolonged rain). Also, once you have a flooded area, what happens to the water? some eventually drains but a lot is available for re-evaporation.

As an aside, we had a flood in my village at the end of winter, pretty much the last serious storm. The reason was not simply the volume of water but that the walls of a drainage culvert collapsed (maybe because of the wet ground conditions and the foundations being undermined), resulting in the drain backing up and flooding through the High Street and a couple of adjacent roads. I'm not sure exactly how old the drainage culvert is, but it did pass under houses built in the 17th century.

Apr 30, 2014 at 2:40 PM | Unregistered CommenterIan Blanchard

Wot's a "rainfall event"? A raindrop? How is it measured. How will you know if you have two contiguous "events". What if the "rainfall event" changes into a “snowfall event” via a “sleet event” or even just becomes a “mist event” via a “drizzle event” ? So many questions. So many reasons for funding.

Apr 30, 2014 at 3:26 PM | Unregistered CommenterBill Irvine

Clovis - I remember The Elements Rage, or at least the great impression it made on me. That's why I find so many programmes nowadays a disappointment - they have similar titles but when you start to watch it's the usual breast beating we are all guilty cobblers.

Apr 30, 2014 at 4:24 PM | Unregistered Commentermike fowle

"Climate change caused by humans"

That sounds like a tacit (if unintentional) admission that there are other sorts. Perhaps the Grauniad would like to quantify the natural contribution..?
Apr 30, 2014 at 9:45 AM jamesp

No. There are no other sorts. 'Climate Change' is by definition caused by humans (ref. IPCC). If it is not caused by humans it is not climate change.

Apr 30, 2014 at 4:51 PM | Registered CommenterMartin A

sandyS wrote: "I have often wondered where the 1 in 100 figure came from, it seems more like a number plucked from the air rather than research of data, which posts above show, is obviously available."

You might be interested in reading this post by Pielke Jr covering the issue:
http://rogerpielkejr.blogspot.com/2013/09/against-100-year-flood.html

Apr 30, 2014 at 4:59 PM | Unregistered CommenterDaveJR

East stuff , wet , dry , rain of frogs not matter what it will be down to AGW and they have the models to prove it.
Try asking the AGW proponents what climate events would falsify the theory, and you be very lucky indeed to get an answer , odd that !
Has for CIF , at best its mild entertainment , but when it comes to AGW , its nothing but centre for the promotion of its dogma , any form of critical analysis if moderated out of existence.

Apr 30, 2014 at 8:06 PM | Unregistered CommenterKnR

DaveJR
I almost stopped reading at as it confirms what I thought.

The ‘100-year floodplain’ is arbitrarily chosen for regulatory reasons and does not reflect anything fundamentally intrinsic to the floodplain.

but I continued as it is an interesting article. This
What can be done? Given the pervasive use of the concept of the ‘100-year flood’ in flood insurance and regulatory decision-making it seems that adoption of an alternative concept is unlikely.

My alternative is that every generation has a worst I can remember for me the winter of 1962/63 for snow/cold and a year in the late 60s early 70s for rain, I can't actually remember which year but can remember the rain. I'm still inclined to the three score year and ten is a good arbitrary measurement.

Thanks for the link.

Apr 30, 2014 at 8:15 PM | Unregistered CommenterSandyS

We have high confidence that there will be weather in the future. Further, we have high confidence that sometimes it will rain and sometimes not. This is unprecedented!

Apr 30, 2014 at 8:45 PM | Unregistered CommenterLeon0112

Tonyb said:

To carry out my research into historic reconstruction of the climate I sped a lot of time at the Met Office library.

I wonder if you have come across the work of W.J.R. Alexander, Professor Emeritus, Department of Civil Engineering, University of Pretoria? He has been working on sought prediction in southern Africa and believes that the sun, not human activity, is primarily responsible for apparent changes in climate. Although his studies concern a much shorter period than yours they do go back to about the 1840s. See in particular the appendices at his website.

TECHNICAL REPORT
Development of a sub-continental drought prediction method
http://www.droughtsandfloods.com/index.html

Apr 30, 2014 at 9:20 PM | Unregistered CommenterRoy

Tonyb 10.13am

Extreme weather in the thirteenth century eh? Medieval period - last time temperatures reached similar levels or greater than the present?! Could this support the grauniad's story rather than not? perhaps not the best examples to quote.

Apr 30, 2014 at 9:29 PM | Unregistered Commentermiket

Apr 30, 2014 at 10:13 AM | tonyb

1239 very wet weather continually from Jan to March, it has continued for four months without intermission.

