There was a great comedy piece a few years back (whose origin escapes us) that gave examples of how the English would use their language when speaking to a non-native speaker to imply the precise opposite of what was actually being understood. This allowed the English to feel superior without actually damaging international relations. One example was the phrase “with all due respect” which is generally understood to imply that the speaker has a great deal of respect for their counterpart, while the speaker is actually implying that they have no respect in the slightest for their interlocutor. The respect due being precisely zero.
This thought occurred to us when a few of us opened our email this week to see a draft ad being sent around by the Cato Institute (i.e. Pat Michaels) looking for signatories prior to being published in “major US newspapers” sometime soon:
There are a number of amusing details here. While we are curious about the credentials of “Dr. N. Here”, we certainly understand why they are looking for a little more variety on the list. More surprising (and somewhat ironically) the mailing list for signature requests includes a number of scientists who don’t agree with these sentiments at all. It’s as if Michaels and Cato actually believe that these various lists of “dissenting” scientists are accurate reflections of support for their agenda. They appear to be have been conned by their own disinformation.
As an exercise for our readers, perhaps people would like to speculate on who is going to end up on the published list? (If indeed it gets published). Ginger Spice would be likely on past form, but they might improve the screening this time around…
But most amusing are the footnotes that they use to bolster their case. There are four: the brand new Swanson and Tsonis (GRL, 2009), Brohan et al (JGR, 2006) (which is there to provide a link to the HadCRU temperature data), Pielke et al (BAMS, 2005), and the oft-derided Douglass et al (IJoC, 2008).
Of these papers, not one has the evidence to support the statements attributed to them in the main text. To wit:
Surface temperature changes over the past century have been episodic and modest and there has been no net global warming for over a decade now.1,2
Well, the first part of the statement is exactly what you expect with a modest long-term trend in the presence of internal variability and is not controversial in the least. The “global warming stopped” meme is particularly lame since it relies on both a feigned ignorance of the statistics of short periods and being careful about which data set you use. It also requires cherry-picking the start year, had the period been “exactly a decade” or 12 years then all the trends are positive.
The use of the recent Swanson and Tsonis paper is simply opportunism. Those authors specifically state that their results are not in any way contradictory with the idea of a long term global warming trend. Instead they are attempting to characterise the internal variability that everyone knows exists.
After controlling for population growth and property values, there has been no increase in damages from severe weather-related events.3
This references a short comment in BAMS that didn’t present any original research. The latest figures show that weather-related damages have increased markedly, though whether there is a climate change component is hard to tease out given the large increases in vulnerable infrastructure and relatively poor data. The actual statement that a clear global warming-related trend in damages hasn’t been clearly demonstrated doesn’t imply that you can state definitively that there is no effect. There might be one (or not), but formal attribution is hard. However, whatever the attribution ends up being, pointing out that there are other problems in the world doesn’t imply that anthropogenic climate change is not worth worrying about. One might as well state that since knee injuries on ski-slopes have increased over time one shouldn’t support flu shots.
The computer models forecasting rapid temperature change abjectly fail to explain recent climate behavior.4
‘Abjectly’? Very strange choice of word…. and an even stranger choice of reference. This is of course the same Douglass et al paper that used completely incoherent statistics and deliberately failed to note the structural uncertainty in the observations. Unsurprisingly, Michaels does not reference the rather comprehensive demolition of the Douglass methodology published by Santer et al (2008) (and on which one of us was a co-author). More fundamentally however, the current temperatures are still within the spread of the models even if you cherry pick your start date. No-one expects the real world (a single realization) to follow the mean forced trend at all times. How is that a failure, abject or otherwise?
More interestingly is what is not cited. President Obama’s statement “The science is beyond dispute and the facts are clear”, can’t possibly refer to every issue in science or every potential fact. Instead he is likely referring to the basic and pretty much uncontested facts that i) CO2 and other greenhouse gases have increased due to human activity. CO2 emissions in particular continue to increase at a rapid rate; ii) the effect of these gases is to warm the climate and it is very likely that most of the warming over the last 50 years was in fact driven by these increases; and iii) the sensitivity of the climate is very likely large enough that serious consequences can be expected if carbon emissions continue on this path. We would be astonished if Michaels disputed this since he is on record as agreeing that the IPCC climate sensitivity range is likely to be correct and has never questioned the human contribution to CO2 and other GHG increases. He and his colleagues have even done analyses that show that after correcting for ENSO effects, there is no sign of a slowdown in global warming at all.
