Thursday, 11 June 2015

Walker Lecture - Sir David King Warns of Coming European Heatwaves Using Graph Ending 2003

Ed Hawkins tweeted about Sir David King's talk at the University of Reading Walker Lecture yesterday. David King, if you are unaware is the UK's Special Representative for Climate Change, appointed by the Foreign Secretary in September 2013. He was previously the Government's Chief Scientific Adviser (2000-2007), advocating action on climate change (global warming as it then was) during his tenure. Here is the graph he was presenting to back up his argument that we should expect, by 2050, heatwaves of the type that hit Europe in 2003, to be the norm - under current GHG emissions scenarios.

I questioned Ed Hawkins about the graph as the axes were not very informative and there was no title. Ed kindly informed me that the graph showed modelled Central European temperatures 1900-2100 vs. observed (black), ending in 2003. So why show observations only up to 2003? The peak is very obvious - 2003 was, by all accounts, a phenomenally hot summer in Europe. European summers since have been nowhere near as hot - often fairly cool - hence the suspicion is that later observations were simply left off of the graph because they did not match the projected rapid rise in summer temperatures. I cannot say for sure whether this is the case but I can say that temperatures in Germany (a fair proxy of Central Europe) have failed to live up to the climate model expectations in recent years. First, let's look at a graph of average German summer temperatures 1997-2012:


As you can see, 2003 stands out clearly, but the 8 years after show a decline in summer temperatures. 8 years of course, is too short a period to judge for sure whether summer temperatures are declining in Germany but the linear trend since 1997 is only very slightly positive and the polynomial fit shows a rise and decline. 2012 and 2014 were average and slightly above average summers in Germany with just 2013 standing out as significantly warmer than the long term average: June, July & August

On a further note, it woud appear that early Spring and Winter temperatures have actually been significantly declining in Germany since 1998. 

So even though King's graph looks impressive, appearing to match observations with models very accurately, all is not quite as it seems. The hindcast data has very likely been 'tuned' to match observations, notwithstanding the fact that pre 1950 temperature reconstructions have hypothesised anthopogenic GHG forcing largely absent, therefore they are, in effect, modeling mainly natural variability, and - perhaps unsurprisingly - seem to do a fairly good job. It's when the models predict increasing global temperatures under ever greater GHG forcing that they seem to run into trouble, with projected temperatures seen to be increasingly divergent from reality. As can be seen from King's graph, temperatures in Central Europe rose rapidly from 1900 to about 1950, cooled to 1975/80, then rose rapidly again - at what looks to be approximately the same rate as the pre-1950 warming. The post 2003 data is highly likely to be flat/very slightly increasing or even declining - unlike the modeled increase. It is this modeled increase in mean summer temperatures which allows King to claim that the damaging 2003 heatwave in Europe will be 'normal' by 2050 - unless, of course, we drastically curb emissions. To my mind, this is not science, it is political posturing ahead of Cop21 in Paris 2015

Tuesday, 24 March 2015

A Brief Conversation with Michael Mann

It has probably not escaped climate change sceptics' notice that there is a new Nature paper by Stefan Rahmstorf, Mann et al on the supposed 'unprecedented' slowdown in the North Atlantic thermohaline circulation (THC) during the 20th Century. The Washington Post and the Independent have picked up on it in typical alarmist media fashion and Rahmstorf himself is promoting it over at RealClimate. Mann is hawking it on Facebook like it was The Day After Tomorrow.

Now Mann has blocked me on Twitter but hasn't got around to doing so on Facebook (might have by now!), so I thought I would add a comment or two to one of his posts on this new paper. As you can see from his Facebook profile, he really is going overboard promoting this study in typical alarmist fashion.

Anyway, imagine my surprise when he actually replied to my first comment, so I added a reply and quickly took a snapshot of the convo guessing that he would do exactly what he did - remove the comments. Here it is.

A (brief) Conversation with Michael Mann - quickly deleted

Add caption

Monday, 9 March 2015

Climate Change by Numbers - Response Pt. 2

Onto the last of the last of the guest presenters, David Spiegelhalter, who helps people like the NHS predict the future. I trust he is better at that than he is at assessing the past! 1 trillion tonnes of carbon he informs us, is our budget beyond which we can expect 'dangerous' climate change (2C rise above pre-industrial levels). We've already burnt around a half a trillion tonnes since the beginning of the Industrial Revolution and "that's given us almost a degree of warming", says Spiegelhalter. So what he is saying in effect is that Hannah's 0.85 degree temperature rise since 1880 is all down to the burning of fossil fuels. Even the IPCC does not go this far. They say:

