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newcrusader at 09:00 AM on 29 May 2011The Critical Decade - Part 1: The Science
Tom Curtis unless there is photographic evidence showing that ice melt comes close to the years 2006-2010, and the minim of 2007, The highly esteemed RCMP report as eyewitnesses to an ice free passage can be taken for what it is worth. Sorry. I guess I like to see absolute empirical evidence. In 1944 there was obviously no Satellites to preserve such an event. It seems improbable in 1944 when C02 levels where still below 300ppm. Nonetheless some kind of anomaly cannot be totally dismissed- misunderstood or misinterpreted perhaps. -
Tom Curtis at 08:45 AM on 29 May 2011The Critical Decade - Part 1: The Science
newscrusader @19, doubting the Royal Canadian Mounted Police when they claim to have transited the North West Passage is unwarranted. On the other hand, Camburn's suggestions that ice conditions now match those of 1944 when in recent years when transits have now become common place, even by cruise liners, and two yachts circumnavigated the globe through the north east passage and north west passage in a single season in 2010 are ridiculous. -
Glenn Tamblyn at 08:45 AM on 29 May 2011Of Averages and Anomalies - Part 1A. A Primer on how to measure surface temperature change
Gary Thanks. This is the first in a series of 4 posts on this over the next week or so. -
jfreed at 08:30 AM on 29 May 2011The Stockholm Memorandum
a. is there a group of Nobel Laureates, in any field, that hold a position in essence contrary to the one held by this group? b. is this group going to influence policy anywhere? c. I agree that so-called climate skepticism is a luxury we can ill afford. But, it is just so damn much fun! -
Kevin C at 07:42 AM on 29 May 2011Can we trust climate models?
Oh, I found it. I posted the right equation but the wrong plot. Yours is spot on. Mine was an earlier version where I fixed the exponential periods to 1 and 50. Sorry for wasting your time. The old version is more stable, as you might expect, but still needs 60 years of data. I need to track down whether the instability is overfitting or the general problem with exponentials. -
Kevin C at 07:20 AM on 29 May 2011Can we trust climate models?
I confirm the first 8 numbers of the step response match yours. (I actually rounded before posting, so I went back and redid my calc with the rounded values. I get an indistinguishable plot to my original.) Your understanding of c is correct (I didn't match the means, I just threw this into the minimizer as another refineable parameter.) For the total temp rise on step forcing I get 0.62925 after 123 years - I didn't got to convergence, I'm guessing you did? (Not that I trust the long tail of the response function.) Could we be using different forcing data? I picked up the NetF.txt file from http://data.giss.nasa.gov/modelforce/. Here's a few sample values: 1880 .0000, 1900 -.0569, 1920 -.0652, 1940 .2839, 1960 .3988, 1980 1.0099, 2000 1.8661 Otherwise, I confess I'm a bit baffled here, but I'll carry on looking at it. I'm getting interesting (non-)results on the cross validation front too. Results are only stable if the data covers at least 1920-2000 or 1900-1990. Truncating before 1990 means you lose the short response completely. I expected to need a volcano to get the short response, but I'm surprised Agung doesn't do it. Fitting exponentials is always tricky, and I'm using a simplex optimizer, which might be the issue. -
scaddenp at 07:06 AM on 29 May 2011Can we trust climate models?
"Writing off the TV presentation without even bothering to watch it." I dont say that TV cant get it right, but mostly doesnt so I dont bother. It did if it is the source of these statements: " the end of the MWP came suddenly and the recovery from the LIA came rapidly too." MCA varied in extent in timing around the world. See figure here and here for SH but especially the Mann et al 2009 paper. "Climatologists are still trying to identify the smoking gun or guns. " "A major reason for doubting the predictions based on GCMs is their inability to model these abrupt climate change events that occurred during historic times." If you believe these, then can I suggest you read the Paleoclimate chapter of AR4 and the papers that would say otherwise. Particularly note of figure this figure showing many model reconstructions of those periods. "Incidentally, you could not classify that History Channel program as "Denialist". " Wouldn't have clue but would doubt it. However, the director will be trying to make a program that people pay money to watch and I doubt very much his skills at surveying science compared to the IPCC panel. -
SouthWing at 06:46 AM on 29 May 2011The Critical Decade - Part 1: The Science
@Camburn; Will we have a rebound in ice in years to come? My gut instinct, which is worth nothing scientific says yes. My dear Camburn, gastroenterologists have determined that the human gut contains no rational thoughts. What it is full of is pretty well known. -
SouthWing at 06:40 AM on 29 May 2011The Critical Decade - Part 1: The Science
@Camburn: Southwing: Show me where East Antarctica is loosing ice mass. And I mean a paper that the loss is out of the error bars. Why should I have to? My challenge to Lambert--and now you--is to explain why you are ignoring the mass loss of the total Antarctic ice sheet. You are cherry picking, just as he is. Indeed, why are you pretending not to notice that the ice mass of the entire planet is shrinking? -
newcrusader at 06:21 AM on 29 May 2011The Critical Decade - Part 1: The Science
Camburn sorry to disagree with you- but the 1944 'story' has never been scientifically verified. I also disagree with you that there will not be an ice free arctic by 2030- by that time C02 will have reached 425-430ppm- and global temperatures will have risen another 1 degree C. What you are saying here, basically flies against what Hansen and Sato have said (which has been very accurate) The IPCC said ice late summer would occur around '2065' and a sea level rise under a foot. (this has recently been changed- to the higher level- 3 feet--- Since the huge melt in 2007, 2008, and last year- and the thin ice now in the arctic 1 & 2 years, and disappearing thick ice, your predictions are totally different then what NASA, the NOAA and the NSIDC predict. -
Charlie A at 06:12 AM on 29 May 2011Can we trust climate models?
@Kevin C, #33. Am I correct in assuming that a step forcing of 1 watt into your model (without the extra offset term) results in a final equilbrium temp increase of 0.6329 degrees? With the first few years being 0.0649, 0.1078, 0.1390, 0.1638, 0.1851, 0.2042, 0.2219, and 0.2385 ? I did in a spreadsheet the formula you posted, and came up with similar, but slightly different results. I overlayed the two results in the graph below. Blue is your plot, red line is mine. Note how my plot rounds off the corners a bit more, particularly in the earliest part of the plot. My plot is without an offset added. You said "c is -0.0764641223, which is a constant which fits the equilibrium temperature." I assume that you really meant to say that c was to match the mean of the GISS observed anomaly temp series and the mean of your model anomalies. Correct?
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Camburn at 06:00 AM on 29 May 2011The Critical Decade - Part 1: The Science
newcrusader: I am not convinced that the Arctic will be ice free in late summer by 2030. I do think this year will have a very low min...my prediction is approx 3.5 using Jaxa data. The particulates coming from China are playing a very heavy toll on sea ice. The last paper that I have read concerning the Arctic was by Schmidt/Lindall etal where they showed that soot etc was more responsable for the decline than co2. The last time that Arctic Ice was flowing out as it is now was in 1944, the year that the St Roch sailed the deepwater Northwest Passage. You can buy the book from the museum in Vancouver that has Capt Larson's log in it where he describes ice conditions on that journey. Will we have a rebound in ice in years to come? My gut instinct, which is worth nothing scientific says yes. Time will tell if my gut is right. I think that pollution in China will become such a social issue that they will take known steps to curb it. I think they are very foolish right now to be using their country as a dumping ground when the teck is well proven with scrubbers etc to virtually eliminate particulate pollution from burning coal. -
newcrusader at 05:21 AM on 29 May 2011The Critical Decade - Part 1: The Science
Camburn what is your explanation for an ice free arctic in late summer between now and 2030? -
Camburn at 05:12 AM on 29 May 2011The Critical Decade - Part 1: The Science
Southwing: Show me where East Antarctica is loosing ice mass. And I mean a paper that the loss is out of the error bars. Thank you. -
GaryB at 04:33 AM on 29 May 2011Of Averages and Anomalies - Part 1A. A Primer on how to measure surface temperature change
Thank you for this. The attempt to educate the local rightwing radio talk show host about how measurements are adjusted has been an upward battle. This will help me clarify my own thoughts about the process which should help me when speaking to local denialists. -
Leland Palmer at 04:29 AM on 29 May 2011Wakening the Kraken
I've been doing some "back of the envelope" math on the results from Isaksen- Strong Atmospheric Chemistry Feedback to Climate Warming from Arctic Methane Emissions. What my Excel spreadsheet seems to indicate is that this paper outlines a mechanism which could plausibly tip the earth into true runaway global heating, leading to indefinite warming which leads to a Venus like atmosphere for the earth. Fitting a curve to the model results, and projecting that curve into the future, it appears that additional forcing of 70 W/m2, roughly the threshold needed to totally destabilize the climate, would occur somewhere between 350 and 2500 ppm of methane, depending on whether a polynomial or a linear curve fit is used. Is this scientifically valid? No, this projects the results far beyond the data points predicted by the model. But I believe it probable that for the first time the authors of the paper have discovered a mechanism which could truly totally destabilize the climate, and lead to a true global heating runaway greenhouse effect. There does appear to be enough methane in the hydrates to do this, although estimates of total hydrate vary by at least an order of magnitude. There are several times as much carbon in the hydrates as is in the atmosphere at the current time, and atmospheric lifetime of methane is projected to increase greatly due to decline of tropospheric hydroxyl radical. Some experts project an 85% dissociation with bottom ocean temperature increases of 5 degrees C. At 13 times current methane concentrations, the authors project a relatively huge radiative forcing of 5.4 W/m2. The project about 1.1 W/m2 from methane with it's current atmospheric lifetime of about 9 years. They project 2.1 W/m2 due to increase of atmospheric lifetime of methane, 1.1 W/m2 due to ozone increase, 0.9 W/m2 due to stratospheric water vapor, and 0.2 W/m2 due to increased CO2. Adding the direct and indirect effects together, they get 5.4 W/m2 for methane concentrations of about 23 ppm. Fitting a curve to their results, and projecting it into the future, the additional 70 W/m2 necessary according to some experts to totally destabilize the climate is reached at methane concentrations of a few hundred to a couple of thousand ppm of methane. I hope that other readers of Skeptical Science, and perhaps the owners of this site will look at this new atmospheric chemistry result, do some similar math, and let us know the results. I'll keep working on it, myself, too, and posting the results. I hope that the authors of the model will query their model about the results of methane concentrations of hundreds of ppm, even if those results are not scientifically valid, to give the rest of us some indication of the probabilities of a true runaway destabilization of the climate. -
Albatross at 03:01 AM on 29 May 2011Monthly Climate Summary: April 2011
Eric, I get the feeling that you are trying to create faux debate here. I'm not entirely sure what you are trying to claim? What is your thesis? That the above papers are all wrong in their findings that the frequency of severe storms are likely to increase in certain regions down the road with AGW? Updraft strength is a good proxy for storm severity, and maximum updraft velocity ~ (2*CAPE)^0.5, where CAPE = convective available potential energy. Note this value overestimates max. updraft velocity because it neglects the impacts of water loading on the updraft speed. Regardless, increasing CAPE via increased low-level moisture with increase max. updraft velocity and potential for severe storm activity. I addressed the importance of vertical wind shear in another post. Yes, synoptic scale forcing can be and is important, but do not underestimate the importance of mesoscale boundaries (e.g., outflow boundaries from existing or old storms) in triggering and organizing storms and for providing low-level vorticity that can be ingested into the updraft to facilitate updraft rotation and possibly tornadogenesis. Regarding dynamics, this has already been acknowledged and addressed Eric. Trapp et al. (2009) state that: "The rate of increase varies with geographical region and inherently depends on (i) low-level water vapor availability and transport, and (ii) the frequency of midlatitude synoptic-scale cyclones during the warm season." But even with that caveat they find an increase in severe storm environments. Del Genio et al. (2007) state: "For the central-eastern United States, stronger updrafts combined with weaker wind shear suggest little change in severe storm occurrence with warming, but the most severe storms occur more often." Trapp et al. (2010) have proposed some downscaling procedures to address some of the issue identified in previous work, and there initial findings suggest that such a methodology holds much promise. So I'm afraid that your arguments are moot. If you insist on taking this further, maybe it is time to take this to another thread. Warning though, I'm busy most of this coming week, so I might only be posting short, non-technical posts at SkS. -
SouthWing at 02:47 AM on 29 May 2011The Critical Decade - Part 1: The Science
@Ken Lambert "4) Recent observations confirm net loss of ice from the Greenland and West Antarctic ice sheets; the extent of Arctic sea ice cover continues on a long-term downward trend. Most land-based glaciers and ice caps are in retreat." With 90% of the planet's ice in Antarctica, should not the vast majority in East Antarctica be mentioned? Why would you not mention that the Antarctic ice sheet as a whole is losing mass? Rhetorical question, of course. You ignore the big picture because anomaly hunting and cherry picking is what deniers do. -
Albatross at 02:36 AM on 29 May 2011Climate Change Denial book now available!
The commentator @28 seems to forget that Tea Partiers and their ilk are on the record (it is on YouTube) stating that they go online to 'game the system" and give bad reviews to books that do not fit their ideology. They even give seminars on how to do it. So expect more negative book reviews at locations like Amazon, and would be surprised if the person offering the negative review has even read the book in its entirety. -
Albatross at 02:33 AM on 29 May 2011Can we trust climate models?
Tom @41 and KR @46, I thought I was missing something--t hat is what happens when you speed read and/or try and do too many things at once. Thanks for pointing that out and correcting me. -
tallbloke at 01:58 AM on 29 May 2011Climate Change Denial book now available!
The first (and only, so far) customer review on the Amazon site is not very encouraging. "This book is an extremely one sided view of the climate change controversy. It trots out conspiracy theories as if they are fact. It attacks the integrity of scientists whose research does not support the theory of AGW and explicitly says they are paid off by "Big Oil" without offering proof. As far as examining what creates "denialism", this book could have balanced that by examing what creates alarmism. The book is fairly well-written, but really fails to make a point."Response:[dana1981] Thanks for pointing that out. I added my review (having read most of the book). Definitely worth 5 stars!
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KR at 01:34 AM on 29 May 2011Can we trust climate models?
Albatross - I have to agree with Tom Curtis; it's a compounding 10%. That came directly from his statements of a logarithmic effect of increasing CO2, and his CO2 doubling sensitivity is stated at 2.4 C. But definitely - it's a fantastic paper, especially for the time. -
Tom Curtis at 01:19 AM on 29 May 2011Can we trust climate models?
gallopingcamel @44: From wikipedia: "According to the Los Angeles Times, The Pirate Bay is "one of the world's largest facilitators of illegal downloading" and "the most visible member of a burgeoning international anti-copyright or pro-piracy movement"." So you wish to use Skeptical Science to incite people to illegal activity? I highly recomend, based on that, that your post be deleted and serious consideration be given to revocation of your posting rights.Response:[DB] I have snipped the relevant portions from GC's comment. He may not have been aware of the status of the linked website.
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gallopingcamel at 01:04 AM on 29 May 2011Can we trust climate models?
scaddenp @30 & 31, You disappoint me. Writing off the TV presentation without even bothering to watch it. You ask "What is the relevance?". If you had watched the program you would understand the relevance; the end of the MWP came suddenly and the recovery from the LIA came rapidly too. Climatologists ( -Snip- ) are still trying to identify the smoking gun or guns. A major reason for doubting the predictions based on GCMs is their inability to model these abrupt climate change events that occurred during historic times. At least there is widespread agreement that the coldest period of the LIA occurred during the Maunder minimum leading to the hypothesis that solar activity might be a factor. ( -SNIP- ) Incidentally, you could not classify that History Channel program as "Denialist". It mentions some of the major hypotheses advanced by climatologists without getting judgmental.Response:[DB] I watched the program (I have it on disc as well). There is ongoing discussion over the THC, but most agree (as stated in the program) that the GW currently underweigh is sufficient to overwhelm the cooling forcings now in play. Implications of dishonesty and link to website of illicit activity snipped.
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WheelsOC at 00:51 AM on 29 May 2011Humlum is at it again
"The AGW theory does not pretend that natural factors cannot affect the global climate." It's incredibly frustrating when I run into people arguing energetically that "climate changed without us before!" in order to rebuff the idea that we're a major driver of climate change now. What is so hard to understand about this? It boggles the mind. -
otter17 at 00:16 AM on 29 May 2011The Climate Show Episode 13: James Hansen and The Critical Decade
This was a great level-headed discussion on the politics with Dr. Hansen. I didn't watch it all, but this is obviously an awesome show. I ought to make some more time to watch the rest. If only this type of stuff displaced the right-wing hot air on the USA airwaves. -
Camburn at 23:46 PM on 28 May 2011The Critical Decade - Part 1: The Science
Ken: What you have written are the current observations. -
LazyTeenager at 23:33 PM on 28 May 2011Even Princeton Makes Mistakes
Ubrew12 says --------- Happer has every right to publish his opinion on this important topic. And we have every right to treat his opinion as uninformed as might be expected of a spin-polarization physicist. --------- Thats quite true. But we have every right to point out that there is an inconsitency between Happer representing his views as those developed by an esteemed scientist and the views themselves which breach the standards expected of an esteemed scientist. Namely: 1. Lack of objectivity 2. Partisan support of poorly supported debating points while ignoring well known counter arguments. 3. Not considering the evidence 4. Misrepresenting other peoples views 5. Repeating lies made up to discredit climate scientists so that he can justify ignoring the evidence collected by others. 6. Logically fallacious arguments. E.g. Stawman -
Ken Lambert at 23:31 PM on 28 May 2011The Critical Decade - Part 1: The Science
Why don't we take a hard look at the latest report from Messrs Flannery, Steffan and Karoly et al - three vocal advocates for the AGW position with a lot of professional skin in the game: "1) The average air temperature at the Earth’s surface continues on an upward trajectory at a rate of 0.17°C per decade over the past three decades." Note that they don't mention the last decade, where the warming has flattened by all measures. "2) The temperature of the upper 700 meters of the ocean continues to increase, with most of the excess heat generated by the growing energy imbalance at the Earth’s surface stored in this compartment of the system." "A growing energy imbalance at the surface stored in this compartment of the system." A carefully compartmentalized description indeed. What about the flattening OHC for the last 7-8 years in the top 0-700m and the overall TOA imbalance? "3) The alkalinity of the ocean is decreasing steadily as a result of acidification by anthropogenic CO2 emissions." It seems that the latest argument is that heat is transported to the 700-2000m depths by a yet undescribed short term deep mixing mechanism - but CO2 does not travel with it, otherwise the pH effect would be infinitesimal. "4) Recent observations confirm net loss of ice from the Greenland and West Antarctic ice sheets; the extent of Arctic sea ice cover continues on a long-term downward trend. Most land-based glaciers and ice caps are in retreat." With 90% of the planet's ice in Antarctica, should not the vast majority in East Antarctica be mentioned? "5) Sea-level has risen at a higher rate over the past two decades, consistent with ocean warming and an increasing contribution from the large polar ice sheets." Last time I looked, Jason 1 and 2 were giving a 1.7-2.0mm/year SLR globally. If the ice melt is an increasing contribution then steric rise is a decreasing contribution, which fits with a flattening OHC increase. By far the greater energy is absorbed in a 1mm steric rise than a 1mm ice melt rise. "6) The biosphere is responding in a consistent way to a warming Earth, with observed changes in gene pools, species ranges, timing of biological patterns and ecosystem dynamics." Evidence of warming is not evidence of AGW. "7) The report notes that the past decade (2001-2010) was the hottest on record, 0.46°C above the 1961-1990 average." If warming has flattened and approached a plateau, this decade will be 'Hotter' than the last decade and the last decade 'Hotter' than the decade before that. Even if warming has stopped, this decade will remain the 'hottest on record'. And as a general comment, Jim Hansen (a major IPCC AR4 author and seminal AGW theorist) in his latest effort "Earth's Energy Imbalance and Inplications" suggests that the 2005-10 planetary imbalance has reduced from a pre-2005 estimate of 0.9W/sq.m to 0.59W/sq.m. His reasons are a prolonged Solar Minimum, largely underestimated Aerosol cooling, and a delayed rebound effect from Mt Pinitubo aerosols. While his reasons are debatable, he has abandoned the 'its there but be can't measure it' argument for maintaining the 0.9W/sq.m imbalance which in theory should be increasing since 2005 due to greater CO2GHG concentrations in the atmosphere and a growing induced positive WV and ice albedo feedback.Response:[dana1981] I don't have the time to respond to this entire Gish Gallop, but you're cherrypicking. The last 30 years includes the last 10 years.
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LazyTeenager at 23:11 PM on 28 May 2011Even Princeton Makes Mistakes
Dr. Jay Cadbury, phd. at 06:47 AM on 27 May, 2011 I think Happer is pretty qualified to speak on climate science considering he has studied the greenhouse effect intimately and the radiative chemistry of the physics aspect. --------- The phrasing of this tells me that Dr J does not have a physical sciences background. A bit of extrapolation says he does not have a PHD or is a friend of Happers. -
Hyperactive Hydrologist at 22:48 PM on 28 May 2011The Critical Decade - Part 1: The Science
Excellent review of the current Science. You could probably find similar documents produced by most developed nations especially those within the EU. -
skagedal at 22:22 PM on 28 May 2011How climate change deniers led me to set up Skeptical Science website
John, did you eventually manage to convince your father-in-law? -
Ed Davies at 20:10 PM on 28 May 2011The Critical Decade - Part 1: The Science
Is the sentence starting "It's worth noting that while Hansen et al. find paleoclimate evidence..." about eventual near 6 °C sensitivity actually summarizing something in the report or is it additional commentary? I couldn't find it in the report looking just at the most obvious page from the context and searching for "6 °" or "6°". If it is an aside I think it's potentially misleading not to label it as such much more clearly.Response:[dana1981] That's my commentary (and it's true). Everything in quotes or bullets is from the report. Everything else is from me.
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Tom Curtis at 19:22 PM on 28 May 2011Can we trust climate models?
trunkmonkey @42, based on calculations by Schmidt et al 2010, removing all of the Earth's atmosphere's CO2 would reduce radiative forcing by 31 Watts/m^2, globally averaged. That represents a loss of energy of the order of 5*10^23 Joules per annum ignoring feedbacks. For comparison, according to the NODC the top 700 meters of the worlds oceans have gained around 15*10^22 Joules over the last 55 years, or less than a third of that which would be lost in a year with the complete removal of CO2. At that rate it would take just 12 years to lower a volume of water equal to the top 300 meters of the oceans surface from 14 degrees to 0 degrees. Of course, with feedbacks, the heat would escape at a faster rate initially, but then at a reducing rate while the planet cools. Perhaps you are being confused because you are not taking into account the logarithmic decline of forcing with increasing CO2 concentration. To obtain a reversed forcing of similar magnitude by increasing CO2 concentrations, we would need to instantly increase CO2 levels to around 90 thousand ppm. I assure you that if you modelled that scenario, temperature increases would be suitably rapid to satisfy you. Alternatively, if you merely halved the CO2 content instantly, cooling would closely match the rates of warming obtained for doubling CO2 levels. -
okatiniko at 18:30 PM on 28 May 2011The Critical Decade - Part 1: The Science
sorry a sentence is incomplete : wouldn't be desirable to quantify the confidence level at which we can exclude that the current warming rate (approx 0.5 °C in 30 years) has occured in the past ? -
okatiniko at 18:10 PM on 28 May 2011The Critical Decade - Part 1: The Science
the statement "Neither multi-decadal or century-scale patterns of natural variability, such as the Medieval Warm Period, nor shorter term patterns of variability, such as ENSO (El Niño-Southern Oscillation) or the North Atlantic Oscillation, can explain the globally coherent warming trend observed since the middle of the 20th century." seems to be rather firmly established. However the content of the report doesn't really confirm this strength. The only detailed argument presented in the report is "The Medieval Climate Anomaly (MCA), a somewhat warmer period from about 1000 to about 1250 or 1300 AD, has sometimes been invoked to infer that the contemporary warming is nothing unusual in the Holocene and that it is thus likely due to natural variability. However, the bulk of evidence for the MCA comes from the northern hemisphere, which makes it difficult to determine whether the MCA was truly global in scale. Furthermore, a spatially explicit synthesis of all available temperature reconstructions around the globe suggests that the MCA was highly heterogeneous, even in the northern hemisphere, with globally averaged warming much below that observed over the last century (Mann et al. 2009; Figure 9). Thus, the MCA is different in magnitude and extent from contemporary warming (Figure 10)." I don't really see how strong this argument is. IPCC has defined a scale of "likelihood" with confidence intervals : wouldn't be desirable to quantify the confidence level at which we can exclude that the current warming rate (approx 0.5 °C in 30 years) ? is it at 90 % ? at 99 % ? what is the accuracy of globally averaged warming 1000 years ago ? -
Paul D at 17:36 PM on 28 May 2011The Stockholm Memorandum
Impressive that Murray Gell-Mann was a participant. -
trunkmonkey at 16:30 PM on 28 May 2011Can we trust climate models?
I'm still stuck on the Hansen 2010 thing about pulling all the CO2 out of the GISS and having GMAT drop 6 degrees C in ONE YEAR, and dropping to snowball earth level in a decade. I suspect we all agree that the glaciers to support this could not possibly form this fast. And the thermal inertia of the Oceans? If CO2 is only in the models as radiative forcing, how is it that it's removal (unforcing?)is 7 times more powerful than it's forcing? -
alan_marshall at 15:59 PM on 28 May 2011The Critical Decade - Part 1: The Science
"There is a very large body of internally consistent observations, experiments, analyses, and physical theory". Indeed, and it is just this internal consistency that is lacking from the sceptic's arguments! -
Eric (skeptic) at 14:42 PM on 28 May 2011Monthly Climate Summary: April 2011
I will look forward to reading that. Crook is interesting, he analyzes and simulates two cases: 1) "This convergence line developed as a cold air surge, forced by previous convection over the Rocky Mountains, propagated eastward, and encountered the low-level southeasterlies over the Plains." 2) Around 1550 LT, several convective storms developed as a low level wind surge moved up from the south and strengthened the convergence line." But then he had difficulty initiating convection in his simulations. He blames measurement and initial conditions to deflect the blame from where it properly lies, the fidelity, scale and even chaotic physics of his model. He seems quite willing to downplay the horizontal forcing that he acknowledged and focus only on vertical forcing perhaps triggered with a few well placed horizontal temperature anomalies. His simulation results are not very convincing. -
Tom Curtis at 14:14 PM on 28 May 2011Can we trust climate models?
Albatross @40, I assumed that it is a compounding 10%, not a fixed value. On that basis, 1.1^7.28 =~= 2, so the climate sensitivity he uses is 7.28*0.3 =~= 2.2 degrees C per doubling, which is quite close to the 2.4 figure he discusses in the last complete paragraph of the first column on page 461. -
Albatross at 13:41 PM on 28 May 2011Can we trust climate models?
Tom @38, I may be reading/interpreting this incorrectly, but the footnote to Broecker's Table 1 says: "Assumes a 0.3 C global temperature increase for each 10% rise in the atmospheric CO2 content". Wow, scientists ahead of their time. -
scaddenp at 13:04 PM on 28 May 2011Can we trust climate models?
The Manabe and Wetherald paper is here -
Albatross at 13:01 PM on 28 May 2011Monthly Climate Summary: April 2011
Eric @30, Sorry, while I agree with some of what you are saying. A careful review of the papers I provided at 27 and 29 and the literature on severe storms (something that I happen to be very familiar with) is not consistent with what you are saying in your post. I am busy now, but will post on this as soon as possible. -
Eric (skeptic) at 12:12 PM on 28 May 2011Monthly Climate Summary: April 2011
My citeseer link above seems to be incomplete (uses cookies maybe?) Try this instead http://acmg.seas.harvard.edu/publications/leibensperger2008.pdf (see fig 4 and note that the surface cyclones are quite often reflected from the upper lows and should have similar trends. -
GFW at 11:56 AM on 28 May 2011Even Princeton Makes Mistakes
I got my PhD from Princeton ... and in fact it was while I was there that Happer returned from Washington. (Aside: Lucky for the younger prof also in atomic spin-polarized physics, he'd pressed for early tenure review and got it shortly before Happer's return - but that's not part of this story.) Anyway, back then I didn't know much about climate or AGW (I was naturally focused on my area of research). But I distinctly recall Happer grousing about his dismissal, and I asked him what the issue had been. He didn't say anything about climate or AGW, and instead implied it was a disagreement over whether high voltage power lines cause illnesses. In retrospect, that's fascinating, because if the true issue was AGW, then this dissembling was because speaking to another physicist (even if only a grad student) he felt safer using another controversy where the "alarmist" viewpoint probably was alarmist so he could sound reasonable and principled. -
Eric (skeptic) at 11:47 AM on 28 May 2011Monthly Climate Summary: April 2011
Albatross, those models for the end of this century (lots of unknowns) are mildly interesting but even their elevated CAPE don't hold a candle to the dynamics in the weather models of today. For example, here's the discussion before the Oklahoma outbreak this past Monday http://www.wxforum.net/index.php?topic=11669.0 The dynamic factors they talk about have nothing whatsoever to do with "a 1 g/kg in low-level atmospheric moisture has significant implication for thunderstorms", but in this case the opposite: "unlike the last 2 days when limited areal coverage precluded more than a slight risk...we may have the opposite problem today with storms becoming too numerous and updraft competition limiting the chances of any one storm to maintain dominance" The primary dynamic factor in this particular discussion was the "very potent negative-tilt upper trough" There are a number of interesting and somewhat conflicting trends in that type of activity. This paper http://stratus.ssec.wisc.edu/papers/key-chan_cyclones_grl1999.pdf shows an increase in upper low frequency in spring in midlatitudes worldwide, but it varies by location as shown here http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.143.290&rep=rep1&type=pdf with a small downward trend in surface cyclone frequency over the N central and NE US from 1980 to 2006 An trend resulting from the increase in low level moisture that you mentioned is most likely to show up as an increase in rainfall intensity : http://journals.ametsoc.org/doi/abs/10.1175/2010JHM1229.1 rather than violent weather which has other more important factors behind it. -
Tom Curtis at 11:06 AM on 28 May 2011Can we trust climate models?
Albatross @36, I'm either looking at the wrong article or I simply cannot find that table. Broecker's Climactic Change: Are we on the brink of pronounced global warming?" (1975) discusses work by Wanabe and Wetherald, and by Rasool and Scneider, and concludes that climate sensitivity for doubling CO2 lies between 2 and 4 degrees, but he employs a value of just under 2.4 degrees per doubling (0.32 per 10%, compared to the 0.3 per 10% he used). Using this value, and making no allowance for aerosols or (so far as I can see) thermal inertia he calculates a temperature increase relative to approximately 1850 of 1.1 degrees C. HadCRUT3v gives a 0.9, which very close considering the limitations of his methods. As the prediction was made while global temperatures where falling, it puts the lie to one of Happer's claims, but that is the subject of another thread. -
scaddenp at 10:22 AM on 28 May 2011Can we trust climate models?
Manabe's model is a marvel of what could be done at the time but the man it was primitive. Its worth thinking back to what else was going on at time. First ice core was bring drilled. d18 thermometry on benthic forams was really setting Milankovich in concrete. Four years later I would be doing my first finite element modelling on rock deformation - card stack at 2am in morning on a Burroughs main frame. The substantial lesson I think though is that the basics of climate arent that complicated. It puts a lie to the idea that climate modelling is somehow curve fitting. -
Albatross at 09:37 AM on 28 May 2011Can we trust climate models?
Scaddenp @35, I just had a quick read of Broecker's 1975 paper. Absolutely incredible how well his projections are working out, not only for CO2 but the global SAT as well. But I should not be surprised, as you say, pure physics, and that solid foundation has been understood for a very long time. I'd like to see a comparison between Broecker, Hansen and Lindzen. Broecker's seminal work really does need highlighting more. And look at the 3 C warming for doubling CO2 that is shown in one of Broecker's Tables.....amazing. Did Manabe's model runs from 1991/1992 produce an estimate of global SAT? I can't recall seeing that in the paper, but I have not looked at it in a while.
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