Instead this is a classic red-herring: Ignore the facts you don’t dispute, pick some others that are ambiguous and imply that, because they are subject to some debate, we therefore know nothing. Michaels (and Cato) presumably thinks this kind of nonsense is politically useful and he may be correct. But should he claim it is scientifically defensible, we would have to answer:
“With all due respect, Dr. Michaels, that is not true.”
#197 Karmakaze
Re: wmanny’s question – how much longer would you need to see a cessation in warming before you would want to see an adjustment to current theory?
A straight answer would would need to be of the form “X years”.
To date no such response has been forthcoming.
[Response: Not true. “Over a twenty year period, you would be on stronger ground in arguing that a negative trend would be outside the 95% confidence limits of the expected trend (the one model run in the above ensemble suggests that would only happen ~2% of the time”. – gavin]
wmanny, if not convinced yet, here is a place I attempted to dumb down the stats to the level where a non-expert could see why a period of say 10 years of apparent non-increases or even temperature drops could occur despite a long-term upwards trend: http://opinion-nation.blogspot.com/2008/04/why-doesnt-it-get-hotter-every-year.html
pardon my ignorance here, but i remember studying a project as a high school student in the 70s where the idea was to have solar collectors in space and “beam” (?) the energy down to receptors on earth. is this even theoretically possible?
(btw, in the 70s the projections were that by now we were supposed to have all kinds of alternate energy sources and 100mpg cars feasibly available – but we underestimated the cleverness of the established energy companies’ disinformation campaign…so here we are 30 years later with these alternate energy technologies still in their infancy… this is why scientists and others in the reality-based community have to ramp up our PR campaign.)
BFJ Cricklewood: “A straight answer would would need to be of the form “X years”.
To date no such response has been forthcoming.”
Horse puckey. It is impossible to make such a statement unless you specify a desired confidence level. You are either disingenuous or ignorant of statistics.
“the age of stupid” and bfjcrickelwood’s comments are more examples of why scientists need better PR.
in the case of that movie: the movie’s out there – people are watching it and it’s reinforcing their belief that a few “free-thinking” real reputable scientists are “skeptical” of AGW. they also get to exercise their regular-guy distain for those egg-head smarty-pants alarmists who first predicted an ice age, then predicted we’d all be fried by now. the “its cooled since ’98” meme ties it all together. to them, mainstream scientists, who can’t even make up their own minds about what the “problem” is, are being exposed by clever “skeptics”.
on bfjcrickelwood’s “simple” request for a straight answer: scientists are just trying to be precise when they answer that question with a complex list of ranges/probabilties/uncertainties. to the layman out here, again, it sounds like the scientist is equivocating or just can’t give a straight answer for fear of exposing the the lie that is AGW theory.
[Response: That the world in general is hostile to nuance and much happier with Yes/No, Black/White, True/False dichotomies is not news. The fact that science in any complex field can’t be sensibly parsed into such binary distinctions undoubtedly makes it difficult to portray the state of scientific knowledge effectively. But this is not a PR issue, it is instead fundamental to the dilemma that scientists have dealt with for decades and it isn’t going to go away if suddenly I come up with a number for Mr. Cricklewood – for instance 17.3 yrs. Does that change anything? – gavin]
Ray, a more charitable interpretation of Mr. Cricklewood’s post is that he found the claim somewhere else, thought it looked like it made sense, or found someone saying it made sense, and carried it here.
Almost everyone is ignorant of statistics to some extent.
And it’s easy to be fooled by people making claims like that, saying flat out that a straight answer would be of the form X years.
It sounds true, doesn’t it? And if it were said about a situation where there isn’t a lot of up and down variation, it’d probably be true.
Say he wanted to know whether a kid had finished growing in height.
That’s simple enough, and it’d be true to say that if the kid’s height hadn’t increased in X years, the kid was probably as tall as she’s going to get.
But if he wanted to know if his own waistline had quit changing in circumference — well, now, that’s a different situation because the number can go up and down, maybe several inches several times in a year. Any trouser or belt manufacturer can probably give you statistics on this kind of thing.
When will you know your belt size has quit increasing? A proper answer would be in the form of “a week or so after you quit eating and drinking” — it depends on the variatio
Mr. Cricklewood, care to say where you got the idea?
Or the encouragement to post it here as a flat assertion?
Why you believe whoever put you up to it?
