“Who would have thought that the climate models used as the basis of IPCC greenhouse forecasts would violate 72 of 89 principles of forecasting. That’s the claim from forecastingprinciples.com a site run by J. Scott Armstrong,
Professor of Marketing at the Wharton Business School, University of Pennsylvania. He and Kesten C Green from Monash University have published an audit of the forecasts from the IPCC Fourth Assessment Report. The auditors come to the view that while the scientists might know something about physics, they understand little about the science of forecasting…
Read the complete blog post by Graham Young here @ http://ambit-gambit.nationalforum.com.au/archives/002137.html
Read the paper ‘Global Warming Audit, Public Policy Forecasting’ by Scott Armstrong and Kesten Green presented at the International Symposium on Forecasting, 27 June 2004, Times Square, New York here @ http://www.forecastingprinciples.com/Public_Policy/global_warming_audit.html
Jennifer Marohasy BSc PhD is a critical thinker with expertise in the scientific method.
Anyone read the ‘paper’. The only references I could see were from Bob Carter, Willie Soon, Essex and Mckitrick etc – all discredited sources. Carter 2007 is not peer reviewed and the graphs are in a word unique.
Hmmmm I think this this is yet another beat up of the IPCC report. BTW this is the AR4 – if these people were so critical of the IPCC forecasting methods they had 6 years to work with the IPCC forecasters since the TAR(2001) to ‘audit’ the methods. Don’t tell me the bad people at the IPCC would not listen to them.
Ender, do you think Armstrong was paid by Exxon to cite Prof Carter? 😉
Did he say he was from “marketing”. Uh-huh – I love market surveys.
Is one of his key references – R Carter – yep – good call
mmmmmmm .. .. looks grim for IPCC modelling – he’s found all the weak spots. Drat there goes the world domination agenda.
So in this situation you’d normally call Ghost Busters or Bet Central for shill survival training – http://julesandjames.blogspot.com/ but I see James has been up early at “More on the “$20,000″ bet ”
You can decide to read James or not. But yep about what you’d expect. What a try-on. Next. And if you don’t know why it’s silly you’re a dill.
Anyway speaking of marketing the blog’s been on the “No” button again. Jen tell me you didn’t click twice.
“Do you think global warming is primarily caused by human activity? ”
yes 39%
no 61%
at http://www.abc.net.au/tv/swindle/vote/total.htm
So looks like 61% of the population will be sent to gulags. Oh well.
Maybe it’s now trendy to be a denialist. Will we see a whole flock of movie stars moving to the “no” camp. Interviews at the Academy Awards running “Well I always had my doubts”; “Yes well my agent said it was silly ” etc
No chance of that Luke, the majority of film stars, and all those in the other performing arts, are lefties who support whatever the current “fashionable” cause is. The current one being AGW. No brain power required; just follow like sheep.
Blow me down – in the ABC’s advert for TGGWS there are those dratted concrete cooling towers again, emitting steam! Can’t Greenpeace commandos abseil down them and fix banners?
Luke, takes up a lot of space to say nothing relevant. 😉
Jennifer – “Ender, do you think Armstrong was paid by Exxon to cite Prof Carter? ;-)”
No I am wondering why these ‘experts’ waited for so long to audit the forecasting. It is not as if the IPCC reports are obscure publications only known to a few people. If the people at the IPCC are so bad at forecasting why did these people not participate in AR4 – they certainly had long enough.
Also why are they using so obviously disreputable sources instead of the peer reviewed research?
Ender, its a messy world out there. that’s why a lot of top down plans don’t work. cause some critical group might, for example, not take any interest until it is too late …
or they make take a big interest and work out how to subvert the grand plan for their own ends.
Maybe Armstrong has only decided to take an interest now, as it is only now that he realizes the many policies associated with AGW are going to start signficantly impacting economically?
Errr relevant – there’s plenty – just read James Annan – and apart from that yawn. P.S. Sid – 61% says it’s not fashionable.
