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Climate is too complex for accurate predictions

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old_user17401

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Message 31121 - Posted: 26 Oct 2007, 9:11:43 UTC

(if you believe this article / paper)

http://environment.newscientist.com/article.ns?id=dn12833

Agree or disagree, I\'m sure people will have opinions. Seems a bit defeatist to say we don\'t know so we can\'t know. I\'m going to continue crunching.
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Message 31123 - Posted: 26 Oct 2007, 10:19:29 UTC
Last modified: 26 Oct 2007, 18:39:22 UTC

I don\'t think its so much a case of just saying that we don\'t/can\'t know as recognising realistically that there are, and to some extent, will be uncertainties in the predictions we make.
Models already look at a range of different scenarios but the climate is an immensely complex system which is not static. If for example, as we hope, significant action is taken to reduce GHGs then that will alter any predictions we already have based on the current status quo. a change in one part of the system will effect other parts. The more we learn then the better chance we have. Not being able to be 100% accurate is not much of an excuse for doing nothing.
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Message 31132 - Posted: 26 Oct 2007, 22:29:37 UTC
Last modified: 26 Oct 2007, 22:35:10 UTC

There is more about this at

Real Climate

In essence, what Roe and Baker show is that this characteristic shape arises from the non-linear relationship between the strength of climate feedbacks (f) and the resulting temperature response (deltaT), which is proportional to 1/(1-f). They show that this places a strong constraint on our ability to determine a specific \"true\" value of climate sensitivity, S. These results could well be taken to suggest that climate sensitivity is so uncertain as to be effectively unknowable. This would be quite wrong.


This is similar to the non linear relationship between climate observables and sensitivity is something that Myles Allen and Dave Frame from this project have been saying.

I think it is worth pointing out that the forecasts of temperature rise for the next few decades are well constrained compared to climate sensitivity. Higher sensitivity (eventual effect of a doubling of CO2) means more committed warming but also that it will take longer to arrive.

http://www.sciencemag.org/cgi/content/summary/318/5850/582

Perspectives
ATMOSPHERE:
Call Off the Quest
Myles R. Allen and David J. Frame
Knowledge of the long-term response of Earth\'s climate to a doubling of atmospheric carbon doixide may be less useful for policy-makers than commonly assumed.


does not seem available without a subscription.

However this presentation
http://www.climateprediction.net/science/pubs/allen_NOC2007.pdf
may give you a flavour of what they are arguing. (Edit 14Mb download)


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Message 31166 - Posted: 29 Oct 2007, 13:49:27 UTC
Last modified: 29 Oct 2007, 13:50:00 UTC

Dave Frame has added a link to the new paper on his publications page: (the topmost item, titled \'Call off the Quest\')

http://www.atm.ox.ac.uk/user/dframe/papers.html

I'm a volunteer and my views are my own.
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Message 31197 - Posted: 30 Oct 2007, 23:02:15 UTC - in response to Message 31132.  

However this presentation
http://www.climateprediction.net/science/pubs/allen_NOC2007.pdf
may give you a flavour of what they are arguing. (Edit 14Mb download)



I think I got that completely wrong. Dave Frame has posted a quick summary which says:



Our basic point in the Perspectives piece is that it\'s probably a mistake to fix a concentration target now, based on some subjective estimate of climate sensitivity. As long as our policy people are allowed to bootstrap their targets occasionally we don\'t really ever need to know the exact value of climate sensitivity very well.


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Message 37343 - Posted: 25 Jun 2009, 10:24:57 UTC
Last modified: 25 Jun 2009, 10:33:52 UTC

Although I have no paid subscription to "Nature" magazine sometimes I am randomly allowed to see their "News" section. In a recent article a Met Office climate model was described allowing to foresee the consequences of climate changes in UK down to a scale of 25 km and even 5 km for some events. This model was rather ridiculed in a post at www.theregister.co.uk with the title:
Mystic Met Office predicts neighbourhood Thermageddon
Who is to be believed?
Tullio
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Message 37345 - Posted: 25 Jun 2009, 11:59:51 UTC - in response to Message 37343.  
Last modified: 25 Jun 2009, 12:13:17 UTC