I’m pretty sure it’s from somewhere else, because we keep seeing people come in with the same belief, stated as a certainty, in almost the same words.
I try to be patient myself seeing this kind of repetition. But when I see it yet another time, I’m sure inclined to expostulate something like “WTF? Lucia? You got some ‘splainin’ to do ….”
Mark # 165
March 2009 at 3:55 AM
I think you may have misunderstood my starting point. When I said I was tired of “this hooey”, I was of course referring to the Cato ad and Michaels’s characterization of climate models as an “abject” failure.
To clarify, the IPCC AR4 projection for surface temperature was expressed as an increase of the moving 20-year average over a 31-year period of about 0.65 deg., or about 0.2 deg per decade.
My point is that, after nine years, the moving average stands at almost 0.17 deg/decade which is reasonably close to the IPCC projection. Thus graphs or statements that purport to show a much lower trend over the last few years are highly misleading.
I apologize if I wasn’t clear enough before, and I hope this removes any remaining confusion.
#32, #34
Re: libertarian,liberal,neo-liberal and Liberal
Only the first of these is unique.
Liberal (UK) = centrist (the most green UK party apart from the little Green party)
Liberal (Australian)= right wing (tendency towards global warming denialism)
liberal (economic)= neo-liberal = Thatcher/Friedmann (hard right)
liberal (political, religious) = pluralist tolerant enlightened (e.g. Isaiah Berlin).
liberal (populist US) = left
liberal (social) = libertarian (approximately)
Hank, I might be rather more charitable to Mr. Cricklewood’s contention if I and several others had not spent several posts trying to explain the subject. As it is, he appears to be able to write, but not to read.
Ray (179) sorry for the delay. (I tried posting this earlier but I must have made some error.) I am not saying I didn’t notice 1998. I have tried to be careful to use language such as “relative flatness” and “mini-trend” but if I strayed from that, I apologize. Again (and again and again), I am not saying global warming has ended or that AGW theory is disproved. I am asking the question: how much flatness, relative to the upward trends leading up to 1998, say, would there need to be before theorists began to scratch their heads?
Thanks for clarifying the distinction between “AGW theory” and climate theory. I could quibble that it’s a minor distinction given that human contributions to “the greenhouse” are just about all that folks are concerned with these days, but I take your point, and I appreciate as well your willingness to discuss a hypothetical future discrepancy between theory and observation, however unlikely. What are the leading candidates in your mind for processes other than CO2 that could end up being bigger contributors than originally thought? I know that’s essentially asking the question, “What are the unknown unknowns” (as Gavin refers to it on his modeling site re. ozone), but I wonder if you have thoughts about it, and, no, I am not trying to trick you. I hate to add that last bit, but I know sensitivities run high on this topic. To wit, I’ll leave the labeling stuff alone, if that’s OK.
http://www.youtube.com/watch?v=uf25tkuxOW4
the fact that this exchange can happen for real in the US congress (not in some twilight zone episode) illustrates how far scientists have to go in educating the public. “it’s plant food”!!! aaarrrrggghhh!!!this testimony should have been greeted with the same reaction as if he had said, “smoking cigarettes is good for you.”
#204 Ray Ladbury
You simply push the question out to : What do you regard as a sensible confidence level? Once you decide that for yourself, you’ll be able to give the requested straight answer.
Gavin’s take seems to be 20 years; ie, he would want to see another flat 10 year period before he would want to see an adjustment to current theory. Do others here agree with him or not?
BFJ Cricklewood wrote in 212:
You might want to check this out…
You Bet!
January 31, 2008
http://tamino.wordpress.com/2008/01/31/you-bet/
… it is based upon 95% confidence and settles things between “warming” and “flat” by 2015.
Oh, and it also shows that currently (at least as of 1/31/2008) there is no basis whatsoever for claiming that global warming has stopped or for that matter that the rate has changed since 1998. Besides, 1998 was a record during an unusually strong El Nino, and it was statistically tied (but beaten according to NASA GIS Temp) by 2005, and then tied again with 2007 — where both 2005 and 2007 had La Ninas — resulting in cooler temperatures than what would have otherwise occurred.
You guys (sigh)
wmanny: “… human contributions to “the greenhouse” are just about all that folks are concerned with these days …”
Cricklewood: “… another flat 10 year period before he would want to see an adjustment to current theory. ….”
Each of you is asking questions with unvoiced assumptions.
Some of those are contradictory assumptions. Some are just wrong.