"Greenhouse gases contributed a global mean surface warming likely to be between 0.5°C and 1.3°C over the period 1951–2010, with the contributions from other anthropogenic forcings likely to be between –0.6°C and 0.1°C, from natural forcing likely to be between –0.1°C and 0.1°C, and from internal variability likely to be between –0.1°C and 0.1°C.
Together these assessed contributions are consistent with the observed warming of approximately 0.6°C over this period. [10.31, Figure 10.5]"

This ties in with the IPCC AR5 attribution statement:

"It is extremely likely that more than half of the observed increase in global average surface temperature from 1951 to 2010 was caused by the anthropogenic increase in greenhouse gas concentrations and other anthropogenic forcings together. The best estimate of the human-induced contribution to warming is similar to the observed warming over this period."

Greenhouse gas concentrations in the atmosphere have only been measured really accurately at Mauna Loa since about 1960, when 310ppm was registered. Before that, scientists rely upon low resolution ice core data which appears to show a very gradual increase from a baseline of about 280-290ppm in 1880. It's only during the 1950s that atmospheric CO2 concentrations really take off.

Note the very rapid 1910 to 1945 warming followed by the sharp cooling to 1950 - all when CO2 was not much above pre-industrial levels and increasing only very gradually. Therefore, we must conclude that natural variability was in charge prior to 1950, certainly with respect to major ups and downs. AGW purists might wish to claim that the general upward trend in temperatures since 1880 is also down to anthropogenic CO2 but then they would have to explain also the longer general upward trend in global temperatures since the end of the LIA, without resort to more plausible natural (solar) influences. In summary, it's quite likely that the increase in global temperature from 1880 to 1950 can be mainly attributed to natural (internal and external) forcings. But the BBC's Climate Change by Numbers would have its viewers think otherwise.

The so called Monte Carlo method of statistically predicting the most likely future outcome of anything from Formula 1 races to NHS medical policy/practice to CO2 induced climate change is a powerful mathematical tool involving multiple repetition of many different scenarios, Spiegelhalter tells us. I am sure it is - given the right data. The climate model runs cluster around a 'most likely' multi-model mean which suggests that we can expect to hit the 2C 'dangerous' threshold within the next 30 years or so if we burn all of that remaining 1/2 a trillion tonnes of carbon. What he neglects to mention of course is that the multi-model mean is way ahead of actual observed temperatures and in fact the vast majority of all of the climate models run significantly warmer than reality. Clearly, something is amiss with the models. The Monte Carlo method is faithfully predicting the most likely future outcome, but an outcome probably based upon incorrect assumptions/data about the real climate, about natural oceanic oscillations, cloud feedbacks, water vapour feedbacks, solar variability, and so on. However complex the climate models are, they are mere simplifications of what is actually going on in the coupled ocean-atmosphere system - and it appears that they are simply wrong. The longer the 'faux pause' continues, the more wrong they get.

Even if the models eventually prove to be right "why should we worry about a rise of two degrees Celsius?" asks Spiegelhalter. Because of weather, extreme weather to be more precise. Climate scientists tell us we can expect more frequent droughts, floods and storms - though the evidence for such thus far is much less than convincing (see Roger Pielke Jr.'s work). But that's only part of the problem. Environmental engineers use a technique called Extreme Value Theory to allow for the occurrence of really extreme (e.g. once in a thousand years) events which will test their structures to the absolute limit. This relies upon collecting a lot of data about past extreme events, but in a warming world, Spiegelhalter tells us, this data becomes rapidly obsolete and hence the predictions of extreme value theory, which rely upon overall stable conditions, become increasingly unreliable. Hence our ability to plan for such events is reduced, placing society at risk. This sounds all quite reasonable but again, it is reliant upon the unproven hypothesis that patterns of extreme weather events will change/are changing due to global warming, which in fact is also not happening - for the past 15 years or so, global surface temperatures have not increased at anything like the pace that was predicted by the climate scientists' models; indeed they have not increased by a statistically significant amount at all in any dataset.

Climate Change by Numbers? A for effort, C- for attainment.
Sorry, you're gonna need more numbers. #CCBN2

Friday, 6 March 2015

Climate Change by Numbers - Response Pt. 1

Well, after all the fuss and the feverish anticipation of this BBC program, I thought I had better get round to watching it and I have managed two thirds of the way through so far! I thought initially I might make a few (probably critical) comments on a blog post but, the more I examine this program, the more I feel I need to respond to specific (and some very unspecific) points made within. So let's start with the grand aim of the program  - the goal of convincing us all that climate change (TM) is real via the wonder of mathematics and the analysis of three simple numbers: 0.85C, 95% and 1 trillion tonnes. Each number is assigned to one of three mathematicians (statisticians) - Dr Hannah Fry, Prof Norman Fenton and Prof David Spiegelhalter - respectively. They are "three numbers which represent what we know about the past, present and future of earth's climate", Professor Fenton tells us right from the off. Oh dear, not an auspicious start!

