Is UK Rainfall Becoming More Extreme? Not at Oxford.
By Paul Homewood
It’s worth taking a closer look at daily rainfall in Oxford, as it has such a long database, back to 1827. It tells us a lot about the weather in recent years, things that the Met Office want to hide from us.
Although we keep being told by the Met Office that our weather has been so wet in recent years because a “a warmer atmosphere can hold more moisture”, the principal factor is, and always has been, the number of days when it rains. In other words a meteorological phenomenon, not a climatic one.
The general definition of a rainday is when rainfall exceeds 1mm. The chart below plots these at Oxford. Data is from KNMI:
https://climexp.knmi.nl/data/pgdcnUK000056225.dat
Last year was 5th wettest and also featured high in the number of raindays. The years 2000, 2012 and 2014 also feature highly, as well as earlier ones such as 1872, 1916, 1927, 1951, 1958 and 1960.
Some periods have plenty of raindays, others much less. But there is no apparent trend in either direction.
But we can also analyse the average rainfall intensity, that is rainfall per rainday:
Last year had one of the highest intensities, in large part because spring and early summer was so dry. These are the times of year when daily rainfall is low, with mainly showery weather, so the overall average is bound to be exaggerated. But 2023 was by no means unusual, as there have been other years with similar rainfall intensity, such as 1915, 1949 and 1960.
More notable though is the occurrence of those years in the 1830s, when rainfall was clearly much more intense. Hardly evidence for the Met Office’s theory!
All of this is, of course, weather. I defy anybody to find a pattern or trend towards rainfall becoming more intense in Oxford in the above chart.
Again the overall trend suggests that rainfall intensity has been declining over the period of record.
Maybe the Met Office would like to explain.
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NOT A LOT OF PEOPLE KNOW THAT 
I’m sure that the Met office would not like to have to explain, to a knowledgeable group anyway.
As with the Thames Barrier issue attribution models now dominate the thinking of the once pragmatic Met Office.
Translation:- “attribution models” = pseudoscientific fraud
I would have thought “WAG” (wide-eyed guess) was a better description than “attribution model”!
Computer game?
The Met Office is already lost to the climerati, it has turned away from empirical science as it chases narrative funding
The entire AGW theory predicates that increased CO2 initiates a water vapour feedback and that water vapour is the “heavy lifter” in increasing the power of the greenhouse effect, not the CO2 itself.
Question on “RealClimate”
“Is there a way to calculate the forcing where increasing concentrations of CO2 causing a feedback of increasing H2O evaporation yield an amplified forcing from the combination of CO2 and water vapor?
[Response: Yes. This is done all the time in simple one-column models of the atmosphere, such as pioneered by Manabe. Since you don’t have the dynamics that control water vapor in such models, you replace all that with a n assumption that the relative humidity remains fixed as climate warms. Thus, more water vapor goes into the atmosphere, leading to more greenhouse effect, and amplifying the initial effect of CO2. Dave Archer’s online model has an option to hold the relative humidity fixed as you increase the temperature of the atmosphere, which allows you to explore this feedback. –raypierre]”
It’s that process which allegedly will drive the planet to 2.9 K extra from doubling CO2.
Anyway, consider this..
First we have a critique of Ferenc Mark Miskolczi where they claim “..Miskolczi’s critics have stated that his theory is incorrect in that it predicts that water vapor will decrease in response to carbon dioxide levels increasing, thus counteracting CO2’s warming effect. However, according to Tony Eggleton, “Observations show that the water vapor content of the atmosphere is increasing in response to global warming, not reducing.”[13]” https://en.everybodywiki.com/Ferenc_Miskolczi#cite_note-11
But then we have a new WUWT post where we see that “..Per state-of-the-art climate models, relative humidity (RH) should decline slightly as a consequence of CO2-induced global warming. But 40 years of observations (1980-) show not a slight declining trend, but a declining trend that is “about an order of magnitude more than the models on average.” In other words, the climate models are wrong by a factor of 10.” https://wattsupwiththat.com/2024/02/19/new-study-climate-models-get-water-vapor-wildly-wrong-a-major-gap-in-our-understanding/
Look at the many posts in RealClimate (NASA blog site) posts from Raymond Pierrehumbert and Gavin Schmidt about the GHE and amongst all the gobbledygook they use you will find they rely entirely on a warming planet having more moisture in the air to push the AGW theory/agenda, so what happens when the observation is not there?
https://www.realclimate.org/index.php/archives/2007/06/a-saturated-gassy-argument-part-ii/
The WUWT quote you make refers to water vapour over dry areas, not the globe as a whole. So your conclusion that the difference to climate models is wrong – it will be considerably less than 10%.
