Reposted from The GWPF by Dr. David Whitehouse
There has been some discussion about a paper in Nature Climate Change by Gleckler et al that says they detect “a positive identification (at the 1% level) of an anthropogenic fingerprint in the observed upper-ocean temperature changes, thereby substantially strengthening existing detection and attribution evidence.” What they’ve done is collect datasets on volume-averaged temperatures for the upper 700 metres of the ocean.
But Yeager and Large, writing in the Journal of Climate, looking at the same layer of ocean, come to a different view. They conclude that it is natural variability, rather than long-term climate change that dominates the sea surface temperature and heat flux changes over the 23 years period (1984 – 2006). They say the increase in sea surface temperatures is not driven by radiative forcing. It’s a good example of how two groups of scientists can look at the same data and come to differing conclusions. Guess which paper the media picked up?
Whilst the IPCC AR4 report says that between 1961 – 2003 the upper 700 metres has increased in temperature by 0.1 deg C, some researchers think that that estimate is an artifact of too much interpolation of sparse data (Harrison and Carson 2007). Their analysis found no significant temperature trends over the past 50 years at the 90% level, although this is a minority opinion.
The interesting thing about Gleckler et al is that their unambiguous detection of a human fingerprint in ocean warming comes from what they say are “results from a large multimodel archive of externally forced and unforced simulations.” To you and me this means with and without anthropogenic carbon dioxide. What they have done is to look at the average of a variety of computer models.
What Does A Multimodel Mean?
But what is meant by a multimodel mean, and how is one to know when the ensemble of models used to calculate the mean is large enough to provide meaningful results? Another pertinent question is if averaging multiple models is a safe thing to do in the first place?
Tweek this or that parameter, change a numerical calculation and a different output from a computer model will be obtained. In some quarters these are described as experiments, which is technically true given the definition of the word experiment. But in my view they are not on a par with physical experiments. Experiments in the real world are questions asked of nature with a direct reply. Experiments in computer models are internal questions about a man-made world, not the natural one. That is not to say there is not useful insight here. One just has to be careful not to get carried away.
For some there is insight in diversity. For example the CMIP3 is an ensemble of twenty major climate models and while many of them are related in terms of code and philosophy, many are not. Advocates of the multi-model approach say this is a good thing as if models produced in different ways agree because it provides confidence that we have in some way understood what is going on.
But the key point, philosophically and statistically, is that the various outputs of computer models are not independent samples in the same way that repeated measurements of a physical parameter could be. They are not independent measurements centred on what is the “truth” or reality.
Given this, does the addition of more models and “experiments” force the mean of a multimodel ensemble to converge on reality? Some, such as the work by Professor Reto Knutti believe it doesn’t. I agree, and think it is a precarious step to take to decide that reality and models are drawn from the same population. How can uncertainty in parameterisation of climatic variables and numeric calculations reproduce uncertainty in the climate system? The spread of models is not necessarily related to uncertainty in climate predictions.
When one averages climate models one has to be clear about what the averaging process actually does. It does not legitimize the spread of climate model output, compensating for each models errors and biases, as if an average of widely different predictions is somehow the ‘correct’ representation of reality. Averaging computer models does not necessarily make things clearer. Indeed it results in a loss of signal and throws away what most models are saying.
There are researchers who point out that the average of an ensemble of models actually reproduces real-world climate data better than any individual model. To my mind this is not a great achievement in their favour, but something about which we should be suspicious. It smacks of selection effects, bias and begging the question.
When climate models are used to make predictions some scientists refer to the past as a “training period” meaning that if the model reproduces the past it will reproduce the future. Perhaps it will, but it is not certain that it will and we cannot prove it, especially when the “training period” is shorter than long-term semi-cyclic climatic influences.
My overall impression is that computer climate models, useful as they can be, have been oversold and that they have been often used without interpreting their results in terms of known processes and linked to observations – the recent standstill in the annual average global temperatures is an example.
Modeling the climate is not like modeling a pendulum in which all relevant information is available to forecast its future movement until chaos theory takes over. General climate models are an approximation of the complex physical, chemical and biological processes that happen on Earth. We have incomplete knowledge of what goes on, we have limited computational abilities and sparse real-world observations of many parameters. All these are reasons to be wary of individual models, let alone an average of an ensemble of them.
Feedback: david.whitehouse@thegwpf.org
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In case you don’t get the pun in the title, see this, or the video below.
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Averaged Garbage In, Averaged Garbage Out.
The 1% (signal) solution?
From models?
hahahahahahahaha
They say the increase in sea surface temperatures is not driven by radiative forcing
Now, what does that mean?
Solar radiation [TSI] is radiative forcing, no?
Change in UV that controls temperatures at interesting places is radiative forcing, no?
