“Global warming predictions prove accurate”– Guardian

Guest post by Paul Homewood

image

http://www.guardian.co.uk/environment/2013/mar/27/climate-change-model-global-warming

The Mail on Sunday ran an article by David Rose a couple of weeks ago, pointing out just how woeful most climate models had been in predicting global temperatures in the last decade or so. Added to other media reports in recent months, the public at large, at least in the UK. are now gradually becoming aware that temperatures have flatlined for several years.

Desperate to counter this, the Guardian have reported on some work by Myles Allen, Professor of Geosystem Science at Oxford University. They report:-

Forecasts of global temperature rises over the past 15 years have proved remarkably accurate, new analysis of scientists’ modelling of climate change shows.

The debate around the accuracy of climate modelling and forecasting has been especially intense recently, due to suggestions that forecasts have exaggerated the warming observed so far – and therefore also the level warming that can be expected in the future. But the new research casts serious doubts on these claims, and should give a boost to confidence in scientific predictions of climate change.

The paper, published on Wednesday in the journal Nature Geoscience, explores the performance of a climate forecast based on data up to 1996 by comparing it with the actual temperatures observed since. The results show that scientists accurately predicted the warming experienced in the past decade, relative to the decade to 1996, to within a few hundredths of a degree.

The forecast, published in 1999 by Myles Allen and colleagues at Oxford University, was one of the first to combine complex computer simulations of the climate system with adjustments based on historical observations to produce both a most likely global mean warming and a range of uncertainty. It predicted that the decade ending in December 2012 would be a quarter of degree warmer than the decade ending in August 1996 – and this proved almost precisely correct.

The new research also found that, compared to the forecast, the early years of the new millennium were somewhat warmer than expected. More recently the temperature has matched the level forecasted very closely, but the relative slow-down in warming since the early years of the early 2000s has caused many commentators to assume that warming is now less severe than predicted. The paper shows this is not true.

  

These claims raise a number of issues, but let’s start by looking at the actual numbers. Plotted below are the annual HADCRUT4 anomalies, (based on y/e August, in line with Allen’s workings).

image

The decade averages, as indicated by the red lines, have increased from 0.196C to 0.467C, so on the face of it, Allen’s prediction was spot on. But we need to delve a little deeper.

1) Let’s start by making a general observation. The Guardian suggest that the results of this one model somehow vindicate climate modelling in general. This is clearly a nonsense, as we will see later, as is their claim that it “should give a boost to confidence in scientific predictions of climate change”

2) The article also talks about “the relative slow-down in warming since the early years of the early 2000s”. This is more nonsense – warming has not “slowed down”, it has stopped.

3) The first thing to notice about Allen’s prediction is just how low it was, compared with most other models. His forecast of 0.25C warming in 16 years equates to about 1.5C/century, well below other predictions. We’ll compare a couple later.

4) His starting point, the 10 years ending 1996 were, of course, affected by Pinatubo. The years 1992-94 were about 0.15C lower than the years before and after, so it is reasonable to assume the decadal average was about 0.04C lower as a result. In other words, about a sixth of Allen’s prediction of a 0.25C increase is no more than a rebound from Pinatubo.

5) As there was warming between 1986 and 1996, the temperatures at the end of that decade were already higher than the decadal mean. The average of 1995/96 was 0.07C higher than the decadal mean. In other words, part of Allen’s predicted increase between 1996 and 2012 had already occurred before 1996.

6) By the time the paper was written in 1999, Allen, of course, already knew that temperatures had climbed significantly since 1996, with the average of 1997 and 98 being 0.46C. Remember that his model predicted a figure of 0.45C for the decade to 2012, (0.196C + 0.250C).

I wonder why we were not told then that there would be no net warming for the next 13 years?

7) Although the model has, fortuitously, accurately predicted the temperature to 2012, this does not mean that it has been validated. The lack of warming for at least 10 years is a significant feature, and any model that fails to predict this cannot be said to be validated. It is ludicrous to posit that it “should give a boost to confidence in scientific predictions of climate change”.

8) As I mentioned, many other models forecast much more rapid rates of warming. The Met Office’s decadal forecast in 2007, for instance, which predicted global temperatures in 2012 would be 0.60C higher than 1996.

image

http://notalotofpeopleknowthat.wordpress.com/2013/02/06/met-office-decadal-forecast2007-version/

9) Or Hansen’s famous 1988 model, that predicted more than a degree of warming, even under Scenario B.

http://i90.photobucket.com/albums/k247/dhm1353/Climate%20Change/HansenvUAH.png

http://i90.photobucket.com/albums/k247/dhm1353/Climate%20Change/HansenvUAH.png

Conclusion

Contrary to the Guardian’s claims, Myles Allen’s work does not indicate vindicate climate modelling in general, nor does it inspire confidence in current predictions.

