Ian - quite right, but I think you could have used more foreceful language. In essence, the models were originally designed as an aid to climate investigations but somewhere along the line scientists got the idea that they could make useful forecasts with them. Somewhere along the line, scientists also got the idea that peer review of forecasts mattered - it does not. The usual proceedure is to make a forecast and hope that the actual results are somewhere near reality.
If they are near reality - 'hey, wow, we got something close to right for once' - then the model might be said to be validated.
Validation is completely absent from climate modelling. Not only have temperatures been declining slightly in recent years - the models say they should be going up - but these models also forecast a certain warming pattern for the troposphere which does not exist. Measurements show a quite different pattern. Time to dump the models as forecasting tools and put them back in their proper place as aids to understanding climate.

My family, myself five kids have been deeply impacted by the Financial Crisis we no longer eat Vegies regularly our diet is carbohydrate ; we no longer can afford Maccas,trips to Mt.Buffalow , fishing at Deni , Steam Rally Lake Goldsmith ; we were stripped bare by the Financial malaise and though we are brave we know that we will never get up again ; we know that when interest rates begin to rise as recovery happens a sign will be erected on our home . We are very bitter and hurt .

I am very ugly with Exec's who frolicked out of their sinking ships with millions of Dollars in bonuses paid for Failing ?
How can this be happening , Sol retired with 30 million what exactly did he do ? Sacked 2/3 of Telstra ? Now when we ring up with a tech issue with Big Pond we get a bill for 9 bucks ? Providing someone answers the phone.

Thank you Ian Read , now I can understand what happened , why we are now bankrupt and why no one is to blame and why no one is in goal ; I assume the Modelers are comfortably reinstalled in their sanatorium hopefully well supplied with nothing more dangerous than Plasticine.

Crikey ! I hope they are not doing the AGW Modeling ....Please Ian tell me NO !

It is refreshing to see an article on ONO that give a proper perspective on climate modelling and the role of science as a whole. In this debate all of us can find 'scientific' evidence to support our particular bias.
When someone comes up with a climate model that can run backwards to accurately predict what the weather was on days randomly picked from the past then it can confidently say we have a model that can predict weather more than 2 days in advance.
But this would be an overkill because we don't need projections for a particular day, only trends.
In trying to predict trends there is the problem of the period of the trends. Like waves within waves there are trends within trends. The projections will vary wildly depending on the period used and anyone can 'proof' anything depending on the period selected. If one doesn't work try another. Sooner or later you will find one that supports you particular prejudice.
Thank you for an article that puts modelling in perspective. What ever position we take on the climate change debate it will be an opinion (informed or otherwise) that will not be backed up by science. The science is far from complete.

Great article, Ian, well done. Australia's own Tom Wigley, a very big man as author of the main suite of models relied on by the IPCC, known as MAGICC, appropriately, because it magically uses his parameter assumption (Tellus, 1993) that the current increases in uplifts of CO2 emissions by the biosphere will soon decline then cease altogether, thereby ensuring the IPCC's nirvana, whereby all emissions are deemed to reside permanently in the atmosphere, raising the projected atmospheric concentration to as much as 1000 ppm by 2100 (today's is about 388). If instead the IPCC used just the observed growth of uplifts and increases in airborne CO2 since 1958, the level by 2100 would be less than 600 ppm. - so no tipping points, and only a modest increase in temperature, less than 1oC in all likelihood

I disagree

A very good contribution to the climate change debate. It opens the lid on how the AGW propaganda is generated. (It is ironical that the article is LITTERED with 'sponsored' "stop climate change advertisements" -- all beyond the authors control.)

1998: 'Our models show conclusively that rising CO2 levels immediately cause an increase in global temperature.'

2009: 'Our models were never meant to suggest that rising CO2 levels immediately cause an increase in global temperature. There could easily be a delay of ten years...'

2019?: '...or twenty years...'

2029?: '...or thirty years...'

Can someone in authority please tell me: how long do we have to have rising CO2 and flat temperature levels before AGW is disproved? I may not be around to see it, but I hope my grandkids will.

June 2008 and the banks in America still have AAA rating. Can you trust the earth worshippers any more than the economist? Already the alarmist have proved wrong time and time again. Get the weather forecast correct for one week and then work on something a little more complicated.

