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dana1981 at 02:44 AM on 30 June 2012Simply Wrong: Jan-Erik Solheim on Hansen 1988
angusmac - the 0.9 factor in the spredsheet was to account for the forcing difference between reality and Scenario B (roughly 10%, though I'll need to revisit that figure in more detail this weekend). You're also penalizing Hansen for the GISS LOTI being more accurate now than it was in 1988, because his model was tuned to the 1958-1984 observed temperature change at the time. That's why I did the calculation using models vs. observations post-1984. -
dana1981 at 02:39 AM on 30 June 2012Michaels and Cato Unwittingly Accept the Climate Threat
vroomie, see the CO2 limits will harm the economy rebuttal. I'll probably have another post on mitigation vs. adaption next week, but it will mostly be a re-tread of the information in that rebuttal. -
KR at 02:36 AM on 30 June 2012Madness over sea level rise in North Carolina
CRV9 - Some reasonable questions! The oceans, as liquids, will move around with expansion in mid-ocean affecting coastlines in pretty short order (almost instantly in terms of the speed of expansion). There are multiple influences in play, though: - Persistent winds (trade winds) pushing and piling water downwind, lowering it upwind. - Gravity has an effect, with water pulling up slightly near continents. - Continents themselves move (rising and falling), mostly due to "Glacial Isostatic Adjustment" (GIA): the redistribution of weight from the ice that melted in the last ice age (several kilometers thick) means many continental areas are still rebounding from that mass, while others (balancing the the rising sections) are sinking. The East Coast of the USA is notably dropping due to this effect, as the northern Canadian sections of the continent are rapidly rising.
[Source]
This is why evaluations of sea level change need to take GIA into account, and use measurements from widely spread tidal gauges and satellites. Otherwise you may get thrown off by local effects.
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CRV9 at 01:53 AM on 30 June 2012Madness over sea level rise in North Carolina
I'm honestly and ernestly asking this. Because I really don't know. I don't even have an associate degree. Don't they behave like bodies of water? What I mean is that like high or low pressure systems in the atmosphere move as bodies of air. They do mix when they meet but it only happens at the front? Most time one system moves others away. So depending on how far away or other factors, the expansion of water in the middle of the ocean wouldn't neccesary or imediately affect coast line? And why does the east coast have higher sea levels than other areas then? Don't all oceans connected? -
angusmac at 01:39 AM on 30 June 2012Simply Wrong: Jan-Erik Solheim on Hansen 1988
Dana@67 The baseline used was 1958 and from that baseline Scenario B has a 1958-2019 temperature trend of 0.0209°C/decade. The sensitivity is based on your simplified methodology in the SkS spreadsheet in which you derived Scenario D by multiplying Scenario B by the factor (0.9*3/4.2). This equates to temperature sensitivity of 0.9*3 = 2.7 °C, compared with 4.2°C for the original Scenario B. I know that LOTI is the GISS temperature index but an 'equivalent sensitivity' for LOTI can be derived from the SkS methodology above by using LOTI's 1958-2011 trend of 0.0118°C/decade, which equates to an 'equivalent sensitivity' ≈ 4.2*0.0118/0.0209 ≈ 2.4°C Furthermore, there seems to be a difference in semantics when you state that, "we're not talking about errors, we're talking about the amount by which the model sensitivity was too high." There are several definitions of error. The most commonly used is a "mistake" but the scientific definition is usually, "the difference between a measured value and the theoretically correct value." I suggest that the "40% too high" value to which you refer is the scientific definition of an error. Finally, regarding “policy makers”, I think your opinion may be a bit too sceptical. In the field of engineering in which I work, there are a whole raft of sustainability regulations and specifications related to climate change (many of which are sensible). These would not be in place without the influence of Hansen and similar people -
vrooomie at 01:27 AM on 30 June 2012Michaels and Cato Unwittingly Accept the Climate Threat
"This is how science works. EPA is not required to re-prove the existence of the atom every time it approaches a scientific question." *Priceless*...;) I'm deep into investigating how mitigation is way less expensive than BAU, for that is the deniers' latest meme. Thanks dana, for the excellent article. -
michael sweet at 22:43 PM on 29 June 2012Mercury rising: Greater L.A. to heat up an average 4 to 5 degrees by mid-century
