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Comments 71751 to 71800:
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Bob Lacatena at 22:17 PM on 25 October 2011Climate's changed before
234, lancelot, Going bottom to top... Relative precision? He gave a range of 23% for known versus unknown forcings, leaving what I would consider to be pretty wide error bars in his estimates (even if the precision of the boundaries seems fine, the range between them is not -- scientists always use precise numbers to define embarrassingly imprecise estimates -- a science habit, I guess -- they like to be very precise in admitting to how much they don't know). What you term "unnaccounted for" by the models actually is accounted for, but it is not the result of ongoing forcings, but rather internal variability. No matter what we do, the system is still chaotic. Like weather, you are just never going to pin it down completely and make everything add up perfectly so that the model exactly matches reality on date X with temperature Y. It's just not feasible. What is more important to recognize, which is the core of your realization that today's CO2 truly represents a unique event in the planet's climate history, is that the temperature range being discussed for the 1,000 years prior to today's crisis covers a mere +/- 0.1˚C range on average and a +/- 0.2˚C range at extreme events. If close to half of that is attributable to known forcings, then in most periods only +/- 0.05˚C is "unaccounted for" and even in the extremes that number is only +/- 0.1˚C. And the greater swings are generally those that are accounted for by notable solar/volcanic events, which makes the real "natural variation" range very narrow indeed. I can't find a free version of the paper, but the figures and data area available here. Too, it is important to recognize the methodology and limitations that Crowley used. First, the inputs for solar and volcanic forcings for the past 1,000 years are themselves only estimates inferred from available proxies. Inputs for other variations, like ocean currents, land/albedo changes and such are non-existent, so what is left as "natural variability" could well have been accounted for with better inputs. Secondly, the temperatures against which he is comparing are also only proxy estimates, so the error range is by necessity broad. Who knows... it's possible that with precise solar and volcanic forcing inputs and temperature outputs, the accountability might be much greater. You have to consider the fog through which the scientists is attempting to squint to get to the inference. On to the last item, the "CO2 must cause" statement. The phrasing is unfortunate, but the take away message should not be "we can't think of anything else so the thought process stops here" but rather "everything we've tried does not account for the warming, and yet CO2 does." CO2 is not the culprit simply because someone saw it hanging around on the street corner the same night that today's Climate was murdered. His fingerprints are in fact all over the gun, and he was the only one with the key to the locked room in which Climate's body was found. What is unsaid on that page (and maybe it should be said to make things more clear) is that this conclusion was reached because models do incorporate every known forcing and none of them did the job. The use of every known forcing successfully models temperatures up to the current time. The dual implication of this is not only that CO2 appears to be the culprit, but also that if there were another, unknown forcing -- why did it never influence anything prior to the current dilemma? Where were similar dramatic changes in GCRs, solar activity and such for the last two thousand years? We know why there were no swings in CO2, but why no swings in any other magically hidden forcings? What's also left unsaid, as we have discussed, is that it is not like scientists then close their eyes to any other possible forcing. There are tens of thousands of scientists around the globe studying everything imaginable, from the Amazon to the Arctic to black carbon to land use changes to methane deposits to solar forces beyond our current understanding. No one is stopping their thought process and saying "let's focus on CO2 because it makes our job easier." Quite to the contrary, scientists would like to find, understand and pin down every forcing imaginable, because in so doing that 41% to 64% range that worries you drops to zero, all doubt vanishes, and the climate models become marvelously accurate. Such an accounting "benefits CO2 proponents" (as if anyone is a sports fan rooting for CO2 in a game) as much as anyone. By the way: Here at SkS it's considered bad form to use all caps (it's shouting). Instead use italics or bold for emphasis. You can click on the "Click for tips on posting images or hyperlinks" link just below the "Post a Comment" text box for instructions on how to do so (or just click this link here). -
