Do different climate models give different results? And if so, why? The answer to these questions will increase our understanding of the climate models, and potentially the physical phenomena and processes present in the climate system.
We now have many different climate models, many different methods, and get a range of different results. They provide what we call ‘multi-model‘ and ‘multi-method‘ ensembles. But how do we make sense out of all this information?
And, do we really need all these different models? Global climate models tend to give roughly similar estimates for the climate sensitivity, but there is nevertheless a spread between the different model estimates. The models often diverge more radically if we zoom down to a region.
Furthermore, a single model may give different answers for the future temperature over North America, depending on which day is used to describe the weather at the starting point of the model simulation (Deser et al., 2012).
So the question is whether the differences in model set-up affect the range of the results, and whether a mix of models is superior to many simulations with a single model in terms of accounting for the unknowns of climate modelling.
The fuzziness associated with the spread between the model results is often referred to by the catch-all phrase ‘uncertainty‘, referring to (unpredictable) chaotic internal variations, vaguely known forcing estimates, and climate model limitation.
Whereas climate scientists find ‘uncertainty’ difficult, it plays a central role in statistics (Katz et al., 2013). The statisticians are experts at drawing knowledge from a large volume of information, incomplete data samples, and have methods for ‘distilling’ the data (using a phrase coined by Bruce Hewitson). Some interesting methods are regression analysis and factorial design.
It is necessary to bring on board more statisticians to participate on climate research. Hence, the motivation for a Statistics and Climate workshop with a high proportion of statisticians among the participants (supported by the SARMA network, Met Norway, Norwegian computing, and the Bjerknes centre).
Bringing together people from different fields can be challenging, and we sometimes realise that we speak about ‘uncertainty’ or ‘models’, but mean different things. Is ‘uncertainty’ a probability distribution, model error, gaps in observations, inaccuracy, or imprecision?
In statistics, a ‘model’ may be a probability distribution or an equation whose coefficients are estimated from the data (‘best-fit’). We can also define ‘weather’ as a time series describing when and how much, and ‘climate’ as a probability distribution saying something about how typical such an event is (illustration below).
During the workshop there were discussions about what is meant by ‘prediction‘ – is it the same as a ‘forecast‘? It is difficult to collaborate before we speak the same language and understand each other.
Sometimes it also may be useful to take a step back and re-examine concepts that we take for granted. It is interesting that the exact meaning of ‘storm‘ and ‘extreme‘ were topics of discussion at the workshop.
Our understanding of physics is needed to identify key scientific questions, but the statisticians have the expertise to design tests based on data and statistics. For instance, we can ask whether the model set-up has a systematic effect on the results of the simulation – as in the text above.
Another aspect is the question of proper sampling. It may be tempting to pick the ‘best’ model for a region, even though the same model performs poorly elsewhere. From a statistical point of view, however, we know that selective sampling will give spurious results, also referred to as a bias.
The Economist recently printed an article with the title ‘How science goes wrong‘, explaining how a bias arises when mostly positive results are reported in the medical literature. This is another form for selective sampling, and for the climate models, it can only be justified if there are physical reasons to exclude a particular model.
Another contribution from statisticians in climate research is to bring in their experience with ‘infographics’ (Spiegelhalter et al., 2011) and ways to convey complex messages through illustrations. This and the ability to make sense of data and model results are valuable for climate services.
We also need reliable data, but there is a concern about the quality (homogeneity) of some of the surface temperature (The International Surface Temperature Initiative ISTI). Resources are also needed for ‘data rescue‘, but it is difficult to find funding for such activity because it is often not regarded as ‘science’.
In addition to high-quality data, we need a common data structure for creating a platform for collaboration that includes observations and different kinds of products (e.g. empirical orthogonal functions), both in terms of data files on disks (e.g. netCDF and the ‘CF’ convention) and in the computer memory.
Standard conventions can reduce the risk of misrepresenting data and make the analysis more transparent. Advanced data structures also make better use of advanced facilities, e.g. the ‘S3’ method in R.