If you would make the effort to read some of the science you’d be able to ask better questions, and cite your sources for the assumptions you’re making. Seriously.
Look, I’m not saying this is the best reference, it was easy to find.
You can then at least say what you are assuming to be true to ask your question, and give a basis for what you’re assuming. Otherwise your questions are too simple to be answered.
Radiative Forcing of Climate Change: Expanding the Concept and Addressing Uncertainties (2005) National Academies Press
Board on Atmospheric Sciences and Climate (BASC)
Chapter 5 begins:
“Uncertainties Associated with Future Climate Forcings
Climate forcings are bound to evolve over the coming decades due to anthropogenic emissions as well as land-use changes. Scientists have developed methods for projecting future emissions and land-use changes, but limitations in these approaches lead to uncertainties in projections of future climate. … In this chapter, current capabilities for projecting future forcings are discussed and critical uncertainties associated with these forcings and their effect on climate are identified…..”
http://books.nap.edu/openbook.php?record_id=11175&page=100
Give it a try.
Otherwise this is just recreational typing.
Climatology is not so easy, I find. Many, even scientists and engineers, do not know enough statistics. (I could name certain blogs, but I won’t.) So lets all try to be gentle with those commenting here who appear to be trying, hmmm?
Thank you.
[reCHAPTCHA entones “commitments overlook”. Seems appropriate.]
Hank,
“You guys (sigh)”
It is to blush, assuming that was a sigh of admiration, and you are too kind.
It is true that we are asking questions. It is also true that you won’t answer them, for reasons I will assume are sound — you are certainly under no obligation to do so. Why not just leave it at that?
Walter
Re: How much more of a cessation in warming would warrant an adjustment to current theory?
So far then, we have these best guesses
– Gavin : ~10 years (response to #201)
– Tamino : ~6 years (ie by 2015) (cited in #213)
Anyone else have, or know of, other estimates, either similar or different?
( In simple terms, these figures I take it relate to how long would be needed for the believed trend to overcome worst-case countervailing noise ).
ha! gavin, that’s funny! i think 17.3 years IS the kind of answer “skeptics”/laymen want. it’s because most of us are so scientifically illiterate that we “can’t handle” all the qualifiers necessary for complete accuracy.
i only call it a “PR” thing because in our culture of “image is everything”, the “skeptics” are winning the image battle. of course ALL the substance is with the scientists, but due their exceptionally disciplined PR machine, “skeptics” come off as clear-thinking rationalists trying to save the world from confused ideology-driven scientists (who are cast as out of touch and only interested in preserving their global warming research grants….). mind you, this IS NOT reality, in fact it is exactly the opposite of reality, but it is the public perception. scientists are battling:
1)the common man’s distrust of smart people (how many times have we whatever politition criticized for being “elitist”? – i mean, really, a rational person should WANT elites in charge, don’t you think?)
2)”skeptics” get to play the skeptic. this is usually a scientist’s default position, and a position ALL scientists should initially adopt – until evidence leads to a consensus. the “skeptic” PR machine has now framed the discussion such that the denialist/obfuscationists get to play the romantic part of the skeptic railing against the recieved wisdom of the establishment. and americans love the little guy.
3)the “skeptics” get to defend the position we all “want” to be true. i think even the most rational reality-based scientist wishes he were wrong about global warming. i mean, it would be much nicer for us all if we didn’t have to worry about carbon emissions and carbon taxes and saving energy and all that. “skeptics” get to let the public harbor that faint glimmer of hope that maybe there’s not really a problem.
4)scientists suffer from the assumption that truth will prevail. they know they are “right” about the science and assume laymen will be able to sort out all the deceptive tactics, half-truths, selective citations. in this area scientists WAY overestimate our ability to see through the denialist’s smoke screens. laymen are not capable of dissecting that CATO statement at the top of this post – and all those footnotes, though they are totally bogus, make it seem real “sciency”.
i know all these points seem really stupid and shallow to scientists, but, well, most of us laymen wouldn’t know a keeling curve if it bit us in the, uh, arse…
Walter (wmanny), they are not answering you because your questions aren’t sound. If you ask someone are you still beating your wife, answer yes or no, don’t expect most people to answer.
That temperatures have not increased significantly above 1998 levels does not mean the increase has stopped. It means that we are in a short patch when natural influences on weather are all pointing down. We have just hit the bottom of the 11-year solar cycle, and been through an extended La Niña. The correct question to ask therefore is why last year was not close to a 100-year record low, rather than close to a 100-year record high.