Daniel Bailey at 21:45 PM on 25 October 2011Linking Extreme Weather and Global Warming
Link to images of the aurora from last nite taken locally: http://www.facebook.com/media/set/?set=a.290369907653519.75544.165862740104237&type=1 -
Kevin C at 21:11 PM on 25 October 20119 Months After McLean
Figure 1 is startling. I'm so used to seeing monthly variations overwhelming year-on-year variations, that a comparison to 50 years ago comes as a bit of a shock. -
lancelot at 19:29 PM on 25 October 2011Climate's changed before
scaddenp: CH6 is indeed a great source. Thanks for reminding me. -
lancelot at 19:07 PM on 25 October 2011Climate's changed before
Sphaerica; Re 'must be CO2': I picked up that particular skeptic meme from the SkS intro - How Reliable are Climate Models? [my CAPS] "So all models are first tested in a process called Hindcasting. The models used to predict future global warming can accurately map past climate changes. If they get the past right, there is no reason to think their predictions would be wrong. Testing models against the existing instrumental record suggested CO2 MUST CAUSE global warming, because the models could not simulate what had already happened unless the extra CO2 was added to the model. NOTHING ELSE could account for the rise in temperatures over the last century." Maybe a bit of anti-meme spraying is needed here before those bugs propagate too far? :) Having said that, I know the history of CO2 greenhouse gas theory, Arrenhius et al, and that CO2 was not just plucked out of thin air to 'fill the gap' because noone could think of anything else. When I say myself use the phrase 'must be C02' I refer to the logic that there is a gap between observed warming and estimated natural warming, there are possible 'suspects', and CO2 is the by far the most likely one; that is fine, but I would want to be assured before a lynching that all other suspects have been fully checked out first! GCR/ cloud forcing theory seems to have some credibility in the scientific community, and certainly looked like a good suspect to me for a while. Even biological influence on cloud formation is a possibility. But while those theories are very appealing, the evidence is very slim to date. And the killer blow is : warming seems to be well beyond any natural variations in recent history. I will certainly look into the references given, thanks to all for those. One point which still is unclear to me: Crowley T J, in Science, 14 July 2000, Causes of Climate Change over past 1000 years: Abstract: "Comparisons of observations with simulations from an energy balance climate model indicate that as much [sic] as 41 to 64% of preanthropogenic (pre-1850) decadal-scale temperature variations was due to changes in solar irradiance and volcanism." [That seems to leaves 36 to 59% of variations pre 1850 unaccounted for by the models, which has really troubled me, seeming to cast doubts on the completeness or accuracy of the models] In view of sphaericas' comment (226) on the inability to precisely determine past temperature, how does Crowley arrive at his conclusion with such relative precision?Moderator Response: No, GCR / cloud forcing theory does not have "some credibility" in the scientific community. See It’s cosmic rays. -
Mark Harrigan at 16:00 PM on 25 October 2011Test your climate knowledge in free online course
Congratulations to the Pacific Institute for Climate Solutions and the collaborative universities for putting together this elegant, simple, clear yet thorough guide to AGW. Big pat on the back to Skeptical Science too for it's role as evidenced by the number of times articles on the site are used as important references in the resources section. It's a great tool to bypass deniers on blogs and just refer people to look to educate themselves if they still have an open mind. I especially liked the simple video demonstration in the 1st section showing how CO2 absorbs heat. Absolutely smashes the denialist myth that the greenhouse effect doesn't exist (of course we knew that anyway but what a great way to show it). Top marks to all concerned -
RW1 at 15:43 PM on 25 October 2011Clouds provide negative feedback
