Recent paper finds extreme weather & flooding became less frequent/extreme in Southwest England

Remember this past winter and the wailing over the floods in the Somerset levels?

Somerset_flooding_climate_changeThe paper, much like our WUWT analysis this past winter, totally contradicts the Guardian’s claims, which seems to be based on “low information pollees”.

Catastrophic Floods of Dartmoor, South West England


Background

The authors write that “extreme floods are the most widespread and often the most fatal type of natural hazard experienced in Europe, particularly in upland and mountainous areas,” noting that “these ‘flash flood’ type events are particularly dangerous because extreme rainfall totals in a short space of time can lead to very high flow velocities and little or no time for flood warning.” And “given the danger posed by extreme floods,” they say “there are concerns that catastrophic hydro-meteorological events could become more frequent in a warming world.”

What was done

In a study designed to see if such a trend may have established itself over the past several decades of climate-model-induced angst, Foulds et al. constructed “a high resolution record of flood activity on Dartmoor over the last ca 150 to 200 years using lichenometry,” thereby enabling “recent devastating floods in the South West of England to be placed in a more meaningful temporal context, which short-term instrumental data cannot provide.”

What was learned

The three UK researchers say their results show that Dartmoor experienced “widespread flooding, with particularly large and frequent events in the mid-to-late 19th and early 20th centuries,” while there has subsequently been “a general decline in flood magnitude that was particularly marked after the 1930s/mid-1940s,” which they indicate was “primarily due to a decrease in heavy rainfall events.”

What it means

From Foulds et al.’s point of view, as they express it in the concluding sentence of their paper, “the dangers of not accounting for historical flood frequency and magnitude may lead to an underestimate of flood risk,” which is clearly correct. In addition, it suggests that in response to 20th-century global warming, this extreme weather event (flooding due to heavy rainfall) became not more frequent and extreme, but less frequent and extreme, in total contradiction of what the world’s climate alarmists claim should be happening in response to global warming.

Source: CO2 Science (h/t to The Hockey Schtick via Twitter)

Reference

Foulds, S.A., Macklin, M.G. and Brewer, P.A. 2014. The chronology and the hydrometeorology of catastrophic floods on Dartmoor, South West England. Hydrological Processes 28: 3067-3087.

http://onlinelibrary.wiley.com/doi/10.1002/hyp.9853/abstract

Abstract

Extreme floods are the most widespread and often the most fatal type of natural hazard experienced in Europe, particularly in upland and mountainous areas. These ‘flash flood’ type events are particularly dangerous because extreme rainfall totals in a short space of time can lead to very high flow velocities and little or no time for flood warning. Given the danger posed by extreme floods, there are concerns that catastrophic hydrometeorological events could become more frequent in a warming world. However, analysis of longer term flood frequency is often limited by the use of short instrumental flow records (last 30–40 years) that do not adequately cover alternating flood-rich and flood-poor periods over the last 2 to 3 centuries. In contrast, this research extends the upland flood series of South West England (Dartmoor) back to ca AD 1800 using lichenometry. Results show that the period 1820 to mid-1940s was characterized by widespread flooding, with particularly large and frequent events in the mid-to-late 19th and early 20th centuries. Since ca 1850 to 1900, there has been a general decline in flood magnitude that was particularly marked after the 1930s/mid-1940s. Local meteorological records show that: (1) historical flood-rich periods on Dartmoor were associated with high annual, seasonal and daily rainfall totals in the last quarter of the 19th century and between 1910 and 1946, related to sub-decadal variability of the North Atlantic Oscillation and receipt of cyclonic and southerly weather types over the southwest peninsula; and (2) the incidence of heavy daily rainfall declined notably after 1946, similar to sedimentary archives of flooding. The peak period of flooding on Dartmoor predates the beginning of gauged flow records, which has practical implications for understanding and managing flood risk on rivers that drain Dartmoor.


 

Of course, a picture always says it better, as in “Dredge the flood channel, you idiots!”.

somerset-bridge_2825383b

 

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wow, wonder how deep that build up is.
hard to tell from pics but looks at least 4 feet on edges.

Doug Proctor

The colour and black and white photos of the bridge are from different positions. The colour photo is taken further away from the water and shows more embankment. Look carefully at the piece of secondary “channel” on the left of the photos: both look similar.
I would suggest that the photos say nothing about the dredging needs (I.e. the question remains to be answered regarding silting up at this site).
Sorry. Skeptical works both ways.

