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Comments 104951 to 105000:

  1. Keep those PJs on: a La Niña cannot erase decades of warming
    Thanks Adelady, although you lost me on the music analogy. - jb
  2. Keep those PJs on: a La Niña cannot erase decades of warming
    scaddenp at 14:01 PM: "More interesting is that La Nina temperatures are now warmer than El Nino temperatures of similar magnitudes in previous decades." Great point, I totally agree. And perhaps why we are seeing coral bleaching during a La Nina. (although there are alternative explanations)
  3. Keep those PJs on: a La Niña cannot erase decades of warming
    This is such a sad reflection of the US weather mans abilities. Just pathetic.
  4. Ice-Free Arctic
    Re: Camburn (34)
    "They took the EM and put it on Polar five and flew grids over the Arctic in 2009. The results were much thicker ice than had been anticipated."
     Actually, thin, “rotten” ice can electromagnetically masquerade as thick, multiyear sea ice, as was found by Professor David Barber aboard the research vessel (NGCC) Amundsen in 2009. So, an Arctic ice expert with decades of researching the ice takes a ship physically through the areas of thickest multiyear ice in the areas covered by the AWI aerial overflights finds ice, though thick, that is rotten and essentially no barrier to late-season navigation. Nor the type of ice to build a recovery around. This also has been covered here, where they include this link (which references the Barber video). The Yooper
  5. Climate change from 40 million years ago shows climate sensitivity to CO2
    #46 CBDunkerson, Thanks for your response, but from what I have been able to find, Mars currently has more CO2 in its atmopshere than Earth does. Oxygen and Nitrogen are IR inert so if Mars had a thick atmosphere these gases wouldn't help it. "Q) Why is Mars so cold? A) Mars is cold because it is much farther from the Sun than Earth. Because of this, Mars receives about 2.5 times less solar energy than Earth." From Solar Energy reaching Mars. If the Sun was significantly colder eaons ago the amount of radiation reaching Mars would be even less. How would that support liquid water? Not sure what information source you are using for you statement: "Thus, astronomers have been able to study the life cycle of stars in considerable depth. The idea that stars get hotter as they grow older is not, as you seem to imply, some vague hypothesis based on nebulous computer models... it is observed reality." My source makes the claim it is a model..."Stellar evolution is not studied by observing the life of a single star, as most stellar changes occur too slowly to be detected, even over many centuries. Instead, astrophysicists come to understand how stars evolve by observing numerous stars at the various points in their life, and by simulating stellar structure with computer models." Source of above quote. A model can imply a generalization of patterns and perform fairly well, it cannot determine a specific case. I am sure astronomers will see various exceptions to predictions and rules.
  6. The Inconvenient Skeptic at 14:19 PM on 8 November 2010
    Climate change from 40 million years ago shows climate sensitivity to CO2
    First off the comment Antarctic being ice free because CO2 levels being above 600 ppm is misleading as when Antarctica started to freeze 34 million years ago CO2 levels were 760ppm. The opening of the Drake passage is likely the key factor that caused the initiation of ice sheets in Antarctica. Cause and Effect are very confused as a cooling Antarctic would have reduced global CO2 levels as the oceans would have absorbed it from the atmosphere. This leads to what is always the biggest problem with paleo records with CO2 and temperature. Changes in ocean temperature CAUSE a change in solubility that leads to the observed EFFECT of changing CO2 levels. Determining the climate sensitivity from a CO2 change that is the EFFECT of changing ocean temperatures is meaningless. For example... The LGM to Holocene experienced a 80 ppm change in CO2 levels. The polar regions experienced an ~12 °C change in temperature. The change in solubility of CO2 in water for only a few meters deep of the polar oceans is more than enough to explain the change in CO2. No forcing required. Did the warming cause the CO2 levels to change? Yes. Much like this case. The polar oceans warmed, even if they were ice free, any water below 18 °C experiences significant changes in CO2 solubility with temperature. How can the climate sensitivity be determined from the FEEDBACK of warming oceans releasing CO2? It can't. Much like the cooling Antarctic region would have reduced global CO2 levels. Saying that lower CO2 levels CAUSED the cooling is not accurate. It is fully accurate to say that cooling oceans CAUSE lower CO2 levels. Much like warming oceans CAUSE higher CO2 levels. Fortunately the solubility of water is not open to debate. John Kehr The Inconvenient Skeptic
  7. Keep those PJs on: a La Niña cannot erase decades of warming
    Typo alert - mistakenly not mistakingly. I do get fed up with this stuff about 'there was record cold somewhere'. Climate change is not like a key change in a piece of piano music - you don't just shift everything up a tone or a third so that everything is the same just with each note played a bit further up the keyboard.
  8. Stephen Baines at 14:15 PM on 8 November 2010
    Keep those PJs on: a La Niña cannot erase decades of warming
    The thing that scares me is that we may be due for a strong El Nino (1998-, 1982-, 1972- like) after this La Nina is over. There seems to be a 10-15 year interval between the big events, and if that coincides with increasing solar inputs...well, it'll get something hot pretty quick. Not looking forward to that.
  9. Keep those PJs on: a La Niña cannot erase decades of warming
    I am deeply unimpressed by the claim that "the 2009-10 El Nino IS the second strongest since 1998". If you look over a slightly longer time frame (say, going back to 1950) there have been at least five El Ninos that were stronger than 2009-2010: 1972-1973 1982-1983 1987-1988 1991-1992 1997-1998 That aside, Camburn should think hard about this comment by scaddenp: More interesting is that La Nina temperatures are now warmer than El Nino temperatures of similar magnitudes in previous decades. Yes, exactly. What is now considered a "cold" year (say, 2008) would have been a record warm year any time before 1998.
  10. Keep those PJs on: a La Niña cannot erase decades of warming
    Camburn writes: Also, the GISS temp data has become the outlier of all data sets. The 1200K radius is not effective at extrapolating air temperatures. Evidence, please. The GISSTEMP trend (1979-present) is virtually indistinguishable from those in other temperature reconstructions. When I wrote this, it was actually identical to most other land/ocean temperature reconstructions (to within the nearest 0.01 C/decade). It's true that they all do bounce up and down from month to month, and right now GISSTEMP happens to show a microscopically larger trend than the other major temperature reconstructions: NOAA NCDC: +0.163 C/decade NASA GISS: +0.166 C/decade UEA CRU: +0.158 C/decade RSS LT: +0.164 C/decade UAH LT: +0.140 C/decade Insofar as there is any "outlier", it's obviously UAH. In any case, the 1200km smoothing radius used by GISS is just fine. Again, see here for a debunking of many myths about the surface temperature record.
  11. Keep those PJs on: a La Niña cannot erase decades of warming
    Second strongest since 1998 is not same as "second strongest". 1983 and 1973 were also stronger. But since these are wiggles on a trend, I still want to understand why you think it is in significant. Obviously you will get record warms in El Nino not La Nina. That's obvious. More interesting is that La Nina temperatures are now warmer than El Nino temperatures of similar magnitudes in previous decades.
  12. Keep those PJs on: a La Niña cannot erase decades of warming
    From the US - Climate scientists plan campaign against global-warming skeptics The American Geophysical Union plans to announce Monday that 700 researchers have agreed to speak out on the issue. The effort is a pushback against congressional conservatives who have vowed to kill regulations on greenhouse gas emissions. http://www.chicagotribune.com/news/nationworld/la-na-climate-scientists-20101108,0,3784003.story
  13. Stephen Baines at 13:55 PM on 8 November 2010
    Keep those PJs on: a La Niña cannot erase decades of warming
    John Bruno is correct. I was watching the NOAA ENSO page regularly because it was relevant context for a couple of papers I was writing at the time. The last El Nino was pretty medicore one - although it persisted for a while longer than initially predicted. It also tended to be most obvious in the Central Pacific rather than along South America. The MEI plotted above can be hard to interpret. Eastern Pacific SS temperature anomolies were typically in the 0.5-1.5 C range (El Nino conditions hold when three consecutive 3 month running averages exceed 0.5). For comparison, anomalies in 1998 were >4.0 C over large at times. I don't know where this notion that it was a strong El Nino comes from. Maybe its a misintrepretation of the phrase "strongest since 1998." Since El Nino's have a 4-7 year frequency, all that phrase boils down to is "it was the strongest since the one before last." Not as impressive. This La Nina looks a whopper though. Wish I was out taking samples (though I'd probably get sea sick!).
  14. Ice-Free Arctic
    Muoncounter: What is the effect of cosmic rays?
  15. Ice-Free Arctic
    muoncounter: Did you read more or just the first few paragraphs? In case you didn't: "An advantage of the EM technique is that it can be deployed from helicopters or airplanes. In the summer of 2001, a new helicopterborne EM sensor ("EM-Bird") was operated in the Arctic for the first, yielding high resolution thickness data of good quality. With the EM-Bird, we will now be able to perform systematic large-scale studies of the ice thickness distribution, improving our ability to better judge observations and predictions of possible climate changes" They took the EM and put it on Polar five and flew grids over the Arctic in 2009. The results were much thicker ice than had been anticipated. I will be the first to admit that one year does not prove anything. However, it does prove that there is large variances in ice thickness that were not expected as the 2009 data showed.
  16. Climate change from 40 million years ago shows climate sensitivity to CO2
    Protestant - trying the "correlation prove causation" again. Did you read responses from the last time? No, the paper attempts to show that a modelled prediction is in accordance with observation. That is how science is done. "They claim there would be almost no greenhouse effect without CO2, thats an outrageous misinterpretation." No, what you are saying is an outrageous misinterpretation. I defy you to find any scientific paper that makes such a claim. From both observations and models, water vapour is temperature-controlled. Sure, water vapour feedbacks amplifies any change in any forcing but to investigate the cause of a trend requires looking at the forcings.
  17. Keep those PJs on: a La Niña cannot erase decades of warming
    John: Hate to quible, but the 2009-10 El Nino IS the second strongest since 1998. Your graph shows this. Read the Murphy etal paper. The answer to your question is contained within the paper. As far as GISS, it is the outlier amongst the big 4. RSS/UAH and CRU. The Arctic temps that GISS showed the summer of 2010 in the Arctic were approx 4.0C different than DMI temps. GISSTEMP uses one sensor, DMI uses hundreds.
  18. Stephen Baines at 13:21 PM on 8 November 2010
    Climate change from 40 million years ago shows climate sensitivity to CO2
    @protestant #42 "Which one of you really believes that we would lose nearly all water wapor and have over 70% cloudiness without CO2? omg..." Actually, I do...and it doesn't take a complex climate model to believe it. Let's try... If you remove all the CO2, the climate will cool as 1/5th of IR absorption by the atmosphere is due to CO2 (that is well measured). You will rightly point out that there is still water vapor present that accounts for at least 75% of the greenhouse effect including clouds (also well measured). But I also know it's raining outside my house right now. That tells me water vapor condenses when the air temperature falls below a critical threshold, and that temperatures on earth often fall below this threshold...we have water in our atmosphere precisely because that atmosphere is warm enough to allow water vapor to keep from precipitating out faster than it evaporates. What happens when we weaken the greenhouse effect by removing CO2? It would lead to a colder atmosphere, which causes evaporation to decrease and precipitation to increase, which leads to a lower greenhouse effect, which cools the earth some more, which causes more water to precipitate, which lowers the greenhouse effect....and on and on until you reach a new much colder and drier equilibrium that depends on the other control knob -- the incoming solar radiation and the earths ability to absorb it and redistribute the remaining heat. You only need the model to estimate that stabilization point and the time frame over which it is reached. You don't need it to tell you that earth would be a lot colder than now in the absence of CO2, and that water would be less abundant. All you need to know that is that it rains, that water vapor absorbs IR radiation and that earth would be a lot colder if there was no greenhouse effect. Those facts are not in dispute. Without an IR absorbing gas(or gasses) that does not condense out when it gets colder, you cannot have a stable climate on earth that is anything like ours. Of course that also means when that non-condensing gas varies in concentration, for whatever reason, climate will follow it. That can happen for natural reasons, as it has in the past, or due to human impacts, as it does now.
  19. CO2 has a short residence time
    Here's a nice graphic to help visualize the "long tail" of atmospheric CO2 (the very long residence time): Kinda heightens the imperative to the danger excess CO2 carries: there is no quick fix. Temps that go up will, like the CO2 elevations, go down slowly. On the plus side, no ice ages in our immediate futures! The Yooper
  20. Keep those PJs on: a La Niña cannot erase decades of warming
    "The El Nino of early 2010 was not "mild" according to NOAA this El Nino was the strongest one since 1998. While this El Nino was not nearly as strong as the 1998 El Nino it still met the criteria for being a moderate to strong El Nino." - Karamanski at 12:26 PM "Yes, the El Nino of 2009-2010 was the 2nd strongest according to NOAA." - Camburn at 12:34 Sorry, your'e both wrong. The 09/10 El Nino was "mild" according to NASA and was not even among the top 7 strongest of the last 50 years. Take a look at the NOAA MEI graph below and then tell me you want to argue the 09/10 El Nino was anything but mild-to-average:
  21. Ice-Free Arctic
    #32: "Using fixed wing aircraft, the Alfred Wegener Institute for Polar and Marine Research found the ice to be thicker than anticipated." From the AWI website: The results have been obtained by means of computations with a numerical dynamic-thermodynamic sea ice model, using six-hourly atmospheric forcing data. Perhaps some modeling is part of that work after all? "the effect of magnetic flux on high latitude temperatures." Sounds like you may have heard that its all due to cosmic rays? Been there, done that: no dice.
  22. Keep those PJs on: a La Niña cannot erase decades of warming
    Camburn at 12:32 PM: please explain the relevance of your comments.
  23. Keep those PJs on: a La Niña cannot erase decades of warming
    HumanityRules at 12:08 PM: Sure, if your'e interested in looking at the peak monthly low, then yes, the monthly data might be better. And why not look at daily temps? Or daily temperature in Jupiter FL? (my home town). The finer the spatio-temporal grain of the measurement, the greater the range of the values. Looking at monthly extremes isn't "more accurate". It is just a finer-grained comparison and inevitably yields a greater extreme value. In an older version of the post I had a section speculating Art was doing exactly what you suggested: start at the peak and measure the difference to the following low. To me, this seems a stretch to use this measurement to quantify how much cooler temp is during La Nina. But I suppose it is important to clarify "how much cooler than what?" My relative value was the baseline/neutral point in the cycle/running average, i.e., I suggest using the cycle amplitude, while you are suggesting a peak to valley measure. Your suggestion is always going to be biased by the strength of the preceding cycle peak: a really strong El Nino high followed by a weak La Nina low, would, by your method, be misleading in suggesting the La Nina was very cold or greatly reduced global temperature. Seems like climate cherry picking to me. Keep in mind though, it doesn't matter how great the amplitude of the cycle is, since it just sits atop of an increasing baseline. -JB
  24. Keep those PJs on: a La Niña cannot erase decades of warming
    Yes, the El Nino of 2009-2010 was the 2nd strongest according to NOAA. And also according to NOAA, this La Nina has recorded the fastest temperature drop of SST since records have been established. This is actually to be expected as Solar Cycle 24 seems to be sleeping.
  25. Keep those PJs on: a La Niña cannot erase decades of warming
    The heat graph from Murphy etal uses guestimates for the heat content of the ocean. The ARGO system is not showing the same results as projected in this paper. Also, the GISS temp data has become the outlier of all data sets. The 1200K radius is not effective at extrapolating air temperatures. One of the reasons that the GISS is showing so high is it incorporates Arctic temps that are extrapolated rather then measured.
  26. Keep those PJs on: a La Niña cannot erase decades of warming
    "That is despite the facts that the El Niño that dominated the early months of 2010 was quite mild" The El Nino of early 2010 was not "mild" according to NOAA this El Nino was the strongest one since 1998. While this El Nino was not nearly as strong as the 1998 El Nino it still met the criteria for being a moderate to strong El Nino.
  27. Ice-Free Arctic
    The St Rock sailed the northern northwest passage in 1944. Henry Larson was the captain. They left Halifax, Nova Scotia and docked in Vancourver, British Columbia 86 days later. Using fixed wing aircraft, the Alfred Wegener Institute for Polar and Marine Research found the ice to be thicker than anticipated. This was done in 2009. This is emperical data, not modeled nor guesses from the current satillites. The approx 60 year ice cycle is not dependent on the PDO. Within that 60 year cycle there is also a ten year cycle. Interesting information to study. One other thing that must be taken into consideration is the effect of magnetic flux on high latitude temperatures. There are numerous published papers that show that cause and effect. Here is something from the US Weather Bureau. "The Arctic seems to be warming up. Reports from fishermen, seal hunters and explorers … all point to a radical change in climate conditions, and hitherto unheard-of high temperatures in that part of the earth's surface. … Ice conditions were exceptional. In fact so little ice has never before been noted. The expedition all but established a record, sailing as far north as 81 degrees 29 minutes in ice-free water. … Many old landmarks are so changed as to be unrecognizable. Where formerly great masses of ice have been were found, there are now often moraines... At many points where glaciers formerly extended far into the sea, they have entirely disappeared." The date was October 1922. Antidoal evidence shows that we have a lot to learn about the Arctic and Ice. And the reasons for the increase and decrease of said ice. While co2 potentially plays a part, it is far from the only reason that the ice varies on a decadal scale.
  28. Keep those PJs on: a La Niña cannot erase decades of warming
    I don't think the annual temp record is the best tool for showing the variation in temp introduced by El Nino/La Nina. Here's the monthly data from 1996-2010. Still not the nicest I know but it does more accurately show how much ENSO affects global temp. You can see the 1998 El Nino introduced 0.7oC of heating. From the peak in 2007 to the low point in 2008 we can see ~0.6oC of cooling in a year. ENSO seems to have a larger short term affect on temp than you are suggesting here. It's worth considering how much the recent El Nino has contributed to the possible record temperatures for 2010.
  29. Climate change from 40 million years ago shows climate sensitivity to CO2
    Norman #46, as it happens there is more than one star in the universe. Thus, astronomers have been able to study the life cycle of stars in considerable depth. The idea that stars get hotter as they grow older is not, as you seem to imply, some vague hypothesis based on nebulous computer models... it is observed reality. As to Mars... the belief that it once had surface water goes hand in hand with the belief that it once had an Earth-like atmosphere. Just as the greenhouse effect keeps Earth habitable it could have once allowed liquid water on Mars. Now that Mars has lost most of that atmosphere it has very little greenhouse warming... and thus is too cold for liquid water. In short, the Sun is not the only thing which could have made Mars warmer in the past. Odd that you would assume that.
  30. Keep those PJs on: a La Niña cannot erase decades of warming
    Some interested observers in Australia with vested interests in the weather, are seeing the onset of the current La-Nina as reminiscent of 1974 which was the beginning of 3 consecutive La-Nina years, even to the extent that in the late 60's, south eastern Australia suffered a severe drought that became a benchmark for droughts at the time, and as then, this drought just ended is also being seen as a benchmark drought. The only difference is that those 3 consecutive La-Nina years came to mark the end of 3 decades of generally cooler and wetter weather where there were 25% more La-Nina years than El-Nino years and the IPO was continually in a negative phase, whilst now is being forecast as marking the beginning of another 3 decades pattern of similar conditions.
  31. Climate change from 40 million years ago shows climate sensitivity to CO2
    Did not put up the link I will use Hyperlink. This chart shows the amount of IR CO2 will absorb from the IR spectrum. Chart of CO2 absorption ability.
  32. Climate change from 40 million years ago shows climate sensitivity to CO2
    #24 The Ville You post "Apart from that, the faint young Sun and the CO2 thermostat would have taken care of long term CO2 effects and levels over hundreds of thousands of years" I still question the "faint young Sun" hypothesis. It is based upon some solar models but are they correct? If our sun was faint in the past (when CO2 levels were in the 6000 PPM range) then how did Mars have flowing water on its surface? These two conclusions are mutually incompatible. Either the Sun was not cooler and could warm Mars or Mars could never had liquid water with a fainter Sun. From studies on downwelling IR radiation, the contribution given by current levels of CO2 is about 10%. That's it. Here is what CO2 will give you: http://www.google.com/imgres?imgurl=http://www.real-debt-elimination.com/images/lynchi2.jpg&imgrefurl=http://www.real-debt-elimination.com/real_freedom/Propaganda/Global_Warming_Myth/lynching_of_carbon_dioxide.htm&h=818&w=870&sz=73&tbnid=mooueGrTNRbqNM:&tbnh=136&tbnw=145&prev=/images%3Fq%3Dcarbon%2Bdioxide%2Babsorption%2Bspectrum&zoom=1&q=carbon+dioxide+absorption+spectrum&usg=__pSKV5BxhGfhn4yRlb1D39C9_ZWw=&sa=X&ei=ITzXTISaNM-cnwfq_fzhCQ&ved=0CB8Q9QEwAw
  33. Climate change from 40 million years ago shows climate sensitivity to CO2
    #42: "When climate warms, more CO2 is released from the oceans, " For starters, when atmospheric CO2 increases, climate warms and oceans become more acidic. "If some warming event coincidences with a volcanic eruption which huge releases of CO2" Sorry, no soap. CO2 volumes from most eruptions are comparatively small. Large eruptions (such as Pinatubo) cause cooling due to their aerosol volume - that's well-documented. Along with that particular early 90's cooling event came a temporary drop in the rate of global CO2 increase -- also well-documented. If you would like references for any of the above, start with SkS search. I'm with Yooper on this, you need to do some research to support your ideas. And please, try harder than the old correlation-causation canard.
  34. CO2 has a short residence time
    Isn't the NASA graphic a bit out-dated? 5.5 Gt carbon from anthropogenic emission? As for ATekhasski's comment, the fact remains that uptake rates in today's carbon cycle appear limited (thus the rapid accumulation). The article seems to hint that the relaxation time is a function of the excess uptake (beyond the natural exchange) vs. the amount of buildup. Don't know how up-to-date this is, but RC had some discussion of the ANTHROPOGENIC PERTURBATION lifetime: http://www.realclimate.org/index.php/archives/2005/03/how-long-will-global-warming-last/
  35. Climate change from 40 million years ago shows climate sensitivity to CO2
    Re: protestant (42)
    "Response to #18 was also a bit silly imho. The paper linked just proves how fatally flawed the climate models are, and thats it."
     Um, are you referring to the linked video in the response to #18? If so, then you should really watch it and try and learn something about CO2. And the specifics about GHG's are that, without their effect, the average temp of the Earth would be 33 degrees C less than it is now (about 59 degrees F less). Since that puts the Earth well below the freezing point of water on a global basis, there would likely be no life, as the Earth would be a global iceball, pole to pole. This is well-understood and has been for over a hundred years. The majority of your posts here thus far are fraught with a lack of understanding of, well, just about anything to do with climate science, actually. And I see by the responses that many commenters have stepped in to help you gain understanding on a post-by-post basis. Have you actually read any of their references they cite? Did you have any questions or reservations on what you read? Quite frankly, I don't think you're trying. I'm not sure anyone here can help you if you're not willing to let anyone actually help you. The Yooper
  36. Ice-Free Arctic
    Thanks, muonocounter. There is time series data for 1870 - 2007 at that page, including extent for the 1930s. http://arctic.atmos.uiuc.edu/SEAICE/timeseries.1870-2008 According to that data set, Arctic sea ice extent (annual) first dipped below 13 million sq/km in 1960. Prior to that it was always greater than 13 mil. From 1979, annual extent has always been below 13 million sq/km, and by 2000 was starting to dip below 12 mil. In 2007, the annual sea ice extent fell below 11 million square kilometers. The first column is annual data. The following four columns are Winter, Spring, Summer and Autumn extents year by year from 1870. Although summertime extent is more variable, the 1930s were relatively stable, and the data show considerably greater extent for that period/season than today. While we have a lot of ice-edge data from the 1930s, it is quite inferior to the satellite period data. All the above should be read with the usual caveats.
  37. Stephen Baines at 10:11 AM on 8 November 2010
    Climate change from 40 million years ago shows climate sensitivity to CO2
    RSVP Ya know, heroin is also biological solar energy ... just kind of processed...like petroleum. And if the point isn't clear...You judge whether something is "bad" based on it does, not where it comes from. Surely you're just taking the mickey, right?
  38. Climate change from 40 million years ago shows climate sensitivity to CO2
    And does correlation prove causation, or in this case climate sensitivity? No. When climate warms, more CO2 is released from the oceans, CO2 lags temp and thats all we know (well yes it can amplify the change but self-evidently its not _the_ control knob). If some warming event coincidences with a volcanic eruption which huge releases of CO2, that does not prove CO2 was the main cause either. The geologic history is SOOOO long it is actually evident such coinsidences occur. Response to #18 was also a bit silly imho. The paper linked just proves how fatally flawed the climate models are, and thats it. They claim there would be almost no greenhouse effect without CO2, thats an outrageous misinterpretation. Which one of you really believes that we would lose nearly all water wapor and have over 70% cloudiness without CO2? omg... Determining climate sensitivity or anything as complex as that from inaccurate paleo-reconstructions is just pop-science. When all of the forcings (including the multi-decaedal and multi-cencennial oscillations) are not known the climate sensitivity can not be determined.
  39. Ice-Free Arctic
    During the 1930's the Russians took extensive pictures of the ice edge during the summer from airplanes. These photos have been used to archive that side of the Arctic. I have not seen American records, but there is undoubtly something. Probably not as systematic as the Russian records. There are many towns in the Canadian and Alaskan Arctic. Those peole keep records every year, going back to the 1800's, of the local ice conditions. It is well known that the Northwest passage was only open to non-icebreakers in the past 5 years. The people who say the passage was previously open are trying to fool naive readers. Around 1900 Peary and Cook were doing their exploring. There is a lot of data about the Arctic ice before satelites were launched.
  40. Ice-Free Arctic
    #27: "we have little from that period corroborating the notion of significantly less sea ice coverage" The reference in Polyak goes through Kinnard et al 2007 to the University of Illinois sea ice data set. There's a slight offset to match the satellite data, but there's enough overlap to work that out.
  41. Climate change from 40 million years ago shows climate sensitivity to CO2
    #40: "and yet it is "a bad thing"." The bad thing in question is: we released the carbon that was stored in fossil fuels back into the atmosphere in the form of CO2. But I'm sure you knew that already. If not, you really should do some more reading.
  42. Ice-Free Arctic
    Here's a full version of Polyak 2010 for anyone to review. http://www.cgd.ucar.edu/oce/mholland/papers/Polyak_2010_historyofseaiceArctic.pdf
  43. Ice-Free Arctic
    Brutus,
    Isn´t it likely that minimum sea-ice extent was much lower in the 1930s when temperatures were (almost) as high as today?
    While anecdotal evidence is hardly foolproof, and a lack of anecdotes even less so, still we have little from that period corroborating the notion of significantly less sea ice coverage than where we started at the beginning of the instrumental record. I'm aware of pictures from the North Pole in the 1930s of areas of open water, but this only reflects local conditions, not the entire Arctic. We also have had open water at the pole from time to time throughout the last 30 years. This is a result of various conditions, mostly to do with how winds blow the sea ice about. We've also had a longer period of warming (since 1970s) today than then, a couple of decades more of sustained warmth. Overall Arctic sea ice doesn't respond in lockstep with temps, but declines as a result of continued warmth over years until an equilibrium is reached. Thus, it is probably unlikely that sea ice coverage in the 30s was less than today's, as there wasn't the same long-term build up and sustained high temps for long-term melt. Reconstructions from observational data (which is admittedly sparse pre-1950) and proxy data support this probability. One could reasonably argue that these findings are not certain, but it would be unreasonable to posit that sea ice coverage in the 1930s was "likely" as low as today.
  44. Ice-Free Arctic
    Brutus no systematic observations does not mean we know nothing. Take a look at Polyak2010 fig. 2a, reproduced below for your convinience.
  45. Ice-Free Arctic
    Various points; Riccardo #14, Arctic ice volume accuracy - While the PIOMAS model results are the only continuous 'record' I am aware of it should be noted that this has been validated against submarine and ICESat records. Thus, there is a fairly strong case for the PIOMAS results being accurate within a relatively small margin of error. Camburn #17, "...we are at the end of the 30 year cycle" - What cycle are you referring to? The usual '30 year cycle' that skeptics go on about is the Pacific Decadal Oscillation... but we are actually ten years into the 'cool' phase of that rather than "at the end". Oamoe #16, Cryosat - Cryosat has actually been "collecting data" since April. They have been fine tuning the sensors and working out the kinks, but the commissioning phase actually ended a couple of weeks ago. I'm not sure whether they will release anything from prior to the end of the commissioning phase since they were still making adjustments during that period, but they should be able to tell us whether the current (remarkably low) volume reported by PIOMAS is roughly accurate.
  46. Ice-Free Arctic
    Camburn.... I also find this from Weather Underground regarding passages of the Northern Passage... "We can be sure the Northwest Passage was never open from 1900 on, as we have detailed ice edge records from ships (Walsh and Chapman, 2001). It is very unlikely the Passage was open between 1497 and 1900, since this spanned a cold period in the northern latitudes known as "The Little Ice Age". Ships periodically attempted the Passage and were foiled during this period, and the native Inuit people have no historical tales of the Passage being navigable at any time in the past."
  47. What should we do about climate change?
    PL #376 The discussion certainly is pointless if you won't answer a straightforward question with a straightforward answer. I see you've written quite a large volume of stuff on energy policy, and that your evaluation of the evidence tends to a conclusion that renewable energy is not terribly viable. I had a question about this which you don't seem to want to answer. Let me repeat it for you: So do you have anything to say about demand management synergestic effects, and renewable generation site optimisation? Have you accounted for these in your conclusions? Can you show me where? Straightforward yes/no answer please. If the answer is "yes" then a link and possibly a page reference will suffice. I'm afraid if the aswer is no, and you haven't evaluated this aspect, then I suspect that you're missing a critical piece of the puzzle, and I would question the validity/coverage of your argument. When people ask me about things that I have written I give them the courtesy of telling them where the passage(s) they are interested in are located - I don't tell them to trawl through my entire output.
  48. Ice-Free Arctic
    Camburn.... Think about it for just one second. Sailing of the NW Passage, on any route, was a fantasy of traders for most of the 19th and 20th century. Lots of attempts made. Many lost ships and men along the way. The first passage by Amundsen took three years, spending two full winters stuck in the ice. This year a guy does it solo in 12 days.
  49. Ice-Free Arctic
    Camburn.... "Kiwi Yachtsman, Graeme Kendall, completes world sailing firsts; Arctic North West Passage solo, non stop & in a record 12 days."
  50. Ice-Free Arctic
    The Canadians use the southern passage yearly. Usually during the month of September to re-supply towns etc in the Arctic.

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