“In other words a climate model is a numerical model or simplified mathematical representation of the Earth’s climate system, or parts thereof. It includes data from real world observations and creates parameters or variables for the unresolved or unknown processes.”

The words “parameters or variables for the unresolved or unknown processes “

Is techno-babble for “speculative guesswork”

Just as terms like “then further approximated through mathematical discretization.”

Means “subjective judgment”

And “restrict the resolution”

Equates to "fuzzy and inacertainable possibility"

In short “personal guess work”,

containing the same sort of logic which suggest someone will win the lottery based on submitting a ticket containing their childrens’ birth dates.

Like the article states:

“This disjunct between scientific and the media presentation, when contained within the paradigm of advocacy, represents a threat to the integrity and falsifibility of science.”

None of the climatological balderdash and bunkum should ever be the foundation for making the serious social and economic policy decisions which will effect our future and our children’s future.

You either have a good reason for doing something or you have the sort of third rate psuedo-twaddle which "grant-hungry" climatologists try to pass off as “science”.

Many centuries ago wars were fought only after inspecting of the entrails of a slaughtered goat.

Climatology presents us with sanitized goats entrails and we are expected to pursue an economic war strategy based upon that gut feeling…

Personally, I would as soon speculate what the moon is made of and if it should collide with the earth, the dairy industry will collapse from the ensuing cheese glut.

I see that we are still awaiting a cogent, well-argued refutation from the AGW alarmists ...

This article should be required reading for all concerned about the issue.

I agree with this article.

But I would go further though, you could take out the word ‘climate’ and most of it would still hold up. In fact it is generally a good criticism on how models are made and how models can be in error in all fields of study. Does that make modelling invalid generally?

No.

The future is inherently uncertain, but modelling is pretty much the only tool that can be used for risk assessment and mitigation. Future projections generally are not terrific, no scientist disputes this, but they are useful in showing us how much we know about whatever system we are modelling.

What is also not being talked about is that policy decisions are not made after the fact. Real data is gathered after the fact, by definition. Policy is made on future predictions of trends and models, this goes for nearly every field of policy making, from town planning and demographic projections and industrial growth to science-based projections such as the effects on agriculture of disease incursion or pest outbreak or pesticide resistance. But for politicians and policy-makers it is usually necessary to attach economic consequences otherwise they find decisions exceptionally difficult to make. Who would want to spend millions of dollars maintaining a quarantine program if it was probable that it wouldn’t save any money for our agricultural industries at all? This is where they become unscientific; they are economic risk models.

What I would like to know from the author is this: should scientists generally stay out of communicating research to the media, just in case their field of research gets politicised?

I think the media have done a great job in misrepresenting what science is and what it does and completely bollixing up the public perception of science on a much more general level than just climate change. Anyone read those “research-has-shown” articles lately? Just for the record, if an ice-cream company pays a PR-firm to show that men prefer food to sex, and then gets “an expert” to comment on it, I think that they do a disservice to everyone.

If this article is saying that models are not the same as the "real world" then I along with all other modellers - of each Ian Reed is one - would agree.

Models do not "prove" anything but they do not stop Ian Reed saying in his article at http://www.agu.org/pubs/crossref/2003/2003WR002042.shtml that "Oak woodland is also predicted to have a significant impact by reducing recharge plus runoff by almost one half as compared with grassland." He hasn't proved that this is the case but there is strong likelihood that this will occur.

The climate change models say things like "If carbon dioxide levels increase by x% then it is likely that temperatures will rise by y degrees and will continue to rise".

If you have enough modellers coming to similar conclusions then it does not "prove" anything but any prudent person will take notice and say. If it is likely that temperatures will rise by y degrees will that make a difference? The prudent person may come to the conclusion that it is highly likely that it will make a difference detrimental to his or her wellbeing.

The prudent person might then say - is there a way to make it less likely that the temperature will rise and come to the conclusion that if we reduce the amount of carbon dioxide and other greenhouse gases in the atmosphere then it is likely that will help stop the temperature rise. The prudent person would then ask the question - By reducing the level of ghg concentrations will they be better off materially? if they come to the conclusion that they would be better off then would be foolish not to try to reduce ghg concentrations.

If the person realises that they can't do it on their own but have to enlist the support of the rest of humankind then they should advocate a policy of reducing greenhouse gases.

I consider myself to be a prudent person and will continue to advocate for a reduction in ghg emissions even without positive proof of its effect.