Hannah Fry (and four-legged friend Molly) tackle the mysteries of measuring global temperature and why 0.85 degrees is so important (or maybe not, as the case may be). Cue bucket talk - canvas and wooden - then on to an explanation of how errors are teased out of the historic global temperature record, using Kalman filtering. Now this, according to the program, is what enabled men to land on the Moon in 1969 and, under a different title - homogenisation - is what enables climate scientists to 'clean up' past temperature data and iron out irregularitiies. All sounds perfectly reasonable. But Hannah Fry tells us that "other people" will "inevitably start accusing" climate scientists of "building bias" into their data, once the raw data is cleaned up in this way and replaced with homogenised data. Those 'other people' sound like those nasty sceptics/deniers/contrarians which your mother warned you about. They also sound suspiciously like those conspiracy theorists which Lewandowsky warned us about - you know, the kind of people who will question the unquestionable - the global temperature record, built as it is upon the solid science which gave us the Moon landings. This subtle re-working of the infamous take home message of LOG12 - whether planned or merely coincidental - was not lost on me; but then again we ideational conspiracists often see hidden messages that others fail to detect!

Next we get on to data 'infilling' (named Kriging, after a South African gold-miner). Then swiftly on to the pause which is not a pause, which does or does not exist, and anyway, which is just one of a number which were always expected to appear to briefly interrupt the general man-made warming trend. No matter that the 'expectation' of a 15 year hiatus was just once in every 375 years of model runs (p.8)! But, you know, limited time and all; the program just couldn't fit the explanation of this mere 'detail' into its breathless schedule, even though it tediously slow-burned its way through endless minutes of story-telling build-up to the main points. "Mathematical manipulation of the raw data can look like fiddling the figures", Fry tells us, and the techniques which climate scientists have used are well understood and "all lead in the same direction". I'm sure this phrase was an unfortunate choice, but yes, I think that's one of the main contentions of some sceptics - the fact that, in general, these adjustments do all lead in the same direction, i.e. more warming! Summing up then, Hannah concludes that, even with all the uncertainties in the past temperature record, the scientific consensus is that the earth's temperature has risen by 0.85C since 1880.

This is fairly uncontroversial, even amongst climate change sceptics, who generally acknowledge that the planet has indeed warmed overall (but certainly not uniformly, either spatially or temporally), since the 19th century and indeed since the Little Ice Age ended. The controversial part, as Hannah points out, is how much we are responsible for that warming, which naturally leads onto the second guest presenter, Prof Norman Fenton. He will tell us how the IPCC are 95% certain that we are responsible for virtually all of the warming, but it's not 'this' warming (0.85C), it's the warming that has taken place since 1950. So why bang on about the 'almost a degree' warming since 1880 when it does not relate directly to the second crucial figure? Why not bang on about the 'slightly more than half a degree' warming since 1950 which the IPCC tells us is all down to CO2? I'll leave the reader to speculate on that.

Norman Fenton is a Spurs fan and a down-to-earth Londoner - so we have one thing in common at least! In order to explain the mystery that is an IPCC climate change 'attribution study', he chooses to model the performance of Premier league teams and finds that, in amongst a variety of factors, one stands out as having a very marked influence upon performance - the wage bill. Fenton creates a simple model which predicts the performance of teams based upon various factors. First he shows us the rather good fit of model vs. actual performance for Man City. Impressive. Then he shows us Liverpool:

FireShot Screen Capture #015 - 'BBC iPlayer - Climate Change by Numbers' - www_bbc_co_uk_iplayer_episode_p02jsdrk_climate-change-by-numbers

Hmmm, not quite so impressive, but unabashed, Prof Fenton says that this good model fit is "true for all of the teams in the Premier League". He goes on: "Now I know I can trust my model, we can move on to the clever bit". He really does seem to have this IPCC attribution study nailed! The "clever bit" is isolating what factor, if any, has a dominant effect upon any team's performance, which turns out to be the wage bill. This is 'attribution' and the principle is the same for climate change, albeit the latter situation is far more complex, with an extremely complicated web of interacting variables needing to be taken into account rather than just a few. Most of these variables are related to natural (internally and externally forced) climate variability but, nevertheless, the IPCC has looked at them all and concluded that their net effect is near zero since 1950 - hence they can attribute to CO2 emissions with startling 95% certainty virtually all global warming since 1950 (but not since 1880). How, you may ask? Well, firstly because of depressed Swedish physicist Svante Arrhenius. He it was who, in a roundabout sort of way, first showed, "using maths", that a doubling of CO2 could warm the globe by 4C via the so called Greenhouse Effect. So that's one crucial piece of 'evidence' in place; now just to 'prove' the assertion that natural variability has played virtually no part in recent global warming.