Svensmark’s ideas about cosmic rays changing the albedo results in radiative forcing, no?
I’m with Luther Wu. The idea of taking various computer modeling software, which on their own are unable to reproduce historic climate trends for the last 50 years, and then average them to expect to gain insight into future trends is simply laughable.
Bright Sunshine is also radiative forcing. Do we know if there is a net increase or decrease over the oceans for the time periods in question?
The very model of the perfect white liberal citizen, from my Real Science comment, pretending to be a guilt-ridden white warmist:
It’s true that the white man pioneered the industrial ways that are now bleeding our world dry of resources. Peak Oil is just maybe 5 years out, and across the board and frequent blackouts due to resource insufficiency, are also just around the bend. We shall see these things come to pass, and it will be proof of our wasteful indulgent unnatural ways, and then I will say “I told you so!” Now, we need to save our resources, and share.
Amazingly, there are some special whites that understand the dire situation, and are leading the way, calling for cuts in energy use, and cuts in the exorbitant extravagance of our sickly overluxurious lifestyles of whites, and redistribution of $ to non-whites.
What really bothers us, the, can I call us, the enlightened whites (and others), is the redneck-style less educated whites who drive big honking cars or worse, trucks, when a little Prius would do, or no car, that’s the idea; walk. Or they run air-conditioners when they could just use a wet towel. Or ridiculous things like energy-using Snow Machines for Ski resorts. It’s not what nature intended. It’s a sin, honestly. And these constant electrical distractions, that waste our vanishing energy and attention, like iPads iPhones iPods iTVs iWhatevers, just constantly blaring music and this and that. We need to get back, and I mean quickly, to local nature, to having just a few non-mechanized things, and simple dwellings. And there’s now a reason to do it. It’s called climate change. We need to change our evil, or, unnatural, ways, now! Or else, yes, the next thing you know, because of terrible climate change, we are going to find ourselves living in huts. Mark my word.
As the upper ocean temperature measurements show such a tiny increase in temperature, this seems to be a “non-problem” so spending money on it makes no sense when there are real problems that need to be addressed.
Is Eric Simpson for real?? Can’t be!!
Mr Simpson, that is without a doubt one of the most racist posts I have seen in years. Please explain to me what the relevance of the melanin quantity in a person’s skin has to do with their human responsibility.
Eric Simpson says:
June 17, 2012 at 6:45 pm
“…we are going to find ourselves living in huts. Mark my word.”
_______________________
You can live in a hut if you want… I’m going to live in a van, down by the river.
Eric Simpson;
We need to get back, and I mean quickly, to local nature, to having just a few non-mechanized things, and simple dwellings.>>>>
Be my guest. Lead by example. I dare you.
Eric Simpson,
You may enjoy this little article:
http://takimag.com/article/green_on_the_outside_red_on_the_inside_brian_lasorsa#axzz1y6gSFtCj
Eric Simpson says:
June 17, 2012 at 6:45 pm
“pretending to be a guilt-ridden white warmist:”
I don’t know how you could miss this.
What a pile of nonsense. Gleckler et al don’t ‘average’ the models in the sense that Whitehouse claims, Yeager and Large aren’t ‘looking at the same data’ – they are looking at a very specific constructed set of fluxes – none of which are directly measured. Horrors – they are even using model output! The plain fact is that the change in heat content of the oceans is real, and much larger than can be explained by any number of ‘natural variability’. If Whitehouse thinks it can be, then where is his evidence?
Leif Svalgaard says:”Now, what does that mean?
Solar radiation [TSI] is radiative forcing, no?
Change in UV that controls temperatures at interesting places is radiative forcing, no?
Svensmark’s ideas about cosmic rays changing the albedo results in radiative forcing, no?”
Correct. But Yeager and Large appear to be claiming that none of these is responsible for the variations over the period they are focused on either. It’s an interesting claim, if true it would meant that the internal dynamics of climate can and have caused trends that elsewhere are being claimed to require “external” causes (ie Human or Solar). Well, I predict that such a result will inevitably be called into question and not be accepted by almost anyone.
Leif Svalgaard says:
June 17, 2012 at 6:15 pm
They say the increase in sea surface temperatures is not driven by radiative forcing
Now, what does that mean?
Solar radiation [TSI] is radiative forcing, no?
Change in UV that controls temperatures at interesting places is radiative forcing, no?
Svensmark’s ideas about cosmic rays changing the albedo results in radiative forcing, no?
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“The indirect inference is that diminished ocean cooling due to vertical ocean processes played an important role in sustaining the observed positive trend in global SST from 1984 through 2006.”
PDO, AMO etc.,- most likely that Santer and his new little group missed this with their simulation boxes in the other paper.
Everyone is familiar with the adage:
.
