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.)