"If the cycles of the Sun were a major cause of the rise in temperature we've measured, then what we would see would be all the layers of the Earth's atmosphere warming together like this":

FireShot Screen Capture #016 - 'BBC iPlayer - Climate Change by Numbers' - www_bbc_co_uk_iplayer_episode_p02jsdrk_climate-change-by-numbers

I must admit, this is a new one on me which I must look into more. Even more interestingly, Fenton then presents us with what he says has actually happened over the last 60 years:

FireShot Screen Capture #018 - 'BBC iPlayer - Climate Change by Numbers' - www_bbc_co_uk_iplayer_episode_p02jsdrk_climate-change-by-numbers

What this shows is accelerated warming of the troposphere and cooling of the stratosphere. The stratosphere has indeed cooled since the 1960s - though this cooling trend has halted since the mid to late 1990s.


Now, Fenton informs us that the that the models show that this pattern (tropospheric warming/stratospheric cooling) only fits well with anthropogenic CO2 being the principle cause of recent global warming. What he neglects to mention is:
  1. The tropical mid-tropospheric 'hotspot' which we clearly see in his 'actually happening' representation above has actually failed to materialise, even though it is one of the key predictions of the climate models. There has been no observed accelerated warming of the mid troposphere over the tropics. So even though the troposphere as a whole has warmed and the stratosphere cooled, the mid troposphere has not warmed significantly compared to the surface.
  2. There is an alternative (anthropogenic) explanation for stratospheric cooling and surface/tropospheric warming which involves CFCs. Basically, the hypothesis is that accelerated ozone loss caused by CFCs in the stratosphere has resulted in cooling of that portion of the atmosphere whilst, at the same time, UV energy which would normally be absorbed by stratospheric ozone (warming the stratosphere) has passed straight through to warm the lower troposphere. This might explain the 'pause' in global warming from about 1998 and the corresponding 'pause' in stratospheric cooling as a direct result of the decline in the concentration of ozone depleting CFCs in the upper atmosphere since the international adoption of the Montreal Protocol in January 1989.
There are also explanations which invoke natural causes for some or even most of the warming we have seen since the 1950s. None of this gets an airing though. I guess, again, lack of programming time probably precluded the mention of these facts, though apparently not the mention of the 'facts' of declining Arctic sea ice, increasing heatwaves and ocean acidification as further 'compelling' evidence for the 'human fingerprint' of global warming. If the viewer is not convinced up to this point, then the almost exact match of the graph of actual warming (yellow) vs. modeled (red - anthro + natural) and the very poor fit of natural only (green) modeled warming is a killer:

FireShot Screen Capture #019 - 'BBC iPlayer - Climate Change by Numbers' - www_bbc_co_uk_iplayer_episode_p02jsdrk_climate-change-by-numbers

Alas, once again the tight programming schedule does not allow Fenton to explain to his viewers about the assumptions inherent within this graphic, namely a high-end climate sensitivity to CO2 (increasingly looking doubtful), negligible solar influence and internal variability which has had nearly zero net effect since about 1950. Those assumptions are challengeable.

Fenton says that the AGW fingerprint in global warming is as clear as the wage bill in his Premier league performance model; in fact so clear that the IPCC assigned 99% certainty to it. It would seem that the poor dears were so embarrassed by the devastating clarity and certainty of their science that they downgraded their figure to merely 'greater than 95%' just in case there were any hidden errors for which they had not accounted! Now ain't that humility and honesty! Professor Norman Fenton appears to have had a bit of a rethink with regard to his presentation in the program. In his blog post he comes across as much more guarded about the role of humans in climate change than as portrayed in the program. Well worth reading.

Sunday, 8 February 2015

Science and Statistics - An Unholy Alliance?