It does, however, show just one of the many assumptions that are made in modelling, and therefore they should not be taken as gospel. The original article authors seemed somewhat baffled by the results – if they were to consult any competent hydrologist they would know the reason (there is a critical depth of the water table at a few metres when the moisture held does not have the ability to reach the surface). You cannot have evaporation when there is no water.
From your references there is also a lack of distinction between water vapour in the atmosphere and relative humidity – important to distinguish between the two.
You might also find it informative to look at the following link:
Record-breaking global atmospheric moisture in April (weatherzone.com.au)
It shows the increase in atmospheric water vapour over the last few decades as recorded from Copernicus satellite. Amazing how similar the trends are compared with atmospheric temperature.
The data and graph you should see in the WUWT post and others and from Ferenc M. Miskolczi is for “the global average annual relative humidity at various elevations in the atmosphere expressed in milli-bars (mb) from 300 mb to 700 mb for the period 1948 to 2008. The data is from the NOAA Earth System Research Laboratory”
Global relative humidity is decreasing and even your met office accepts that and that that means that the air is not as saturated as it was, a less saturated atmosphere must have a decreased GHE.
Not sure how to attach a graph but a simple Google search
“relative humidity climate4you”
will show this at different heights in the atmosphere from Ole Humlum and using NOAA earth system research data and mush more up to date and all is falling.
I would add that without the water vapour feedback the predicted increase in T from x2 CO2 is only 1.4 K which is next to nothing, considering these models make any such change up in CO2 levels convert to temperature when that does not have to be the case.
That sort of energy can be converted into photosynthesis for instance.
In other words, green the planet further.
The Royal Met Office dictum – Never Explain
O/T but our phenomenal wind drought Hsiang windmills producing oh point eight per cent of our electricity as I write. Four days plus Fri and Sat?
Sorry not Hsiang
Apologies for this O/T post, but at 19-35 today, 24th May, Gridwatch show Wind supplying a whopping 1% of demand. What do you naysayers have to say about that then? The Plan is therefore on-track and with evidence of this magnitude, perhaps you will refrain from denigrating the massive achievements made to make the World’s environment significantly cleaner and healthier.
The Met Office still has this on their website:
https://www.metoffice.gov.uk/weather/climate-change/causes-of-climate-change
I’m sure this is a lie
Says that the IPCC ‘unequivocally’ says humans cause climate change etc but does not mention the IPCC’s terms of reference which are to discover the human effects on climate change ( viz ignore sun etc). Is this a lie? Yes, smells like it.
One neat way to analyze stochastic series is to develop a residual mass curve where ordinates are cumulative residuals (observation less mean of series) plotted vs time. Sub-series sloping up means period of observations above normal and sloping down period of observation below normal.
In the case of the Oxford series the residual mass curve of annual precipitation totals yields the following salient sub-series:
Period No. years % Normal Precipitation
1827-1874 48 96%
1886-1902 17 108%
1997-2023 27 107%
Other sub-series are of lesser interest.
The main conclusion is that below-normal (dry) or above-normal periods (wet) can last quite a few years thus invalidating some of the assumptions made in a number of climate studies (randomness). This is known as Hurst’s Phenomenon or Joseph Effect (the seven fat cows followed by seven lean cows in the Bible). Unfortunately, the analysis of this phenomenon, far superior to moving average, trend analysis or the like seems to be the exclusive purview of water resources and/or hydrology engineers. These specialists, besides producing arcane technical reports for their clients seldom publish at large. Notable exceptions are Demetris Koutsoyiannis, professor emeritus of Hydrology and Analysis of Hydrosystems in the National Technical University of Athens and the late Vít Klemeš of Environment Canada. Anyone practising or dabbling in climate change analysis should be aware of this phenomenon before trusting blindly climate models whose main characteristics is their lack of parsimony.