Captcha says: Battle Historical. I concur.
wmanny and bfj crickelwood,
just curious, have any of the explanations by the scientists here convinced you that scientists have good reasons for “believing in” global warming?
You’re oversimplifying again, Mr. Cricklewood.
Tamino’s on break doing real work, so don’t expect him to give you a prompt review.
You realize there are stretches in the record where even 30-year trends are look like this picture?
This is the time series from 1880, showing 30-year trends:
http://atmoz.org/img/avg_length30.jpg
“The years 1880 to 1910 still show a negative trend, as do the years in the 1940s.”
http://atmoz.org/blog/2008/01/29/on-the-insignificance-of-a-5-year-temperature-trend/
This is time series from 1970:
http://scienceblogs.com/stoat/upload/2007/05/5-year-trends.png
“Compute 5, 10 and 15 year trends running along the data since 1970 and get (black lines data, thicker black same but smoothed, thin straight lines non-sig trends; thick straight blue lines sig trends)”
http://scienceblogs.com/stoat/2007/05/the_significance_of_5_year_tre.php#more
See how you can always find stretches with negative trends? Which of those intervals with negative trends that you see in those pictures would you have found impressive at the time?
You realize that what you lump as “current theory” is a wide variety of possibilities and estimations of how things work and how strong they are and how they interact — all that are being investigated?
Another such stretch will support some of the assumptions in some of the models — those that have indicated another such stretch is likely — Hadley a few years ago, I think, was the first one.
You don’t get proof _or_ disproof. Probability is all you get.
And you probably know all this, I’m belaboring the obvious because some kid writing a term paper will be able to use the background.
BFJ Cricklewood wrote in 217:
Global warming has ceased? Since when?
If I were you, I would check the following:
http://data.giss.nasa.gov/gistemp/graphs/Fig.A2.lrg.gif
http://data.giss.nasa.gov/gistemp/graphs/
2005 appears to have been the global record.
Oh, and as I indicated in 213, I would keep in mind the fact that 1998 had a particularly strong El Nino (which made that year warmer than the trend) whereas both 2005 and 2007 had La Ninas (making them cooler than the trend) and that otherwise the trend doesn’t look like it has changed at all.
Walter, Understanding the distinction between a “theory of climate change” and a theory of climate that implies anthropogenic causation is important. With a theory of climate change, all you would have to do is find a theory that explained the observed data fo climate change better than anthropogenic causation. When you view climate change as a prediction based on a theory of Earth’s climate, any changes you make must be at least as successful as the current consensus model with respect to paleoclimate, response of the climate to perturbations like volcanic eruptions, the aerosol-induced hiatus mid last century, etc.
Any change we make to account for some yet-to-be-observed hiatus in warming would have to be fairly minor to preserve the successes of the consensus model. A negative feedback pretty much has to indicate that for some reason, the current temperature range is particularly stable, and there’s no evidence for that. It could be that recent development in China and India were again producing enough aerosols to slow warming. If so, this would imply a brief hiatus as in 1945-75. Aerosols are one place where there is still considerable uncertainty. Clouds are another. The thing is, you can’t have a Charney sensitivity much less than 2 degrees per doubling, or you have a really hard time producing an Earthlike climate. As yet, however, it’s a purely hypothetical question.
BFJ Cricklewood Says:
Note, however, that the adjustment to current theory would NOT result in what denialists claim.
Funky happenings over the next decade would NOT disprove the physics that shows that CO2 is a GHG, for instance, and that adding CO2 to the atmosphere will heat the planet. That physics isn’t based on observed climatic trends, not in the least.
In absence of any observed phenomena – the sun going out, huge volcanos erupted, etc – the first question that would be asked would be “where’s the heat hiding?”, not “oh, CO2 isn’t a GHG after all”.
Philip Machanick (219) — Well stated.
dhogaza,
I don’t see anywhere that wmanny, BFJ Cricklewood or I say that we do not believe CO2 to be a greenhouse gas. I accept that an increase in CO2 will cause warming. I know of no skeptic that thinks that an increase in CO2 will not cause warming (I suspect that there are a few, but they are a minority). Even Pat Micheals believes that CO2 is a greenhouse gas.
So why to you keep telling us that CO2 is a greenhouse gas?
Also, I don’t know that any of us have claimed that the decline in the rate of increase over the last ten years (1999! to 2008) is proof of anything.