I came across this very interesting article the other day, written in 2010. It basically reinforces my own long held sense of unease with regard to statistical analysis. My reaction against statistics started early, in school, when first I was presented with its somewhat bizarre pseudo-mathematical methodology and nomenclature. My early rejection of the subject was more visceral and emotive rather than common sense factual and logical. It just hit a raw nerve with me somehow and all these years later, reading this article by Tom Siegfried, I begin to see perhaps why. So let me begin by quoting a few passages from Siegfried's text:

 "During the past century, though, a mutant form of math has deflected science’s heart from the modes of calculation that had long served so faithfully. Science was seduced by statistics, the math rooted in the same principles that guarantee profits for Las Vegas casinos. Supposedly, the proper use of statistics makes relying on scientific results a safe bet. But in practice, widespread misuse of statistical methods makes science more like a crapshoot."

So it's not statistics itself, but the misuse of this analytical toolbox which is the problem. To this I would add over-reliance, especially evident in the field of climate science. Too often in the peer reviewed climate science literature we find papers which base their conclusions almost totally on the results of some new statistical analysis/re-analysis of existing data. In order to fully appreciate what they are saying and, more importantly, in order to question what they are saying, one needs to be an expert not primarily in climate science, but in statistical analysis.

"Statistical tests are supposed to guide scientists in judging whether an experimental result reflects some real effect or is merely a random fluke, but the standard methods mix mutually inconsistent philosophies and offer no meaningful basis for making such decisions. Even when performed correctly, statistical tests are widely misunderstood and frequently misinterpreted. As a result, countless conclusions in the scientific literature are erroneous, and tests of medical dangers or treatments are often contradictory and confusing."

This does not inspire confidence.

"Experts in the math of probability and statistics are well aware of these problems and have for decades expressed concern about them in major journals. Over the years, hundreds of published papers have warned that science’s love affair with statistics has spawned countless illegitimate findings. In fact, if you believe what you read in the scientific literature, you shouldn’t believe what you read in the scientific literature."

With the increasingly pervasive use of statistical analysis in climate science, backed up by increasingly complex computer models, the above statement is magnified 10-fold in consideration of the results of the latest peer-reviewed scientific research. Much of this said research is aimed at pointing the finger at man as being responsible for the majority of post 1950 global warming, claiming also that we will continue to drive climate significantly into the future. Yet much of it is based upon statistical reanalysis of existing data.

"Nobody contends that all of science is wrong, or that it hasn’t compiled an impressive array of truths about the natural world. Still, any single scientific study alone is quite likely to be incorrect, thanks largely to the fact that the standard statistical system for drawing conclusions is, in essence, illogical. “A lot of scientists don’t understand statistics,” says Goodman. “And they don’t understand statistics because the statistics don’t make sense.”"

A perfect illustration: the recently released paper by Marotzke and Forster. The main impetus for the paper was to address the apparent mismatch between climate models and real world observations (in particular the 'pause') which sceptics use to question the validity of the AGW theory. The paper concludes:

"The differences between simulated and observed trends are dominated by random internal variability over the shorter timescale and by variations in the radiative forcings used to drive models over the longer timescale. For either trend length, spread in simulated climate feedback leaves no traceable imprint on GMST trends or, consequently, on the difference between simulations and observations. The claim that climate models systematically overestimate the response to radiative forcing from increasing greenhouse gas concentrations therefore seems to be unfounded."

So, climate models do not overestimate the response to GHG forcing, even though the CMIP5 model mean is increasingly diverging from actual recorded global mean surface temperatures (GMST) and even though almost all models clearly run 'too hot' when compared with actual GMSTs. Apparently, this impression is not borne out by statistically analysing the past temperature record and comparing that with the models [?] It's opaque to me and probably a lot of other people besides. Nic Lewis thinks it is plain wrong, and says so at Climate Audit, laying out his reasons. He gave Marotzke and Forster the opportunity to reply to his concerns about their paper but they failed to respond before Nic Lewis published at Climate Audit. Instead, they have chosen to issue a rebuttal of Lewis' rebuttal at Climate Lab Book here. I've no idea who will eventually be proved to be right or wrong in this kerfuffle, but I quote from statistical expert Gordon Hughes (Edinburgh University), being one of two people whom Nic Lewis asked to review his conclusions about M & F, 2015:

"The statistical methods used in the paper are so bad as to merit use in a class on how not to do applied statistics.
All this paper demonstrates is that climate scientists should take some basic courses in statistics and Nature should get some competent referees."  

The wider point here is that we have yet another paper which relies almost exclusively upon statistical methodology to draw conclusions about the real world - another paper which may have to be withdrawn. Science - and climate science in particular - is suffering from the all too pervasive influence of staistics. There is a place for statistics in the analysis of real world data and even I must (reluctantly) acknowledge this. However, science has, as Tom Siegfried points out, become "seduced" by the false promise of this "mutant" form of mathematics and is suffering from its misuse and its overuse.