Randomness means clumping. A dice can turn up a six a number of times in a row without being loaded. And rainfall in Oxford has multiple causes, so may well appear to be non-random but the causes may be entirely different each year. Climate science does not understand the climate.
May I make the observation that you explained that point superbly well. I wish I could write so succinctly!
Australian climate agitators have deployed something like that to turn no-trend into something to scare the unwary. They define “normal” rainfall to be an average of a very rainy period around 1970. Nothing much is changing in recent decades with rainfall in Australia, but the “accumulated rainfall deficit” keeps growing!
Hurst’s phenomenon was new to me. Found link:
Full article: The scientific legacy of Harold Edwin Hurst (1880–1978) (tandfonline.com)
it’s Friday now and an unbelievable oh point four one gigawatts. Decarbonise it!
When you understand what is happening to the climate … it is really really really boring. Never has so much been written about a subject as exciting as paint drying.
I’m unconvinced “climate” exists other than the macro observations due to latitude and the position of the continents. The claim Oxford has a climate that can be observed changing is I suspect utterly meaningless. Weather varies over quite a wide range over a very long period of time.
The word “climate” has been laser-focused to me “temperature” and, thus, has become useless for characterizing the nature of places as intended by Wladimir Köppen, a German botanist and climatologist. [note – botanist] It is shameful that the fieldwork of Köppen, Rudolf Geiger and others has been swept to the dustbin.
No rainfall trend, coupled with higher temperatures = quicker evaporation of surface water = less flooding (other things being equal).
Meanwhile, on the subject of rainfall, I note that Yorkshire water is still unable to produce its March figures for rainfall/reservoir levels.
“Climate science does not understand the climate.”
Phoenix 44
Indeed.
It looks to me that climate science does not yet have a complete list of the factors that affect weather [and climate]. That is, it can’t write down those factors – let alone understand them … or weight them, even in a discrete area.
To suggest that ‘the science is settled’ is arrogance, and hubris, of a high order.
Auto
Correct, Auto. You can’t model what you don’t understand.
Solution? A bigger computer.
Uhh . . . no. Hardware isn’t the limitation.
There problem is to be found in the foundation documentation of the IPCC where they incredibly begin their “science” with a conclusion which in a nutshell reads, “CO2 is to blame now go prove it”. So from the get go, whatever work was done has not been science. That they have been trying to do that since the 1980’s and failed is no surprise. That they continue to try reminds me of the definition of insanity.
Any normal people would begin to think “maybe our models do not work because CO2 is not the control knob”, so enter stage left other naughty greenhouse gasses to prop up the greenhouse gas theory AND STILL their models will not work.
A child would get an F grade for laying out a science experiment by starting with a conclusion. In the IPCC people have drawn generous salaries for more than 30 years on the back of such corrupt thinking!
Finally the way that RCP 8.5 what jumped upon and embraced by all the looneytunes and is to be found underpinning all of the NetZero krapola after being thoroughly discredited says all we need to know about the science. What the politicians wanted was the worst possible scenario to beat us into submission with and RCP 8.5 provided that rod regardless.
No, they would definitely not like to explain. It is much more to their liking to issue statements and not have to justify them.
O/T but interesting.
A hiker discovered a wealthy traveler’s remains on a skiing glacier in Switzerland. They turned out to be 400 years old
https://www.businessinsider.com/ancient-wealthy-traveler-discovered-thawing-glacier-archaeology-2024-3
This must have happened during the LIA.
Thanks Paul for the nice post and the link to the data.
Thanks Charly for mentioning me.
I am inviting you to read Section 1.3, “Precipitation and its extremes as seen in a long record” in my book “Stochastics of Hydroclimatic Extremes – A Cool Look at Risk” (in open access). I trust you will find answrers to the questions that are relevant to this post.
”Again the overall trend suggests that rainfall intensity has been declining over the period of record. Maybe the Met Office would like to explain.“
Because of global warming? – he asked innocently