100 stopped clocks will indicate the correct time 200x per day… but I still don’t see how this facilitates determining the actual correct time?? GK
@RAYQ MCMULLEN Donahue. “Is Eric Simpson for real?? Can’t be!!” I’m real here, but not sure the nature of your critique.
@Geoffrey Withnell. “Mr Simpson, that is without a doubt one of the most racist posts I have seen in years…” I’m not sure if you got the parody aspect. A degree of caricature perhaps, but the comment was left in reply to this Real Science post: http://stevengoddard.wordpress.com/2012/06/17/white-men-destroying-the-climate-for-almost-200-years
My point was to satirize the white liberal who lives in non-flyover spots like San Francisco, an area which is rushing to implement Agenda 21, and is chalk full of the, it’s true, white liberals that led the way, and continue to lead the way, in duping us on global warming.
@Luther Wu. Lol with the van by the river. No gas, though!
@Brendan, thanks for pointing out the satire: “pretending to be a guilt-ridden white warmist:”
@Smokey. Thanks for the link. Looks like a good read, with great comments: http://takimag.com/article/green_on_the_outside_red_on_the_inside_brian_lasorsa#axzz1y6gSFtCj
Quotes:
“A massive campaign must be launched to de-develop the United States… [we] must design a stable, low-consumption economy in which there is a much more equitable distribution of wealth.” -John Holdren (1973), Obama’s Science Czar
“We have wished, we ecofreaks, for a disaster… to bomb us into the stone age, where we might live like Indians, with our localism, our appropriate technology, our gardens, our homemade religion.” -Stewart Brand, Whole Earth Catalogue
Eric Simpson says:
June 17, 2012 at 6:45 pm
“because of terrible climate change, we are going to find ourselves living in huts. Mark my word.”
We may well be living in huts because of a lack of energy resources, however, the cause of that problem resides in the Big White House at 1600 Pennsylvania Avenue! Drill, baby, drill and the lights stay on!
Would dinosaurs have become climatologists and modelers? It is a favorite topic in Sci fi with the idea being that given enough time dinosaurs would have evolved intelligence, (Harry Harrison, for instance). Donald B. DeYoung in Dinosaurs and Creation cites a poem by Bert Leston Taylor of the Chicago Tribune (1912) called The Dinosaur. This is based on the then recently discovered mass of nerves in the base of the tail bone. They thought it was a second brain. Many critters have these masses of nerves—even cockroaches. (I once knocked a bunch of cockroaches out with carbon dioxide and then cut the top of the heads off and scooped out the brain. I threw the bodies in a pile. When the carbon dioxide diffused back out of the tracheae they took off running. If humans could do that after brainectomy they could still do peer review and vote in national elections. But I digress from my digression. )
Here’s the poem:
Behold the mighty dinosaur
Famous in prehistoric lore,
Not only for his power and strength
But for his intellectual length.
You will observe by these remains
The creature had two sets of brains—
One in his head (the usual place),
The other at his spinal base.
Thus he could reason “A priori”
As well as “A posteriori”
No problem bothered him a bit
He made both head and tail of it.
So wise was he, so wise and solemn,
Each thought filled just a spinal column.
If one brain found the pressure strong
It passed a few ideas along.
If something slipped his forward mind
‘Twas rescued by the one behind.
And if in error he was caught
He had a saving afterthought.
As he thought twice before he spoke
He had no judgment to revoke.
Thus he could think without congestion
Upon both sides of every question.
Oh, gaze upon this model beast,
Defunct ten million years at least.
Eric Simpson says:
Nice attempt a redirect.
do you remember what the past was about?
You also forgot the /SARC at the end. Unless you wanted to reel some in.
Eric Simpson says, June 17, 2012 at 7:49 pm
And simultaneously burdened the world with systemic negativity that will take generations to undo. You know not what you have already done, not even the half of it. Read up on the Dark Ages in an effort to comprehend what your homemade tyranny is fully capable of. But I would suggest you avoid the blatant revisionism evident here; part and parcel of what your ilk has already wrought.
AJB, my ilk often wonders why your ilk doesn’t catch the obvious SARC in posts from Simpson’s ilk.
Somehow, the Gilbert & Sullivan operetta seems most appropriate to the establishment’s promotion of Dr Mann’s CAGW fantasy. The Pirates of Penzance above could be retitled The Pirate of Penn State when it comes to the hockey stick.
Luther Wu says:
June 17, 2012 at 7:05 pm
Eric Simpson says:
June 17, 2012 at 6:45 pm
“…we are going to find ourselves living in huts. Mark my word.”
_______________________
You can live in a hut if you want… I’m going to live in a van, down by the river.
============================
SNL a long time ago. You must be an old white guy. 😉