Furthermore, Allen’s work fails to explain why temperatures have flatlined in the last ten years, and why his original model did not predict it. More importantly, it has nothing to say about what this pause means for temperatures during the next decade.

But you would not expect to hear any of this from the Guardian.

Advertisements

  Subscribe  
newest oldest most voted
Notify of

There are people who live in the real world then there are the people in the above story.
(facepalm)

Anyone with a print copy of the Grauniad is probably burning it right now to keep warm.

ConfusedPhoton

I see the Guardian has not taken up another prediction Myles Allen was involved in-
“Myles Allen first hit the headlines when a research project that he was involved with issued a press release (26th Jan 2005) predicting that temperatures could rise by 11° C even if the amount of CO2 in the atmosphere is limited to only double the level before the Industrial Revolution.”
http://ccgi.newbery1.plus.com/blog/?p=81
Strange how the press release does not seem to be available on climateprediction.net!

Mycroft

The Guardian is to jounalism what Ghengis Khan was to diplomacy!

dahun

It seems global warming modeling is remarkably accurate at predicting past temperatures.

lurker passing through, laughing

AGW promoters have very little sense of shame.

Gunga Din

I’m going to make a prediction what the high temperature on my front porch will be today.
Tomorrow I’ll let you know what it will be today.

Rick Bradford

Even a blind pig finds an acorn sometimes.
Given the enormous number of ‘prediction’ darts thrown at the global warming board, it is hardly news that one has landed somewhere near the center.

Michael in Sydney

It’s not the Guardian, which amazes me, but the source. I just can’t understand how a Professor at Oxford, can produce a report which frankly, worms its way around the observed facts, and produces results which intentionally obscure the truth.

Mycroft

Basically then, Myles Allen has modified climate models retrospectively to fit observations. A crude piece of PR supporting his climate change hypothesis.

Bill Illis

I imagine Allen’s forecast was not two straight flat lines. It was a line going up as shown in Figure 3 in the 1999 paper.
http://140.208.31.101/bibliography/related_files/mallen0001.pdf
Its really the forecast from HadCM2 prepared for the IPCC 1992 supplement using IS92 scenarios (and which was amended from time to time up to about 1998 and hence the projections might start in 1997).
The temperature projections from this report are the lowest of any climate model forecasts made. The primary IS92A scenario only gets to 2.0C (from 1990 levels) by the year 2100 while the current forecasts are all in the 2.8C (from 1990 levels) range.
http://www.cics.uvic.ca/scenarios/img/is92_temps.jpg
You can get some kind of data for the IS92 runs of HadCM2 here. I believe Myles Allen says he used the GSA-identified scenario – the second group of forecasts on this page at the bottom. They are only available in long-term means and the grid system data is unusable so don’t bother downloading.
http://www.ipcc-data.org/is92/hadcm2_download.html
Mike Hulme also published about the projections here.
http://www.sciencedirect.com/science/article/pii/S0959378099000151

Elizabeth

If I was a Climate Scientist or ex warmist mainstream news reporter, I would run now. When the depth and scale of this scam is realized (as is now happening) your own mainstream media will have absolutely no mercy on you. It will become the story of the decade LOL

Phillip Bratby

Nobody other than left-leaning BBC luvvies read the Grauniad. It panders to the weird belief system of the chattering classes who live in leafy London and get their income from the hard work of taxpayers.

Lew Skannen

Every day some clairvoyant somewhere predicts a plane crash.
Every now and then one of them gets lucky….

Graham W

You’ve got “indicate vindicate” there in the conclusion.
[Thanks- sorted]

In other headlines: Tesco to Reshelve Pork with Other Poultry

Australis

“… what this pause means for temperatures during the next decade”.
What pause? Why do you believe the 15-year flat trend is a “pause”?
Earlier, you quite correctly say that warming has not “slowed down”, it has stopped. The entire warming episode lasted only 20 years, and then it was over. Eventually a new trend will commence, heading either upwards or downwards, but it won’t be a resumption of the 1980/90 trend.
We don’t describe the 1940-77 period as a “pause” between the two warming trends that occurred last century.

CheshireRed

The Guardian reveal their true colours not by what they say, but rather by what they don’t.
If AGW really was as bad as they claim (“The Gravest Threat To Humanity, Ever”) then any weather or climate event that even remotelychallenges the theory of climate catastrophe would be great news for the future of us Earthlings, and woulld be greeted with optimistic headlines of “Has climate catastrophe been averted”? But never shall such words pass the Mods attention at the Guardian’s CiF, let alone the actual Editor.
Thus their agenda is revealed as pre-determind, with nothing allowed to challenge their pro-AGW prejudice, or the social policies that are ‘urgently required’ to ‘tackle climate change’. They even knowingly refute the obvious implications of the observed reality of no global warming for well over a decade – despite record CO2 emissions, as it rather embarrassingly flatly contradicts the entire AGW theory that their predjudice is predicated on.
They should be ashamed of themselves.
No matter, as temperatures continue in flat-out the wrong direction as per the climate models doom-laden predictions we can console ourselves with the knowledge they’re heading for perhaps the most humiliating climbdown in UK newspaper history.