References
- C. Deser, R. Knutti, S. Solomon, and A.S. Phillips, "Communication of the role of natural variability in future North American climate", Nature Climate Change, vol. 2, pp. 775-779, 2012. http://dx.doi.org/10.1038/nclimate1562
- R.W. Katz, P.F. Craigmile, P. Guttorp, M. Haran, B. Sansó, and M.L. Stein, "Uncertainty analysis in climate change assessments", Nature Climate Change, vol. 3, pp. 769-771, 2013. http://dx.doi.org/10.1038/nclimate1980
- D. Spiegelhalter, M. Pearson, and I. Short, "Visualizing Uncertainty About the Future", Science, vol. 333, pp. 1393-1400, 2011. http://dx.doi.org/10.1126/science.1191181
Aaron wrote (#38): “That very little is done is, to my mind, thus not really a communication problem (a convincing problem) anymore. Yes, scientists and statisticians can always learn to communicate their knowledge more effectively and that definitely can help, but I think it’s mostly at the margins. The problems are power politics, money, and status-quoism, generally speaking.”
I think that is quite right. For the most part, I think “scientists and statisticians” have been communicating what they have to communicate quite well, and the constant overwrought agonizing about how to better communicate “the science” is misplaced.
The problem is that many people never even hear what the scientists have to say, because they are being drowned out by the massively funded bellowing bullhorn of the denialist propaganda machine and the deafening roar of pseudoscientific drivel, outright lies, slanderous hate speech and crackpot conspiracy theories that they call “reasonable doubt”.
And the job of that propaganda machine is made that much easier because most scientists seem reluctant to raise their voices much louder than a whisper.
Scientists don’t need to learn to “communicate their knowledge more effectively”, they need to learn how to shout.
Speaking of statistics, studying past business decisions offers some insights. Quoting from http://www.eea.europa.eu/publications/late-lessons-2
(a very soberly reasoned book, second volume, studying Cassandra’s world)
Shorter:
Few people intend to be evil, most decisionmakers in business think they’re making rational economic choices under the rules they’re obligated to follow (e.g maximizing stock price in the short term).
Demonizing tends to increase the number of demons, duh.
And speaking of the topic, thanks to Rasmus for an opening article -loaded- with links to relevant useful interesting information about statistics-and-climate; seeing how many people are actively working at making us smarter about this, and seeing local and national as well as global information accumulating, is helpful.
Folks, read the linked pages. Lots of good science, I hope more of the scientists speak up.
@48 Ray, thx for the response there. I am not sure what others think about it, but from where I sit it pretty well confirms the basis of my own overview comments and key suggestions of the core issue re “communication’ is all about. So I’m at a loss why you believe you disagree with me. What’s the purpose of effective communication, and how does one know when it has been successful? (Rhetorical)
Now nothing I have said has been about ‘blaming’ anyone nor fault finding, but speaking to the reality as it is. eg you say ” You merely sought to blame the current situation on poor communication by scientists.” I did not. Ray I have checked my prior posts and word searched various pages, and only ONCE did I use the word “poor” and it was in regard poor word choices, ala semantics etc. If you or anyone else sees that as over the top “blame and fault finding” well, whatever. What is a comments page for? (rhetorical)
@50 Aaron. Most of my focus was/has been on the IPCC specifically and/or lack of any central ‘authoritative responsible’ body being active in the field of the public domain. I suggest you have not understood my meaning at all and are cherry picking aspects of it only, not the whole of it. and rather than making silly online “bets” you are right, how about reading up on what academic papers actually say about ‘public opinion and understanding’?
Skepticism, disinformation, and media hype is one thing. They do have an effect on others. Climate science communication is another. It too has an effect on others. BOTH exist within the same SPACE. To pretend they do not and that people simply need to read the IPCC Reports or RC is a joke and all is well with ‘communication’ is a joke. (isn’t it?)