Sphaerica (RE: 211), "The feedback is a response to any input, whether that input is part of constant change and chaos, or a new, steady input." Yes. It's interesting that you would mention this because it leads into my next point, and that is the physical processes and feedbacks that maintain the planet's energy balance cannot be separated from those that will act on additional 'forcings', such as GHGs. -
RW1 at 15:37 PM on 25 October 2011Clouds provide negative feedback
Sphaerica (RE: 211), "The question, rephrased so that you can understand it, is: If you have a net negative feedback, why does the system succeed in fluctuating so greatly? Why does the negative feedback not keep the system stable and within very narrow confines?" Because the feedbacks take time and the system is largely chaotic. Over time, the net negative feedback does keep the system tightly constrained, which is why longer-term globally averaged there is generally very little change relative to the much larger more local and regional short-term change. -
Bibliovermis at 15:35 PM on 25 October 2011Clouds provide negative feedback
RW1, Your current question to me (#202) is effectively "How can 2 + (2 * 1.5) = 5?" In the context of your question, positive feedback is simple math. -
Bob Lacatena at 15:24 PM on 25 October 2011Clouds provide negative feedback
The question, rephrased so that you can understand it, is: If you have a net negative feedback, why does the system succeed in fluctuating so greatly? Why does the negative feedback not keep the system stable and within very narrow confines? And separately there is no requirement that the inputs be the "constant change and chaos." Yes, I understand that it fits with what you are trying to arbitrarily impose on the system, but it is too narrow a definition. The feedback is a response to any input, whether that input is part of constant change and chaos, or a new, steady input. Any attempt to frame the definitions and system only within the narrow confines of a predetermined conclusion will confuse the issue. Please stick with proper, true definitions, rather than reframing things in order to score points or twist the argument in a certain direction. -
dana1981 at 15:14 PM on 25 October 20119 Months After McLean
I think wingding's second hypothesis is plausible:"Or he hadn't bothered looking at a global record at all but had just plugged numbers into some SOI->global temp equation he had incorrectly derived and hadn't bothered to even question the plausibility of the result."
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Bert from Eltham at 15:13 PM on 25 October 2011The BEST Kind of Skepticism
As a retired physicist who was taught to look for internal consistency with ALL the evidence for any hypothesis. I find the posts on WUWT merely an exercise in partitioning the bits of evidence that fit their preconceived beliefs. I must admit my bias as I have read this (SkS) site in totality before posting and found it completely self consistent. I read as much as I could stomach at WUWT and concluded it was a waste of time. It is all over the place with no coherence scientifically. It seems to be trying to be the devil's advocate that pulls evidence out of thin air. They seem to be looking for counterfeit dollar bills to prove that all the other bills are counterfeit. Conversely I have learned a lot that I had not even considered from SkS that fills in all the missing bits as I am not a climatologist. Thank you to all here for clearing up quite a few of my misconceptions. When I get fully up to speed may be able to contribute more. Bert -
skywatcher at 15:11 PM on 25 October 2011Clouds provide negative feedback
RW1, I must have missed your answer to my question - how do you explain palaeoclimate variations (glacial-interglacial cycles and so on) with a net negative feedback? Maybe you can provide an answer where Pielke, Spencer and Lindzen have not (to my knowledge)? -
Michael Hauber at 15:05 PM on 25 October 20119 Months After McLean
Being picky I could argue that McLean's predictions being for 'coolest year since 1956 or even earlier' means he only has to be colder than 1964 to be correct. That makes him out by about 0.45 degrees so far instead of 0.5. I can't help wondering whether he knew his prediction was absurd, and was just trying for a sensational hook to get maximum media exposure for his claims that AGW was false. -
Chris G at 14:55 PM on 25 October 2011SkS Weekly Digest #21
Yocta, nice one! Daniel, I had missed that post, thanks. Not that I was unaware of clathrate potential, but that post is succinct. -
RW1 at 14:50 PM on 25 October 2011Clouds provide negative feedback
Sphaerica, Feedback is the response to changes in energy flux. I'm not sure I understand the question. Yes, the constant change and chaos fits well with what I'm saying. That's largely my point. -
Bob Lacatena at 14:45 PM on 25 October 2011Clouds provide negative feedback
204, RW1, 205, RW1, In case I'm being too subtle, what I mean by that is stop playing games and answer the question. -
Bern at 14:45 PM on 25 October 20119 Months After McLean
winding: If you remove the long-term (rising) trend from the data, then it is indeed possible that 2011 may be at or below 1956 levels. In that case, though, what you're plotting is the variation about the trend, rather than actual anomalies. But that's not what was predicted, as far as anyone can tell. Bob Loblaw: Scientists don't speculate, they hypothesise... :-D But seriously, yes, I agree, speculation is good, so long as it's followed up by investigation and analysis. -
Bob Lacatena at 14:33 PM on 25 October 2011Clouds provide negative feedback
205, RW1, Yes, we all know that. It doesn't answer the question. Except for the "from all the chaos that results in the constant variation" part. You added that just to make it look like it fits well with your own hypothesis, but you just made it up. Feedback is the response to the inputs. Period. -
Bob Lacatena at 14:33 PM on 25 October 2011Clouds provide negative feedback
204, RW1, Yes, we all know that. It doesn't answer the question. -
RW1 at 14:10 PM on 25 October 2011Clouds provide negative feedback
Sphaerica (RE: 203), Feedback, by definition, is the response to the changes in energy flux from all the chaos that results in the constant variation. -
RW1 at 14:08 PM on 25 October 2011Clouds provide negative feedback
Sphaerica (RE: 203), "Can you explain how such variability could exist with a net negative feedback damping the system?" It's a highly dynamic and chaotic system with large changes in incident energy flux. Changes from day to night, changes in atmospheric circulation patterns, etc., etc. It's constantly changing everywhere all the time. -
Bob Lacatena at 13:44 PM on 25 October 2011Clouds provide negative feedback
202, RW1, Can you explain how such variability could exist with a net negative feedback damping the system? -
Daniel Bailey at 13:14 PM on 25 October 2011Linking Extreme Weather and Global Warming
Speaking of extreme weather, the sun's kickin' out some major whup-a** (for us NH aurora geeks):
http://www.swpc.noaa.gov/pmap/gif/pmapN.gif
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RW1 at 13:07 PM on 25 October 2011Clouds provide negative feedback
Bibliovermis (RE: 201), "No, net feedback in the climate system is not required to be negative." Then can you explain how the current energy balance is maintained despite such significant amount of shorter-term, local, regional, seasonal hemispheric and even sometimes globally averaged variability? -
Daniel Bailey at 13:03 PM on 25 October 2011Linking Extreme Weather and Global Warming
Nice headline over at Climate Progress today:Study Finds 80% Chance Russia’s 2010 July Heat Record Would Not Have Occurred Without Climate Warming "… the majority of monthly records like the Moscow heat wave must be considered due to the warming trend. In highly aggregated data with small variability compared to the trend, like the global-mean temperature, almost all recent records are due to climate warming"
"For July temperature in Moscow, we estimate that the local warming trend has increased the number of records expected in the past decade fivefold, which implies an approximate 80% probability that the 2010 July heat record would not have occurred without climate warming."
"Our statistical method does not consider the causes of climatic trends, but given the strong evidence that most of the warming of the past fifty years is anthropogenic, most of the recent extremes in monthly or annual temperature data would probably not have occurred without human influence on climate."
Fun stuff, this global warming thingy. The study itself can be found here (H/T to Mark Harrigan). -
Mark Harrigan at 11:28 AM on 25 October 2011Climate Change Demands New Decision-Making Strategies by National Leaders.
Whaddyaknow! here's one Increase of extreme events in a warming world or at least a statistical analysis. Anyone know of any hard global datasets? -
Mark Harrigan at 11:02 AM on 25 October 2011Climate Change Demands New Decision-Making Strategies by National Leaders.
Is anyone aware of a validated statistcal compilation being published about the changes in frequency (if any - though I'm betting they are on the rise) and severity (if any - though again I suspect worse) of climate related disasters and their negative impacts? There's been quite a debate about the attribution of any individual event to AGW - rightly so as any evidence will be, at best, indirect and challengeable - but a statistical picture over time would be more convincing and useful in the armory against "skeptics" and in the political arena as these events have very real "here and now" immediately felt sconomic costs. -
Mark Harrigan at 09:51 AM on 25 October 2011Climate's changed before
This paper in a recent edition of Climate Research by Svante Björck would appear to debunk the skeptics argument Current global warming appears anomalous in relation to the climate of the last 20000 years In fact it would seem global climate has NOT changed by as much as it has recently in 20,000 years. The abstract states To distinguish between natural and anthropogenic forcing, the supposedly ongoing global warming needs to be put in a longer, geological perspective. When the last ca. 20000 yr of climate development is reviewed, including the climatically dramatic period when the Last Ice Age ended, the Last Termination, it appears that the last centuries of globally rising temperatures should be regarded as an anomaly. Other, often synchronous climate events are not expressed in a globally consistent way, but rather are the expression of the complexities of the climate system. Due to the often poor precision in the dating of older proxy records, such a statement will obviously be met with some opposition. However, as long as no globally consistent climate event prior to today’s global warming has been clearly documented, and considering that climate trends during the last millennia in different parts of the world have, in the last century or so, changed direction into a globally warming trend, we ought to regard the ongoing changes as anomalies, triggered by anthropogenically forced alterations of the carbon cycle in the general global environment. and there's a pretty good explanation of it at Science Daily Would like to see skeptical science do a feature on this paper please?Moderator Response: [DB] I have invited Dr. Björck to participate via a guest blog on the paper. -
Daniel Bailey at 09:39 AM on 25 October 2011SkS Weekly Digest #21
You were expecting maybe a Kraken???
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john byatt at 09:12 AM on 25 October 2011Arctic Ice Volume is diminishing even more rapidly than Area
papers, week #42 Ari..... Assumed negative feedback, Arctic winter.... positive feedback. http://www.nature.com/ngeo/journal/vaop/ncurrent/full/ngeo1285.html -
yocta at 08:43 AM on 25 October 2011SkS Weekly Digest #21
RE#2 Chris G or perhaps somebody near by facing the other way having a tea party? -
les at 08:31 AM on 25 October 2011The BEST Kind of Skepticism
89 Dana Thanks. -
Chris G at 08:26 AM on 25 October 2011SkS Weekly Digest #21
In the cartoon, I wonder what would make a good three-heads metaphor. I suppose if someone wanted to, they could draw 7 heads, and note that CO2 absorbs/emits strongly at wavenumber 666. But, bringing in a biblical boogeyman would probably not play well, with anyone, science-based or religious. For some reason, a Greek mythological monster does not raise eyebrows in the same way. -
yocta at 08:14 AM on 25 October 2011SkS Weekly Digest #21
Great work everyone at SkS. Can't wait for the new ones in the pipeline! -
scaddenp at 07:49 AM on 25 October 2011Climate's changed before
lancelot - you should probably make a start with Ch6 of AR4, WG1 report. In it, there is diagram (Fig 6.13) showing various reconstructions of temperature with hindcast modelling in grey, giving you a good idea on the uncertainties too. -
dana1981 at 07:35 AM on 25 October 2011The BEST Kind of Skepticism
les - see my comment #47. Yes, the BEST paper only looked at decadal variations in de-trended data, meaning that their analysis could not say anything about long-term global warming causes (same as the McLean and Carter ENSO paper). Basically they found a good correlation between AMO and land surface temp variations on decadal timescales and then said "hmm maybe this means AMO could be contributing to global warming", but they didn't actually investigate that supposition. Nor did they think about it very hard, since as I noted in comment #46, oceanic cycles like AMO and ENSO don't create heat or cause long-term warming trends. Though over a few decades it could be more positive than negative, and thus could marginally contribute to a warming trend over a few decades, so that's probably what Muller et al. were suggesting. But they didn't actually investigate that possibility in their paper. Frankly the line in question was kind of a throw-away that the "skeptics" have latched onto in desperation. -
wingding at 07:07 AM on 25 October 20119 Months After McLean
I cannot fathom how that 1956 prediction could emerge from any, even wildly incorrect, assumptions. I can only presume that he was looking at a regional (arctic, US?) record where 1956 is closer to present and was interpreting it as a global prediction. Or he hadn't bothered looking at a global record at all but had just plugged numbers into some SOI->global temp equation he had incorrectly derived and hadn't bothered to even question the plausibility of the result. -
les at 06:53 AM on 25 October 2011The BEST Kind of Skepticism
84 - Dana 1981 Regarding AMO Tino says (edited bits):M2011 specifically examine variations on time scales from 2 to 15 years. ... Subtracting the low-order polynomial effectively acts as a high-pass filter, removing the very slow fluctuations. .... Eliminating slow fluctuations was motivated by a desire to remove the long-term trend due to global warming or other influences.
So this is just about medium term fluctuations and not about the causes of global warming; is that right? Then the appeal to this work as BEST saying "it's not us" by the 'skeptics' is some other paper? I'm confused. -
Bob Loblaw at 06:23 AM on 25 October 20119 Months After McLean
When I first read the post, it struck me that the largest annual change (a decrease) occuring between 1963 and 1964, just happened to coincide with the Mt. Agung eruption. Coincidence? (Granted, there are other large decreases that do not seem to correspond to volcanic eruptions, and large increases of simlar magnitude, too.) Re: speculation. Without speculation, scientists would never develop new research questions. Scientists speculate all the time. It's just that they should identify it as speculation, and follow it with data collection and analysis to show whether it is reasonable or not. The denial PR machine will take it out of context whenever they can, but speculation is part of life. -
Hyperactive Hydrologist at 05:57 AM on 25 October 20119 Months After McLean
michael sweet, I disagree scientist should not speculate. Yes I agree they can make predictions based on current knowledge and scientific evidence but speculation, especially by sceptics, just feeds the denial PR machine. I'm pretty sure Hansen's prediction wasn't speculative but based on the vast quantity of data being generated by models. Also we were overdue a strong El Nino. -
The BEST Kind of Skepticism
Albatross - Mea culpa, I was looking at the wrong paper. That said, you are quite right about the Watts surface station data not being continuous even over the last 30 years, and the fact that he's offered nothing but unsupported assertions. He certainly could use the data made available by BEST to run his own analysis, but based on past history I consider it quite unlikely that he'll make that effort. -
michael sweet at 05:33 AM on 25 October 20119 Months After McLean
Hyperactive: On the contrary, real scientists make predictions about the future to show their predictive powers. Four years ago Dr. Hansen predicted that in the next three years one would set a new record high. He was proven correct in 2010 when it set a new record. That shows the his methods have skill. McLean has shown how much skill his methods have. -
dana1981 at 05:30 AM on 25 October 20119 Months After McLean
CBD - maybe, but Figure 1 shows there's virtually zero chance of even a single month falling anywhere near 1956 levels. But I guess climate 'skepticism' is a very hopeful and optimistic mindset in general. -
Hyperactive Hydrologist at 05:22 AM on 25 October 20119 Months After McLean
This is why scientist should not speculate. -
pbjamm at 05:06 AM on 25 October 2011The BEST Kind of Skepticism
Albatross@83 The only thing accurate in that cartoon is the Sour Grapes. -
Alexandre at 05:03 AM on 25 October 20119 Months After McLean
No surprise. 'Skeptics' never consider themselves to be wrong. It will be fun to ask him about his prediction on January, though. If he ever answers that, of course. -
Hyperactive Hydrologist at 05:02 AM on 25 October 2011The BEST Kind of Skepticism
James Delingpole with his view on the BEST research. No pretty, usual collection of misinformation and not surprisingly the line; we knew the planet was warming. Interestingly he did a blog post last year referencing D'Aleo and Watts claiming the opposite. Global Warming: is it even happening? -
CBDunkerson at 04:52 AM on 25 October 20119 Months After McLean
He's probably hoping that one month this year will drop below the 1956 level so that he can say that he meant one point during 2011 will be colder than 1956, not that the entire year would be. Even there he is facing long odds, but it verges closer to rationality than any other explanation I can think of. -
dana1981 at 04:51 AM on 25 October 20119 Months After McLean
NewYorkJ - your speculation #1 is probably the most likely excuse. I can see McLean claiming that his prediction was wrong because La Nina wasn't as strong as he expected. It will be fascinating to see his explanation, because as the above blog post (particularly Figure 2) shows, his prediction was utterly ludicrous and completely indefensible. I don't know what he can possibly say to save face after getting a one-year prediction wrong by ~0.6°C.
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