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Comments 84551 to 84600:

  1. The Critical Decade - Part 1: The Science
    Apart from the point raised by boba 10960, I have only one minor quibble with this informative article, which states … “humans are causing dangerous global warming”. I would argue that the past tense would be more accurate …”humans have caused” or … “humans continue causing dangerous global warming”. Humans have now emitted sufficient greenhouse gases to initiate methane emissions from onshore permafrost and offshore clathrates, both entering the atmosphere as CH4. Those emissions were 4 and 8 tonnes per annum in 2005 and neither the melting of ice or the magnitude of their release is going to decrease. Both are predicted to increase –Shakhova et al (2010). Hansen et al (2011) warn that as a result of anthropogenic emissions and these slow emissions, polar temperature can be expected to more rapidly reduce sea ice and increase Arctic amplification. This is predicted to result in decadal doubling of ice loss from the Greenland Ice Sheet, initiating its eventual collapse and raising sea level by 5m before 2100. Hansen goes further. He expresses the view that as ocean warming continues it will result in them releasing CO2 and those releases increasing in magnitude such that the net ability of oceans to absorb CO2 reduces. It should be noted that this outcome is expected to occur during a period when human emission of greenhouse gases can be expected to increase. It seems to me that these developments provide sufficient pointers to the fact that humans have been causing dangerous global warming for well over a decade and are continuing to do so, irrespective of consequences which are dire indeed!
  2. Antarctica is gaining ice
    Following up on posts by Camburn here, the most recent paper on Antarctic Ice Mass Balance I can find is Rignot et al 2011, published in March of this year. It finds:
    "In 2006, the Greenland and Antarctic ice sheets experienced a combined mass loss of 475 ± 158 Gt/yr, equivalent to 1.3 ± 0.4 mm/yr sea level rise. Notably, the acceleration in ice sheet loss over the last 18 years was 21.9 ± 1 Gt/yr2 for Greenland and 14.5 ± 2 Gt/yr2 for Antarctica, for a combined total of 36.3 ± 2 Gt/yr2. This acceleration is 3 times larger than for mountain glaciers and ice caps (12 ± 6 Gt/yr2). If this trend continues, ice sheets will be the dominant contributor to sea level rise in the 21st century."
    It does not distinguish between ice lost from West or East Antarctica. The most recent article I found that does distinguish between them is a review article by Cazenave and Llovel (2010) which finds the majority of the ice loss on the West Antarctic Ice Sheet, with East Antarctica being found to be "in near balance". The most recent GRACE data I can find is from Chen et al (2009) which finds:
    "In agreement with an independent earlier assessment, we estimate a total loss of 190 +/-77 Gt yr^1, with 132 +/-26 Gt yr^1 coming from West Antarctica. However, in contrast with previous GRACE estimates, our data suggest that East Antarctica is losing mass, mostly in coastal regions, at a rate of 57 +/-52 Gt yr^1, apparently caused by increased ice loss since the year 2006."
    This evidence clearly supports the view that ice loss from West Antarctica significantly excedes that from East Antarctica, but is ambiguous about whether East Antarctica is loosing ice. On balance, it is probably loosing ice, but the GRACE experiment may well be overestimating the rate of loss.
  3. gallopingcamel at 14:06 PM on 29 May 2011
    Can we trust climate models?
    scaddenp @49, You should be aware that AR1 included a paleo temperature reconstruction that Hubert Lang would have approved. The TAR showed an entirely different paleo reconstruction based on MBH 1998. In this analysis the MWP disappeared and the LIA was just a gentle dip in temperature. It was really easy for the climate models to create hindcasts that agreed with the TAR reconstruction as the temperature from 1000 A.D. to 1850 was shown as a gently falling straight line. What I am trying to tell you is that the TAR and subsequent IPCC publications demand that you ignore history. [snip] History Rools!
    Moderator Response: [Dikran Marsupial] Moderator trolling snipped.
  4. The Critical Decade - Part 1: The Science
    More on Black Carbon; http://ehp03.niehs.nih.gov/article/fetchArticle.action?articleURI=info%3Adoi%2F10.1289%2Fehp.119-a172 As I have stated before, I am very keen on seeing particulate pollution reduced as the health benifits are without question.
  5. The Critical Decade - Part 1: The Science
    Tom Curtis @27: I must be getting either older or tired. Here is a link to the effects of black carbon etc on Arctic temps: It was Shindell, not Lindell. That is the reason both of us had such a hard time finding it. http://www.nasa.gov/topics/earth/features/warming_aerosols.html
  6. The Critical Decade - Part 1: The Science
    Tom Curtis @ 27: It was published in science, the paper by Schmidt/Lindell. I will see if I can find a link. As far as East Antarctica, where over 90% of the worlds ice is, there is no conclusive evidence that the ice in increasing, nor is there evidence that the ice is decreasing. It appears to be static at this time.
    Response:

    [DB] Please take further discussion of this to the Antarctica Is Gaining Ice thread.

  7. Of Averages and Anomalies - Part 1A. A Primer on how to measure surface temperature change
    Glenn, will you be addressing in a later part why station numbers might change? For example, in the GHCN the Toronto Canada temperature station has one of the longest records of both max & min temperatures in the world so it’s a good one for certain analyses. But it had Station ID CA006158350 from 1840 to mid 2003 and then temperature reporting ceased (though precipitation records continue until now). There’s a gap of a few months and then from 2004 to present Toronto temperatures are reported as Station ID CA006158355 instead. The latitude, longitude & altitude are identical for both Station IDs. Major instrument changes maybe? This complicates getting the full data set.
  8. The Critical Decade - Part 1: The Science
    Camburn, the paper you are looking for is Chen 2009. There is some small ice loss in East Antarctica but as everyone points out, the is net ice loss for all of Antarctica and it appears to be accelerating.
  9. The Critical Decade - Part 1: The Science
    Ken Lambert: here's an SkS post from a year and a half ago that suggests that the East Antarctic Icesheet is now losing mass. I'd say, though, that more data is needed over a longer timeframe to definitively answer that question. I'd suggest the "Antarctica is gaining ice" thread is the appropriate place to discuss this, though.
  10. The Critical Decade - Part 1: The Science
    Ken Lambert @26, yes cherry picking because you continue to insist or reporting only the recent short term trend when the duration of that trend is no where near long enough to determine if it is a genuine change in the long term trend, or merely a short term fluctuation. Labelling of the various denier cherry picks and gish gallops as cherry picks and gish gallops may have become uncomfortably frequent, but the solution lies entirely in denier hands. Stop producing them and we will no longer have to call you on it.
  11. The Critical Decade - Part 1: The Science
    Camburn @18, can you provide a clearer reference to Schmidt Lindall et al. I can find no relevant paper from them in a search of google scholar. What I did find was a paper by Screen and Simmonds (2010), who write:
    "Here we show that the Arctic warming is strongest at the surface during most of the year and is primarily consistent with reductions in sea ice cover. Changes in cloud cover, in contrast, have not contributed strongly to recent warming. Increases in atmospheric water vapour content, partly in response to reduced sea ice cover, may have enhanced warming in the lower part of the atmosphere during summer and early autumn. We conclude that diminishing sea ice has had a leading role in recent Arctic temperature amplification. The findings reinforce suggestions that strong positive ice–temperature feedbacks have emerged in the Arctic, increasing the chances of further rapid warming and sea ice loss, and will probably affect polar ecosystems, ice-sheet mass balance and human activities in the Arctic."
    (My emphasis) Black carbon is, it appears, hardly worth a mention in the Arctic. That is not surprising given the large distance to the primary sources (India, China) and the low residence time in the atmosphere of black carbon.
  12. The Critical Decade - Part 1: The Science
    "[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." I was responding to the "main points" of the report in your original post. So that is a cherry pick? Labelling uncomfortable facts 'gish gallops' and 'cherry picks' is becoming a devalued currency on this site.
    Response:

    [dana1981] Pulling 10 years out of the 30 year period being evaluated is pretty much the definition of a cherrypick.

  13. The Critical Decade - Part 1: The Science
    Southwing #15 #20 I pointed out that the report highlighted the Greenland and West Antarctic ice loss without mentioning the majority of the planet's ice in East Antarctica. An AGW cherry pick par excellence I would have thought. Last time I looked, East Antarctica was neutral or slightly increasing ice mass, and the overall Antarctic was a slight loss (Camburn might correct me on this if I am not right up to date). This overall loss equates to a 0.12mm contribution to the global SLR which is officially 3.1mm/year, but Jason 1 and 2 show 1.7-2.0 mm/year. Global tide gauges are showing even less than this. Overall global ice melt is very small contribution to the net global energy imbalance even when Hansen's smaller imbalance is taken into account.
  14. The Critical Decade - Part 1: The Science
    Anyone who really wants to know the facts about crossings of the Northwest passage (as Tom Curtis has noted), can easily discover the truth and will notice the difference between previous trips and those that are currently undertaken : In 1944, St. Roch returned to Vancouver via the more northerly route of the Northwest Passage, making her run in 86 days. The RCMP ship was the 104-foot, schooner-rigged St. Roch, which was specially built for resisting the crushing pressures of sea ice that would destroy her. Although the return trip to Vancouver presented certain navigational difficulties, these were far less life-threatening than the ones encountered on the more southerly route. It took only 86 days to sail from Halifax to Vancouver. The route taken, through Parry Channel, and then Prince of Wales Strait at its western end, will most certainly be the one first used by commercial shipping as global warming accelerates the thinning of the Arctic ice cover. 1st commercial ship sails through Northwest Passage. Rayes, who was on the vessel during its trip through the Northwest Passage, said the company informed the coast guard, which put an icebreaker on standby. "They were ready to be there for us if we called them, but I didn't see one cube of ice," he said. "They were informed about our presence [and] they were ready to give us the support needed. However, since there was no ice whatsoever, the service was not needed, we didn't call for it." In 2009 sea ice conditions were such that at least nine small vessels and two cruise ships completed the transit of the Northwest Passage. On 28 August 2010, Bear Grylls and a team of 5 were the first rigid inflatable boat (RIB) to complete the North West Passage [in 11 days].
  15. Can we trust climate models?
    Re Kevin C #51. Glad to see we get the same results. I used the RadF.txt file from the same page as your NetF.txt file. It has the radiative forcing components broken out separately. The sum of forcings differs from your file by 0.0001 W/m2 here and there from roundoff errors. No real effect. It is interesting to compare this dataset of forcings with the ones in Hansen et al 2011 white paper. The ones used for the 1800-2003 AR4 simulations flatlined the aerosols at the 1990 levels. The Hansen whitepaper sets the sum of forcings from aerosols to be exactly -0.5 time the sum of wmGHG forcings. I'm still looking for a copy of the latest forcings from GISS, but lacking that, I'll just estimate them from the Hansen paper. ------------------------ One other thing to consider in your model is the effect of doing annual steps rather than continuous integration. A reasonable argument can be made for replacing your R(t) = 0.0434*exp(-t/1.493) + 0.0215*exp(-t/24.8) with R(t) = 0.06066*exp([-t+0.5]/1.493) + 0.02194*exp(-[t+0.5]/24.8) Where the time constant is long compared to the step (as in the 24.8 year exponential decay) the annual steps are reasonable approximation of exponential decay. But for the 1.493 year time constant, having the first coefficient of R(t) be a 1.0 isn't as good of an approximation as having the 1st coefficient be the value of R(t) at the midpoint of the year. Another way of looking at this 2 box model is that the forcings are passed through an exponential filter. The sum of the 1st 250 coefficients is 25.3023 for the 24.8 year filter, and 2.0484 for the 1.493 filter. For a continuous exponential filter, the area under the weighting curve is simply the tau. The discrete version is only 2% high for the long filter, but is 37% high for the short one. Shifting R(t) over 1/2 year makes the sum of coefficients 24.7973 and 1.46545 -- essentially equal to tau for the long filter and about 2% low for the fast one. Replacing your 0.0434 weighting factor for the short filter with 0.06066 compensates for the change in sum of filter coefficients. I haven't done the calculations, but I'm pretty sure that moving from annual to monthly calculations won't change the optimization as much if you start with R(t+0.5)as the estimate for annual response. The sum of coefficients makes for an easy test on the equilibrium sensitivity: 0.0434*2.0484 + 0.0215*25.3023 = 0.6329 C step response from 1 watt m-2. So if CO2 doubling is 3.7W m-2, the doubling sensitivity will simply be 0.6329*3.7= 2.3 C/doubling of CO2. ------------------------------------------------ Next on my agenda is to look at the correlations between various models and global anomaly time series, and then see what happens when different forcing sets are used with my emulations of the various AOGCMs. Some prelim data is that my ultra simple model using just one exponential, approximated by 6 coefficient terms, has R of 0.99 or R-squared of 0.98 with the GISS-E model. GISS-E model to GISS observed Global-Average-Temperature-Anomalies is only 0.76 r-squared. Your parameters do better than GISS with r-squared of 0.82. If the GISS observed GATA was filtered a bit, I'm pretty sure your model will come out even better in comparison to GISS-E AOGCM. IPCC suggested a 5 point filter with coefficents of 1-3-4-3-1 to reduce the year-to-year and El Nino timeframe variation. It still leaves most of the decadal variation.
  16. The 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.
  17. The 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.
  18. Glenn Tamblyn at 08:45 AM on 29 May 2011
    Of 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.
  19. The 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!
  20. Can 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.
  21. Can 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.
  22. Can 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.
  23. The 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.
  24. The 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?
  25. The 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.
  26. Can 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?
  27. The 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.
  28. The Critical Decade - Part 1: The Science
    Camburn what is your explanation for an ice free arctic in late summer between now and 2030?
  29. The 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.
  30. Of 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.
  31. Leland Palmer at 04:29 AM on 29 May 2011
    Wakening 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.
  32. Monthly 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.
  33. The 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.
  34. Climate 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.
  35. Can 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.
  36. Climate 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!

  37. Can 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.
  38. Can 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.

  39. gallopingcamel at 01:04 AM on 29 May 2011
    Can 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.

  40. Humlum 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.
  41. The 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.
  42. The Critical Decade - Part 1: The Science
    Ken: What you have written are the current observations.
  43. LazyTeenager at 23:33 PM on 28 May 2011
    Even 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
  44. The 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.

  45. LazyTeenager at 23:11 PM on 28 May 2011
    Even 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.
  46. Hyperactive Hydrologist at 22:48 PM on 28 May 2011
    The 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.
  47. How climate change deniers led me to set up Skeptical Science website
    John, did you eventually manage to convince your father-in-law?
  48. The 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.

  49. Can 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.
  50. The 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 ?

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