Thursday, 26 June 2014

El Nino killed off by Global Warming

A warming world was supposed to be a world in which El Nino events dominated, powerful events, like the super Nino of 1998 and the slightly less powerful event in 1982/3. Warmist doctrine requires that this is the mechanism par excellence whereby excess heat trapped by CO2 and other greenhouse gases, which makes its way into the world's oceans, is suddenly unleashed upon the globe in one big hit. Hence AGW theorists were eagerly anticipating the development of a super Nino this year and on into the next, buoyed by record SST anomalies in the pacific in March. Alas, it was not to be and that early promise faded rapidly.

Now we are in the situation where it is looking increasingly like El Nino 2014/15, if it even develops, is going to be something of a damp squib and any rise in global temperatures as a result very very modest, perhaps insignificant. The World Meteorological Organisation has come up with a novel explanation for this: the failure of El Nino 2014/15 to live up to expectations is down to . . . . wait for it . . . . . global warming! Specifically, they point the finger at the 'record' warm May 2014 recently reported by NOAA (and duly disseminated across the leftist media as 'evidence' for continued global warming). In other words, one superhot month created by the accumulation of anthropogenic greenhouse gases in our atmosphere has effectively killed off El Nino 2014/15!

So, what does the WMO propose as the mechanism whereby global warming is able to kill off budding super Ninos?

“One explanation for the lack of atmospheric response so far may be that the sea surface temperatures are above average across virtually the entire tropical Pacific, not just in the eastern and central portions. This may be maintaining west-to-east temperature differences more typical of neutral conditions,”

There you have it, above average SSTs caused by generalised global warming interfering with the 'temperature difference' across the entire Pacific. I'm sure there are holes in this theory you could drive an aircraft carrier through. It just sounds so brainless and desperate. Reporting Climatescience, in response to WMO's suggestion above, cautions its readers:

"However, it is worth noting that this WMO suggestion apparently runs counter to the conclusions of peer reviewed research published in Nature last year that warned higher temperatures associated with climate change would actually result in twice the number of more powerful El Ninos in the future (see our report here)."

I should say so! Having cake and eating it springs to mind. Had El Nino 2014/15 turned into a super Nino, doubtless we would all be regaled by stories in the press about climate scientists being vindicated in their theories that the 'pause' was really not a pause after all. The proof of the pudding, they would say, is the global warming now being unleashed upon the world courtesy of an El Nino spawned by the extraordinary amounts of heat which disappeared into the oceans during the 'fake' hiatus in global temperatures which all those doubting sceptics took to be proof that man-made global warming was nonsense. But as it's not going to happen, the WMO comes up with a whizzo explanation which neatly lets warmists off the hook - there'll be no El Nino warming because it's too warm!

Saturday, 10 May 2014

2014/15 - Most Hyped El Nino in History?

It would be hard to have missed all the hype surrounding the predicted El Nino this summer, the odds of which happening have recently been increased to 65% according to NOAA. The buzz surrounding it has been going on for 18 months or so now but has recently hotted up - in tandem with the waters of the equatorial Pacific - with speculation now reaching fever pitch in some quarters.

The boys and girls over at SkS were at the forefront of such speculation in April, suggesting that, though it was early days, 2014/15 might rival 1997/98 in intensity:

"Every now and then a very large event occurs, such as the one in 1997-1998 which broke surface temperature records at the time and caused worldwide disruption and damage. . . .

A powerful El Niño is by no means guaranteed, but should one develop mid-2014 to mid-2015 would likely be the hottest 12 months ever recorded. . . . .

As stated earlier, we only have just over two decades worth of reasonably detailed observations, so it is by no means guaranteed that a powerful El Niño will develop. But, based on what we have observed and our current physical understanding of the phenomenon, the evolution of an intense El Niño event is possible. It's true the models are not yet predicting a large event, but they did fail to predict the magnitude of the 1997-1998 event, so are not necessarily a reliable indicator of scale this far in advance. . . ."

Though they are at pains to stress that the arrival of a powerful El Nino later this year "would entail widespread weather-related disruption and suffering around the world" and so is not to be welcomed, it is not difficult to read between the lines to see that the authors would indeed in many ways welcome such an event because, besides being a Pause Buster par excellence, it would lend credibility to the idea mooted for years now by warmists that the 'missing heat' from anthropogenic global warming (not) these past 17 years 9 months has been lurking in the deep ocean.