Although I have no paid subscription to "Nature" magazine sometimes I am randomly allowed to see their "News" section. In a recent article a Met Office climate model was described allowing to foresee the consequences of climate changes in UK down to a scale of 25 km and even 5 km for some events. This model was rather ridiculed in a post at www.theregister.co.uk with the title:
Mystic Met Office predicts neighbourhood Thermageddon
Who is to be believed?
Tullio

... there is indeed some discussion about this, including from CPDN's own Myles Allen:
http://news.bbc.co.uk/1/hi/programmes/newsnight/8109923.stm (3:20 into the clip). However, The Register has a bit of a history on the topic.

[Thanks to Marj for spotting that.]
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Message 37346 - Posted: 25 Jun 2009, 12:34:47 UTC - in response to Message 37345.  

Although I have no paid subscription to "Nature" magazine sometimes I am randomly allowed to see their "News" section. In a recent article a Met Office climate model was described allowing to foresee the consequences of climate changes in UK down to a scale of 25 km and even 5 km for some events. This model was rather ridiculed in a post at www.theregister.co.uk with the title:
Mystic Met Office predicts neighbourhood Thermageddon
Who is to be believed?
Tullio

... there is indeed some discussion about this, including from CPDN's own Myles Allen:
http://news.bbc.co.uk/1/hi/programmes/newsnight/8109923.stm (3:20 into the clip). However, The Register has a bit of a history on the topic.

[Thanks to Marj for spotting that.]

Yes, I am aware of the Register bias.
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Message 37439 - Posted: 8 Jul 2009, 22:46:29 UTC - in response to Message 31132.  

I read the journal article "Call Off the Quest" and the presentation by Allen.

The notion of finding an upper bound on climate sensitivity may be foolish. What if there is none? What upper bounds do you put on physics, and what assumptions must you make to put those bounds on the earth? Predicting the "most likely" scenario given conditions and human history IS a focus worth pursuing.

Based on what I saw in the presentation: It seems to me that mean climate sensitivity value is Euler's constant e^1.

There, I just saved years of research time. :)
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Message 37443 - Posted: 9 Jul 2009, 2:23:19 UTC

A tiny proportion of CPDN models have predicted temperature rises of up to 11C this century while a very few have predicted a fall in temperatures. This is inevitable when the starting parameter values explore the full range of plausible possibilities. The results need to be explained in terms of the approximate % probability that any of the future scenarios will happen.

With large model ensembles like those produced by CPDN the range of error is reduced somewhat, but Roe and Baker of the University of Washington have shown why uncertainty cannot be eliminated from climate models: Why is climate sensitivity so unpredictable? The full paper can be read starting from the link on Roe's publications page though you have to register on the Science website.

Not all our models are designed to predict future climate. Some of the experiments using our models are designed to attribute the causes of climate change.
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Message 37445 - Posted: 9 Jul 2009, 14:09:15 UTC - in response to Message 37443.  
Last modified: 9 Jul 2009, 14:13:20 UTC

Not all our models are designed to predict future climate. Some of the experiments using our models are designed to attribute the causes of climate change.


I'll read those articles when I get a chance. Sounds interesting at least.

I would think that attributing the causes of climate change would be far more interesting (both politically and environmentally) than predicting the future. Really, once we understand the causes of climate change, only then can we make someone accurate predictions. Human behavior (and government policy) is always subject to randomness, of course, but I'm sure you guys try several likely scenarios for these factors.

In fact, for a short time I did participate in the Seasonal Attribution Project. Isn't that where the HadAM3 models originated that we crunch here?

I ask because I tend to be picky with my CPU time/project commitments, so I only select a couple of climate models.
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Message 37447 - Posted: 9 Jul 2009, 16:21:39 UTC
Last modified: 9 Jul 2009, 16:22:16 UTC

Yes, the HadAM models from the SAP project were later added to this main CPDN project. They're designed to show up causes for effects (well, the data generated by the models needs to be analysed to do this). HadAM models are now being used for the Validation and Attribution Experiment.