Fickle Pickle says - "The climate change models say things like 'If carbon dioxide levels increase by x% then it is likely that temperatures will rise by y degrees and will continue to rise'."

Fickle Pickle then develops the argument further with - "The prudent person may come to the conclusion that it is highly likely that it will make a difference detrimental to his or her wellbeing."

Prudence may be an admirable quality, but it does not assure solid science.

The prudent fool may come to such a conclusion, because the fool is gullible in believing things beyond the fool's own life experiences and knowledge. However, the prudently wise will question the parameters and make value judgments based on personal prudent experience and established evidence.

Prudence alone is no guarantee of sound judgment.

The prudently wise will ask questions like -

Where is the evidence that increasing 'x' causes increases in 'y'?
How does such a physical/meteorological mechanism work?
Could it be that it works the other way around, an increase in 'y' causes an increase in 'x'?
Where is all the evidence for all of this?

In answer, presently, the only real evidence available to the prudently wise is a smidgen of gathering science that suggests that the IPCC modeling is completely wrong.

The prudently wise will proceed with caution and continue to question the data.

A point of clarification: Fickle Pickle, Sunday, 28 June 2009 7:14:43 AM incorrectly identifies me, Ian READ, the author of this article, with Ian REED, presumably a climate modeller. Fickle Pickle states that he/she too is a modeller. Fickle, I think you have missed the point of my article that deals, in part, about the accuracy of inputs into models, and that outputs may be used as data, especially in the SRES models.

You also suggest prudence regarding your advocacy for a reduction in GHG emissions even without positive proof of its effect. Perhaps you could answer this: given that anthropogenic CO2 emissions are a fraction of the annual natural CO2 emissions, that anthropogenic CO2 behaves exactly the same way as naturally emitted CO2 in the atmosphere in terms of ‘greenhouse effect’, that both natural and anthropogenic CO2 are reabsorbed within a 3 to 12 year time period (this time frame is supported by about 90% of all the peer-reviewed literature) and that, in part, anthropogenic CO2 is absorbed locally by vegetation, then this raises questions about how effective globally or locally applied emissions trading schemes (ETS) will be in reducing current and future anthropogenic CO2 levels equivalent to a proportion of the anthropogenic CO2 levels emitted in the year 2000 (or 1990, as is sometimes quoted).

During the author’s research the greatest reduction he could find, assuming a globally applied ETS, was the indeterminate ‘several’ ppm of total atmospheric CO2, in other words, a reduction from the current (at the time of writing) 387ppm to, approximately, 380ppm. Given that an ETS is designed to only reduce anthropogenic CO2 and not the 50% to over 90% (depending on the reference) of natural CO2 outgassed from oceans or transpired by plants then what difference will an ETS make?

My apologies to the other Ian. To the author of this article Ian Read I am not arguing the rights or wrongs of the models. I am arguing that we know that burning fossil fuels puts "stuff" into the atmosphere. We know that if we put "stuff" into the atmosphere then it will have an effect. It may be benign or it may be detrimental to our overall well being.

What I am proposing is that if we have alternative ways of generating energy that does not put "stuff" into the atmosphere then it is prudent to use the alternative way and not get into arguments about the rights or wrongs of a particular climate model.

We can generate energy in ways that have a lower impact on the atmosphere. We can do it in ways that will increase our overall economic wealth and so the prudent and economic rational approach is to go that route as quickly as we can.

People think that doing something about burning fossil fuels is going to impose an unacceptable economic burden. I am saying that we can stop burning fossil fuels and at the same time increase our economic well being by increasing our overall wealth. If this is the case then let us stop using the rights or wrongs of climate models as an excuse for inaction.

I think I have twigged why politicians are so hell bent on emmission
control and reducing CO2.
They have been told the models predict the dangerous warming of the planet.
That feeds directly into their previous experience with economic models.
Therefore the AGW proponents must be right as their experience with
economic models has been quite reasonable.

Their understanding is faulty, even though a computer modeling total
non expert like me can see the near impossibility of predicting the
temperature range in 50 to 100 years.
The politicians are univerally out of touch with reality.

Fickle Pickle; it will be much cheaper to pay for mitigation as it
happens if AGW is real.
I wonder if it will be possible to sue for the return of taxes when
AGW is proved to be false, hmmm.