UK Study 2011: *Scepticism and uncertainty about climate change: 1) Scepticism is strongly determined by environmental and political values rather than by education or knowledge. 2) Public uncertainty about climate change has remained remarkably constant since 2003, although BELIEF that claims about the issue ARE exaggerated has DOUBLED. 3) The paper describes a novel and highly reliable measure of public scepticism about climate change, the Scepticism Scale.
http://www.sciencedirect.com/science/article/pii/S0959378011000173
UK Study 2012 Uncertainty & attitudes towards climate change – “In both groups, attitudes towards climate change became significantly MORE Sceptical after reading the editorials, but we observed no evidence of attitude polarisation – that is, the attitudes of these two groups did not diverge.” http://psychdemo.cf.ac.uk/home2/whitmarsh/Biased_assimilation%20pre-print.pdf
What is climate change scepticism? http://www.sciencedirect.com/science/article/pii/S0959378013001477
Role of the IPCC? IPCC is THE leading international body for the assessment of climate change. It was established by the United Nations Environment Programme (UNEP) and the World Meteorological Organization (WMO) in 1988 to provide THE WORLD WITH A CLEAR scientific view on the current state of KNOWLEDGE in climate change and its POTENTIAL environmental and socio-economic IMPACTS.
Because of its scientific and intergovernmental nature, the IPCC embodies a UNIQUE opportunity to PROVIDE rigorous and balanced scientific INFORMATION to decision makers. By endorsing the IPCC reports, GOVERNMENTS acknowledge the AUTHORITY of their scientific content.
Oslo, 10 December 2007 – The IPCC and Albert Arnold (Al) Gore Jr. were awarded the Nobel Peace Prize “for their efforts to build up and DISSEMINATE greater KNOWLEDGE about man-made climate change, and TO LAY the foundations for the measures that are NEEDED to counteract such change”.
It is now 2013 – 25 years post-IPCC being created, and 6 years since the IPCC won the Nobel Peace Prize. Judge the current RESULTS and OUTCOMES in the real wolrd right now today, and compare that with the *theory* and *goals*. Successful or not at disseminating greater knowledge, providing scientific knowledge, and SEEN AS THE AUTHORITY by ALL Governments and by ALL People? .. yes/no/don’t know. (rhtorical) Thx and Best
@51 SA “Scientists don’t need to learn to “communicate their knowledge more effectively”, they need to learn how to shout.”
If the message is being drowned out by denialist propaganda, and that is the reality, then Climate Scientists / IPCC / whoever need to deal with that reality and counter it with more effective communication techniques that work in order to achieve the desired results.
If shouting is the answer and it works, then that is being MORE EFFECTIVE in their communication style by default. Which is the complete opposite pov of “how to better communicate “the science” is misplaced.”
Either their is a lot of cognitive dissonance going on here or multiple mind mudhras or outright and irrational ** denial ** of what I have been saying. Best.
@26 Hank (btw I always appreciate your straight forward contributions with add-on info here for years)
OK, attempt to refute I will. I am aware of other studies similar to this one, and they too show similar conclusions. I don’t argue those conclusions. I agree with them because they are rational and reasonable. I have had some experience in internal “surveys” and understand the dynamics involved here to a fair level, not expert. Don’t claim to be. I express my opinion as best I can and will explain it or provide more info nuances if asked. No one has asked me a single thing in this direction thus far. No problem my end.
OK I’ll stick with the summary on the page linked: “refute the idea that those who do hold non-majority views just need to be “educated” about climate change;” I don’t refute that, there’s a lot of truth in it. However I claim it is misplaced and off-base. Do not conflate “education” with “communication” – they are not equivalent. If this needs explaining then I suggest people should Google scholar it.
re: “convey the widespread scientific agreement about climate change” is another good conclusion in the survey I agree with. This truth extends across the public sphere as well. It’s a core issue. Way too many believe there is limited consensus, when the opposite is the truth.
One recent public poll/study I saw (by memory) only 7% were found to be profound non-AGW sceptics (others had some doubts). When asked how many others were skeptics they said 47% would be. When asked what was the scientific consensus they believed it was 50/50. iow they totally rejected or did not know about any of the studies putting the scientific consensus for AGW/CC risks at ~97%.
You and others seem to be only “blaming” the denialists for this. Why?
May I use an analogy instead of “data”? 5 people over several years come to my son denying I am his father. When he comes to me each time and asks, I refer him to the documented “data”, his birth certificate listing me as his father. I do not discuss it further. I refuse to get a DNA test done. Why? Because even a DNA test may only be 97% accurate anyway.