The various experiments are described on the CPDN website here except that the Millennium experiment hasn't been launched yet. It's behind schedule and Hiro wants its models beta-tested soon.

There's a lot of other interesting research about climate change going on in Oxford and elsewhere that doesn't depend on our models. The publications of Max Boykoff are very interesting from a social and political point of view; some of what he says is shocking or quite funny because he sees the crazy aspects of some of the stuff he analyses. I liked Ye Olde Hot Aire and Lost in Translation. His methodology looks to me impeccable.
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Message 45143 - Posted: 24 Oct 2012, 3:28:25 UTC - in response to Message 31132.  

This is a really old pdf. Is there anything that has been written recently? Also, probably a stupid question, but will this project ever be finished and the results publicized in Lehman's terms? I am an accountant, not a scientist. While i did understand a lot of the PDF below, it is a bit too technical


http://www.climateprediction.net/science/pubs/allen_NOC2007.pdf


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Message 45147 - Posted: 24 Oct 2012, 5:00:44 UTC - in response to Message 45143.  

There is mention of a recent publication here on the front page of the project. (Recent updates at the top left of the page.)

The project is unlikely to ever end, because it's about studying climate.

In the early days of the project, the work was generated by students at the University of Oxford, and the results published by them and the Uni.
These days, the work comes from external sources, from climate research organisations around the world. Their work is ongoing, and any results they come up with will be published by them, where ever they decide. As in the case of the above mentioned papers.

Climatologists tend to publish for other climatologists, not the general public.
Is there anything that you're looking to find out? Someone may be able to point you to more general reports.


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Message 45154 - Posted: 24 Oct 2012, 16:38:29 UTC

Some of the publications that resulted from this project are listed here and most are pretty technical.
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Message 46222 - Posted: 14 May 2013, 19:41:01 UTC

Most of the Links are down - pleas try to update the links.

The numeric models like HadAP/CM have a general uncertainty. They only will calculate what the programmers have implemented. Many causes in climate are known and described scientifically correct, others are unknown. The models can only create (calculate) what we would exped.

I think, at the end of 2010 decade we will get a basically new generation of computers for scientific problems. The answer for actual uncertainties could be the cognitive computers based on neural network techniques in opposition the von-Neuman-architecture.

Few months ago i found a paper (http://journals.ametsoc.org/doi/abs/10.1175/2008JCLI1869.1) "Constraints on Model Response to Greenhouse Gas Forcing and the Role of Subgrid-Scale Processes" in which they used a software neural network to improve parameter-settings for Had-Models we calculated.
Also 2001 was published a dissertation "Zur Anwendung Neuronaler Netze in der Klimatologie" to the neural network-techniques by Andreas Walter (german weather forecast DWD) find on amazon (http://www.amazon.de/Zur-Anwendung-neuronaler-Netze-Klimatologie/dp/3881483780). He said "neural networks have big potential for modeling non-linear Input-Output-Relations. If we found a way to set objective criteria, with neural networks the climatology can be get a huge knowledge acquisition". The original paper is in german language.

Computers who can learn autonomously und find coherences in the System we actually dont know/see. Neural Networks are already available only in Software. Next step was the presentation of a Processor based on Neorons and Synapses based on the structure of human brain called "Synapse" and evolved by IBM in 2011. Maybe this fully new architecture can revolutionize the climate-prediction.

Then we talk about speed-increases in dimensions. So be patient...
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Message 46224 - Posted: 14 May 2013, 21:16:08 UTC

The links are down because the server has been removed. This was because of the hack attack that took place in mid March, as mentioned in the News thread.

There has been work since then to update all of the front end of the project.
Nearly finished.

Currently, this is the "front page", with a recently added message in red.

******************

The work being done here is in collaboration with climate physicists in various research centres. They pay for, and provide data for, standard climate models.
These models have been written by and for the UK Met Office over many decades.
Any changes to or for new types of models and hardware will be done by the Met Office.
And this may well be happening already "behind the scenes".



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