Russ R.

Rather that “Global Warming Predictions Prove Accurate”, a better title would have been, “One Global Warming Prediction Accurate”.
Does anyone know where to find the original Allen 1999 paper and prediction?
The chart image in the Guardian article is a bit strange… It shows observations (yellow diamonds for annual data, red for 10 year means), and it compares these observations to the prediction (a dashed black line). However, it also shows a solid black line growing at an even higher rate, but says nothing about what this line is, or why it’s shown.

Kon Dealer

What do you expect? It is the “Guardian” second only to the BBC in spreading the AGW gospel.
Moonbat (Monbiot) is a regular columnist for this loss-making rag.

Mervyn

I was stunned when I first read the Guardian article … and then I realised Duncan Clark must obviously have been caught up in a ‘global warming time-warp’ that left him confused, and not realising that April Fools Day – April 1st, 2013 – is actually tomorrow.

Should I find it hilarious that their baseline temp is ‘pre-industrial’? I mean, I guess that makes sense if you’re trying to define human effect on the temperature but it still seems like garden of Eden bias.
I’ll never need more to know it’s true what they say about the Guardian though. Describing this one particular model as an “Analysis of climate change modelling for past 15 years” punches my sense of reality in the face the same way the President of Iran does when he says he might be the 12th Imam.

Felflames

As a mere electronics technician , with no science training past the high school level, I would say 1.That if your theory does not match observable facts, you have an invalid theory and it is back to the drawing board.
2. If you have a model that seems to fit the observable facts, you need to confirm the model by feeding in different test data and see if your model still produces a similar result.
If it does, you may have a problem with your data handling procedures that will invalidate the model.
3. If 1 and 2 both happen to you as a scientist ,well ,we don’t shoot people for honest errors.
4.The biggest mistake you can make, is being unwilling to admit you made one.

Luther Wu

dahun says:
March 31, 2013 at 5:13 am
It seems global warming modeling is remarkably accurate at predicting past temperatures.
___________________
Not really- they don’t even backtest with accuracy, regardless of the Guardian’s claim.

Vince Causey

Good observation. But I would also add the “clairvoyants” fallacy to what is wrong with this prediction.
Just as clairvoyants claim to have made an accurate prediction, statistics have shown such outcomes are based on no more than chance. When taken together, the numerous predictions made by clairvoyants nearly always turn out to be false. Occasionally a prediction comes close to observed outcome.
In this case, we have not clairvoyants, but a panopoly of climate predictions. In some ways, these are even less impressive than predictions made by clairvoyants. At least the clairvoyants have a large domain of possible events to draw on – assassinations, natural disasters, wars, etc. The predictors of climate, however, have a very limited domain – globaly averaged temperatures. It does not take many predictors for one of them to have a very high probability of being correct.
How anyone can attribute a climatic meaning to this is beyond me. It has no more merit to be published in a scientific journal than a “paper” by Mystic Meg claiming to have predicted the banking crisis of 2008.

John Page

The Mail has returned to the charge
http://www.dailymail.co.uk/news/article-2301757/Governments-climate-watchdog-launches-astonishing-attack-Mail-Sunday–revealing-global-warming-science-wrong.html
including this
And last week, The Economist repeated our claims that many scientists now believe that previous estimates of ‘climate sensitivity’ – how much the world will warm each time the level of carbon dioxide doubles – are far too high.
In a key 2007 report, the UN Intergovernmental Panel on Climate Change suggested this was most likely to be about 3C, with 4.5C considered ‘likely’. However, recent research suggests the true figure is much lower – between 1.5C and 2C – giving the world many more decades to avoid disaster through effective new technologies.

Peter Miller

I looked, but could not find, the original Allen and Tett article in 1999. I could not find it, but I did find references to it, all behind paywalls.
As it’s ‘climate science’, this begs the question: “What did the 1999 paper really say?”
Anyhow, the article is written in the Guardian, the natural home of the UK’s leftie, ‘intellectual’, self-proclaimed elite..

Pamela Gray

This is an article fit only for the Enquirer. The Enquirer used to do clairvoyant predictions and alien invasion stories but stopped after they were gifted with hollywood stories of stars turning up in jail. Could be why the Guardian took up the prediction stories, since NO ONE else is stupid enough to let climate prediction stories be a significant permanent part of their rag history.

I find it amusing that the Guardian is entirely dependent for its very existence on Autotrader magazine — a publication which relies for its very existence on the internal combustion engine!
Big Oil sponsors The Guardian! You couldn’t make it up.