RTB

Except the culverts are draining into open water on the old picture and are surrounded my grass on the recent picture. Maybe they rebuilt the bridge and moved the culverts or maybe you are seeing what you wanted to see?

ShrNfr

The channel has indeed gotten more narrow on the basis of what you say. How deep it may or may not be is an open question. I suspect that they dredged the channel and just threw it over toward the embankments that used to be stone in the older picture. In the newer one you cannot even see the old stone.

The photos are from the Telegraph which says the river width was halved. It says “The overflow holes in the sides of the bridge which were once above the water line now sit redundantly in the side of the banks, surrounded by grass and mud.”
See http://www.telegraph.co.uk/topics/weather/10644101/How-Somerset-Levels-river-flooded-after-it-was-not-dredged-for-decades.html

James Bull

A friend of mine who lives near the river Thames in Laleham was telling me the other day that they saw something not seen on the river for many years and which they were sure the EA (environment agency) had got rid of as not needed.
What was this strange thing you wonder?
A dredger
James Bull

Was the sequence of the photos first the old one then the flooded one finally the receded flood one?
There is a line on the new bridge photo which is pretty close to the flood line?
Does it flood there often or was some of the dirt in the new photo left behind from the flood?
The old photo shows a fairly high flood line also.
Curious.

Okay, retraction: my skeptical partner looked at these photos and pronounced me wrong. The right hand side shows significant bank development in the newer photo. At a minimum the drainage width has decreased at flood time. It would be reasonable to believe – though not necessary to be true – that the depth of the channel has also decreased. Which means significant total volume for flood release has been lost.
Mea culpa. Blame me, I blame the margarita I’m drinking in Palm Springs, California, as I avoid the 43C temperatures in this open-canal irrigated desert in a State experiencing a 8+ failure of the winter snows (replenishing the reservoirs).
Regardless, I was wrong!

Robert Kral

Spoken like a man. We could use more of that in this world.

SandyInLimousin

+1

Bruce Cobb

The “more extreme weather” myth is a convenient one for alarmists, and one that the low-IQ and mentally lazy readily fall for. It’s believable only because reporting on weather has reached epic proportions both in scope and volume, and because the myth keeps being repeated non-stop.

Stacey

If they asked the people who live on the Somerset Levels or close by I’m sure that 97% would say the floods were due to the Environment Agency and National Rivers Authority. Who decided not to dredge, close pumping stations and deliberately created wet lands for the lesser spotted three legged vole?

asybot

There you go again! Here I thought it was for the Blotched spotted , hockey sticked legged mannmot.

Leo Smith

You are both wrong, it was for the lesser brained rent seeking green environmentalist.

John Law

What do locals know? We have an army of green bureaucrats in London to run Somerset.
What could possibly go wrong?

joelobryan

Obama signs proclamation making September “National Preparedness Month.” In this one pager, his proclamation says, “Our Nation also faces longer wildfire seasons, more severe droughts, heavier rainfall, and more frequent flooding in a changing climate. ”
At least his advisors likely told him not to say more severe storms.
http://www.whitehouse.gov/the-press-office/2014/08/29/presidential-proclamation-national-preparedness-month-2014
He probably really believes that with being surrounded by Liars such as Dr. John Holdren.

I’ve just driven the coast road from Washington state through Oregon and to the southern end of California. I’ve been to the Salton Sea and am now siting in Palm Springs awaiting a new radiator and air conditioner condenser – vehicles break down when you are in 43*C temperature, running solid 7 hours per day. I’ve done 3700 km so far.
The drought is real, and south of San Francisco it is obvious that the trees are uncomfortably dry. The locals all along, though, say that dry is not so unusual. And the desert parts are, after all, deserts. What we see is huge areas dependent on irrigation, and by the amount of land in development or recently planted or built on, an area that has had increasing fresh water demands. What those we have spoken to say as a consistent group is that water management and overdemand is the problem.
The winter snows have failed. Resupply of the reservoirs has not occurred. But in all this we are still daytime open water irrigatiing the farmlands. The canals from the Colorado into the Salton Sea are open, as are the irrigation lagoons/ponds. Water loss through evaporation is high.
We have seen what looks like drip irrigation, but the area of wine grapes, citrus fruit and date palms under construction is astonishing for an area with multiple year water problems. Water is rightly viewed on posters as the energy that puts food on America’s tables, but you have to ask if the trajedy of the commons isn’t being replayed here with respect to water: we just read that an Indian tribe was recognized as having greater call on water from the Colorado that the farmers wanted to take for their crops, the Indians harvesting salmon from rivers proposed to be reduced for irrigation purposes. Agriculture, aqquaculture and human culture are battering at their common borders.

lee

Yep vehicles breakdown in Australia too. We generally service them if we are going on long runs, especially in summer.

Joanie B

It is most definitely poor management and too much demand. The bureaucracy cannot break its dependence on new housing, more sprawl, and more tax streams. On the other hand, they fight against a well considered management program or investment in infrastructure. We live in an arid coastal desert, ‘drought’ does not seem like the best word, it implies a temporary or unusual situation. Aridity is NORMAL here in So Cal. Punctuated by massive flooding. People’s memories tend to blur the extremes and to imagine a more idealized climate, but thoughtful natives know that is not the case.

Latitude

which they indicate was “primarily due to a decrease in heavy rainfall events.”
What it means………….global warming causes drought…we’re all going to die

Leon Brozyna

Of course, there’s always the obvious that’s never mentioned … if you live on a flood plain, you can expect to experience a flood from time to time …

asybot

You are kidding right? pointing out logic, say it isn’t so

DonK31

What I hear here is that 97% of those who choose to read The Guardian believe what is written in The Guardian without bothering to check the accuracy of the report.

pat

doesn’t stop this kind of rubbish being published:
2 Sept: UK Telegraph: Tom Brooks-Pollock: Mini-heatwave could be shape of things to come
Met Office’s three-month forecasts suggest “above average” temperatures for September, October and November
As temperatures rise to an unseasonably warm 25 Celsius (77F) by Thursday and Friday, longer term forecasts issued by the Met Office raised further hopes of an Indian summer…
The Met Office’s three-month outlook, used by the government for contingency planning, suggests “above-average” temperatures for September, October and November.
It says: “Overall, the probability that the UK-mean temperature for September-October-November will fall into the warmest of our five categories is around 35 per cent and the probability of falling into the coldest of our five categories is between 10 and 15 per cent.”
Higher temperatures this week have been prompted by high pressure from the jet stream of ex-Hurricane Cristobal as it has tracked north-east across the Atlantic…
http://www.telegraph.co.uk/topics/weather/11070965/Mini-heatwave-could-be-shape-of-things-to-come.html
***great to see “climate change expert” Anthony get a mention, even if they got his name wrong!
3 Sept: UK Daily Mail: Victoria Woollaston: ‘Global warming has been on pause for 19 years’: Study reveals Earth’s temperature has remained almost CONSTANT since 1995
•Professor Ross McKitrick studied land and ocean temperatures since 1850
•He also compared this to satellite data from 1979 to 2014
•Trends in this data revealed global warming has been on pause for 19 years
•And it has been on hiatus for between 16 and 26 years in the lower troposphere – the lowest portion of the Earth’s atmosphere
•This is longer than the 15 years previously predicted by the IPCC
***Climate change expert Anthony Watt recently illustrated these findings by using Hadcrut4 data available online…
http://www.dailymail.co.uk/sciencetech/article-2740788/Global-warming-pause-19-years-Data-reveals-Earth-s-temperature-remained-CONSTANT-1995.html

diogenese2

“Ross McKitrick studied land and ocean temperatures since 1850……”, Wow whatever he is taking is pretty good stuff.

climatereason

I live very close to Dartmoor and will have been walking there twice in the last week. A few years ago there was a plan to deliberately take measures to retain MORE water on Dartmoor as it was thought that climate change had made it drier.
I was on a committee that was able to point out that it depended on what time scale you looked at, as whilst the more recent past had been dry (for a decade or so) there was plenty of evidence for both very wet and very dry climate states. It depends on how prominent the westerly winds are, as that is where Dartmoor receives its rainfall from.
As a local researcher fortunate enough to have the Met Office archives on my doorstep this fluctuation can be detected locally going back a thousand years. The rainfall in particular during parts of the LIA was prodigious. Downstream Exeter (where the Met Office is located) was flooded numerous times, bridges swept away, mills destroyed and famine ensued due to crop failure.
Lets hope we don’t return to those extremely wet times but I guess it will depend on the westerly winds and other factors that for a thousand years of records can be seen to have radically changed Dartmoor rainfall levels at times, without the benefit of added co2.
tonyb

Tonyb, here are some Guardian flood stories the luvvies won’t be reading:
http://www.theguardian.com/weather/page/0,,2208302,00.html
Seems it was, er, worse than they thought.