Pierre: It is good that we agree that UHI has not caused significant temperature increases in the past. You claim future temperature might be affected by UHI when it has been shown that past temperature have not. While it is always possible for the future to be different than the past, it does not seem to me to be a legitimate question. AGW fake skeptics repeatedly ask the same questions to be constantly addressed again and again. This is not how science works. If we show something was true in the past you need to provide data to support your contention that in the future those properties will change. The model described in the OP is sufficiently detailed that it is unreasonable to suggest that experienced scientists did not consider UHI without providing data to support such an extraordinary claim. You have not provided any data to support your position, merely hand waving. Hand waving claims can be dismissed with a hand wave. This discussion has deteriorated. If you do not provide data to support your claims I will no longer respond. -
ralbin at 22:40 PM on 29 June 2012Michaels and Cato Unwittingly Accept the Climate Threat
"To the conservatives' credit, cap and trade systems have worked remarkably well" This is actually less clear than the general popular impression. The usual example is acid rain control in North America. Roger Backhouse, a highly competent intellectual historian specializing in history of economics, has a good discussion of the acid rain program in his recent book, The Puzzle of Modern Economics. While Backhouse guardedly endorses the success of the cap-and-trade model in this case, he is careful to specify that evaluating cap-and-trade success for acid rain control is confounded by other important developments, notably the fact that abatement technology proved considerably less expensive than projected. David Hounshell, a specialist in history of technology, has pointed out that pollution regulatory regimes have consistently prompted the development of improved and less expensive abatement technologies. Its plausible that any regulation of acid rain, cap and trade or not, would have led to better abatement technologies. Its worth remembering that the only modest success in GHG mitigation to date is banning CFCs, a piece of outright regulation. -
Dikran Marsupial at 19:25 PM on 29 June 2012Simply Wrong: Jan-Erik Solheim on Hansen 1988
Thanks for the comment Tom, it doesn't unduly surprise me that the observations are skirting the 2-sigma range of Hansens model, given that they are not that far from the 2-sigma range of the CMIP-3 models as well. It would be a useful exercise to perform multiple runs of Hansens model as you say and generate the error bars properly. Rules of thumb are useful, but shouldn't be relied upon of the statistical analysis has already been done. Of course this is the difference between science and "skepticism" a scientist is searching for the truth and will carry on until they get to it, even if they find out their hypothesis was wrong, whereas a "skeptic" will stop as soon as they have found a reason not to accept an argument that doesn't suit their position. -
BBD at 18:25 PM on 29 June 2012Madness over sea level rise in North Carolina
As Rob Painting reminds us @ 12, thermal expansion is but the usher. Wait 'till the WAIS really gets going. It's only just starting. -
Pierre-Normand at 13:54 PM on 29 June 2012Mercury rising: Greater L.A. to heat up an average 4 to 5 degrees by mid-century
Michael, the part that you put in bold is a point that have explicitly granted twice. To suggest that this point didn't seem in dispute was the very reason I replied to you in the first place. Daisym was inquiring about model predictions, not past reconstructions from station measurements. This is a different topic. You need not lash at someone just because the "UHI" acronym figures in her post. You now ask me for a reference that shows the models are finely gridded enough to discern between industrial and residential areas. That's in the OP. "The study overlaid this entire area with a grid of squares 1.2 miles across and provided unique temperature predictions for each square. This is in contrast to global climate models, which normally use grids 60 to 120 miles across." This seems finely gridded enough to make Daisym's question at least relevant. -
Tom Curtis at 09:34 AM on 29 June 2012Simply Wrong: Jan-Erik Solheim on Hansen 1988
Dikran Marsupial @71, Hansen et al 88 provides us two pieces of information that allow us to approximate the range of unforced variability. Specifically, Hansen determines (section 5.1) that the unforced variability over the twentieth century has a standard deviation of approx 0.13 C. Over the short period since 1988, therefore, the scenario A, B and C predictions should be treated of having a 2 sigma (95%) error range of at least +/- 0.26 C. Further,as best as I can determine from Hansen et al (1984), the climate sensitivity of the model is 4.2 C +/-20%. Combining these two sources of error, and on the assumption that the Scenario B projection represents a multi-run mean, then actual temperatures are skirting the edge of the lower 2 sigma range, and will falsify scenario B if they do not rise shortly. Of course, the assumption that the scenario B projection represents a multi-run mean is false. It is an individual run, and may well be up to 0.26 C above a genuine multi-run mean. Where the fake "skeptics" serious in their skepticism, they would use the program for the model used in Hansen 88 with actual forcings and perform 100 or so runs to determine the multi-run mean. They would then compare that with the actual temperature record, or ideally with a record adjusted for elements not including in a multi-run mean (ENSO, volcanic forcing, solar cycle) and determine if the model was any good. The most likely result of such an effort would be the discovery that climate sensivity is less than 4.2 C, but greater than 1.8 C. Of course, rather than employ the scientific method in their analysis, they consistently misrepresent the actual forcings and ignore extraneous factors effecting temperature to create an illusion of falsification; then insist the falsification of a 1983 model with a climate sensitivity of 4.2 C also falsifies 2006 models with a climate sensitivity of 2.7 C (Giss model E series). -
Riccardo at 08:10 AM on 29 June 2012North Carolina Lawmakers Turning a Blind Eye to Sea Level Reality?
A century ago the so-called "Indiana Pi Bill" story ended "when one senator observed that the General Assembly lacked the power to define mathematical truth". I was not aware that things have changed. -
Dikran Marsupial at 07:31 AM on 29 June 2012Simply Wrong: Jan-Erik Solheim on Hansen 1988
angusmac, O.K., so can you describe the statistical methodology that justifies the the +/-30% range? The reason that I ask, is that the statistics have already been done. The spread of the model runs is our best estimate of the range of unforced variability, in which case even if the model were perfect, there is no good reason to expect the observations to lie any closer than that. Hansen didn't have the computing facilities to do this, but there is little reason to suppose that if he had the uncertainty range would be less than that of more modern models. Thus if you want to insist on some higher level of accuracy, it seems reasonable to ask exactly what is the basis for such a requirement. -
kampmannpeine at 06:55 AM on 29 June 2012North Carolina Lawmakers Turning a Blind Eye to Sea Level Reality?
one thing is missing there: the Evangelicans ! -
John Bruno at 06:53 AM on 29 June 2012Madness over sea level rise in North Carolina
OK, maybe I was being overly optimistic. According to the Daily Tar Heel (UNC school newspaper): Rep. Pat McElraft, R-Carteret, who is the primary sponsor of the bill the original study was flawed because it only used one model and ignores historical data, even though she said the panel was asked to incorporate multiple models and historical data. She said the bill will commission another study into the matter. “We needed to direct the state agencies not to use the 39 inches that the science panel came up with, because we don’t feel that was good science,” she said. McElraft, who said she doesn’t believe climate change is caused by humans, said it was difficult to use the study to predict climate change. “In 1974, the alarmists were talking about the ice age coming in,” she said. “What has happened, has the ice age come in?” -
Rob Painting at 05:58 AM on 29 June 2012Madness over sea level rise in North Carolina
Sphaerica - Steve Case is correct - sea level has increased in a near-linear manner over the last two decades. But as discussed in this post David Evans: All at Sea about Ocean Warming and Sea Level Rise), that's not greatly surprising considering the trend in aerosols and ENSO. However, El Nino seems to be forming, and we're likely to see a return to an El Nino-dominant period sometime soon. Sea level is therefore likely to spike upwards for a time. Indeed, globally-averaged sea level has already risen over 10mm in the last year:
The longer-term problem is that ice mass loss from the Greenland & Antarctic Ice Sheets is accelerating and this, coupled with the Earth's current energy imbalance (that dictates further warming is effectively dialed in), suggests an acceleration of sea level rise is likely at some point in the future. This will be influenced by how the trend in human-made and natural volcanic reflective aerosols develop too.
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John Hartz at 04:21 AM on 29 June 2012Simply Wrong: Jan-Erik Solheim on Hansen 1988
Angusmac: A quick scan of the term Scientific Method posted in Wikepedia suggests that your definition of "scientific methodology" falls way short of the commonly accepted understanding of the term by the scientific community. -
KR at 03:38 AM on 29 June 2012Simply Wrong: Jan-Erik Solheim on Hansen 1988
angusmac - I believe Dikran was asking what methodology you used in establishing a +/-30% range. What statistics, data, and period? Or did you use the "eyecrometer"? I will note that the tone of your post, while technically within the comments policy, is quite insulting overall. -
angusmac at 02:53 AM on 29 June 2012Simply Wrong: Jan-Erik Solheim on Hansen 1988
Dikran Marsupial @65 The scientific methodology is statistics and reliability. (-Snip-)Moderator Response: Inflammatory comments snipped. Please try and keep the discussion civil. -
michael sweet at 02:41 AM on 29 June 2012Mercury rising: Greater L.A. to heat up an average 4 to 5 degrees by mid-century
Pierre; I re-read the abstract of the paper that I linked above. You seem to have misinterpreted their conclusion. Your quote above is incomplete and gives an incorrect summary of the abstract. It should read: "Contrary to generally accepted wisdom, no statistically significant impact of urbanization could be found in annual temperatures. It is postulated that this is due to micro- and local-scale impacts dominating over the mesoscale urban heat island. Industrial sections of towns may well be significantly warmer than rural sites, but urban meteorological observations are more likely to be made within park cool islands than industrial regions." My emphasis. I have provided data that shows UHI is not important to the OP. Please provide data to support your claim that UHI is important. As I said above "In general, UHI is a non effect that deniers cite to confuse people. AGW fake skeptics often raise tone questions of this type to suggest data issues that do not exist. What is your point?" -
michael sweet at 02:31 AM on 29 June 2012Mercury rising: Greater L.A. to heat up an average 4 to 5 degrees by mid-century
Pierre: Please provide a reference that shows the models are finely enough gridded to discern between industrial and residential areas. It seems to me that if I misinterpreted Daisym's question it is up to her to clarify the misunderstanding. You might be the one misinterpreting her question. While UHI is a real effect, it is very small. Numerous studies, including BEST, showed that it makes no difference to temperature trends whether you correct for UHI or not. Since the authors and reviewers of the paper are professionals it should be presumed that they considered any important effects unless data is provided to show that they did not. No data has been provided to show anything important was left out. Asking a question does not show that the authors made a mistake. If you think it is a good question, read the paper and see what they say. -
chuckbot at 01:59 AM on 29 June 2012Madness over sea level rise in North Carolina
sigh. First NC legislated straight marriage as the only acceptable relationship. Now they're legislating straight lines as the only acceptable graph. We're not all loonies here, I promise :/ -
Bob Lacatena at 23:57 PM on 28 June 2012Madness over sea level rise in North Carolina
Steve, You may find this helpful in correcting your misunderstanding. -
Bob Lacatena at 23:54 PM on 28 June 2012Madness over sea level rise in North Carolina
Steve Case, 8, When you say "not according to the satellite record" do you mean "not if you ignore the data that doesn't show what you'd like it to show, while further putting undue weight on short-term trends that are heavily influenced by short-term factors?" -
vrooomie at 23:39 PM on 28 June 2012North Carolina Lawmakers Turning a Blind Eye to Sea Level Reality?
TC@1: I apologize for the all-caps; I simply forgot to revert to another method of emphasis. As for the 'imputations of dishonesty,' I'll let stand the original wording and actions of the legislators in question. -
Steve Case at 23:38 PM on 28 June 2012Madness over sea level rise in North Carolina
"Globally, sea level rise is known to be accelerating..." Not according to the satellite record. -
vrooomie at 23:35 PM on 28 June 2012Madness over sea level rise in North Carolina
Just as an aside: The King Canute story is so ofttimes mistold, it's now risen to a level of mythical urban...myth! Canute was not trying to control the sea: he was trying to show the limits of kingly power. His sitting by the sea (perhaps apocryphal) was to show his minions that a king's powers had limits. Back to our regularly-scheduled science...;) -
Jim Eager at 23:17 PM on 28 June 2012Madness over sea level rise in North Carolina
heijdensejan, no that should be 20th century. The increase to 3.2mm/yr took place in the 1990s. -
Pierre-Normand at 22:36 PM on 28 June 2012Madness over sea level rise in North Carolina
The argument is flawed but makes some kind of sense. If surface water only warmed away from the coasts, then, indeed, the immediate effect would be the same as if that water expanded through freezing. It wouldn't tend to displace water underneath. But the flaw in the reasoning, of course, is that this water wouldn't remain there. Unlike floating ice, some of the raised volume of warmer water would tend to flow towards the coasts. If one delicately poured warm water on top of cold water in in the middle of a container, it wouldn't remain in the middle to form a stable reversed-bowl-shaped liquid surface. -
chriskoz at 21:44 PM on 28 June 2012North Carolina Lawmakers Turning a Blind Eye to Sea Level Reality?
I cannot help but remind these images of Irene in NC. Each mm of SLR increases the probability of destructions on the pictures. Just wait and see the insurance/reinsurance rates. If the legislators keep denying the obvious the crash (when re won't be able to cover it and Obama won't be able to dig in fed coffer) will be even bigger and more spectacular. NC coast infrastructure in a bubble waiting to burst. You don't need to understand climate science to put big money on it if you're a panter.Moderator Response: [Riccardo - link fixed] -
Paul D at 21:26 PM on 28 June 2012Madness over sea level rise in North Carolina
ahhh. Just noticed Rob Paintings reference to Canute in a similar post. Plagarism wasn't intended :-) -
Paul D at 21:23 PM on 28 June 2012Madness over sea level rise in North Carolina
The stories of King Cnut trying to control nature and the sea are probably a myth. He probably wasn't mad. Yet now we have an American state government trying stop the sea by doing a 'big brother' and re-writing history. Yep, in comparison Cnut had all his marbles. -
Glenn Tamblyn at 20:15 PM on 28 June 2012Madness over sea level rise in North Carolina
"Moreover, although thermal expansion does cause satellite-measured mid-ocean sea level to rise, it does not necessarily cause coastal sea level to rise. If deep-ocean water were to expand, it would, indeed, affect coastal sea levels. But when surface water warms, it rises in place, like ice, and its displacement is unaffected, so it does not affect coastal sea levels." WTF! I want some of their Kool-Aid! -
heijdensejan at 18:41 PM on 28 June 2012Madness over sea level rise in North Carolina
29th century? -
scaddenp at 14:19 PM on 28 June 2012Hansen and Sato Estimate Climate Sensitivity from Earth's History
Just one other note - a global average temperature isnt really that complex a thing. For any planet rotating fast enough to equilibrate temperatures, then surface temp is function of incoming solar radiation, planetary albedo, geothermal heatflux (insignificant on earth) and atmospheric composition (GHG). eg a calculator or here for some of the equations. The tricky bit is predicting how atmosphere composition and albedo will change if alter something. -
scaddenp at 13:52 PM on 28 June 2012Hansen and Sato Estimate Climate Sensitivity from Earth's History
curiousd - my understanding of the calculated temperature in Fig 3, is that depends on only 3 inputs - CH4, CO2 and sealevel. However, they are are not directly "fitted" to a curve. N2O is also important but not preserved, but because it strongly correlated with CO2 and CH4, its contribution is added in as a 1.12 multiplier on the forcing strength of CO2 + CH4. This no. being consistent with radiative codes. Albedo is sum of a great many changes - ice shelves, ice sheets, changing land/ocean ratios, changing vegetation, but the earlier work (2007 from CLIMAP 1981) showed that it could estimated by sealevel alone as a "good enough" approximation. Clouds are problematic but clouds have both positive and negative effects and net forcing for current time is thought to be close to zero. There is no proxy for clouds but this data is at least consistent with assumption that net contribution has been very small compared to GHG and albedo. Note the cause of the ice-age cycle is solar variation but solar forcing isnt included. The global solar forcing is very small but the regional distribution means that it is expressed an albedo forcing. Note also, that the climate sensitivity that produces the good fit is dependent on 4.5C temp difference between LGM and Holocene. Use a different temp diff and you get a different sensitivity as discussed in detail in the paper. -
Pierre-Normand at 12:37 PM on 28 June 2012Mercury rising: Greater L.A. to heat up an average 4 to 5 degrees by mid-century
Michael, I only pointed out that your reference 'denies that...' in the sense of 'affirming the falsity of...' in its conclusion. That was an innocent use of the word "denies". The paper concludes that the UHI doesn't introduces significant bias in temperatures reconstructions. But that conclusion doesn't speak at all to Daisym's question. Daisym only seemed to be inquiring if the UHI effect (that your reference acknowledges to be real and significant albeit not a source of measurement bias) is accounted for in the models predictions. This is a good question, it seems to me, since the models are so finely gridded so as to geographically discriminate some industrial from residential or rural areas. -
curiousd at 11:20 AM on 28 June 2012Hansen and Sato Estimate Climate Sensitivity from Earth's History
To someone who needs to explain/impress both smart but non technical students, and to physics phds who are nearly ignorant of climate change, that figure 3 above could be a "game changer". The agreement between experiment and theory is rather like one sees in many areas of condensed matter physics. For instance it is like one obtains in fitting extended x-ray fine structure (EXAFS)data to a structural model. But one needs to know the number of adjustable parameters. When I first read the article, I thought that since they were able to figure out the albedos, CO2 concentrations, and temperatures that that figure represents only one adjustable parameter, the short term (transient) CO2 climate sensitivity. Now I am not so sure because of the mention of the N2O and CH4. In EXAFS theory a big deal is made about the number of independent data points and the number of adjustable parameters. If it is only one (or two ) (or three) parameters that are being fitted here the result is spectacular. (Nobel Prize Hanson?) Any help on what you think the number of adjustable parameters is? BTW...he gets rid of the "clouds" uncertainty by this empiricle method, right? Another "Lindzen ism" dealt with? -
Chemware at 10:32 AM on 28 June 2012North Carolina Lawmakers Turning a Blind Eye to Sea Level Reality?
@ newcrusader To quote Bohr's retort to Einstein ... Stop telling God what to do. -
Chris G at 08:47 AM on 28 June 2012North Carolina Lawmakers Turning a Blind Eye to Sea Level Reality?
John (#3), It would be nice if they read it and acknowledged the reality of what scientific studies indicate, but it is not as though there were not plenty of other evidence that they have chosen to pretend doesn't exist. I don't think a little more would make any difference to them. -
newcrusader at 08:21 AM on 28 June 2012North Carolina Lawmakers Turning a Blind Eye to Sea Level Reality?
The legislature in NC denies global warming because God will not permit it. -
John Hartz at 05:53 AM on 28 June 2012North Carolina Lawmakers Turning a Blind Eye to Sea Level Reality?
Every member of the North Carolina State Legislature should be required to read: Hot spot of accelerated sea-level rise on the Atlantic coast of North America This peer-reviewed paper by Asbury H. Sallenger Jr, Kara S. Doran & Peter A. Howd published online June 24 by the journal Nature Climate Change. -
shoyemore at 04:09 AM on 28 June 2012North Carolina Lawmakers Turning a Blind Eye to Sea Level Reality?
The legislators of North Carolina should remember that the original King Canute (or Knut) lived during the Medieval Warm Period, no doubt enjoying wine from the many English vineyards which flourished back then. But even he had to show humility in the face of sea level rise, which respects neither King nor commoner. -
vrooomie at 02:32 AM on 28 June 2012North Carolina Lawmakers Turning a Blind Eye to Sea Level Reality?
I remember thinking, while first reading about this mind-numbingly stupid story, that I thought (imputation of dishonesty snipped) I take some solace in that, eventually, the sheer stupidity of this will become apparent to all but the dimmest of lights, and that science, once again, shall become valued and heeded. That they NC lege "torpedoed" the amendment may be a sign of rational thought triumping over those who would deny science, at any and all costs. With the help of all here, and all who endeavor to hold out against the forces of dark, and by"common' scientists like me speaking to those we can, we might just win the day. *Maybe*. "No matter how cynical you get, it's impossible to keep up." -Lily Tomlin, "The Search for Signs Of Intelligent Life In The Universe."Moderator Response: TC: Please refrain from suggestions of dishonesty and all caps, both of which violate the comments policy. -
shoyemore at 02:18 AM on 28 June 2012Adding wind power saves CO2
Paul D :)) -
dana1981 at 01:59 AM on 28 June 2012Simply Wrong: Jan-Erik Solheim on Hansen 1988
angusmac @66:Dana, you seem to be focused on "Hansen would have been right"
No, you're still not understanding. It's not about whether or not Hansen was right (no model is ever "right"), it's about what we can learn from comparing his projections to real world observations.Your 2.7°C sensitivity Scenario D is running ≈ 12% above LOTI (1984-2012), which has a sensitivity ≈ 2.4°C.
LOTI is the land-ocean temperature index (observational data, not a model) so I have no idea where you get this 2.4°C sensitivity figure from.Furthermore, Hansen's temperature projections were used by policy makers
What does that even mean? First of all, the USA has not implemented any climate policy. Second, if they had implemented policy, it would not be dependent on the precise sensitivity of Hansen's 1988 model.Additionally, the errors in Hansen's scenarios are higher than the 40% stated by you.
First we're not talking about errors, we're talking about the amount by which the model sensitivity was too high. And my figure is correct. You're probably using the wrong baseline in addition to not accounting for the Scenario B forcing being 16% too high. -
dana1981 at 01:51 AM on 28 June 2012Gleckler et al Confirm the Human Fingerprint in Global Ocean Warming
Thanks Albatross. I think this is a very useful paper in responding to the misconception of a large model-data OHC discrepancy that we've previously discussed. As the authors note, most other studies have only used one or two models, whereas their study uses several from the CMIP3 ensemble for a much more thorough survey. The difference between the models incorporating volcanic effects and those excluding them is also very interesting and useful to know. And Domingues' feedback was very helpful. There's another post in the pipeline for which I got feedback from Trenberth and Dessler. It's nice that these prominent climate scientists are willing to take the time to help us make sure we get the science right in our blog posts. -
Albatross at 01:12 AM on 28 June 2012Gleckler et al Confirm the Human Fingerprint in Global Ocean Warming
Excellent summary Dana. It was very kind of Dr. Domingues to provide SkS with valuable feedback, especially given how busy scientists are preparing papers for the deadline for the fifth IPCC assessment report. This is a devastating paper for the fake skeptics and those who deny the theory of AGW. [So expect push back and obfuscation from the usual suspects] For example, "Gleckler et al. on the other hand examine several different CMIP3 models, and do not identify a notable model-data discrepancy" So much for the much touted claim on blogs by fake skeptics that the models grossly overestimate the warming in the climate system Also, Domingues et al. show that "...when we continue to consider longer and longer trends, the human-induced signal becomes more and more evident (stronger relative to the noise)." This is of course the very reason why fake skeptics and those who enable advocates of delaying taking meaningful action to reduce GHG emissions (e.g., Dr. Pielke Snr.) insist on focussing on unrealistically short periods when examining the climate system, even when strongly advised to the contrary. The paper also indicates why the same fake skeptics can continually cherry-pick their start and end points to try and disappear the warming and accumulation of heat in the climate system. All this compelling evidence right before people's eyes, yet some continue to deny the reality and deny the science at everyone's peril. -
angusmac at 00:13 AM on 28 June 2012Simply Wrong: Jan-Erik Solheim on Hansen 1988
Dana@53, I read all of your post, including the final section, and I comment as follows. "What this tells us is that real-world climate sensitivity is right around 3°C." Dana, you seem to be focused on "Hansen would have been right" - if only he had used 3°C. Nevertheless, this sensitivity value appears to be a little high. Your 2.7°C sensitivity Scenario D is running ≈ 12% above LOTI (1984-2012), which has a sensitivity ≈ 2.4°C. Furthermore, Hansen's temperature projections were used by policy makers. He gave them temperature estimates that were significantly too high. Consequently, he was wrong. Additionally, the errors in Hansen's scenarios are higher than the 40% stated by you. When compared with LOTI (0.52°C in May 2012), the errors are as follows: Scenario A 1.18°C (126%) Scenario B 1.07°C (105%) Scenario D 0.67°C (28%)
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