Wamron

RE point “3”: So in effect the Guardian is saying that of all climate models the one that DOES NOT predict “catastrophic” climate change IS THE ONE they tout as accurate!
Thats pretty …ahem…”cool”.

cloa5132013

From 0.00000001% to 0.01% is big jump in confidence- 100000000%. All modeller need to take note- make the most carbon dioxide effect minimising model and you might be this lucky.

cbrtxus

Gunga Din says:
March 31, 2013 at 5:21 am
I’m going to make a prediction what the high temperature on my front porch will be today.
Tomorrow I’ll let you know what it will be today.
==============================================================
Can you predict yesterday’s lottery numbers too?

Pamela Gray

Re the graph in the Guardian: Interesting yellow diamond pattern of individual year data toying with his prediction. I’ll wager a bet he is hoping, maybe even praying to the god of yellow diamonds, that those gems start “playing” a more congruous tune and start moving up a little bit more in the direction of his future prediction. That prediction rises like the Grand Tetons, as do all other AGW predictions. My prediction is that Mother Nature will also sink this boat in due time. It has already developed a leak.

Latitude

You mean out of all those predictions…….they found one!
….I’ll be damned

Nik Marshall-Blank

I was going to post on the Guardian website but my posts are so heavily moderated now.
I like the way they just gloss over the fact that initially their forecasts did not show the rapid warming that happened and then had to wait until the model “caught up” with the real world.
Oh well. I suppose a broken clock is correct twice a day, you just have to wait until the time catches up with it.

sparky

Bit off topic but whats do you think the odds are of somebody posting a comment on the guardian website pointing out the cherry picking and not being deleted ?

The Iconoclast

I have created thirty eight models for predicting the outcome of a spin of a roulette wheel. They are amazing. I don’t want to get into too much detail about how they work, but no matter what number comes up, one of my models correctly predicted it.

JimF

Maybe some Brits are starting to get it:
It’s the cold, not global warming, that we should be worried about
No one seems upset that in modern Britain, old people are freezing to death as hidden taxes make fuel more expensive
By Fraser Nelson8:07PM GMT 28 Mar 2013
http://www.telegraph.co.uk/health/elderhealth/9959856/Its-the-cold-not-global-warming-that-we-should-be-worried-about.html

It’s still freezing here in Blighty!

dmacleo

I notice no comments allowed in that article. gee why is that…..

Leon0112

1.5 degrees C/ 100 years. Oh, my! This implies very limited feedback from clouds, etc.
Catastrophe averted. Let’s go back to using cheap energy.

John Tillman

A single carefully cherry-picked forecast, not “predictions”, plural. Looking at predictions made in the 1980s presents as very different picture, particularly those of Hansen from Venus (defended by Mann from Mars by stopping at 2005).
What becomes evident is that the Earth apparently (at what level of statistical significance & reliability, I don’t know, given cooked book data) enjoyed about 20 years of much-appreciated warming from ~1977 to 1997 (or less time, since the latter was a mega-El Nino year), followed by 16-17 years & counting of flat temperatures (longer in some series & actual cooling without “adjustments” that always make observations warmer recently & colder in prior decades), despite continually rising CO2 levels.
CAGW FAIL.

commieBob

The Guardian didn’t get the memo. Global warming is over. We can forget about it. The new demon is ocean acidification.
This morning the CBC interviewed Rob Stewart who has just made a movie “Revolution” which he is promoting. The interviewer asked him “What about the people who don’t believe in global warming?” He replied “Forget about global warming, this isn’t about global warming, it’s about ocean acidification.” (The quotes aren’t exact but I think the meaning is correct.)
There we have it folks. The environmentalists aren’t even bothering to defend “global warming”. It’s a distraction from the new disaster.

David L.

More moving of the goalposts
I should predict every possible trend of future stock market performance and then in a few years dig up the one that was correct, then sell my consulting services to stock brokers everywhere.

It seems to me that the most important point to make is that Allen’s model predicted only mild warming. Skeptics should use this article to say “Look, the Guardian is using the accuracy of a climate model which actually supports the skeptics’ perspective as evidence of the accuracy of the alarmists’ perspective. What sense does that make?”

Kindlekinser

Theory validation requires understanding the difference between prediction and explanation. The theory-derived prediction can be incorrect, based on observed data. But the explanation for why the prediction was wrong can still match the underlying theory. This would lead to a new prediction, still based on the same theoretical assumptions. So, to invalidate a theory requires more than just inaccurate prediction. It also involves finding another theory that better explains the observed results. As long as current theory continues to hold the best explanatory power, it will appropriately guide future predictions.

Lew Skannen

Every week somebody seems to be able to predict the lottery numbers here. Different person every week but what an amazing ability to have eh!