It seems impossible to have simple conversations.
[Response: Not true. “Over a twenty year period”
This is what the consensus is saying.
Starting point is under review.
Tim
Philip Machanick #219
Unless you don’t take the models as gospel, esp as regards the amount of warming they attribute to anthropogenic CO2.
Re: How much more of a cessation in warming would warrant an adjustment to current theory?
So far then, we have these best guesses
– Gavin : ~10 years (response to #201)
– Tamino : ~6 years (ie by 2015 he says) (cited in #213)
Hank Roberts #221
Yes, as have Gavin and Tamino I’m sure.
Are you then saying you would want to see ~30 years (ie another 20) ?
Timothy Chase #222
About a decade, as per those Giss graphs you cited. Do you deny this recent temperature plateau?
BillB, snorbert believes that CO2 won;t cause warming. He cited a paper that said that CO2 will act differently in a closed vessel for experimentaton than it does in an atmosphere and that the radiative models are incorrect. Read earlier on.
The reason to continue to tell ou that CO2 is a GG is that if our CO2 emissions are not a cause of temperature increase, you MUST provide two things:
1) What stops our CO2 warming the atmosphere
2) What else is adding more temperature so it LOOKS like our CO2 is causing the warming
You can’t just go “It’s not us” because you have to explain why our CO2 doesn’t make a contribution. Why? Because (as you have admitted) you KNOW CO2 is a GG. So why isn’t it doing so when we pump it out?
just my own thought on the how many years of cooling for AGW to be over arguments – firstly average global temps aren’t a direct measure of the Earth’s net energy balance, I don’t know how variable that is but cooler SAT’s than last year isn’t less global warming than last year – the energy just goes elsewhere and will contribute to overall climate change in other ways like warming the oceans and melting ice rather than directly changing temps at the surface. Secondly, the preferred 30 year mean is still arbitrary and a trend only has meaning in relation to understandings of what climate processes are doing during the period. A bit of a plateau in average global surface temps ( when every year of this century is amongst the warmest on record and we’ve seen greater ‘cooling’ previously only to be followed by record breaking ‘warming’ I can’t see how the last decade can seriously be considered a cooling trend) is cause for looking for climate processes, natural and AGW effected, to explain the variations, not firm declarations of the ongoing climatic effects of GHG’s being over. Even a downward 30 year or longer trend isn’t sufficient by itself to declare AGW over – it’s about how well understood the underlying processes and conditions that give that trend are.
BJF, 229, but those graphs do NOT show that there has been no warming over the last 10 years.
bfj cricklewood,
i think phillip mackanick said it best with,
“That temperatures have not increased significantly above 1998 levels does not mean the increase has stopped. It means that we are in a short patch when natural influences on weather are all pointing down. We have just hit the bottom of the 11-year solar cycle, and been through an extended La Niña. THE CORRECT QUESTION TO ASK THEREFORE IS WHY LAST YEAR WAS NOT CLOSE TO A 100-YEAR RECORD LOW, RATHER THAN CLOSE TO A 100-YEAR RECORD HIGH.”
all the other cyclical pressures are in a down cycle, and the 2000s have been as hot as any comparable period. 1998 was an anomaly – it was a record year. of course if you start with record high the “trend” will be down from there. as gavin and countless others here have shown the downward “trend” is a statistical trick based on starting with a record high year. try starting the graph in 1999 and see what the “trend” looks like.
ignoring for a moment the false premise of your question (see phillip #219, re: wife beating), as a layman, i will give you a layman’s answer to your question of “how much longer”?
tamino says 6 yrs – that’s pretty good. you could begin to be somewhat confident of the “trend” if it continues for 6 more years, but it wouldn’t “prove” anything. gavin says 10 more years – that’s a little better. your confidence should begin to grow if it lasts 10 more years. others have said on the order of 20 more years – that’s even better. you could have more confidence in a “trend” that lasts 20 more years. i think you can see the pattern here: the longer the “trend” the higher the confidence (it’s not rocket engineering). it’s kind of an unsatisfying answer because you have to hold these varying degrees of uncertainty in your head.
#230 Mark
I can find no reference to ‘snorbert’ or the abovementioned issue above. ‘Earlier on’ in a different thread perhaps?