The 5 people have seeded him with compelling doubts to a point where he does not believe me, and yet still I stay silent. he asks intelligent questions and yet still I refuse to say a word about the 5 people falsely accusing me of not being his father. I know these 5 people, and I know what they are like, and they know they are wrong, and yet still I say nothing about them and ignore my son and do not instigate direct communicate with him about what I know to be true and know to be false. Why should he believe me?
Any other questions? Best.
@29 SA ” multiple eye-witnesses ”
It’s been proven scientifically that eye-witness accounts are more often than not unreliable, even when honestly believed by the witness to be true and accurate. Research it.
Here’s two examples of the efficacy of the law courts getting it right (especially in the US) Hurricane & O.J.
Surely you don’t need more examples? Nice theory. It has manifold flaws in it and provably so. It’s all about who wins the “debate”, the “rhetoric” and the sophistry in the court room. Until you brought in “plea bargaining” which essentially has knee-capped your Justice system. Plus a ton of unconstitutional and unethical irrational laws. :)
> lack of any central ‘authoritative responsible’ body being active
Name one case where that’s worked out, for any global problem?
These things are solved by people cooperating, to the extent they get solved.
Look again at that ‘Late lessons from early warnings’ documents; the first book didn’t discuss climate change at all, explicitly because of the uncertainties. The new second volume does, because there’s more known.
Look again at the discussion of beryllium disease — a modern example of the industry lawyer lobbyist lies and deception approach to a problem, quite clear.
>You and others seem to be only “blaming” the denialists for this. Why?
I don’t blame the poor stupid credulous copypasters for being what they are: easily misled and easily exploited. Because I’m aware people are like that. We fall for this sort of bogosity all the time.
Look at the Climate Reality project again, at the rate it’s growing. Those folks are working with the real problem, with presentations that are being improved — and fact-checked by scientists.
If we solve this, it’ll be their presentations that accomplish the change.
Sean,
If memory serves (which it often doesn’t for me) this topic of communication became a sore spot a few years back. There is a tendency toward clumsy assessments or outright blaming-the-victim which trolls discovered could be used to derail conversation. Ironically, though the trolls have moved on to other stratagems, conversations are still getting derailed by default whenever the topic arises.
On the one hand, it’s a knee jerk reaction, on the other nobody wants to give trolls an opening. It’s unfortunate, but bottom line, if you want to discuss communication here, adjust your language accordingly in order to communicate about it.
But — Sean —
you’ve taken over a wonderful science topic that’s worth us learning from.
Could you take your issue and those attracted to it somewhere else?
Because the Statistics and Climate thread could still be about statistics and climate.
I’ve read about half of the links in the original post and mean to read them all and try to learn about statistics and climate. Here, if possible. Now, with luck.
Education starts with us, here.
If we’ll shut up long enough for the scientists to educate us.
Challenge: list the links in the original post.
Read them, check them off your list.
Ask smart questions showing a beginner’s understanding of the statistics.
Better yet, let’s hope some actual statisticians wanting conversation with the climatologists show up and ask better questions.
Give them a chance. Better places for offtopic stuff are plentiful.
Education, available here, is damn rare.
[Response: Hank, thanks. I have moved some of Sean’s comments to Unforced Variations. – gavin
Sean: “The responsibility of being clearly understood is totally upon the shoulders of those wishing to communicate something from themselves to others. Until that is improved doesn’t make much difference how good or accurate the science is.”
Does that paragraph sound familiar, Sean? It is what you wrote back in #17. It is also simply flat-assed wrong. Communication by definition involves a sender and a receiver. Both have to work if the communication is is to be successful. Yes, a speaker can pitch his presentation incorrectly for his audience. However, an audience that is lazy or unwilling to hear what the speaker has to say will also torpedo the process.
Sean: “imho, the worst thing that has negatively affected global understanding of the importance of climate science and future risks was in fact Al Gore’s Inconvenient Truth.”
And then you come up with some vague suggestion that the IPCC should have made AIT rather than Gore. As if the chuckleheads whose oppose Gore find a UN panel any more credible. Gore had been making the same presentation for years. A documentary maker merely decided to film it. Now at any point during those years, a Republican politician could have stood up with Gore and depoliticized the topic. Did they? Nope. At the same time, scientists all over the world were also giving popularized talks on climate change. Ask Jim Hansen if his expert status saved him from accusations of “political activism”.