"The hottest 12 months ever recorded" might coincide with such a Super El Nino if it were to form, says SkS. Goodness me, no wonder warmists are getting feverish with anticipation. Imagine the CAGW propaganda coup! Imagine the funding! So, when world temperatures suddenly accelerate as a direct result of the anticipated powerful El Nino, they can sit back smugly and say, 'We told you so':
'Be afraid, be very afraid'
'Climate change is happening', they will say.
'Gaze upon it in awe all ye non-believers and pesky anti-science, pseudo-sceptic deniers. Look and weep - 4 Hiroshimas per second, every second for nearly 18 years, suddenly unleashed upon the globe in just a few months courtesy of the Pacific belching out a big menacing cloud of AGW  Awesome! Trenberth et al were right, so stick that in your Faux Pause and smoke it! Only Big Green can save us now'.

So much for the hyperbole. Let's look at the facts as we understand them. A more sober and informative look at the prospects for a 2014/15 El Nino can be found at this Wattsupwiththat post by Bob Tisdale which compares the evolution of the powerful 1982/83 and 1997/98 El Ninos with the current one. Bob Tisdale points out that the Nino3.4 regional anomalies for 2014 are within "spitting distance" of the +0.5C threshhold to declare an official El Nino. Comparing water temperatures across the entire equatorial Pacific, Tisdale notes that:

 ". . . . warm water volume is lower and depth-averaged temperatures are less in 2014 than they were in 1997. Then again, they’re higher than they were in 1982".

So, in theory at least, 2014/15 could be slightly more powerful than 1982/83, but probably not quite as intense as 1997/98. Tisdale ends the post on a cautionary note:

"That feedback will eventually kick in to allow the 2014/15 El Niño to strengthen, if it hasn’t started already. The only questions now are how strong the El Niño will become and how long El Niño conditions will last. Everything depends on the weather in the tropical Pacific, which is why no two El Niño events are the same."

Joe Bastardi, in his excellent Saturday Summary gives his own personal take on the evidence (or not, as the case is) for 2014/15 being a Super El Nino here. He is in no doubt whatsoever that 2014/15 is being hyped like crazy at the moment by those who have an 'agenda'. It's hard not to agree with him.

On the subject of El Ninos in general and their effect upon the global climate, Judith Curry recently ran an excellent and very interesting guest post on Climate etc. authored by Donald Rapp. Rapp begins by questioning whether there is a link between rising levels of CO2 in the 20th Century and the prevalence of El Ninos:

"Why after 400 years of La Niña precedence, did periods of El Niños dominance start in the 20th century? And why did the two periods of strong El Niño dominance in the 20th century occur during a period when the CO2concentration was rising? Is there a link between rising CO2 and the El Niño – La Niña balance? But if there is such a link, why did El Niños become less prevalent than La Niñas from 1941 to 1976 and be in balance after 1998?"

Bob Tisdale thinks there is probably not a link between CO2 and ENSO. With reference to Tisdale's views on El Nino/La Nina Rapp says:

"The Pacific periodically goes through transitions from El Niño to neutral to La Niña, and vice versa. In an El Niño, warm waters cover a sizable portion of the Pacific, which heats the atmosphere. Tisdale has shown that at least in the 20th century, one can correlate durations of increase in global temperature with periods of El Niño dominance. Actually, the global warming of the 20th century correlates better with Niño indices than it does with CO2 concentration. He has therefore argued that a substantial part (if not all) of the global warming of the past ~120 years can be attributed periods of imbalance in favor of El Niños, rather than the effect of rising CO2concentration."

So we have two opposing theories. Firstly, global warming via increasing concentrations of CO2 causes there to be a predominance of El Ninos, which release excess heat stored in the Pacific resulting in rapid global warming, superimposed upon a more general warming trend, we might suppose. Very little or none of it natural. Secondly, we have the natural climate change hypothesis which says that warming per se is due to the prevalence of El Nino type conditions in the Pacific and cooling happens when La Ninas predominate. The most obvious question here of course is what, if anything, drives the pendulum swing from La Nina dominance to El Nino and vice versa? It's probably been happening for many thousands of years, so we can eliminate CO2 emissions, at least prior to the industrial era. Again, the most obvious candidate is solar activity.

But getting back to Rapp on Climate etc., he says:

"Starting in year 1900, and continuing to about 1941, El Niños were more prevalent and stronger than La Niñas. Also during this period, the earth warmed significantly. From about 1941 to about 1976, El Niños and La Niñas were fairly balanced, although there was a slight excess of La Niñas. The earth cooled slightly during this period but the prevalence of La Niñas was weak. From 1976 to 1998, El Niños strongly dominated over La Niñas. This 23-year period included the very strong El Niño of 1982-3 and culminated in the very strong El Niño of 1997-8. The earth warmed rapidly during this period from 1976 to 1998. In fact, about half the warming of the 20th century occurred during those 23 years. With the termination of the great El Niño of 1997-8, we entered a period of balance between El Niños and La Niñas and the earth’s temperature remained essentially unchanged from 1998 to 2014."

