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Comments 87501 to 87550:

  1. Extreme weather isn't caused by global warming
    johnd#20: "cause and effect are confused ... evidence found by Dr. Jeffrey Dean of a historical major disruption in the area's typical rainfall " Confused? Hardly. No dispute that there was a disruption in typical rainfall. But from your link, Recent climatological studies by other scientists suggest that rainfall patterns were disrupted in a way that might have made the Anasazi disillusioned with their old religion. ... Suddenly, the customary pattern of heavy snows in the winter followed by summer monsoons had become unpredictable. Even if there was not a great drought, moisture may have been coming at the wrong times. The summer rains, so necessary to keep the spring crops from dying, were no longer reliable. The rain dances were not working anymore. Apples: the rain dances weren't working as they had. Oranges: heat waves, drought and wildfire; monsoons; cold winter with deep snow, meltwater floods. Tornadoes. Thundersnow. But maybe it was just like that back in Anasazi days. And so the rain dance of today, 'don't worry, nothing unusual is going on,' isn't working either.
  2. CO2 effect is saturated
    muoncounter, OK. Maybe KR is right and there should be a dedicated thread to the Trenberth diagram and energy budget.
  3. Extreme weather isn't caused by global warming
    muoncounter at 11:28 AM, it will obviously seem an apples and oranges comparison if cause and effect are confused as you have done so. However the evidence found by Dr. Jeffrey Dean of a historical major disruption in the area's typical rainfall that I referenced, is a valid apple on apple comparison to your comments regarding present day emerging patterns, and thus also relevant to this thread.
  4. Daniel Bailey at 12:58 PM on 26 April 2011
    A Flanner in the Works for Snow and Ice
    Continuing in the vein of offering mute testimony to the growing dominion of the summer sun in the Arctic: [Courtesy L. Hamilton] "No icecube is an iceberg, entire of itself; every icecube is a piece of the iceberg, a part of the Arctic Sea Ice cap. If an icecube be melted away by the sun, the Arctic Sea Ice cap is the less, as well as if a promontory were, as well as if a manor of thy friend's or of thine own were: Any icecube's demise diminishes me, because I am involved in the Arctic Sea Ice cap, and therefore never send to know for whom the bell tolls; it tolls for thee." Apologies to both Hemingway and Donne. The Yooper
    Moderator Response:

    [DB] Forgot to post the linear relationship details on the chart:  R = .94

  5. The e-mail 'scandal' travesty in misquoting Trenberth on
    mclamb6 #158 I did not mean to ignore your contribution. It is just that the Moderators are zealously snipping me. "The theory is sound as are the observations supporting the theory. Nonetheless, you cherry pick ARGO measurements (which apparently is the new gold standard despite the fact that the ARGO measurements are being refined and there isn't even close to a statistically significant period of observation) and attach your cherry picked measurements to your skewed interpretation of Trenberth's email." I have not spent the best part of 2 years reading everything about AGW to make a trite comment about Argo. Anyone who understands the first law can also make the leap to the critical point that any warming imbalance must show up somewhere in the Earth system as heat energy - over 90% stored in the oceans. OHC increase is a direct measure of TOA imbalance. Accurate measurement of OHC will make or break the AGW case.
  6. Lindzen Illusion #1: We Should Have Seen More Warming
    h pierce at 05:46 AM on 23 April, 2011 Don't get carried away with these kind of graphs because temperature mesurements used for calibration aren't that accurate. In the US temps at weather stations are measured to +/-1 deg F. In Canada temperature data is reported to nearest +/- 0.5 deg C. Where are the error bars for plots in the graph? You need at least ca. 1 deg C difference between means of two sets of temperature data for stat significance at p < 0.05. ---------------------------- Err no. This is a very common misconception in climate skeptic land. I have explained why it is wrong before without success. It's amazing the number of people with technical backgrounds don't/won't understand how averaging of data produces a higher resolution result than the input data.
  7. CO2 effect is saturated
    Tom Curtis (RE: 130), I might also add that Trenberth's "window" of 70 W/m^2 is not referenced in the paper. It appears to just be a rough estimate or guess. He also has greater than half of the surface power absorbed by the atmosphere being emitted up out to space, which is inaccurate. To get half up and half down requires a "window" of 82 W/m^2 with his numbers (396 - 82 = 314; 314/2 = 157; 239 + 157 = 396 at the surface). Even this site's hfranzen from first the link I posted in #124 has diagram on page 19 of his paper showing a "window" of 88 W/m^2. Take a look: "Flux balance on the Earth"
    Moderator Response: [muoncounter] We've been through the half up/half down bit before. By assuming that model, your argument is turning circular. You're also veering off topic (and it's hard to do both at the same time). This thread is on CO2 absorption band saturation.
  8. A Flanner in the Works for Snow and Ice
    Daniel Bailey #130 I assume by your entry to the thread Daniel that you are informing Tom Curtis' rather than me. " Melting ice cares not for sophistry. Or is it that Arctic Sea Ice declines from it's current winter maximum of about 13.5 million square mile area to it's melt season low of about 4.2 million square miles out of sheer habit...:" I assume you mean sq.km not sq.miles Daniel. And what is 'sophistry' about my sound calculation which points out the trail of basic errors in Tom's elongated journey.
    Moderator Response: [DB] "I assume you mean sq.km not sq.miles Daniel." Thanks for the heads-up on the slip-up. And sadly, no: 'Tis not Tom engaging in sophistry.
  9. CO2 effect is saturated
    John Cook, Moderators - Might I suggest a thread on the Trenberth diagram and energy budget? This has been repeatedly misunderstood, misquoted, and misused for more instances of mathturbation than just about any graphic I can think of. - It's not a model, contains no information whatsoever about interdependent changes of climate elements upon perturbation. - It's a four layer accounting of energy interchanges between these layers (Sun, surface, atmosphere, space). Some of these exchanges (161 insolation, the 40 W/m^2 "window" from surface to space) skip a layer, most do not. - Energy entering a level of this accounting does not retain identity/sourcing with what goes out; it's all joules, all the way down, which for example is why the atmosphere can radiate 169 W/m^2. - If somebody disagrees with a number in the Trenberth budget, they should take it up with Trenberth, who has done a clearly sourced and researched work with plenty of references to look at for each individual number. "I don't see how this is possible" is not a valid objection; it's certainly not science.
  10. Lindzen Illusion #1: We Should Have Seen More Warming
    I find this Lindzen thing getting a bit confusing. In the first place he doesn't say what models he is referring to. As far as I am aware the most sophisticated models do in fact take into account the oceans and so thermal inertia should be part of the model and be reflected in the model output. The article seems to be arguing that we have the ?some? unspecified model which we have to apply thermal inertia corrections to. This looks kind of wrong. I think it would be more to the point to show a specific model's predictions and mark on it what Lindzen says the model prediction is and what the actual temperature is. That way we have an instant conclusion: Lindzen is right or wrong!!!
  11. A Flanner in the Works for Snow and Ice
    Tom Curtis #131 I hung in there Tom, because I could not let you get away with the litany of error and denegration of both my calculations and 'principles'. Your final paragraph tells the story of this bizarre exchange. Quote: "More importantly for this thread, Flanner estimates that the increased net energy absorption (additional energy absorbed - additional energy lost) due to arctic sea ice melt is around 5*10^20 Joules, or approximately 42% of the conservative estimate of additional incoming energy flux. As Ken would say, this is quite close to Trenberth's figure of 3.4*10^20 Joules needed to explain melting and warming of Arctic ice." So Flanner's actual number for NET energy absorbed is around 5E20 Joules (presumably per season or per year). Is not what global warming is all about - the NET increase in heat gained by the Earth?? So where did you get the number "2004-2008: 6.97E+021 Joules" which is 69.7E20 Joules over 4 years or 17.4E20 Joules per year?
  12. CO2 effect is saturated
    Tom Curtis (RE: 130), "RW1 @127, I don't want to buy into another fruitless conversation but, Trenberth 09 shows a 40 Watt/m^2 atmospheric window, and also shows 30 W/m^2 emitted to space from cloud surfaces, with another 169 W/m^2 emitted from the atmosphere other than from clouds. These three combine to make up the OLR." I don't see how this is possible. Think about it. How can the clear sky atmosphere emit 169 W/m^2 to space when surface only emits about 131 W/m^2 to the clear sky in the first place? We know this because the ISCCP data says clouds cover 2/3rds of the surface, which means 1/3rd of the surface is clear sky. 396 W/m^2 x 0.33 = 131 W/m^2 emitted from the surface to the clear sky.
  13. Extreme weather isn't caused by global warming
    johnd#18: "compare what changes may be appearing now with those that confronted the Ancient Pueblo People" An apples and oranges comparison. We have no idea how sensitive their civilization was to climate change; however, we may surmise that without air conditioning and turbo-diesel backup generators, they were more sensitive than we are. However, anthropology is hardly the topic of this thread; the pace and intensity of current climate change's impact on weather is.
  14. CO2 effect is saturated
    RW1 @127, I don't want to buy into another fruitless conversation but, Trenberth 09 shows a 40 Watt/m^2 atmospheric window, and also shows 30 W/m^2 emitted to space from cloud surfaces, with another 169 W/m^2 emitted from the atmosphere other than from clouds. These three combine to make up the OLR.
  15. CO2 effect is saturated
    KR (RE: 128), I'm not disregarding any spectra. I'm also well aware there are bands that are saturated. I also agree that the CO2 absorbing bands are not saturated - there is room on the wings to expand and capture a little more outgoing surface power. This is where the additional 3.7 W/m^2 from 2xCO2 is coming from.
  16. CO2 effect is saturated
    RW1 - Got it, you are going to continue to disregard the spectra between 600-750 microns, let alone around 450 microns, where IR from the surface cannot reach space unintercepted, and where increasing CO2 concentrations raise the effective emission to space to higher/colder altitudes. Quite frankly, I cannot take your discussion of the greenhouse effect seriously when you ignore major components like this.
  17. CO2 effect is saturated
    KR (RE: 125), Trenberth et al 2009 has a transmittance or "window" of 70 W/m^2 (40 through the clear sky and 30 through the clouds). If when CO2 is doubled, the "window" decreases by 3.7 W/m^2 (or 7.4 W/m^2) and 1.85 goes up out to space and 1.85 goes down to the surface (or 3.7 goes up and 3.7 goes down) (*Trenberth actually has it being 52% up and 48% down).
  18. CO2 effect is saturated
    KR (RE: 125), "As has been said to you before, the windowing effect (where IR goes straight from the surface to space) is only part of the reduction in IR. The rest occurs in the full absorption bands (where IR from the surface makes it only 10's or 100's of meters before absorption)" When I refer to the "window", I mean transmittance - the amount of the whole spectrum of emitted surface power that passes through to space without being absorbed by the atmosphere (not just one particular band). This is the amount that should reduce by 7.4 W/m^2 if the referenced 3.7 W/m^2 is all incident on the surface as claimed when CO2 is doubled. There appears to be some confusion in regards to the definition or use of the term "window". Some refer to this as the mostly transparent region between about 8u and 13u, but this is not how I use the term. Nor do I believe this is how 'novandilcosid' is using the term either. You don't seem to understand that there are other parts of the spectrum besides the CO2 absorbing bands that are not completely saturated and a portion of surface emitted energy passes through them unabsorbed out to space. The aggregate amount that passes through the whole spectrum of emitted surface energy is the "window" or transmittance.
  19. A Flanner in the Works for Snow and Ice
    Ken Lambert @128 and further to my 129, when going over the figures I noticed that the historical sea ice extent data defines summer as July, August and September, while I have been using solar altitude data for May, June and July. This means that I am over estimating sea ice area for the relevant period (although the large underestimates I use on other factors still mean I am underestimating additional incoming energy flux). Never-the-less, the name of this game is give Ken every bias in the data he could ask for, and I have a personal preference for greater accuracy. Therefore I corrected by calculated values as follows: 1) For each of May, June and July, I determined the 1979 and 2010 values of sea ice area from the following chart: The chart tracks the trends in median monthly Arctic sea ice area. I used the trend chart to avoid distortions from start point or end point effects. 2) I then determined the mean of the three monthly values, and the May and July values. For both of these, I determined the difference between 1979 and 2010 values, and took the lowest value (May, July as it turns out). 3) I then used this value to calculate the additional energy absorbed by the ocean over the summer months in the Arctic in 2010 relative to 1979 on the trend due to the shrinking of Arctic sea ice. As previously noted, this is the gross energy absorbed over the summer, and does not factor in any increased energy losses over that period. The final value thus determined is 1.21*10^21 Joules. That is 13% less than my previous best conservative estimate @84. It is no where near the 75% reduction Ken thinks he has found in the data. In other words, even allowing every possible bias in his favour, and taking into account all the factors he considers relevant, there is still more than three times additional energy coming in than he thinks there should be. More importantly for this thread, Flanner estimates that the increased net energy absorption (additional energy absorbed - additional energy lost) due to arctic sea ice melt is around 5*10^20 Joules, or approximately 42% of the conservative estimate of additional incoming energy flux. As Ken would say, this is quite close to Trenberth's figure of 3.4*10^20 Joules needed to explain melting and warming of Arctic ice. But though he might say that, 1.6*10^20 Joules is a lot of additional heat left over after that process. Regardless of that, the conservative calculation of additional incoming energy shows (unsurprisingly) that low arctic insolation due to low solar altitude in the Arctic does not provide a principled basis to reject Flanner's results.
  20. CO2 effect is saturated
    RW1 - As has been said to you before, the windowing effect (where IR goes straight from the surface to space) is only part of the reduction in IR. The rest occurs in the full absorption bands (where IR from the surface makes it only 10's or 100's of meters before absorption), as increased CO2 concentrations raise the level of effective tropospheric radiation to colder altitudes. Why are you disregarding that very significant effect? Why are you claiming that all of the IR decrease occurs by a reduction of the 40 W/m^2 window, when that is clearly not the case?
  21. Cosmic ray contribution to global warming negligible
    The atmosphere of Venus is mostly CO2 and full of dense clouds of sulphuric acid. Its surface is far hotter than Mercury which is closer to the Sun, and is due to a runaway global warming. The sceptics can choose which element is predominant in its high tempertures CO2 or cloud cover.
  22. CO2 effect is saturated
    novandilcosid, I don't want to rehash this debate here. See the posts by 'co2isnotevil' and myself in the following threads: Here and Here Also, this paper by co2isnotevil: "Proof that only half of absorption affects the surface"
  23. CO2 effect is saturated
    KR (RE: 121), You even stated the following here: "As has been said here, repeatedly, the 3.7 TOA number means that 7.4 W/m^2 is being absorbed and radiated isotropically from CO2." There is definitely a halving effect. The fundamental question is if the 3.7 W/m^2 represents the post or pre halving effect. If it represents the post halving effect, as claimed here, then the "window" or transmittance (i.e. the amount of surface emitted that passes straight through the atmosphere unabsorbed and goes out to space) should reduce by 7.4 W/m^2.
  24. CO2 effect is saturated
    RE: DB and KR, I haven't ignored or disregarded anything. Just because I was given an answer doesn't mean it is the correct answer. I'm still working on the issue and hope to eventually resolve it once and for all.
  25. CO2 effect is saturated
    Re: my past post - CO2 effects are on topic. However, George White/co2isnotevil's incorrect assumptions about 'halving' really are not. 3.7 W/m^2 is the decrease in IR leaving the atmosphere for a CO2 doubling, as per line-by-line multi-level atmospheric modeling, CO2 spectra and physics, and confirmed by top of atmosphere satellite measurements. No 'halving' occurs.
  26. CO2 effect is saturated
    RW1 - Your erroneous "halving" has been addressed repeatedly, you have simply chosen to disregard the answers you have received. 3.7 W/m^2 is the drop in IR emitted to space for a doubling of CO2. This is due both to the rise in tropopause and effective emission altitude from increased CO2 concentration (and hence lower CO2 emitting temperature) and absorption band expansion. The window decreases slightly, but the predominant change is decreased emissions across the CO2 absorption bands. Hence "If the net effect at the surface is 3.7 W/m^2, then the "window" should close by 7.4 W/m^2 when CO2 is doubled" is simply wrong. There are two effects, not one, and your insistence on assigning all change to one effect has been corrected over and over again. Anyone interested in that discussion should look at the Lindzen and Choi thread, where RW1 and others were informed of the details over 448 postings. Please do not rehash that here. This thread is about CO2 saturation, and it is hence off-topic.
  27. Berényi Péter at 08:17 AM on 26 April 2011
    It's not bad
    #117 Albatross at 07:12 AM on 26 April, 2011 of course, not linked Here is the full exchange (open access).
  28. CO2 effect is saturated
    I should say the "window" should decrease by 7.4 W/m^2 when CO2 is doubled (not close). Trenberth et al 2009 has the window being 70 W/m^2 with the atmosphere emitting 157 W/m^2 down and 169 W/m^2 up (48% down and 52% up), if your interested in running some numbers.
  29. CO2 effect is saturated
    novandilcosid (RE: 110), If the net effect at the surface is 3.7 W/m^2, then the "window" should close by 7.4 W/m^2 when CO2 is doubled.
  30. CO2 effect is saturated
    novandilcosid (RE: 110), "I note in passing that increased Radiative Forcing (=energy inbalance at the Tropopause) is entirely different to increased absorption of Surface Energy, so that Tom's entire post is a confusing non-response to the question. Does anyone have a figure for the decrease in Surface Energy passing through the window due to a doubling of CO2 and assuming no temperature change at the surface?" The figure is 3.7 W/m^2. When CO2 is doubled, the window (i.e. transmittance) reduces by 3.7 W/m^2 and the atmosphere absorbs an additional 3.7 W/m^2 of surface emitted radiation, half of which goes down to the surface and half of which goes up out to space (1.85 W/m^2 up and down). It has been claimed here and elsewhere that the halving effect is already accounted for in the 3.7 W/m^2 figure; however, I have not been able to verify this through numerous inquiries to the climate science community. No one can give me a straight answer, but I'm still working on it.
    Moderator Response: (DB) In reality, you were given an answer, which you have chosen to ignore.
  31. Extreme weather isn't caused by global warming
    Again it would be prudent to compare what changes may be appearing now with those that confronted the Ancient Pueblo People that led to their displacement. This an excerpt from an article examining the Anasazi Collapse "Studying tree rings from 27 sites across the Southwest, Dr. Jeffrey Dean of the University of the Arizona tree-ring laboratory has found evidence of a major disruption in the area's typical rainfall. Suddenly, the customary pattern of heavy snows in the winter followed by summer monsoons had become unpredictable. Even if there was not a great drought, moisture may have been coming at the wrong times. The summer rains, so necessary to keep the spring crops from dying, were no longer reliable."
  32. It's not bad
    Please note, re the critique of the phytoplankton paper by Boyce et al. (2010) cited @116: Boyce et al's response to the critique was, of course, not linked.
  33. Berényi Péter at 06:57 AM on 26 April 2011
    It's not bad
    Would you please update this reference under Environment in the Intermediate version of the post? Decline in global phytoplankton (Boyce 2010) It is thoroughly debunked (see all three Brief Communications linked on the paper's page at the Nature site, April, 2011). Phytoplankton in fact is not declining.
  34. Daniel Bailey at 06:45 AM on 26 April 2011
    Wakening the Kraken
    @ muoncounter: Mark-US's linked source is on-topic. A preliminary read is interesting. I have some issues with parts of it, but reserve full judgement until I've had a chance to review it properly. Open copy available here (for now, anyway). Thanks, Mark! The Yooper
    Moderator Response:

    [muoncounter] That link takes me to a blank scribd doc.

    [DB] Sorry, muoncounter; I've checked it several times and it works for me. Dunno what to say.

  35. Wakening the Kraken
    Re #23.... sorry, try these active links The Paleocene-Eocene Thermal Maximum: A Perturbation of Carbon Cycle, Climate, and Biosphere with Implications for the Future Fossil Sirenians, Related to Today's Manatees, Give Scientists New Look at Ancient Climate
    Moderator Response: [muoncounter] Please provide some context for your links.
  36. Extreme weather isn't caused by global warming
    Continued from here: But while the world has got hotter in the past 100 years, Nielsen-Gammon said, Texas rainfall has actually gone up by about 10 per cent. Much of it has come from more-frequent extreme rainfall events rather than a general increase in normal rain. This is the pattern that seems to be emerging: More frequent higher intensity events, rather than a monotonous increase. In the case of current droughts, long weeks and months of dry weather punctuated by heavy rain. Those 'gully washers' make the statistics even out, but mostly result in runoff rather than soaking rain.
  37. Wakening the Kraken
    I'm deeply grateful for your work here at Skeptical Sci! Intending to help, I'd like to quibble with two parts of this post: "massive extinction of animals, most recently at the time of the Paleocene-Eocene Thermal Maximum (PETM), about 55.8 million years ago." "Resulting hypoxic conditions would cause large extinctions, especially of water breathing animals, which is what we find at the PETM." In this year's Annual Review of Earth and Planetary Science, the authors claim that extinctions were pretty much limited to benthic forams. The ranges of other life forms were re-arranged. By which I mean "extensively and painfully" rearranged. But they survived. Apparently it is a misperception to assign mass-extinction to the PETM. See also http://www.sciencedaily.com/releases/2011/04/110421161725.htm
  38. A Convention for Persons Displaced by Climate Change
    Everyone, I think that we should defer the last word to the experts regarding the Texas drought and wildfires. This is what Dr. Nielsen Gammon (Texas state climatologist and eminent climate scientist) and Dr. Hayhoe (climate scientist) have to say. Personally, I am far more concerned about the tens of millions of environmental refugees around the world than these fires.
    Moderator Response: [muoncounter] Take the drought discussion to the extreme weather thread.
  39. Harry Seaward at 04:19 AM on 26 April 2011
    A Convention for Persons Displaced by Climate Change
    Muon @ 56 and Sweet @ 61 Our information on the weather and rainfall disagree. We agree on the drought. Please review the following info and tell me if you still disagree. Winter Weather: From the NY Times on Texas weather from the winter of 2011 "Though a February snowstorm is not unusual in North Texas, this one followed an ice storm on Tuesday and three successive days of frigid temperatures. As a result, the ground was cold when the snow hit, and there was still ice on many roads, according to state traffic officials and forecasters with the National Weather Service. “Our temperatures rarely stay this cold for this long,” said Bill Bunting, the meteorologist in charge at the National Weather Service office in Fort Worth." Rainfall Totals: From the NOAA website for Lubbock, TX "Another way to put the rain into perspective is to look at the percent compared to normal. The below map shows that most of Oklahoma and Texas saw well above normal during the two week span from late June through early July 2010. Much of the South Plains and Rolling Plains received an astounding 400 to 800% or more of normal. The exception was across the southwest Texas Panhandle and extreme northwest South Plains where totals were near or just slightly above average for the two week period."
  40. A Convention for Persons Displaced by Climate Change
    If discussion of drought in Texas is allowable in this thread, then it should be put into historical perspective against those earlier civilisations from the region that were displaced by drought, for example, the Ancient Pueblo People and the Mayans, and the relevance of the 300 year drought, known as the Great Drought that began around 1150. What differentiates any recent changes in precipitation patterns to such earlier changes?
  41. Cosmic ray contribution to global warming negligible
    @rhjames: In addition to the other comments, it appears that you are ignoring nighttime effects. Surely you don't dispute that nighttime clouds have a warming effect.
  42. Daniel Bailey at 02:55 AM on 26 April 2011
    A Flanner in the Works for Snow and Ice
    The warming anomaly in the high Arctic is quite apparent in the DMI data: [Source] And in the overall temperature anomaly over time: [Source] Yields a declining winter maximum Arctic Sea Ice extent over time: [Source] Resulting in a declining Arctic Sea Ice cap: [Source] Melting ice cares not for sophistry. Or is it that Arctic Sea Ice declines from it's current winter maximum of about 13.5 million square km area to it's melt season low of about 4.2 million square km out of sheer habit...: [Source] As much as I'd like to vote for sheer habit, I'm going with the physics-based insolation & the damage it inflicts on the ice...and the resulting changes in albedo over time. The Yooper
  43. A Flanner in the Works for Snow and Ice
    Ken Lambert @128, the sea ice does not start melting at the beginning of summer, and nor does it magically return to the winter state at the end of summer. Further, there is less winter sea ice in the arctic now than 30 years ago. Therefore your adjusted sea ice area calculation is nonsense. For what it is worth, on average over winter, there was 0.63 million square km less sea ice over the period 2004-2008 than the period 1979-1983. There was, on average 1.08 million square kilometers less in the spring. There was 2.04 million square kilometers less on average in the summer. There was on average 1.69 million square kilometers less in the Autumn. Even if these where the minimum seasonal extents, therefore, that would only represent a 25% reduction in the calculated energy, not the 50% you calculate. However, these are not the minimum values, but the average value taken over the season. Early in the summer there is less than 2 million square kilometers exposed, but late in the summer there is significantly more than an extra 2 million square kilometers exposed. The average over the whole season is an extra two million square kilometers. So, there is no need to adjust the figure to find the average, for the figure is already the average. These figures are based on the seasonal sea ice extent data linked @88. I extrapolated the autumn 2008 figures to determine the average by adding the average difference between summer and autumn ice to the summer ice of 2008. Prior to using those figures, I had based my calculations on, first, the area of the difference in latitude band taking the month of the season with the least change of latitude (based on the chart in 58) and on sea ice area graphs compared over a season choosing the minimum difference for the season. Neither method was entirely accurate but where conservative. I find it gratifying that the one figure I have not had to change over the whole exercise, though I have used three entirely different and conservative methods to determine it, is the difference in sea ice.
  44. A Flanner in the Works for Snow and Ice
    Sorry- accidental 'Enter' posting at #123 Tom Curtis: Here are your assumptions as I understand them: 1) Your 97W/sq.m is based only on average incoming energy flux due to the difference in albedo from Sea Ice compared with Seawater for an range of incidence angles over the Arctic Summer above 75 degrees N latitude. 2) The Area of additional Sea Ice melt is assumed to be 2 million sq.km melted over the period 1979 - 2011 (32 years) 3) The whole 2 million sq.km is assumed to be exposed to the 97W/sq.m for the length of the Arctic summer (90 Days) 4) No account is taken of any change of outgoing energy flux due to surface temperature increases in the 90 day period. 5) No acount is taken of transfer of heat to the Arctic by other means (ocean currents eg.) Based on these assumptions you then calculate the total energy absorbed over a 90 day Arctic summer as follows: 97W/sq.m x 90 days x 24 hr/day x 3600 seconds/hour = 7.54E8 Joules/sq.m. You then multiply 7.54E8 Joules/sq.m x 2 million sq.km (2E12 sq.m) = 1.51E21 Joules. (15.1E20 Joules). So far, this matches your number. Now, the same problem arises with the additional 2 million sq.km melted relative to 1979. It did not all happen in one summer season. It is not in linear increments for 32 years, but not all in one summer either. But even if we heroically assume an extra 2 million sq.km was melted in ONE 90 day summer, then the 2 million sq.km of extra Seawater is only fully exposed at the END of the 90 day period. The melt curve is roughly sinusoidal with time. If you break up the summer into 3 x 1 month periods, and assume a linear approx for the decline in ice area, then after 1 month you will expose 1/3rd of the 2 million, after 2 months 2/3rds of the 2 million and, after 3 months the whole 2 million. Whichever way you break it up, the average area exposed to the 97W/sq.m is HALF the 2 million sq.km. for the 90 day period. Hence your 15.1E20 Joules should be half that: about 7.6E20 Joules per 90 day summer - making the heroic assumption that the whole 2 million sq.km is melted and Seawater exposed in one summer. Dr Trenberth says in his "Tracking the Earth's Energy" Aug09 paper: Quote "Sea ice is important where it forms. Record losses of Arctic sea ice of about 10^6 km2 occurred in summer of 2007 relative to the previous lowest year [25], although the thickness and volume of the ice is quite uncertain. To melt 10^6 km2 of ice 1 m thick and raise the temperature of the water by 10 degC requires 3.4 x 10^20 J, or globally 0.02 W/m2. For 2004–2008 this is about 0.9 x 10^20 J/yr." Endquote So if we assume that the worst year (2007) melted a 1 million sq.km area then we HALVE the 2 million area and the calculated figure of 7.6E20 Joules to a number of 3.8E20 Joules in one 90 day summer. This is quite close to Dr Trenberth's number of 3.4E20 Joules needed to quote "melt 10^6 km2 of ice 1 m thick and raise the temperature of the water by 10 degC requires 3.4 x 10^20 J" With a global imbalance of 145E20 Joules/yr, the 3.8/145 equals 2.6% of the planet's warming from the melting of 1 million sq.km of Arctic sea ice in one summer (year). This similar to the 2.8% I calculated previously.
  45. A Flanner in the Works for Snow and Ice
    les @125, having investigated that possibility I have discovered that Google docs won't recognize Open Office files for import; and that a cut and past transfers values only, not formulas, which is pretty useless. It is IMO not worth my time to redo my spreadsheet again from scratch for the benefit of someone who is being at best, obtuse.
  46. A Flanner in the Works for Snow and Ice
    Ken Lambert @123:
    "1)Your 97W/sq.m is based only on average incoming energy flux due to the difference in albedo from Sea Ice compared with Seawater for an range of incidence angles over the Arctic Summer above 75 degrees N."
    The highlighted phrase is ambiguous. Do you intend to indicate that I only calculated the difference in incoming energy between the early 1980s and the last few years that resulted from the reduced summer sea ice? Well, if so, yes. That is in fact what I have stated all along that I am calculating. Alternatively do you intend to say that I only took albedo into account in calculating this value? But that is a ridiculous statement given that I had just spent several paragraphs explaining the total number of factors I had taken into account including, path length through the atmosphere and consequent atmospheric absorption, cloud albedo, the relative footprint of solar radiation given the high latitude, and even the orbital eccentricity; with formulas given for how I handled each factor. Further, it is not just any range of angles of incidence. It is a range of angles that is traversed during an arctic day which underestimates the altitude of the sun for each time interval. Finally, you do not call the results of a calculation an assumption.
  47. A Flanner in the Works for Snow and Ice
    Tom, Ken; why don't you set up a google docs spreadsheet (maybe under an anonymous account or two) and plug your numbers / equations in? you could both edit it (it has track changes) and see if you can converge to an answer?
  48. A Flanner in the Works for Snow and Ice
    Mod, I purposely did not direct my comment at anyone in particular. I made a broad, general statement. You are free to delete the comment, if you see fit. I did hesitate for some time before hitting submit, weighing the alternative of simply disappearing from the thread in silence. But I felt that it needed to be explicitly said.
  49. A Flanner in the Works for Snow and Ice
    Tom Curtis #121 t looks like I will have to sort this out for you Tom, sonce you won't show your exact calculation: This is what you say you did at #73: "4) From the half hourly values obtained in (3), I calculated the additional energy absorbed by ocean surface exposed by melting sea ice as the difference between the albedo (0.9) of the sea ice and the albedo of the ocean given the angle of incidence, multiplied by the effective surface radiation (as calculated in 3). Taking the mean of that value, the average additional power absorbed by the ocean is 97 W/m^2. 5) Using that value, I calculate the total additional energy absorbed as 7.57 x 10^8 Joules per meter squared over a notional 90 day summer, or 1.51 x 10^21 Joules over the whole 2 million square km of additional ice cap melted over the period 1979-2011." Here are your asumptions as I understand them: 1)Your 97W/sq.m is based only on average incoming energy flux due to the difference in albedo from Sea Ice compared with Seawater for an range of incidence angles over the Arctic Summer above 75 degrees N.
  50. A Flanner in the Works for Snow and Ice
    I will not engage with anyone who demonstrates a blatant and total lack of integrity. I would hope that casual readers will recognize these traits for what they are, when demonstrated, regardless of that person's position, and so take anything stated by that person either now, previously, or subsequently with an appropriately healthy degree of skepticism. Trust should not be blindly given to those who simply state what you wish to believe. If anything, those are the people for whom the bar should be set highest, because they have you at a disadvantage, and so can take advantage of you most easily and completely.
    Moderator Response: [mc] While you are certainly free to question another's statement and advise others to question them, questioning personal integrity is not necessary.

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