1) Nothing; the basic physics in not in question here. What is in question, is how much is it warming the atmosphere? Does anybody really know? [edit]
[Response: Climate sensitivity – gavin]
Philip (219)
The wife-beating analogy is a bit facile, I believe, though others have noted it. In any event, we are talking about temperatures, and I agree with you that the increase has not stopped just because your short patch (my mini-trend) has arrived. As you point out, there are some natural influences getting in the way of a constant derivative, and you at least seem willing to inch closer to answering the unsound question, which can now be re-phrased: How much longer can natural influences be used to explain things before they rather than CO2 become the focus of things? I don’t think you’re going to find much support here at RC for your solar influence, though, as that is routinely dismissed as miniscule.
Walter
Thanks, Ray, for the further clarifications in 223. Given there are so many models and modelers, though, what do you believe the “current consensus model” is, or are you of the opinion they are all more or less the same?
As to aerosols (I admit I am fearful someone has already raised the issue and been hammered for asking) is there any research being done on the prospect of introducing “safe aerosols”, if such things could be contrived, into the atmosphere? Given the difficulty this and other governments are sure to encounter trying to increase prosperity and lower CO2 emissions at the same time, has there been much thought given to other, less politicized avenues?
#231 Ken
Yes, surface temps alone do not provide the whole picture of GW. It may well be the case that GW is continuing, and the heat is simply going elsewhere (equally though, melting ice may just be heat coming from elsewhere). But it’s also possible that GW may not be continuing. The proof of this pudding would be in how well ocean temperatures etc can be tracked; the evidence here is not too clear, as far as I can tell.
I don’t think anyone here is saying this plateau means the 100+ -year GW trend is definitively over. Rather they are saying it raises questions about just how well the underlying processes are understood, and how valid it is to call it AGW rather than just GW. The longer the lack of warming continues, the more force the questioning acquires (and vice-versa). There must surely be some point – 10, 20, 30, 50…. years – at which the AGW hypothesis must be deemed to be failing.
pardon me if this is off-topic…and maybe it should or has been discussed elsewhere, but…
when wmanny mentioned “safe aerosols” it reminded me of some “outside the box” thinking on global warming i read a few months ago. the idea was to limit incoming sunlight by having 1,000,000 (?) little mirror/reflector/shades stationed, i think, at the L1 point btwn the sun and earth. they could be placed closer to earth i suppose. i understand, in theory, the kinds of problems (moral and technical) associated with controlling the weather, and also understand that this would not solve other “problems” (e.g. ocean acidification, other?) associated with “excess” CO2, but can you think of any negative unintended consequenses of this mirror idea? do you have any idea what percentage of sunlight you’d have to block to “fix” things?
the problem with introducing chemicals into the system is we don’t know of unintended consequences, and it’s almost impossible to “undo” if it turns out badly. this idea would be easy to abandon if it didn’t work.
Walter, There are areas where the models disagree, and there are areas where they agree. The consensus is reflected in the latter. You will notice that not one model has a climate sensitivity for CO2 doubling of less than 2 degrees. You can be certain that this is not simply a coincidence. A low-sensitivity, earth-like climate model would be quite an interesting beast in its own right, quite independent of its significance to climate policy. So I would estimate that the IPCC contention of >90% confidence of 2
Oops!, forgot about that ol’ less than sign. Full post here:
Walter, There are areas where the models disagree, and there are areas where they agree. The consensus is reflected in the latter. You will notice that not one model has a climate sensitivity for CO2 doubling of less than 2 degrees. You can be certain that this is not simply a coincidence. A low-sensitivity, earth-like climate model would be quite an interesting beast in its own right, quite independent of its significance to climate policy. So I would estimate that the IPCC contention of >90% confidence of sensitivity between 2 and 4.5 degrees is conservative.
Now if there are no negative feedbacks that are specific to the current temperature range, it’s kind of hard to see how you avoid a conclusion that we’re behind the current warming. I note that there is no evidence favoring such a specific negative feedback.
Beyond that, models may quibble about how the forcings get divided up between aerosols and clouds, but these do not affect the consensus that humans are behind the current warming. This is because no matter how you slice and dice these forcings, they don’t mimic CO2’s signature as a well mixed, long-lived greenhouse gas. That signature stands out like a sore thumb in the climate record, and only another well mixed, long-loved ghg could fill the role.
The thing is, Walter, the climate models work for a broad range of phenomena. Where they fall short, you can’t make them do better by reducing climate sensitivity, but rather they always perform worse. Climate is a difficult subject, but some parts of it are easier than others.
Timothy Chase :
2005 did not have a La Nina according to the ONI , NOAA’s official metric. (There was a La Nina in 2007 – 2008.)