Sean, my criticism of your position is that you are criticizing those who have been most active for the longest in getting the truth out there rather than those funding and running the lie machine of anti-science. And what is more, you are criticizing people who are trying to popularize the science on their own time even as they try to come to a better understanding of the frontiers of climate science in their day job.
I would suggest that rather than making scientists take time out from their important day jobs to refine their presentations to the point where even the most blinkered imbecile cannot understand them, we might better expend some effort getting the average lay person to better comprehend how science fricking works. I contend that this would pay benefits not only for climate science, but would also benefit the lay person by making them a better consumer of medical research, safety research, etc.
I contend that the problem is not with what scientists are saying but rather with the public’s inability to comprehend what real science sounds like and how to distinguish it from the blatant and transparent crap dished out over at WTFUWT.
Typically, Hank Roberts and Ray Ladbury have, together, accurately summed up the off-topic science communication comments.
Steve
@Hank .. I mentioned a study in a reply to you from memory, the refs are here fyi if you’re interested in ‘statistics’ related to ‘climate science’ https://www.realclimate.org/index.php/archives/2013/11/global-warming-since-1997-underestimated-by-half/comment-page-5/#comment-428368
@59 Radge, thanks for your comments again. Much appreciated. I hear what you are saying. I’ll simply state that it is intentional with each step shift dealing with the reality of what comes back.
Despite the fact that my basic pov/idea is going over people’s heads, that in itself is actually proving my point. I am saying what I say and the form that I write it for a rational proven reasons. Damn it is annoying though. Is my communication effective relative to purpose? Well that depends on how one looks at it. I say yes it is.
There’s an assumption (actually at least 10+, but to keep it short) being made by all that an improvement in communication by scientists would be able to sway entrenched ‘sceptics’ to a scientific view of the evidence.
What one should, could, might be able to see here now (per the reactions) is the exact same dynamic utilised by denier website to deny what is actually being said and twist it into sometime else entirely. It’s human nature. Next step is Gavin shipping me off to the bore hole. :) which is fine by me, it’s his website.
[Response: I moved your posts to the open thread because they were (are) off topic. Please continue your discussion there. -gavin]
And there is no point speaking to people to do not wish to listen or remain open minded enough to consider they may be mistaken about their initial reactions and the subsequent effects that come from that. Nothing exists in a vacumme.
I’m merely planting seeds. A gardener will show up one day and the penny will drop. I have nothing to prove. I don’t live by others agreeing or fawning over me, nor laying garlands at my feet that I am right or brilliant. :) Best.
@48 Ray “Sean, You did not ask for any concrete suggestions.”
That is correct. I didn’t. Show me the rules of RC that says I should have?
It’s a public forum – as your responses show, one doesn’t need to ask, it is GIVEN that someone who has a suggestion or a criticism will speak up. [edit – please try to be less belligerent]
richard pauli (9) said:
“It may be worth further simplifying your perfect weather/climate definition, now to say that a series of weather events makes up a climate, and climate is defined as a group of weather events.”
I don’t think it’s worth it – on one level your definition is a tautology (since the climate IS the sum/average of all weather events) and on another level – quite a counterproductive one, because it obscures important differences between climate and weather – that both forcing and predictability of climate and weather are very different. Let me explain:
It is my understanding (and if I am wrong I would welcome setting me straight) that weather is very sensitive to chaotic processes, while in climate much of this individual variability of weather events simply “evens out”, thus filtering out the signal of chaotic forcing and leaving a more predictable signal of underlying fundamental thermodynamic forcing. So when you write:
“I have been shocked to hear meteorologists publicly address the issue and apply the 30 year rule to define a changed climate”
I’d suggest that the reason for this “shocking” practice may have a very good reason – the “30-year rule” filters out (all? most?) of the chaotic variability of weather events, as well as short-term fluctuactions (El Nino/La Nina cycles + perhaps part of the decadal variability). As a result, what’s left behind should be the long-term change – i.e. tha what we area after when discussing “climate” change. Your disapproval of this practice and promoting instead the definition of a climate as a simply “series of weather events” seem to obscure this reality.