The implication is that the much talked about 'Pause' is caused by a neutral La Nina/El Nino balance. If 2014/15 produces a very powerful El Nino, this might kick start global warming again and end the current phase of ENSO neutrality with a return to a more general warming trend overlying a predominance of El Ninos. Personally, I think this scenario is unlikely, but we shall see.

Trenberth's view is that CO2-based global warming is mediated via heat stored in the oceans and periodically released via the incidence of El Ninos. Rapp questions this hypothesis:

"Trenberth’s view is that the earth is out of balance (acquiring more heat from the Sun than it can reject to space) and this excess heat finds its way into the oceans. When enough heat is stored in the surface waters, it eventually comes out as in the form of an El Niño. But, we have had El Niños on and off for hundreds of years without rising greenhouse gases, and there was very significant El Niño activity between 1900 and 1942 when CO2 concentrations were much lower. The regime shift at year 1900 was just as dramatic as the regime shift of 1977, and the persistence of El Niños from 1900 to 1942 was just as pervasive as that from 1977 to 1998. Any proposed explanation would have to deal with this widely ignored early phase of high El Niño activity."

So the 'small' issue of past natural La Nina/El Nino activity is actually a major stumbling block for those who argue that there are grubby black carbonaceous anthropogenic fingerprints all over the 20th Century warming period and the observed dominance of El Ninos throughout much of that time. But I am sure that this will not stop Trenberth and others loudly trumpeting that they have been vindicated if El Nino 2014/15 does indeed turn out to be the powerful "pause buster" which they are all hoping for. Certainly, it will provide added impetus for Obama's mad rush to green energy generation in the States and lend wholly artificial credence to loony Ed Davey's plan to push all of us here in the UK into energy poverty by reliance upon wind energy, whilst at the same time gobbling up large tracts of virgin US forest to feed Drax during periods of calm weather when each 350 foot turbine barely produces enough juice to boil a kettle.

Though the odds have shortened considerably on the incidence this summer of an El Nino, it is still by no means a certainty and there is no real way of predicting with any degree of accuracy the intensity or duration of any event. What strikes me though is the pattern of the Pacific Decadal Oscillation (PDO) throughout the 20th Century, which mirrors closely the shorter period ENSO oscillations throughout.

One can clearly see the intrinsic periodic oscillatory nature of PDO. One can clearly discern the various 'regime shifts' in the Pacific Ocean from positive (warm, El Ninos dominating) to negative (cool, El Ninas more prevalent). Though it is argued that the PDO is distinct from ENSO in that ENSO is a feature of the tropical pacific whereas PDO represents a spatial pattern of temperature anomalies across the North Pacific and occurs over decadal time-scales rather than months, there is reasonable evidence to suggest strongly that the oscillatory PDO modulates to some extent the behaviour of ENSO. To see that this is the case, one has only to look at the graph of smoothed Nino3.4 SST anomalies and compare it with the graph of PDO to immediately notice that the two are correlated, with positive Nino3.4 anomalies occurring largely within the envelope of the positive phase of the PDO.

Here is another plot of the PDO taken from climate4you:

Note the clearly defined regime shift in 1977 and the decline post 2000. The PDO has gone into negative phase. For this reason particularly, I suspect that, if we do see an El Nino this year and on into next, it probably will not be very intense. I personally would be most surprised if it got anywhere near the strength of the1997/98 El Nino or even the lesser 1982/83 event. The next few months will tell. Whatever the case, besides being probably the most hyped El Nino in human history, 2014/15 will no doubt also be the most intensively studied.

Correction 5th July 2014:

Latest data on PDO indicates that it moved into positive territory at the beginning of the year and has been increasing ever since. 

As can be seen from the above graph, it is in fact quite normal for PDO to go positive or negative in contrast to the predominant 'regime', but the magnitude of the positive shift looks to be quite unusual. So maybe there is indeed a chance that a moderate strength El Nino will form later this summer/autumn, though it still looks very doubtful that it will ascend 'super Nino' status. 

There is still the fact that subsurface warm anomalies in the Eastern Pacific have tailed off and unusually warm surface waters across the entire basin are tending to neutralise conditions favourable to the formation of El Nino. Latest assessment from NOAA: