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Comments 72501 to 72550:

72501. dana1981 at 12:08 PM on 14 October 2011
       Pielke Sr. and SkS Disagreements and Open Questions
       Let's please move any discussion of TLT trends to the new blog post on the subject, and move on to the discussion of OHC data here.
72502. Riduna at 11:25 AM on 14 October 2011
       Every Picture Tells A Story
       Very informative - as is the well selected reading list.
72503. pielkesr at 11:18 AM on 14 October 2011
       Pielke Sr. and SkS Disagreements and Open Questions
       muoncounter - I took 2002 because visibly there appears to be a change in slope. I request you plot that as well.
72504. pielkesr at 11:16 AM on 14 October 2011
       Pielke Sr. and SkS Disagreements and Open Questions
       Dikran Marsupial - I had three hypotheses. I request you complete the test and see what you obtain. It is a starting point for our further discussuions.
72505. pielkesr at 11:09 AM on 14 October 2011
       Pielke Sr. and SkS Disagreements and Open Questions
       Tristan - You asked "Dr Pielke, [many policy makers] believe that the flat temperatures between 1998 and 2011 are a result of a cessation of anthropogenic warming, [will you acknowledge] that that flatness is [a temporary result] of natural variability[...]? " There is no question that the diversity of human climate forcings, including that from added CO2, has continued even as global warming has flattened. However, this behavior of the climate system illustrates our still incomplete knowledge of the climate. Policymakers, in my view, are being misled into believing that the climate should more-or-less monotonically warm when in reality both natural variability and the diversity of human climate forcings makes the issue of climate system heat content much more complex.
72506. hank at 10:44 AM on 14 October 2011
       Pielke Sr. and SkS Warming Estimates
       > the regional/local scale that matters much more to > society and the environment. On the regional/local scale, absorbign damages are of different kinds in different locations, you can absorb a whole lot of losses. That works for a while -- while the trading/transportation/financial system holds up, because each area can buy what it can't produce and sell what it overproduces. That's the definition of overshoot, ecologically. http://www.google.com/search?q=catton+overshoot It's not a solution. It's a way of postponing and increasing the damage while hoping the problem doesn't keep adding up. Remember the advertising slogan "The solution to pollution is dilution!" from the 1950s? Because impacts could be avoided. For decades.
72507. Michael Hauber at 10:40 AM on 14 October 2011
       The Earth continues to build up heat
       An interesting chart. Enso does act to move heat between the surface and the subsurface, with El Ninos moving heat from subsurface to the surface, and vice versa for La Nina. However most of this effect seems to happen above 700 metres if you track the detailed evolution of ENSO events, but possibly the effect extends deeper down in a more subtle manner. On this basis the strong La Nina period of the early to mid 70s increased heat content in 700-2000. Then between 1980 and 1998 a strongly El Nino dominated period resulted in a loss of heat which was a little more than enough to offset the heat that global warming put into this layer. Then since 1999 a more La Nina dominated period combined with global warming resulted in a rapid rise of 700-2000 metre heat content. Although squinting at the colours with my partially colour blind eyes, it looks like the strongest heat gain is in the Atlantic? Whereas if ENSO was driving the multi-decadal variation I'd expect it to be strongest in Pacific.
72508. Tom Curtis at 10:37 AM on 14 October 2011
       Over 31,000 scientists signed the OISM Petition Project
       Tristan @10, the petition was originally circulated to "virtually every scientist in every field" in the US according to one of its critics. But the OISM refuses to indicate the size of the mailout. From SourceWatch:

       "OISM has refused to release info on the number of mailings it made. From comments in Nature:

       "Virtually every scientist in every field got it," says Robert Park, a professor of physics at the University of Maryland at College Park and spokesman for the American Physical Society. "That's a big mailing." According to the National Science Foundation, there are more than half a million science or engineering PhDs in the United States, and ten million individuals with first degrees in science or engineering. Arthur Robinson, president of the Oregon Institute of Science and Medicine, the small, privately funded institute that circulated the petition, declines to say how many copies were sent out. "We're not willing to have our opponents attack us with that number, and say that the rest of the recipients are against us," he says, adding that the response was "outstanding" for a direct mail shot. [16]"

       The original mail out only garnered about 15,000 responses. Despite Robinson's claims, without a precise statement of the mail out number, no significance can be assigned to the petition as a survey of scientific opinion. What is more, given the anecdotal evidence of the size of the mailout, and the small size of the respondents (15,000) compared to the number of "virtually every scientist in every field", the reasonable conclusion is that the response rate was very small. Indeed, if it were not, you can be sure that the OISM would be trumpeting not only the absolute number of signatories, but the response rate as well. Since the original mail out, the petition has been available online to add the signature, and has been frequently trumpeted by various political figures, so its presence has been known. Given that, the response rate is best given by the number of signatories divided by the number of potential signatories as given in the main article, ie, 0.3%. As such, this petition is no more significant than any of the various creationist petitions that get circulated. Indeed, given the close ties of the OISM and the Discovery Institute (an Intelligent Design creationist site), it can be viewed as one of the various petitions circulated by creationists.
72509. Chemware at 08:45 AM on 14 October 2011
       Every Picture Tells A Story
       Anyone care to draw a line of best fit through the Annual Mean NH Snowfall Extent of Fig 3 ?
       Response:

       [DB] The seasonal graphs have trend lines already in place, here.

72510. Rob Painting at 08:15 AM on 14 October 2011
       The Deep Ocean Warms When Global Surface Temperatures Stall
       Thanks Pete. And this is from the NODC data? Interesting how it can change so quickly, almost as if someone has flipped a lever and heat is now tracking down deeper. Just been reading Sutton & Roemmich (2011). Although I don't cover it in the post, most of the heat funneled down to the depths in the climate model used by Meehl (2011), occurs in the Southern Ocean (figure 4 in the post). That's what Sutton & Roemmich find looking at the WOCE (World Ocean Circulation Experiment) and ARGO data. The "missing heat" is running out of places to hide.
72511. muoncounter at 07:08 AM on 14 October 2011
       There is no consensus
       Continued sensitivity discussion is better suited to the existing sensitivity thread. The consensus there is 3.5 deg C per doubling.
72512. scaddenp at 06:54 AM on 14 October 2011
       There is no consensus
       Jonathon, I am curious. What is your reference for Hansen believing sensitivity to be 6? Wasnt what he said in public meeting I attended. Also, in consensus. Am I correct in assuming that in your mind, if there is a published value outside a consensus range, even in a refuted paper, then consensus doesn't exist?
72513. muoncounter at 06:49 AM on 14 October 2011
       Pielke Sr. and SkS Disagreements and Open Questions
       pielkesr#103: ""The lower tropospheric global annual average temperature trend (TLT) from 2002 until now cannot distinguished from a zero trend."" The rationale for choosing 2002 as a breakpoint is still unclear. However, if you take what appears to be a natural breakpoint (1998), you see something completely different. Here is UAH from start to the beginning of 1998 with a 6 month running mean. The trend line is shown. Here is UAH from mid-1998 to present, same mean; the trendline has a higher slope than does the prior period. I seem to recall a video interview with Dr. Pachauri in which he clearly stated that warming was not expected to be monotonic (can't find the link to it at the moment). Perhaps the nonlinearity in the system that everyone agrees is present is expressed in these temporary flattenings along the overall rising curve. In view of that characteristic of these data, choosing arbitrarily short periods for analysis seems utterly counterproductive. And given the data have a high frequency noise, short periods are likely to be more contaminated -- and therefore misleading -- than long periods.
72514. DSL at 06:44 AM on 14 October 2011
       Book review: The Inquisition of Climate Science
       1. Here's a sourcewatch wiki on Koch Industries, with references. Readers can do their own explorations from that starting point. You should add no. 3, Sasquatch, if you want to provide complete coverage: "Where does the industrial funding money come from?" Remember, the government isn't the only economic entity that engages in taxation (it's just the only one that offers representation (such as it has become)).
72515. DSL at 06:30 AM on 14 October 2011
       Over 31,000 scientists signed the OISM Petition Project
       An intermediate argument at the level of most intermediate articles on SkS would be pointless. All that needs to be stated is the obvious: 1. Those who hold science degrees (and in particular undergraduate degrees only) are probably clueless in many areas of science. 2. What is the basis of the signers' expertise? 3a. If 32,000 is impressive, and I find 32,000 people who think you should die, will you kill yourself? 3b. If I find 32,000 atheists who say you should worship the Flying Spaghetti Monster (praise its name), will you? 3c. If I find 32,000 science majors who think the Earth is 6000 years old, will you then believe the Earth is 6000 years old? 3d. If I find 32,000 English majors who say that Joyce's Ulysses is the greatest work of fiction in English, does that settle the matter? 3e. (etc. ad nauseum) 4. If I create a petition that says the opposite, and I get 32,001 signatures from science majors, are you forced to believe my petitioned claim? 5. What happens if all of these 32,000 change their minds? Does your mind change as well? What if these 32,000 are then replaced in a new petition by a different set of 32,000? Will you short-circuit? 6. If 32,000 climate scientists put their expertise up against that of 32,000 science majors, who would be right about issues within climate science? Here you see that the maximum number is important. If I ask, "If 100 of the most-published climate scientists put their expertise up against that of 32,000 climate scientists, who would be right about issues within climate science?" then the denominator is critical, because I could bring it down to 1 vs. 32,000. It's all goofiness designed to prey upon people who, again, do not have the time, means, energy, training, and/or motivation to come to an understanding for themselves--or designed to confirm what we already suspected, the Great GW Hoax!
72516. Dikran Marsupial at 06:06 AM on 14 October 2011
       Pielke Sr. and SkS Disagreements and Open Questions
       pielkesr The hypothesis that "The lower tropospheric global annual average temperature trend (TLT) from 2002 until now cannot distinguished from a zero trend." is not a particularly interesting hypothesis for the simple reason that the statistical power of the test of a non-zero trend is very low because the timespan over which the trend is computed is too short. Your hypothesis is effectively the null hypothesis for the usual test for a non-zero trend. The statistical power is the probability that the null hypothesis will be rejected when it is false so if the test has little statistical power, we should not expect to be able to distinguish from a zero trend, even if the underlying trend is the same as the long term trend and global warming has continued unabated, but its effects are being masked by noise (i.e. internal climate variability, e.g. ENSO). Now if you want to suggest there is any scientific interest in this hypothesis, then you need to show that the hypothesis test has meaningful power. So my question is, what is the statistical power of the test?
72517. Sasquatch at 06:02 AM on 14 October 2011
       Book review: The Inquisition of Climate Science
       1. From where do the figures on funding from industrial sources come from? 2. How much money has been spent on supporting AGW research, and where does it come from?
72518. pielkesr at 05:59 AM on 14 October 2011
       Pielke Sr. and SkS Disagreements and Open Questions
       Dikran Marsupial -Regarding "But heat going into the deep oceans doesn't impact surface temperatures or the ratio of TLT to surface temperatures" if the surface temperature trends are being used as quantifying the magnitude of global warming (and the so-called "clmiate sensitivity"), heat in the deeper ocean is not included in such an assessment. If the heat were at the surface, it would be seen in the temperature trend.
72519. Jonathon at 05:59 AM on 14 October 2011
       There is no consensus
       Dikran, I am not missing the point. I never said that there is a consensus on the exact value, so you can stop repeating yourself on this issue. I have yet to see anything that support a consensus on the range of plausible values, and highly doubt that one exists. Typically the evidence against a consensus is to present data which does not conform, which I have already done. The Pagani estimates are estimates of the value, not a bound. The uncertainties listed after each value are his calculated range. Clear? Philippe, When assembling a range of value such as this, each individual measurement is assigned the same probability, assuming they were determined independently, just like rolling the dice. If additional research yields values which begin to cluster around a specific range, then we can assign higher probability to those values. In the case of climate sensitivity, we see values clustered not around a mid-range value, but at the high and low ends, but still yielding a similar mid-range value. This anti-Gaussian distribution would indicate that the mid-range value is less likely than either end.
72520. KR at 05:58 AM on 14 October 2011
       There is no consensus
       Jonathon - Looking at the Pagani paper, they are estimating equilibrium sensitivity, not transient sensitivity (the number usually listed as ~3°C/doubling of CO2.). Hansen estimated equilibrium sensitivity at ~6°C? So while the Pagani numbers are rather higher, they are really not directly relevant to the short term transient sensitivity of 3°C. Also, keep in mind that the high end of the sensitivity tail is much less determined than the low end. --- This is all smoke and mirrors on your part anyway, Jonathon. The consensus on values and ranges come from the evidence - if you wish to assert a climate sensitivity outside that range, present some evidence, not a petition.
72521. pielkesr at 05:56 AM on 14 October 2011
       Pielke Sr. and SkS Disagreements and Open Questions
       Dikran Marsupial - Regarding "What exactly is the hypothesis that you seek to support using the post-1998 trends?" I suggest that the hypothesis be that "The lower tropospheric global annual average temperature trend (TLT) from 2002 until now cannot distinguished from a zero trend." using data from http://www.ssmi.com/msu/msu_data_description.html Also, "The lower stratospheric (TLS) global annual average temperature trend from 2002 until now cannot distinguished from a zero trend." and the trends during this time period are different than the trends earlier in the time period. I will be interested in what you conclude.
72522. Philippe Chantreau at 05:45 AM on 14 October 2011
       There is no consensus
       Jonathon, you're treating the extremes of the possible range as if they were equally probable as the mid range values. I doubt it is the case. The Pagani numbers should certainly give us cause for great concern.
72523. Dikran Marsupial at 05:45 AM on 14 October 2011
       There is no consensus
       Jonathon, you appear to be missing the point. Nobody is claiming there is consensus on the exact value of climate sensitivity. There is however consensus on the range of values that would be plausible. If you want to claim that the scientists don't agree on the range of plausible values then please provide some evidence to support that assertion. Your comment on the Pagani estimate(s) still doesn't clarify whether it is a bound or an estimate of the most likely value.
72524. Jonathon at 05:36 AM on 14 October 2011
       There is no consensus
       Dikran, I guess it comes down to what we understand to be the range of plausible values, and if that range is sufficient to state that there exists a consensus. I am not comfortable making that claim at this time, as I would prefer to see a narrower range of plausible values before making that assertion. Also, I do not believe that scientists would agree on the range. This does not mean that a consensus could not be formed in the future. I do not need to know the exact value, but the concept that the high end of the range is a factor of three higher than the low end implies that we still have a long way to go. Given the EPA range of atmospheric CO2 to lie between 535 and 983 by 2100, the resultant temperature increase lies in the range is 0.5 - 7.0 C (low-low to high-high). The pagani value was a calculated number for three different times in the recent geological past: 7.1 +/- 1.0, 8.7 +/- 1.3, and 9.6 +/- 1.4 C/doubling. http://earth.geology.yale.edu/~mp364/data/2009%20Pagani%20et%20al.pdf
72525. Philippe Chantreau at 05:34 AM on 14 October 2011
       Pielke Sr. and SkS Disagreements and Open Questions
       Doesn't the 700m mark have to do with limitations of the earlier Argo network?
72526. Philippe Chantreau at 05:31 AM on 14 October 2011
       Over 31,000 scientists signed the OISM Petition Project
       Of all the nonsense spewed by deniers, this one is certainly one of the most ridiculous. The self contradictory arguments go like this: "There is no scientific consensus." Since it's quite easy to show that, in fact, there is one, this is often followed by "science is not done by consensus" with all manners of misundertanding what scientific consensus actually is. Attempts to correct the misunderstanding by pointing that consensus follows from the science instead of preceding it usually falls on deaf ears. This in turn, is often followed by arguments like the stupid petition thing, portraying a consensus of opinion among non experts as a valid one, right after insisting that consensus among experts is not. When emotionally charged, ideology driven opinion puts up its defenses, there is no amount of rational thinking that can tear them down.
72527. Tristan at 05:22 AM on 14 October 2011
       Over 31,000 scientists signed the OISM Petition Project
       I guess I just can't abide the idea of audience appropriate logic, especially when it's under the heading 'intermediate'.
72528. DSL at 04:34 AM on 14 October 2011
       Over 31,000 scientists signed the OISM Petition Project
       Tristan, what is useful about the estimate of opinion of a bunch of non-experts? Tristan: "Assigning the maximum possible denominator to the 32000 and saying 'look how small it is' is almost as bad as saying '32000 is a really big number!'." I agree, but unfortunately the original argument was made, and it has to be addressed, and it has to be addressed with the audience-appropriate logic (as "bad" as it is). The people who accept the "over 31,000" argument (as silly as it is) will be forced to accept the "10 million" number, or else they'll be forced to recognize the silliness of the "over 31,000" argument. Tristan: "What would be far more relevant would be an estimation/examination of the petition's distribution and a discussion about why 32000 signatories isn't of itself, a useful estimate of opinion." Again, would you expect anyone who accepts the "over 31,000" argument to be willing to do or read what you suggest?
72529. Albatross at 04:32 AM on 14 October 2011
       Pielke Sr. and SkS Disagreements and Open Questions
       Dana @99, "However, there's nothing special about the 700 meter mark, either. And the warming of the upper 1500 doesn't appear to have slowed appreciably." Agreed, I do not know why some people are so fixated with the top 700 m of the ocean, especially when we know the oceans are much deeper than that and when we have data down to 2000 m. Dr. Pielke says "With respect to the reported deeper ocean heating, why would this heating recently have become larger?" Not sure whether or not this answers the question. Peter Hogarth has just posted a very neat image of the OHC data for 700-2000 m for different basins. Those data show a notable warming trend in the 700-2000 m OHC since 2000. The data before 1970 are probably not worth much given the sparse coverage back then. Anyways, looks like yet another Hockey Stick to me, but caveat emptor, these data should probably to be considered preliminary. [Source]
72530. NewYorkJ at 04:24 AM on 14 October 2011
       Every Picture Tells A Story
       Minor error: In "Related Links", #1 and #3 are duplicates.
       Response:

       [DB] Fixed (thanks!).

72531. Tristan at 03:55 AM on 14 October 2011
       Over 31,000 scientists signed the OISM Petition Project
       The theoretical maximum number of signatories is almost irrelevant. What would be far more relevant would be an estimation/examination of the petition's distribution and a discussion about why 32000 signatories isn't of itself, a useful estimate of opinion. Explaining the distinction between results from a petition and a survey is also important. I've seen people say 'they're calling 32000 a tiny fraction and then relying on a survey of 3000 individuals?!' Assigning the maximum possible denominator to the 32000 and saying 'look how small it is' is almost as bad as saying '32000 is a really big number!'.
72532. Dikran Marsupial at 03:50 AM on 14 October 2011
       There is no consensus
       Jonathon As I said, there is a concensus, the concensus is on the range of plausible values because at this stage there is insufficient evidence to make a stronger statement given out current state of knowledge. Of course there is no agreement on a specific value for climate sensitivity, nobody is claiming that there is, and indeed it is an unreasonable expectation. However that doesn't mean we can't have a concensus on the spread of plausible values. Note that a spread of plausible values is what we need for impacts studies, so that the distribution of plausible loss properly incorporates our uncertainty regarding climate sensitivity. You need to get away from the idea that we need to know the exact value of climate sensitivity. I note that your comment regarding the Pagani value does not address the question as to whether it is a most probable value or a bound.
72533. DSL at 03:37 AM on 14 October 2011
       Over 31,000 scientists signed the OISM Petition Project
       Tristan: "Too much attention spent focusing on how many people theoretically could have signed it. Saying there are 10M science grads since 1970 isn't any sort of refutation." There's nothing to refute. What argument does the petition make? The only arguments that the petition makes are that "strength is in numbers" (bandwagon) and "undergraduate science degree = universal scientific expert" (false authority). If an audience exists for these arguments, then an analysis of the strength of the arguments is relevant and in order. A useful counter to such moves is the analysis of strength, in this case showing that an impressive number like 31,000 is pretty weak when set against the maximum number who could have signed. The stronger criticism (of the false authority) won't work in this case, because the target audience won't be willing to spend the time to consider the actual authority represented in the 31,000 (or they would have already done it intuitively). It's fairly clear that the 31,000 argument is designed for people who don't have the motivation to even open the cover of climate science basics. To make such an argument is to express a desire to shape the opinion of these people without providing them with the critical context (and the petitioners have been reticent regarding methodology) necessary for making ethical choices. Using the 31,000 argument says a lot more about the integrity of the user than it does about climate science. Reading anything about climate science from the results of the petition says more about the critical ability of the reader than it does about the truth of the petition.
72534. Tristan at 03:34 AM on 14 October 2011
       Pielke Sr. and SkS Disagreements and Open Questions
       I'd like to echo Tom's sentiment: Dr Pielke, [many policy makers] believe that the flat temperatures between 1998 and 2011 are a result of a cessation of anthropogenic warming, [will you acknowledge] that that flatness is [a temporary result] of natural variability[...]?
72535. Jonathon at 03:31 AM on 14 October 2011
       There is no consensus
       Dikran, Using ranges is a very good way to narrow down uncertainties in many instances. For such a complicated scenario, different methods are used in an attempt to ascertain the most likely value (or range of values). In genetics, significant research has been able to narrow down the genes responsible for specific traits. Initially, there would be no consensus, but as pieces were placed together, a general picture appeared, resulting in an agreement among the scientists involved. At some point, you could say a consensus occurs, because the scientists agree that certain genes are responsible, without nailing down the specifics. The point at which that occurs may be somewhat nebulous. The same could be said for climate science. At what point can we say there is a consensus on climate sensitivity? My conclusion is that the range is still too wide to claim a general agreement. Some have tried to narrow the range, but then lose enough scientists to preclude calling it a consensus. BTW, the Pagani value was determined from paleo measurements, and Hansen and Sato (2011) recently stated that fast climate sensitivity was 3, while equilibrium climate sensitivity was 6. Excluding the Pagani value, with may not e relevant to today anyway, to claim a consensus opinion on the range of climate sensitivity, one would have to choose values from ~1-7! IMO, this does not constitute a consensus.
72536. Hyperactive Hydrologist at 02:53 AM on 14 October 2011
       Greenland ice loss continues to accelerate
       Anne-Marie, Thanks for the link.
72537. dana1981 at 02:40 AM on 14 October 2011
       Pielke Sr. and SkS Disagreements and Open Questions
       Dr. Pielke:

       "The OHC accumulation for the upper 700m since 2003 is positive but small [see http://oceans.pmel.noaa.gov/]. We seem to agree on tha (as does others such as Kevin Trenberth)."

       Yes, I think we're all in agreement that the accumulation in the upper 700 meters has been relatively small, as compared to previous decades. However, there's nothing special about the 700 meter mark, either. And the warming of the upper 1500 doesn't appear to have slowed appreciably.

       "If there is heat accumulating at depth (and I have been discussing this issue at Real Climate, the question is whether we see this transfer of heat downward in the Argo data)."

       I'm not sure that is the question. It's an interesting question whether or not the ARGO network could detect this transfer, but regardless of the answer to this question, the heat at greater depths has been measured. I view your question more in the "interesting" category than "important", necessarily.

       "Regardless, if the heat is actually there, it has important consequences: 1. The use of the global annual average surface temperature to monitor global warming misses a component of this heating. This means the current trends using this metric underestimate global warming, but also make the difference between its trend and that of the lower tropospher even greater."

       I don't follow you here. I agree with the first sentence about the heat in the deeper oceans not being reflected in surface temperatures. But heat going into the deep oceans doesn't impact surface temperatures or the ratio of TLT to surface temperatures.

       "With respect to the reported deeper ocean heating, why would this heating recently have become larger?...If this heat was going to depths for all of the previous years, it increases the magnitude of global warming during those years."

       I don't know - I'm no oceans expert, and I'm sure there will be a lot of research on this subject in the near future, just as there has been more research on OHC in deeper layers. It's an important question.
72538. Tristan at 02:32 AM on 14 October 2011
       Over 31,000 scientists signed the OISM Petition Project
       A few issues with this post: "The IPCC AR4 WG1 report was written and reviewed by approximately 2000 scientists." - needs a link, given rebuttals such as this. Too much attention spent focusing on how many people theoretically could have signed it. Saying there are 10M science grads since 1970 isn't any sort of refutation. Broken link to the 2009 Pew survey.
72539. Albatross at 02:10 AM on 14 October 2011
       The Deep Ocean Warms When Global Surface Temperatures Stall
       Peter @54, Nice graphic! But, "Oh No! Another Hockey Stick"! ;) I recall reading in a new paper that they suspect that there were problems with the data over the Atlantic in the seventies, with an abnormally warm blip being an artifact of data issues. A couple of studies have suggested that the data before 1970 are not of much use due to poor spatial coverage and that is reinforced by church et al's finding that they can only close the seal level budget from the early seventies.
72540. Dikran Marsupial at 02:08 AM on 14 October 2011
       There is no consensus
       Jonathon If say Annan publishes an estimate of climate sensitivity of 3, that does not mean that he thinks Hansen's estimate of 6 (I'll take your word for it that is Hansens most probable value rather than a bound) is implausible, and vice versa. This is not at all unlikely as scientists know that estimates made via different methods, with different sources of uncertainty, will have different results, without that meaning that one s right and the other is wrong. It just means that the plausible range for the true value, given what we actually know, lies somewhere in beteen the two estimates. Thus they would have a concensus opinion that climate sensitivity lies in the range 3-6. As the new estimates are considered, if they are considered plausible (even if not very likely) then the concensus range will increase. The point is that the concensus is on the range of plausible values, not on the individual point estimates. This is actually a good way to narrow down the uncertainty of the estimate of climate sensitivity by performing research that places constraints on climate sensitivity, beyond which they are not plausible (or inconsistent with the observations). I rather suspect that the Pagani value for instance is not a estimate of the most likely value, but an upper bound resulting from some physical constraint. BTW, climate sensitivity is not specific to CO2 radiative forcing, it applies more or less equally to any other forcing.
72541. Dikran Marsupial at 01:44 AM on 14 October 2011
       Pielke Sr. and SkS Disagreements and Open Questions
       Prof. Pielke The set of six steps suggested by sciencebuddies.org seems like very good guidance to me. I don't know how to say this less bluntly, but as far as I can see, you have skipped step four/five in that you are making arguments here based on short term trends without properly testing the statistical significance those trends, or examining the statistical power of the test, before communicating your results. In addition as far as I can see the hypothesis has not been clearly and unambiguously stated in a way in which it can be properly tested, so step three has also recieved less attention than perhaps it should. What exactly is the hypothesis that you seek to support using the post-1998 trends?
72542. pielkesr at 01:35 AM on 14 October 2011
       Pielke Sr. and SkS Disagreements and Open Questions
       Dikran Marsupial - Hypothesis testing involves seeking to refute it. In my post http://pielkeclimatesci.wordpress.com/2010/11/15/hypothesis-testing-a-failure-in-the-2007-ipcc-reports/ I wrote "There has been a development over the last 10-15 years or so in the scientific peer reviewed literature that is short circuiting the scientific method. The scientific method involves developing a hypothesis and then seeking to refute it. If all attempts to discredit the hypothesis fails, we start to accept the proposed theory as being an accurate description of how the real world works. A useful summary of the scientific method is given on the website sciencebuddies.org where they list six steps 1. Ask a Question 2. Do Background Research 3. Construct a Hypothesis 4. Test Your Hypothesis by Doing an Experiment 5. Analyze Your Data and Draw a Conclusion 6. Communicate Your Results"
72543. Jonathon at 01:33 AM on 14 October 2011
       There is no consensus
       While I agree that there is agreement that CO2 has contributed to the observed warming (i.e. climate sensitivity is greater than zero), I disagree that there is agreement as to the value of the climate sensitivity. Posts made on the other thread claimed that any sensitivity greater than zero was part of a consensus about the climate sensitivity. There is little agreement on the range of climate sensitivity values (the most commonly quoted ranges are 2-4.5, 1.5-4.5, and 1.5-5). With the exception of James Annan, the five scientists I mentioned in my earlier post are all outside this range, and there are others which make claims of even higher and lower values. Sure, Spencer will not agree, but I doubt that Hansen will either. There appears to be a misconception on the other thread that since scientists agree that CO2 has contributed to warming, that there is a consensus as to how much.
72544. Dikran Marsupial at 01:22 AM on 14 October 2011
       Pielke Sr. and SkS Disagreements and Open Questions
       Prof. Pielke wrote "This test is certainly worth doing." I would go further such a test ought to be a necessary pre-condition; it ought to be incumbent on the scientist to be able to state whether the hypothesis has statistically significant support from the data prior to publically putting forward the hypothesis. This is especially true in a contentious issue of public interest, such as climate change.
72545. pielkesr at 01:02 AM on 14 October 2011
       Pielke Sr. and SkS Disagreements and Open Questions
       dana1981 - With respect to the reported deeper ocean heating, why would this heating recently have become larger? I recognize that the data has become better in recent years, however, the mechanism of heat transfer to depth likely would not have changed that much of time. If this heat was going to depths for all of the previous years, it increases the magnitude of global warming during those years. What is your perspective on this?
72546. pielkesr at 00:57 AM on 14 October 2011
       Pielke Sr. and SkS Disagreements and Open Questions
       Hyperactive Hydrologist - This test is certainly worth doing.
72547. Dikran Marsupial at 00:49 AM on 14 October 2011
       Pielke Sr. and SkS Disagreements and Open Questions
       Hyperactive Hydrologist Breakpoint detection methods are indeed applicable to temperature data, they are used for example in homogenising raw surface statation data to account for issues such as a change of measuring device or moving the site of the station etc. There are a variety of methods for performing a statistical test for the existence of a breakpoint, segmented regression just had a fairly clear Wikipedia page. The important thing is to actually perform some appropriate statistical test rather than relying on judging by eye, which is notoriously unreliable.
       Moderator Response:

       [DB] Dikran, if I'm not mistaken, Tamino explores a method of breakpoint detection here:

       http://tamino.wordpress.com/2010/08/13/changes/

       [Dikran Marsupial] Yes, Taminos article is well worth reading, although the test he uses is a little basic, ideally the test ought to account for the increase in the degrees of freedom of the model, but that is a more subtle issue not needed to make the basic point of letting the data choose the model, rather than unintentionally cherry picking by eye (and performing a significance test).
72548. Hyperactive Hydrologist at 00:39 AM on 14 October 2011
       Pielke Sr. and SkS Disagreements and Open Questions
       Maybe I should have read Dikran Marsupial post @ 90. I think my girlfriend uses a different method, I will have to ask her.
72549. Hyperactive Hydrologist at 00:36 AM on 14 October 2011
       Pielke Sr. and SkS Disagreements and Open Questions
       Prof. Peilke @88, Would it be possible to do a statistical test to determine whether there is a change point in the data. My girlfriend does this with rainfall data, I don't pretend to understand the methodology but it basically detects if there is a change in the data to a new trend or phase. With rainfall these changes can often be partially attributed to teleconnections such as the NAO. I believe it can also be applied to discharge data but I'm not sure whether it would be applicable to temperature data.
72550. Dikran Marsupial at 00:09 AM on 14 October 2011
       Pielke Sr. and SkS Disagreements and Open Questions
       Prof. Pielke wrote: "You split data when you see an obvious breakpoint but do not have a preconceived test of what you are expecting." This is simply incorrect. There are statistical tests for determining whether there is significant evidence for the existence of a breakpoint (e.g. segmented regression, although I personally would probably use a Bayes factor based approach). Seeing an "obvious breakpoint" would be a good reason to perform the test, but it would not be good scientific practice to assert the existence of a breakpoint without first demonstrating that there were statistically significant evidence for that hypothesis (or a physical reason as muoncounter suggests). "You would not split the data if you are examining an hypothesis (i.e. a "weak long term" global warming)." This is also incorrect, whether you split the data or not would depend on the nature of the hypothesis. If the hypothesis were "the climate has warmed more slowly since 1998", for example, it would be difficult to formulate an appropriate statistical test without splitting the data. "Both approaches are appropriate." I certainly agree with that, however regarldless of which approach is taken, it would not be good scientific practice to base an argument on a trend in the absence of statistically signifiant evidence. It is a very bad idea to analyse the data using your eyes only, as I said human beings are very good at seeing patterns in data where they don't actually exist, which is why we have statistics so we can test objectively if our intuitions are reasonable. It is a safety valve that science has found very useful over the years.

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