I have to agree with Luke, Jennifer. The sound of crickets chirping after he posts a relevant link to scientific studies is becoming deafening around here.
Jennifer – “Maybe Armstrong has only decided to take an interest now, as it is only now that he realizes the many policies associated with AGW are going to start signficantly impacting economically?”
Well he is very slow on the uptake if that is the case. How does he know that policies relating to AGW WILL impact economically. As far as I can see that is the economic doomsayers that inflate the economic effects of reducing greenhouse emissions.
We are in the position we are in because of very short sighted policies of self interest. However that does not mean shifting to significant amounts of renewable energy will have a huge impact as coal will still be mined and some power will still come from coal albeit only in a limited role. Coal is still required for steelmaking and aluminium smelting to make the electrodes so the future of coal is assured.
These people don’t have a clue. It’s not an open ended system, which can go either way. The heat coming in is going to be trapped, making the earth warm. There won’t be a sudden whim on the part of the planet to decide that radiation will make it cool. There isn’t some mechanism like a giant fridge that will turn the heating into cooling. CO2 is a greenhouse gas, it will warm the earth. Given that, the only question is by how much? Feedback mechanism have already been identified which are already being monitored and are acting as a positive feedback, as predicted.
The problem for these critics is that they think the scientists modelling the climate don’t know all this already, and haven’t taken it into consideration already. Yes, the modelling is far from perfect, and that’s still better than sitting back and taking an ‘act of god’ approach to it all. Some geologists are saying the weather has always changed, as if it does so for unkowable reasons. The model critics say we cannot produce a perfect model, don’t bother.
The scientists are getting on with the job, and seeing their predictions coming true to a large extent.
The modelling also serves another purpose. It allows the known temperature record to be analysed. By making the models fit the known record, then taking out the various forcings, it can be demonstrated that CO2 is the major forcing behind the current warming. That is, without making predictions about the future, the models analysing the existing record provide valuable information.
On Kesten Green on Counterpoint.
He starts off by talking all about how you can’t model politics or conflict. Good, they aren’t modelling that, they are modelling physical processes, which obey cast iron laws.
He then complains that there are people claiming it could also be cosmic rays, for example, he doesn’t know, he’s not an expert. Good, because the experts have looked and cosmic rays, and they aren’t a factor.
Overtuned models can give spurious results, because they model noise. Yes, that’s why the most basic science is based on the simplest models, they just model a one dimensional system. That is, radiation in, greenhouse effect traps heat. That’s well known, and proven. The modelling is not trying to predict the climate at any one place on earth, they are trying to predict overall climate. As it is, the prediction that the south east will get drier are correct, for example.
He then waffles on about, once again, the parts he doesn’t understand what they are doing, reeling off anecdotes, for example, about how the models can even predict cooling sometimes. He doesn’t understand what he is criticising, but that doesn’t stop him criticising it.
Ender would have us believe that the IPCC is this wonderfully inclusive body that welcomes inconvenient feedback. [enter Dorothy singing “somewhere over the rainbow”]
And it seems that anyone who actually uses the same discount rate to determine future costs and benefits is an “economic doomsayer”. Stein’s use of different discount rates to fudge his “projections” would be a criminal offence if he did the same in a prospectus. If he did it in a finace proposal for a merchant bank he would find himself driving a bus.
Come to think of it, perhaps he already has and the best gig he can get is with the planet ponces.
The modelling also serves another purpose. It allows the known temperature record to be analysed. By making the models fit the known record, then taking out the various forcings, it can be demonstrated that CO2 is the major forcing behind the current warming
You have got that around the wrong way round TJS
The models assume co2 causes warming
They don’t demonstrate co2 is the major force behind warming
Tuning the models to the known record doesn’t give them any ability to “predict” the future.
“The scientists are getting on with the job, and seeing their predictions coming true to a large extent.”