The threshold for La Nina is ONI < -0.5. The minimum duration is 5 months. The data:
For NDJ 2005, DJF 2006, and JFM 2006 – only 3 overlapping 3 month periods – the ONI was over the threshold. Since it didn’t stay over the threshold for five overlapping 3 month periods, it wasn’t a La Nina by the ONI metric.
You can look up other metrics like the SOI or the MEI, but you’ll find that the event at the end of 2005 and beginning of 2006 was at best a very short-lived, borderline La Nina. (Since ONI is the one ENSO metric defined entirely in terms of temperature, it may be more relevant than the others.)
By contrast, if you check out the ONI numbers for the end of 2004 and the beginning of 2005, there was a weak El Nino at that time. In particular – the ONI was above the El Nino threshold for more months of 2005 than it was below the La Nina threshold. The idea that 2005 was a La Nina was bandied about a lot in the US press, but as far as I can tell that was originally a fumbling attempt to explain the extraordinary Atlantic hurricane activity of that year. ONI values may explain a minority of the post season Atlantic hurricane activity (not your point), but La Nina can’t explain the perceived inability of 2005 global temperature anomaly estimates to substantially exceed 1998 temperature anomaly estimates. (1998, of course, had large ONI values for much of the year, and ENSO was a substantial influence on its global temperature anomaly.)
Global average surface temperature anomaly estimates, do not, of course measure the temperature of the whole climate system – with 5 miles of atmosphere above the surface, and 2 miles of ocean below it, it is at best only the average of a cross-section. So it’s quite reasonable to suggest that changing distributions of heat in the climate system explains year-to-year variations in the GISSTEMP and Hadley estimates. Since ENSO is essentially a redistribution of heat in the climate system, it explains some of the variations. But not all of them.
Wmanny, you give a reasonable question. The answer is to look at a dataset and approximate the noise. Looking at GISSTEMP, I’ll ballpark 0.5C. Then take the theory’s increase per decade. I’ll take 0.2C. Divide, and we get 25 years. After 25 years of flat temperatures from an obvious high outlier (1998) (assuming no change in BAU), the theory is seriously suspect.
llewelly wrote in 241:
I stand corrected — by someone who is clearly more familiar with this than I am.
llewelly continues in 241:
Given my awareness of all the different climate modes/oscillations I wouldn’t argue otherwise. However, thank you very much for driving home the point the “cross-section.”
*
Captcha fortune cookie:
Jury rises
Back to the ‘petition’:
Anyone willing to bet that the Cato Institute won’t add a few unwilling names to their list of ‘signatories’, and then later try to ‘explain’ the presence of those names with a ton of idiotic conspiracy theories?
— bi
Mr. Cricklewood writes at 8:33 am on the 29th of March, 2009:
“The proof of this pudding would be in how well ocean temperatures etc can be tracked;”
Here is a a paper by Levitus et al.
ftp://ftp.nodc.noaa.gov/pub/data.nodc/woa/PUBLICATIONS/grlheat08.pdf
with the latest corrections.
I like figure S9. Ocean Heat Content (OHC) continues to increase. The figures are for the top 700m. This upper layer of the ocean has absorbed heat over the last 40 years at the rate of 0.364 Watt/m^2 (Table T1)
bi–IJI,
the big question about that CATO petition is how many scientists named JIM will they have?!
Bill Bodell writes:
No, it is not. A “trend” has to be statistically significant.
ah, well, the answer is 5. that ad was published in today washington post. i counted 5 scientists named “james” (and one named “j. scott armstrong” – don’t know if he’s a james…) c’mon gavin, we can do better than 5!
walter crain,
The concept was called SPSS, for “Solar Power Satellite Stations,” and yes, it is theoretically possible. NASA made a major bid for increased funding in the 1970s on that basis. They were going to build a gigantic, orbiting “space colony” at Earth’s trailing “L5” trojan point, which would manufacture solar power stations from lunar material and use them to beam microwave power down to “rectennas” on the Earth. Congress never even came close to treating the proposal seriously.
I suspect that, if done, it would be more expensive than simply building solar power stations on Earth.
BFJC writes:
Unless you don’t take the models as gospel, esp as regards the amount of warming they attribute to anthropogenic CO2.
He said NOTHING about the MODELS. He was talking solely about observed temperatures. 2008 was close to a record high. For God’s sake, read what you’re quoting before responding to it.