The above and the preceding years might well explain the Little Ice Age. There are two ways to get glaciers growing - lower temperatures and more precipitation. Volcanos not required.

Apr 30, 2014 at 10:11 PM | Unregistered CommenterBilly Liar

The poor UK: If the track record of your weather forecasters stays on course, the UK is in for years of terrible droughts now.

May 1, 2014 at 2:51 AM | Unregistered Commenterhunter

At university hydrology (for civil engineering) classes we spent a lot of time learning how to estimate the "extreme" probabilities of rainfall, river flows, etc. using Gumbel Distribution (http://en.wikipedia.org/wiki/Gumbel_distribution). When plotted on "special" Gumbel graph paper (pictured in this Wikipedia article) we would seek a straight line fit. With that we had a bit more confidence about the extrapolations which were used to set design basis for, say 100 year or 500 year storms. I must have missed the folks at Oxford using that technique. I guess the difference is they used computer simulations and we used real data.

May 1, 2014 at 8:20 AM | Unregistered CommenterRob Schneider

Like other commenters, I cannot find any evidence that there was any attempt to calibrate the model results to real-world data. Confirmation that the base "observed" model can capture the frequency distribution of observations in the real world is a minimum necessary condition for drawing any conclusions from the comparison between the two (ensembles of ?) models. Not only is there no mention of such model calibration, but the real-world observations themselves suggest that the exceedance data from models bear no relationship to reality.

The UK Met Office Hadley Centre has conveniently archived seasonal precipitation data for subregions of the UK going back to 1874 for the winter months - DJJ. The two regions considered by the Climateprediction exercise correspond to "SEE (SE England)" and "SWE (SW England and Wales)". I downloaded the data and used an eyeballed areal weighting factor of 40% and 60% to obtain areal weighted average precipitation over the two regions.

From the measured data, there were 30 years (out of the last 141 years sampled) where winter precipitation over the Southern UK exceeded 400mm - identified from the Climateprediction graph as a 1 in 10000 year exceedance level. There were 30 years out of the last 141 years sampled where precipitation exceeded 328mm - identified from the Climateprediction graph as a 1 in 100 year exceedance level for the "observed" model case.

There are possibly some useful inferences that can be drawn by a direct examination of the historical data. However, the only inference I can draw from the Climateprediction exercise is that it is possible to waste enormous amounts of human and computing resource and costs to produce absolutely meaningless results.

May 1, 2014 at 12:38 PM | Unregistered CommenterPaul_K

Erratum:
In my last post, I should have written:-

"There were SEVEN (7) years (out of the last 141 years sampled) where winter precipitation over the Southern UK exceeded 400mm..."

Disconnect between brain and hand, sorry.

May 1, 2014 at 12:42 PM | Unregistered CommenterPaul_K

This reminds me of a story that Texas heat waves have become twenty times more likely due to climate change. John Nielsen-Gammon explained the problems with that report. This is not necessarily an exact parallel, but sounds rather similar.

May 1, 2014 at 2:00 PM | Registered CommenterHaroldW

There is near certainty that within the next 50y some emergent phenomenon pops up that completely cancels all of the dire "predictions". This ranges from nuclear war , bio attacks a decimation of humankind, a major tsunami say 10x bigger than the 2005 one, a comet or volcano or earthquake out of our past 200y "experience", cheap fusion energy, a new physics, our exit towards other planets, etc etc

But while we are awaiting this the usual leftwing parasites will keep living the good life off our backs, at indefinite entitlement and privilege, while trying to subvert all work and achievements of others. 't was always thus.

May 1, 2014 at 2:56 PM | Unregistered Commenterptw

Miket


The 13th century was very much one of transition from the mwp to the First episode of the lia. There was very mixed weather with some very warm and some very cool periods. The late 12 th century looks to be very warm and after the mixed climate during the 13th century The weather really perked up again in the late 14th century with what looks to be long settled weather years appreciably warmer than today.

Tonyb

May 1, 2014 at 9:31 PM | Unregistered CommenterTonyb

HaroldW,
Thanks for the reference. The JNG article is highly relevant. It sets out in rather more detail what I was referring to when I wrote:-"Confirmation that the base "observed" model can capture the frequency distribution of observations in the real world is a minimum necessary condition for drawing any conclusions from the comparison between the two (ensembles of ?) models." An examination of the real observed data for the present exercise suggests that the "model observed" data bears little relationship with reality. The risk factor curve also shows a truncation at the zero point - suggesting that the study authors have eliminated any models which showed a reduction in precipitation - no reasons given. I am sure the study is valid in some virtual world, somewhere.

May 3, 2014 at 9:22 AM | Unregistered CommenterPaul_K

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