Which predictions have come true? I have read of various scenarios and possibilities, even the IPCC only presents a series of ‘what if’ scenarios
The inability to properly predict is reflected in the range of ‘solutions’, in another thread ‘poetry’ srecommends “to replace our fleet of vehicles but will not buy anything that does get at least 50 mpg if it is gasoline based, or it must be a hybrid, or it must be fueled with renewable fuels.”
What difference exactly will any of those 3 options make? If China switched over to all hybrids 9 am tomorrow they will still increase their consumption of fossil fuels at an enormous rate for the forseeable future.
I guess the bottomline is that not even the IPCC believes they are into forecasting
(though Ender, Luke and SJT might):
Head of the US Centre for Atmospheric Research, and a key advisor to the IPCC, Kevin Trenberth, has cautioned against using any of the models from the IPCC for predicting climate.
He emphasised the IPCC models were all “what if” projections of future climate that correspond to certain greenhouse gas emission scenarios.
… i think he blogged this somewhere?
You mean this Jennifer?
Predictions of climate
I have often seen references to predictions of future climate by the Intergovernmental Panel on Climate Change (IPCC), presumably through the IPCC assessments (the various chapters in the recently completedWorking Group I Fourth Assessment report ican be accessed through this listing). In fact, since the last report it is also often stated that the science is settled or done and now is the time for action.
In fact there are no predictions by IPCC at all. And there never have been. The IPCC instead proffers “what if” projections of future climate that correspond to certain emissions scenarios. There are a number of assumptions that go into these emissions scenarios. They are intended to cover a range of possible self consistent “story lines” that then provide decision makers with information about which paths might be more desirable. But they do not consider many things like the recovery of the ozone layer, for instance, or observed trends in forcing agents. There is no estimate, even probabilistically, as to the likelihood of any emissions scenario and no best guess.
Even if there were, the projections are based on model results that provide differences of the future climate relative to that today. None of the models used by IPCC are initialized to the observed state and none of the climate states in the models correspond even remotely to the current observed climate. In particular, the state of the oceans, sea ice, and soil moisture has no relationship to the observed state at any recent time in any of the IPCC models. There is neither an El Niño sequence nor any Pacific Decadal Oscillation that replicates the recent past; yet these are critical modes of variability that affect Pacific rim countries and beyond. The Atlantic Multidecadal Oscillation, that may depend on the thermohaline circulation and thus ocean currents in the Atlantic, is not set up to match today’s state, but it is a critical component of the Atlantic hurricanes and it undoubtedly affects forecasts for the next decade from Brazil to Europe. Moreover, the starting climate state in several of the models may depart significantly from the real climate owing to model errors. I postulate that regional climate change is impossible to deal with properly unless the models are initialized.
The current projection method works to the extent it does because it utilizes differences from one time to another and the main model bias and systematic errors are thereby subtracted out. This assumes linearity. It works for global forced variations, but it can not work for many aspects of climate, especially those related to the water cycle. For instance, if the current state is one of drought then it is unlikely to get drier, but unrealistic model states and model biases can easily violate such constraints and project drier conditions. Of course one can initialize a climate model, but a biased model will immediately drift back to the model climate and the predicted trends will then be wrong. Therefore the problem of overcoming this shortcoming, and facing up to initializing climate models means not only obtaining sufficient reliable observations of all aspects of the climate system, but also overcoming model biases. So this is a major challenge.
The IPCC report makes it clear that there is a substantial future commitment to further climate change even if we could stabilize atmospheric concentrations of greenhouse gases. And the commitment is even greater given that the best we can realistically hope for in the near term is to perhaps stabilize emissions, which means increases in concentrations of long-lived greenhouse gases indefinitely into the future. Thus future climate change is guaranteed.
So if the science is settled, then what are we planning for and adapting to? A consensus has emerged that “warming of the climate system is unequivocal” to quote the 2007 IPCC Fourth Assessment Working Group I Summary for Policy Makers (pdf) and the science is convincing that humans are the cause. Hence mitigation of the problem: stopping or slowing greenhouse gas emissions into the atmosphere is essential. The science is clear in this respect.
However, the science is not done because we do not have reliable or regional predictions of climate. But we need them. Indeed it is an imperative! So the science is just beginning. Beginning, that is, to face up to the challenge of building a climate information system that tracks the current climate and the agents of change, that initializes models and makes predictions, and that provides useful climate information on many time scales regionally and tailored to many sectoral needs.
We will adapt to climate change. The question is whether it will be planned or not? How disruptive and how much loss of life will there be because we did not adequately plan for the climate changes that are already occurring?
Kevin Trenberth
Climate Analysis Section, NCAR
(Dr. Kevin E. Trenberth is head of the Climate Analysis Section at the National Center for Atmospheric Research. He was a lead author of the 2001 and 2007 IPCC Scientific Assessment of Climate Change (see IPCC Fourth Assessment Report) and serves on the Scientific Steering Group for the Climate Variability and Predictability (CLIVAR) program. In addition, he serves on the Joint Scientific Committee of the World Climate Research Programme, and has made significant contributions to research into El Niño-Southern Oscillation.)
“GCMs “assume linearity,” says Trenberth, which “works for global forced variations, but cannot work for many aspects of climate, especially those related to water cycle … the science is not done because we do not have reliable or regional predictions of climate.”
Back to the tennis
Rog,
The authors of the audit have covered this.
From page 8 of their audit:
“In apparent contradiction to claims by some climate experts that the IPCC provides “projections” and not “forecasts, the word “forecast” and its derivatives occurred 37 times, and “predict” and its derivatives occur 90 times in the body of Chapter 8. Recall also that most of our respondents (29 of whom were IPCC authors or reviewers) nominated the IPCC report as the most credible source of forecasts (not projections) of global average temperature.”
Found the comments of Luke, Ender et al interesting. They’re obviously having trouble reading and understanding the audit. The authors don’t say that forecasting is impossible, but that the climate models don’t obey the known rules.
Oh, and talking about forecasting – I correctly predicted that critics of this report would seize on the references to Bob Carter to try and discredit it.
Trenberth is saying that despite all the problems with the models, they still give us our best insight into what the future climate will be like. I have said all along, the models are not perfect, and the resulting climate will not be accurately predicted. We do know that CO2 is a greenhouse gas. It is not going to make the climate colder. It can only make it warmer. The energy it traps will not disappear. You can take an ostrich approach, and say that we should not make any attempt to understand it, since the results will not be perfect, or we can take our best estimate, and work from that. The proof of the pudding is in the eating, and so far, the predictions are amazingly accurate, look at Hansen’s projections from ten years ago.
Trenberth himself says.
“The current projection method works to the extent it does because it utilizes differences from one time to another and the main model bias and systematic errors are thereby subtracted out. This assumes linearity. It works for global forced variations, but it can not work for many aspects of climate, especially those related to the water cycle. For instance, if the current state is one of drought then it is unlikely to get drier, but unrealistic model states and model biases can easily violate such constraints and project drier conditions. Of course one can initialize a climate model, but a biased model will immediately drift back to the model climate and the predicted trends will then be wrong. Therefore the problem of overcoming this shortcoming, and facing up to initializing climate models means not only obtaining sufficient reliable observations of all aspects of the climate system, but also overcoming model biases. So this is a major challenge.”
So initialising a model will cause it’s own problems. We have to set it to a ‘model’ state.
He also says.
“The IPCC report makes it clear that there is a substantial future commitment to further climate change even if we could stabilize atmospheric concentrations of greenhouse gases. And the commitment is even greater given that the best we can realistically hope for in the near term is to perhaps stabilize emissions, which means increases in concentrations of long-lived greenhouse gases indefinitely into the future. Thus future climate change is guaranteed.
So if the science is settled, then what are we planning for and adapting to? A consensus has emerged that “warming of the climate system is unequivocal” to quote the 2007 IPCC Fourth Assessment Working Group I Summary for Policy Makers (pdf) and the science is convincing that humans are the cause. Hence mitigation of the problem: stopping or slowing greenhouse gas emissions into the atmosphere is essential. The science is clear in this respect.”
That’s pretty clear.
A thought provoking paper. Uses a method of objectively analysing forecasts to better inform policy and decision making. Sounds like old fashioned prudence to me.
The decision trees on the http//www.forecastingprinciples.com web site outline how this system is applied. The audit as applied to climate forecasts by scientists is clearly explained and makes for interesting reading. Armstrong’s “Seer-sucker theory” is a hoot.
The graphs on page 10 clearly demonstrate that temperature trends depend upon the beginning and end data dates. And the graphs on page 12 question whether Co2 precedes or follows temperature rise. Well worth reading.
Hey Graham – how’s it going. Now now. I said it was good call to cite Prof Carter. Let’s not be too familiar with using “Bob”.
Armstrong should stick to his marketing. He isn’t a climate systems modeller’s bumhole. He’s a long way from home and as Jame’s Empty Blog well illustrates he isn’t even up with the fundamentals. But he wouldn’t be that silly so he’s probably foxing. Anyway what a long rambling boorish essay it all is. Sounds like an advert.
I enjoyed this little gem “It is not clear to what extent the models produced by the IPCC are either based on, or have been tested against, sound empirical data.” WTF – find out !!
“However, some statements were made about the ability of the models described in Chapter 8 to fit historical data, after tweaking of their parameters.” huh they did ??
If he had a better formal skill test or some novel statistics it might be worth an argument but in lieu of that I’ll let you guys have your fun. He’s telling the climate modellers how to suck eggs. Do they need a hand from marketers?
On the bright side – I admire SJT’s tenacity to try to inform the debate with some rational comment. 10/10.
chrisl – “You have got that around the wrong way round TJS
The models assume co2 causes warming
They don’t demonstrate co2 is the major force behind warming”
How do you know this? Are you involved with atmospheric modelling?
Perhaps rog should have posted the actual NCAR release:
“Thoughts on interpreting climate models and their results
Trenberth provides an overview of the strengths and weaknesses of global atmospheric models in his article “The use and abuse of climate models.” He points out that humankind is now “performing a great geophysical experiment” by modifying the environment in a way that threatens to change the climate. Lacking a spare earth on which to run a true experiment, “we have to do the next best thing–try to understand the climate system well enough to build a good model of the planet earth system . . . a virtual model of the earth in a computer.”
However, Trenberth notes, a climate model is only as realistic as the theoretical understanding behind it and the complexity allowed in it. Computer resources, while growing rapidly, still restrict the detail and sophistication of current models. NCAR’s climate system model, for example, requires weeks of actual time for a single 100- or 200-year climate simulation. “Computing power is one key to future progress,” says Trenberth. Another is to improve the representation of common processes such as cloud formation and ocean circulation in order to minimize the number of “flux adjustments”–shifts in energy, water, and momentum exchange that are artificially prescribed in order to make a model more stable. These adjustments run the risk of causing unforeseen and unrealistic side effects in the modeled climate.
In his article, Trenberth describes a strategy for carrying out climate experiments that removes much of the impact of flux adjustments and other potential sources of error. However, this strategy does not eliminate the possibility of complicated feedback effects. Among other sources of difficulty, clouds represent “probably the single greatest uncertainty in climate models,” notes Trenberth. “The enormous variety of cloud types, their variability on all space scales . . . and time scales (microseconds to weeks) poses a special challenge.”
To help gain confidence in model results, Trenberth advocates the use of such tools as sensitivity tests, to see how much a result varies with small changes in the input conditions or model procedures, and simplified models, which require less computer time, to check approximations and assumptions. He also suggests that the burden of proof for claims that model results are incorrect should be on the critic, not the modeler.
For policymakers hoping for guidance from computer models, Trenberth emphasizes the value of using pooled knowledge and results from a number of different models, such as those used in the estimates from the Intergovernmental Panel on Climate Change of a projected global warming from 1.3 to 2.9 degrees C by the year 2100. “Statements such as these, given with appropriate caveats, are likely to be the best that can be made because they factor in the substantial understanding of many processes included in climate models. Such projections cannot offer certainty, but they are far better than declaring ignorance and saying nothing at all.””
GCMs used properly can provide some view of what might happen in the future. NOBODY using them thinks they give accurate predictions. Their primary purpose as Trenberth says is as scientific tools to try to find out how the atmosphere works. The problem is when they are mistakenly thought of as infallible crystal balls – a mistake very often made in the media, but not at all often in the scientific community.
The IPCC give what-if scenerios and gives an idea of the risk that there will be climate change. Insurance companies do not forecast the rate of home break ins and then set premiums. They look at past data and come up with a risk for a suburb that then sets the premium. If they are wrong they lose money if the are right they make money. Forcasting break-ins would introduce two levels of uncertainty where there only needs to be one.
In the same way scientists use the output of computer models plus observations of the recent and distant past plus their years of experience working with the climate plus thousands of different observations from thousands of different sources to decide that there is a significant risk that there will be some degree of climate change from global warming.
The role of the IPCC is to communicate that risk assessment to politicians to decide what to do about it. So far that response is sweet bugger all so we had all better hope that there is no dangerous climate change and that they are all wrong because it looks like we are going to see the results of the grand experiment first hand.
Well,
Now that we know the IPCC fails the most basic expectations, we can move on.
Maybe to criminal trials involving the obvious charges of fraud, collusion, etc.
Ender thinks that he has struck a mortal blow; unfortunately the *actual NCAR release* was made in 1997.
Notwithstanding the antiquity of Enders referenced material it is still valid; Trenberth warns that “projections cannot offer certainty”
http://www.ucar.edu/communications/newsreleases/1997/nature.html
rog – “Ender thinks that he has struck a mortal blow; unfortunately the *actual NCAR release* was made in 1997.”
Mortal blow yeah right is that what this is? However what he said in 1997 is valid today that is why I posted it. GCMs are scientific tools no more no less. There is no computer model in the world that can offer certainty about the future. For that I would advise you to consult a crystal ball gazer.
Forcasts even when they adhere to whatever principles that this person is attempting to say the IPCC does not adhere to can still be wrong. Are you trying to say that if the IPCC had adhered to all 97 points or whatever the forecast would have been 100% accurate??????
Schiller -“Well,
Now that we know the IPCC fails the most basic expectations, we can move on.
Maybe to criminal trials involving the obvious charges of fraud, collusion, etc.”
Sure if they were in the forecasting business then yes if they were wrong. Two problems: One the projections and scenerios of the IPCC could be perfectly correct and two the IPCC is not responsible for our stupidity. If we knowingly heat the earth so that life becomes difficult then that is our problem not the IPCC.
In my opinion the the only fraud and collusion charges will be laid firmly at the door of the paid schills that sold their scientific opinions to the the highest bidder. There might be a few angry people in 20 years time and the usual suspects might like to be in the corporate green zones.
Mortal Blow? How can someone even begin to compare human behaviour, which can change at a whim, to processes involving inanimate objects that must obey physical laws? The guy is a goose, he should start with valid criticisms, and acknowedge for a start the qualifications made by the scientists involved of what they believe the shortcomings of their models are, and why they have made the compromises they have.
As I said already, CO2 can’t just decide to not be a greenhouse gas anymore.
Those that have access to Science mag can read this:
http://www.sciencemag.org/cgi/reprint/317/5834/28a.pdf
CLIMATE CHANGE: Another Global Warming Icon Comes Under Attack
Richard A. Kerr
Science 6 July 2007: 28-29.
Twentieth-century simulations would seem like a straightforward test of climate models. In the run-up to the IPCC climate science report released last February (Science, 9 February, p. 754), 14 groups ran their models under 20th-century conditions of rising greenhouse gases. As a group, the models did rather well (see figure). A narrow range of simulated warmings (purple band) falls right on the actual warming (black line) and distinctly above simulations run under conditions free of human influence (blue band).
But the group of three atmospheric scientists–Charlson; Stephen Schwartz of the Brookhaven National Laboratory in Upton, New York; and Henning Rodhe of Stockholm University, Sweden–says the close match between models and the actual warming is deceptive. The match “conveys a lot more confidence [in the models] than can be supported in actuality,” says Schwartz.
I also note that CSIRO have gotten into the ring with a newspaper rebuttal to Prof Carter in the Courier Mail. (the Courier being Queensland’s most read daily newspaper).
http://www.news.com.au/couriermail/story/0,23739,22017075-27197,00.html
in response to
http://www.news.com.au/couriermail/story/0,23739,21977114-27197,00.html
Perhaps more to come?
Sounds of crickets doing whatever they do.
Luke, I’ve always maintained that the best model is planet earth. We know that CO2 has been at these levels, and greater, before, and we know that the place didn’t turn into a cinder. So the best evidence that we have is that while the planet may be getting hotter because of greenhouse gases, this is not a human life-threatening situation.
So any model that suggests it is, probably has the wrong parameters in it. That’s the sort of check that prudence would suggest that you should apply to a model, but it’s not one that the IPCC process applies.
The modelling at the moment is largely of academic interest. Interesting, but not relevant. We’d be in the same position of predictive knowledge using the back of an envelope, which is what the study suggests.
Graham – it’s a bit more than that. The temperature itself is not the issue. It’s the tails of the distributions – hot and cold, effects on complex ecosystems, peak events like storms and floods, and events like drought. The mean temperature is the least of your worries.
We live in a world of 6 billion humans, 30 days food supply, and we are already maladapted to climate variation.
Things like mid-latitude drying come out of the modelling. Not everything is intuitive. And actually models not behaving as per observations is very useful. Indicates a lack of understanding. Climate models are validated against 100s of processes not just temperature curves.
Graham said “I’ve always maintained that the best model is planet earth. We know that CO2 has been at these levels, and greater, before”
Graham: By the same means we can see that the sea level was also higher in recent times. Returning to that old level would wipe out a lot of our more valuable realestate and a few good crops. In fact much of what we do in future depends on a lot of human activity remaining below that margin given out current coastline and delta development.
Transport too is structured behind some fragile dunes. It could get quite tricky launching a 787 in a number of places. But it’s that hockey stick that’s going to haunt us in the long run.
True: Rate of change determined initially from climate models will simply help with some of our engineering.
If you read the Fourth Assessment report from the IPCC it is abundantly clear that significant doubts still surround the quality of models.
http://ipcc-wg1.ucar.edu/wg1/Comments/wg1-commentFrameset.html
These doubts include;
• the role of clouds and cloud-radiation interactions and feedback
• the extreme complexity of the climate system and its multiple interactions create limitations on the accuracy of predictions.
• Climate change has inherently chaotic aspects which can create sudden changes to climate.
• Cloud feedbacks are the largest source of uncertainty and whilst improvements have been made the uncertainty has not yet been reduced.
• The cryosphere is considered to be of particular importance and yet the IPCC admits that many physical processes are still not well understood.
So in a nutshell, the models could be ok….but also they could not be………. Now lets cut co2 output by 90% shall we …..no one will be hurt…honest
ummm – no have a go evaluating both sides of the risk ledger.
Jen , back to the top where it began where you pondered ‘Who would have thought that the climate models used as the basis of IPCC greenhouse forecasts would violate 72 of 89 principles of forecasting?. But, is there any evidence that close adherence to the 89 principles leads to better forecasts or even better decisions.?