The filtering out of chaotic events has also other serious implication: improves the reliability of predictions. Again, you definition obscures it, and by doing so, plays into a frequent line of argument of climate change denialists, who say that if scientists can’t predict the weather 2 weeks from now, how on Earth are we to believe them when they make predictions about climate 100 yrs from now. To which I answer that I have no idea what temperature will be in my town on, say, February 15 (weather), but I am pretty sure that it will be lower than on July 15 (climate) – and I can plan accordingly (e.g. inviting my friends for a BBQ on July15 instead of February 15). The definition of climate as a simply a series of weather events – obscures this reality too.
To sum up – I don’t see any upside for your redefinition of climate as series of weather events – as a tautology it does not bring any new insights and only downsides – obscuring the important differences in forcing and predictability between climate and weather and by doing this opens itself to be used to mislead the public by the people of bad will.
(If I have made errors in my assumptions, I’d appreciate pointing them out to me)
Responses, thx, answers to genuine queries and ideas by RC include:
Comment by jesper — nil
Comment by Jan Galkowski — nil
“I was really quite surprised that something like their work wasn’t already part of the routine workflow.” Comment by tmb — nil
Comment by richard pauli — Nil
“occasionally been some resistance when it comes to prying tetchy climate nerds out of their ivory towers.” said Radge Havers — Nil
——
@19 Dag Flolo https://www.realclimate.org/index.php/archives/2013/09/on-mismatches-between-models-and-observations/comment-page-1/#comment-408413 said in part:
“The model is analogue [sic – analogous] to: Increase in global average atmospheric temperature (K) = Effect from CO2 (K/ppm CO2) * Increase in CO2 level (ppm CO2)
He got a response from Gavin that reads: “You have a very impoverished view of what utility is. Is it useful to know that a medical treatment improves outcomes by 0 to 30% in different trials? The answer for the FDA is very different than for a patient or a researcher. – gavin]
Impoverished? Who does that serve? Why not simply state the basic facts and the science nicely or at least in a straight forward manner absent the “put downs” and personal “judgments” made (denier skeptic or not) ??? BY WAY OF EXAMPLE (edit out any inaccuracies and use your own words – this is but a “sketch”) ::
“Dear Dan, thx for the question. The increases in global avg mean temps are in fact NOT directly tied like a multiplication table to CO2 ppm in the atmosphere. The system is far more complex than that. Please let me explain a few of the variables involved – CO2e is only ~50% of the AGW forcing, on top of this factor there is land use, forest clearing, concrete use and much more involved in driving up Temps. Also CO2 itself is only ~50% of the total GHGs ie CO2e AGW forcings. There are time lags with the climate system responses plus natural variability on top that which is is undefinable. There is ~90% of excess heat being absorbed by the oceans that does not show up fully in surface temps measurements. There are regions not covered by accurate temp data collections and thus those areas ‘modeled’ on estimations. Given all the above and more, one cannot take a view of a *direct co-relation* being present for atmospheric CO2 levels and Surface temps as measured. Does this help clarify the situation better for you? Feel free to ask more questions and I’ll do my best. Also check our site here, and here, and here which goes into more details, regards ‘Gavin RC’ ”
—————-
@83 June 2013 https://www.realclimate.org/index.php/archives/2013/06/yamal-and-polar-urals-a-research-update/comment-page-2/#comment-377014 Jan Galkowski says in part:
“Now professionally, I’ve always found looking over the shoulders of people grappling with experimental problems in geophysics to be enlightening, principally because the character and distributions of your data are so different than most people are taught. I learnt about directional data that way and went on to appreciate things like Best Linear Unbiased Estimation in the spatial realm, a.k.a. “kriging”. So keep on!”
Again no response/comment by RC nor anyone, but lot’s of Deja Vu there regarding the Nov article about “Cowtan and Way …. method called kriging ”
No body really expects a response by default, as nice as it feels to be acknowledged. Yet on a science academic based supposedly mature website nobody expects the Spanish Inquisition either. :)