Village Idiot

Lichenometry??
http://en.wikipedia.org/wiki/Lichenometry
Ha,ha,ha,ha,ha,ha! :-)))))))) Ha, ha, ha ,ha ,ha. Choked on my tea :-))))
This would have received short shrift if the paper’s conclusion had been the opposite.
You’ll be telling us to believe in tree rings and fairy rings next

lee

For your continued amusement –
‘Most of the arctic and alpine crust lichens, especially the genera Rhizocarpon and Lecidea grow very slowly. This can be concluded indirectly from maximum diameters on rock surfaces of known age or repeated measurements. The over all constant increment after an initially sigmoidal growth allows dating of rock surfaces exposed up to 1000-4500 years B.P., depending on the climatic conditions. Lichenometry permits relative dating of events which led to the exposure of bare rock surfaces within the age limit of the lichens in similar macroclimates. This can be converted to an absolute scale if one event is dated by other means, e.g. historical information, or if the growth rate is measured directly. From lichen measurements obtained in West Greenland, the Alps, and the Ruwenzori Mountains, the synchronism of glacier behaviour within the advance period of modern times (400-40 B.P.) appears very high. Early hypothermal moraines and boulder streams can be separated clearly from early modern ones, even if other morphological criteria fail. Lichen growth rates are inversely proportional to the hygrocontinentality of the area. This permits calculation of this or similar combined climatic factors through lichenometry, or the prediction of lichen growth rates from the known climate. Lichenometry is especially useful where dendrochronology is impossible.’
http://www.bcin.ca/Interface/openbcin.cgi?submit=submit&Chinkey=34736
see also
http://www.jstor.org/discover/10.2307/520831?uid=2&uid=4&sid=21104116584471
http://onlinelibrary.wiley.com/doi/10.1111/j.1502-3885.1984.tb01128.x/abstract

Village Idiot

My point exactly

Stephen Richards

Doug Proctor
September 2, 2014 at 5:54 pm
Sad, but Still nothing compared with past droughts and normal weather for Cold PDO and La Niñas. All that was needed was a communist with a brain. Oh, sorry, that is an impossibility.:)

Stephen Richards

The Met Office’s three-month outlook, used by the government for contingency planning, suggests “above-average” temperatures for September, October and November.
That explains why their planning is sooooo bad.
Higher temperatures this week have been prompted by high pressure from the jet stream of ex-Hurricane Cristobal as it has tracked north-east across the Atlantic
That’s a first. A hurricane that carries it’s own jet stream with it.

rtj1211

Saying in the Guardian that global warming isn’t human-induced and dangerous is rather like the Pope saying that the Virgin Birth didn’t happen and Mary was a naughty little girl who old Joe took pity on…….
Not very likely, is it?!

Jared

Tornadoes down, Hurricanes down. It’s amazing that the believers claim ‘catastrophe, we must act now’ when the real world says ‘no change’. I can’t wait for these believers to tell us flash floods will cause the Grand Canyon to overflow causing disaster. Act now or the Grand Canyon will overflow. Act now or a Hurricane will hit you. Act now or a Tornado will hit you. Scary. It’s a whole 0.7 degrees warmer. Yikes that’s hot.

Johanus

“If you believe that elves make the rain, every time it rains you will see proof of elves.”
If you are taught that manmade CO2 causes catastrophes, then every climate disaster will seem like proof of CAGW.

Johanus

… to be fair, I must point to the fairly large literature on “proof of elves
🙂

This recent study by Phil Jones also finds no trend in extreme precipitation for England (though it does in Scotland)
http://notalotofpeopleknowthat.wordpress.com/2014/09/03/new-paper-finds-no-increase-in-extreme-rainfall-in-england/

ralfellis

I have seen these pollsters and these pollees in action. If you dress up as a council official, and wear a badge, the afternoon drunks and dossers of the modern welfare society will say ‘yes’ to anything you ask. Their sole goal is to not rock the boat too much, to keep the welfare cheques a-rolling in.
Ralph

Sleepalot

Sigh. We’ve (England) been digging ditches since the neolithic: we’ve been filling them in since the war.

Ulric Lyons

“In addition, it suggests that in response to 20th-century global warming, this extreme weather event (flooding due to heavy rainfall) became not more frequent and extreme, but less frequent and extreme, in total contradiction of what the world’s climate alarmists claim should be happening in response to global warming.”
There is a fundamental problem here, warming will increase winter rainfall, but reduce summer rainfall.