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All IPCC definitions taken from Climate Change 2007: The Physical Science Basis. Working Group I Contribution to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, Annex I, Glossary, pp. 941-954. Cambridge University Press.

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Comments 95151 to 95200:

  1. CO2 was higher in the past
    Uncle Marc: Please take some time to get acquainted with SkS. See the newcomers guide, browse the 'Skeptic arguments.' There's a lot to learn; it will take some reading, but if you want to understand what's happening, it's well worthwhile. As far as the geocraft graph, see prior discussion starting with comment #6 on this thread, in which this graph gets debunked.
  2. A Swift Kick in the Ice
    RW1: "a much larger confluence of factors are determining how much ice melts or doesn't melt?" Into all of the accumulated threads on Arctic ice melt here on SkS (there are quite a few), you play the 'confluence of factors' card? Can you be any more specific? Offer some peer-reviewed science to back you up? "30 years isn't a very long period of time. The Artic climate is notoriously variable." We've posted the longer term reconstructions of Arctic ice on prior threads. The trend of summer minima is down and accelerating. Ice-free summers ... not too far off. You can find the graphics with 'Search'. "SEALS ARE FINDING THE WATER TOO HOT" Please. Quoting a single weather report from 1922 says nothing at all about climate and trends.
  3. A Swift Kick in the Ice
    Tom (RE: 60), "RW1 @56, and you were wrong about the average as I clearly indicated. As the second graph shows, there is little variation in Top Of Atmosphere annual average insolation north of about 60 degrees latitude. Insolation at the surface is more complicated because of cloud cover, but as the third graph shows, there is again little variation over sea north of about 60 degrees, with an exception north of Europe." Are you forgetting that the Earth is sphere and as you get closer and closer to the poles the angle increases, resulting in less and less insolation?
  4. A Swift Kick in the Ice
    RW1 @59, what a revelation. Do you mean to say that in the summer of 1922 arctic sea ice had no more extent (ice free in some locations as far north as 81.5 degrees than it has in the winter of 2011: Well that certainly puts a whole new perspective on things!
  5. A Swift Kick in the Ice
    Nice try RW1 @59. Really, this silly argument that "it has happened before" is a ridiculous red herring used to confuse and mislead lay people. Of course scientists know very well that conditions warmed between 1910 and 1940-- no-one in the know is denying that. However, the rate of warming then not as great as in recent times. Also, that was a transient event, what we are in store is going to last much longer. Anyway, this has all been refuted before, b/c this Monckton Myth #12 that you floated has been soundly refuted here.
  6. A Swift Kick in the Ice
    RW1 @56, and you were wrong about the average as I clearly indicated. As the second graph shows, there is little variation in Top Of Atmosphere annual average insolation north of about 60 degrees latitude. Insolation at the surface is more complicated because of cloud cover, but as the third graph shows, there is again little variation over sea north of about 60 degrees, with an exception north of Europe. @57, you appear to confused about which side of the argument you are on. You are arguing that high winter snowfall and ice formation will limit the summer melt, and hence the Ice albedo effect. But now your want to use a lack of correlation between winter ice extent and summer ice extent as proof that ice albedo effect is irrelevant. In fact, the proof of its relevance is given in my immediately preceding post where I point out the correlation between minimum summer ice extent and springtime temperatures. For a large initial (springtime melt) to reliably reproduce large summer reductions in ice volume independent of the summer temperature suggests a strong feed back mechanism in which early ice melts drive later ice melts.
  7. CO2 was higher in the past
    I've seen this graphic come up a few times to refute this argument and similar ones. Here's the original source: http://www.geocraft.com/WVFossils/Carboniferous_climate.html The page's author, Monte Hieb, is listed at the bottom. Poking around a little more on Google will give you a sense of his paleoclimate qualifications.
  8. A Swift Kick in the Ice
    Rob (RE: 54) "No one claims that the trend is going to be a steady decline. You get year to year noise in the data, as expected. If you look at the annual sea ice extent you'll notice that it only rebounded to the long term declining trend line." 30 years isn't a very long period of time. The Artic climate is notoriously variable. Consider this report from the US Weather Bureau: "THE ARCTIC OCEAN IS WARMING UP, ICEBERGS ARE GROWING SCARCER AND IN SOME PLACES THE SEALS ARE FINDING THE WATER TOO HOT. REPORTS ALL POINT TO A RADICAL CHANGE IN CLIMATE CONDITIONS AND HITHERTO UNHEARD-OF TEMPERATURES IN THE ARCTIC ZONE. EXPEDITIONS REPORT THAT SCARCELY ANY ICE HAS BEEN MET WITH AS FAR NORTH AS 81 DEGREES 29 MINUTES. GREAT MASSES OF ICE HAVE BEEN REPLACED BY MORAINES OF EARTH AND STONES, WHILE AT MANY POINTS WELL KNOWN GLACIERS HAVE ENTIRELY DISAPPEARED." The problem is this is from 1922!
  9. A Swift Kick in the Ice
    RW1 @52: Seeing you are discussing ice melt, you should be discussing Ice Volume rather than Ice Extent: Large reductions in ice volume correlate very well with elevated arctic spring time temperatures, so temperature is the determinant of arctic ice melt. Wind strength and speed, along with the extent of multiyear (thick) ice are additional factors determining ice extent. Of course, no body has claimed that the greenhouse effect or the ice albedo feedback are the sole determinants of global temperatures, let alone regional temperatures, which can vary based on a large number of factors, the most important of which regionally is the direction of prevailing winds. So you can put that strawman firmly back in the basket.
  10. A Swift Kick in the Ice
    Tom (RE: 55) "There will be less and less ice to melt, but as you point out, in winter that ice (and snow) comes back. Therefore the albedo can keep on decreasing as a result of earlier snow/ice melts and later snow falls and ice formation." Then explain why the winter maximum doesn't seem to be any indication of what the summer minimum will be? For example, why was the winter maximum less in 2006 than in 2007 yet the summer minimum was greater in 2006 than it was in 2007?
  11. Skeptic arguments about cigarette smoke - sound familiar?
    I might add another argument in favour of smoking:
    8. Smoking suppresses your appetite and helps keep you thin. We hear all the time about how obesity is nowadays the worlds worst public health problem, yet the fat alarmists never tell us how many lives are saved by tobacco keeping us trim.
    Similar in some ways to the argument that cold kills more than seven times as many as heat does. I'm not sure if that particular argument has been rebutted here or not. Perhaps this: Heat stress: setting an upper limit on what we can adapt to
  12. Skeptic arguments about cigarette smoke - sound familiar?
    Just read RJR CEO Colin Stokes' letter introducing Frederick Seitz as the head of the tobacco industry's medical research program. See if any of Stokes' arguments sound familier. http://legacy.library.ucsf.edu/tid/hzb66b00/pdf
  13. A Swift Kick in the Ice
    Tom, "However you are simply wrong about the insolation at the North Pole. At the height of summer, insolation at the north pole is at least 37.5% greater than that at the equator, and remains so for at least a month:" I meant lower average.
  14. A Swift Kick in the Ice
    RW1 @46: "Not really. There becomes less and less ice to melt, and you'll never melt it all because half of the year the Artic is dark and the ice grows back. Also, as more ice melts, you get closer and closer to North Pole, which means lower and lower insolation." 1) There will be less and less ice to melt, but as you point out, in winter that ice (and snow) comes back. Therefore the albedo can keep on decreasing as a result of earlier snow/ice melts and later snow falls and ice formation. 2) However you are simply wrong about the insolation at the North Pole. At the height of summer, insolation at the north pole is at least 37.5% greater than that at the equator, and remains so for at least a month: What is more, because of the structure of solar insolation, even the annual average is more or less constant above the arctic circle: So, what you are doing here is invoking speculations and errors of fact to refute empirical observations because in this instance you happen to prefer the model results. Your hoped for reduction of the effect will probably occur, but only once ice formation and snowfall are confined to those months and areas with no insolation, but by then the increased global warming due to the arctic sea ice albedo feedback will be an irreversible fact.
  15. A Swift Kick in the Ice
    RW1... "Then why was the summer minimum in 2008 over 16% larger than the record low the previous year in 2007" No one claims that the trend is going to be a steady decline. You get year to year noise in the data, as expected. If you look at the annual sea ice extent you'll notice that it only rebounded to the long term declining trend line.
  16. A Swift Kick in the Ice
    Time for a dog pile ;) Norman, choice of the base line makes no difference to the relative anomaly. By choosing the last ten years for the baseline, you may make the current anomalies look small, but you have done so by making the negative anomalies for earlier in the century much larger. They, of course, don't show up on your map. But we could do the reverse, say, choosing 1900 to 1910 with equal legitimacy.
  17. A Swift Kick in the Ice
    muoncounter (RE: 51), "So the time duration for your cooling-due-to-increased-albedo is shrinking." Then why was the summer minimum in 2008 over 16% larger than the record low the previous year in 2007, for example? What caused it to grow back (or melt less) just the next year and subsequent years after? How is this behavior consistent with positive feedback? Furthermore, why don't the smaller summer minimums in the Artic correlate with years where average global temperatures are generally higher and vice versa? If global warming is what is causing Artic sea ice melt and will cause more in the future, shouldn't this be the case? Or maybe a much larger confluence of factors are determining how much ice melts or doesn't melt? Also, what about the uncorrelated minimum trends in the Antarctic? What's your explanation for those? "And isn't that increased snowfall occurring in the winter, when Arctic albedo is irrelevant because there's little or no daylight?" Yes, but more snow can persist longer as the days and weeks move into the Spring - keeping temperatures colder, and thus reducing the overall amount of melting that occurs at summer minimum.
  18. Skeptic arguments about cigarette smoke - sound familiar?
    Nice post. It's especially relevant as the same people who put together the defense of cigarette smoking are working hard against the science of AGW. Here's one more: If everyone stopped smoking, it would put all those tobacco farmers out of work and that would harm the economy; that shows up at Economic impacts of carbon pricing.
  19. Meet The Denominator
    Alex... Great stuff. And well put. Just ordered a copy of the book. Their definition is interesting. It seems like it would eliminate most paleoclimate reconstructions that we rely on to understand climate today. But I'll check out the book.
  20. Skeptic arguments about cigarette smoke - sound familiar?
    Good work Mac. A small point - "Actually fire and smoke is necessary for some plants and seeds to grow in parts of Australia" - isn't true. It would be more accurate to say that "the growth and germination of many plants all over the world can be enhanced by smoke sometimes". This smoke thing isn't an adaptation of Australian plants, isn't an adaptation to fire, and isn't related to smoke from burning Australian vegetation. Your point is still valid (smoke, like CO2, is "good for plants") though.
  21. Skeptic arguments about cigarette smoke - sound familiar?
    Oh, I sure recognize the first argument about cigarette smoke. I've heard it a lot of times. Great comparison between the arguments!
  22. Meet The Denominator
    Here's the most conservative estimate for the denominator that I could find. It comes from The Atlas of Climate Change. I've scanned in a part of it here. Using the term 'climate change', they searched the database at Web of Science and found 17,761 papers published between 1971 and 2005. Bearing in mind that they define Climate change thus (my emphasis): 'A statistically significant variation in either the mean state of the climate or in its variability, persisting for an extended period (typically decades or longer). Climate change may be due to natural internal processes or external radiative forcing, or to persistent anthropogenic changes in the composition of the atmosphere or in land use. The UNFCCC, in its Article 1, defines it as: "a change of climate which is attributed directly or indirectly to human activity that alters the composition of the global atmosphere and which is in addition to natural climate variability observed over comparable time periods." This Atlas generally follows the UNFCCC's distinction between "climate change" attributable to human activities altering the atmospheric composition, and "climate variability" attributable to natural causes. Although often used to mean climate change, global warming is only one aspect of this - the increase in global mean temperature.' 850 papers is 4.8% of 17,761, making it very close to KR's estimate at comment 238.
  23. Meet The Denominator
    I've been moved to post on this site for the first time due to the utterly depressing nature of this thread. Poptech - I'd never heard of you before this, and I wish you no ill will, but after 600+ comments you've come across as someone who's much more interested in arguing rhetorical points for the sake of it, rather than investing time in learning about climate science. Your debating style reminds me of an evasive politician, and as such you lose a significant amount of credibility. As for the rest of you commenting here, you're all understandably exasperated with this, but it's made you lose your cool many times, which also diminishes your credibility. Please find some way to avoid this kind of situation in the future, because it damages the reputation of this otherwise useful resource.
  24. A Swift Kick in the Ice
    RW1: "as more ice melts, you get closer and closer to North Pole, which means lower and lower insolation." Warm water seems to melt ice quite well. From a study quoted in Science Daily 28 Jan 2011: ... the rapid warming of the Arctic and recent decrease in Arctic sea ice extent are tied to the enhanced heat transfer from the North Atlantic Ocean, ... "Such a warming of the Atlantic water in the Fram Strait is significantly different from all climate variations in the last 2,000 years," "Furthermore, increasing temperatures can lead to increases in evaporation, which can lead to increasing snow accumulations, which in turn increase the earth's surface albedo and have a cooling effect, which in turn can cause more ice to grow back." Wishful thinking, RW1? Countered by Markus et al 2009, who find that warming temperatures are pushing the melt onset date earlier and the freeze onset later. For the entire Arctic, the melt season length has increased by about 20 days over the last 30 years. Largest trends of over 10 days/decade are seen for Hudson Bay, the East Greenland Sea, the Laptev/East Siberian seas, and the Chukchi/Beaufort seas. Those trends are statistically significant at the 99% level. So the time duration for your cooling-due-to-increased-albedo is shrinking. And isn't that increased snowfall occurring in the winter, when Arctic albedo is irrelevant because there's little or no daylight?
  25. Global warming stopped in 1998, 1995, 2002, 2007, 2010, ????
    Continued from comment here by Norman. "The interesting thing about the GISS anomaly map above is the choise of base=line (1951-1980). This was a relatively cooler period of time and to use that to show Arctic warming may distort what has recently been going on. I went to the GISS page ... GISS Arctic temp map using 2000-2010 as the baseline. " A baseline needs to be a long time period -- its supposed to represent an average condition, so that anomalies are relative to that average. Your 10 year baseline doesn't accomplish that. It is interesting to choose an historically relevant baseline and look at the relative anomalies. Prior to 1946, carbon emissions were increasing at a steady rate; however, after WW2, carbon emission rates exploded. So much so that the cumulative CO2 emissions from fossil fuels after WW2 virtually eclipses all CO2 emissions in the prior 150+ years (you can verify this with data and graphics readily available at CDIAC). So 1900-1946 is a relevant baseline period. Here is the anomaly for 1970-1980. Here is the 1980-1990 anomaly. Fast forward, here is the 2000-2010 anomaly. Look at the numbers in the upper right hand corner, which are the estimated global means for the period mapped. It's obvious that warming rates dramatically increased in the '80s, nearly 4 decades after the rapid increase in CO2 emissions began. Considering that it takes time for the warming effect of CO2 to be fully realized (see the 40 year delay thread) that result is not surprising.
    Moderator Response: [DB] Your images aren't showing up anymore (and the links don't work so I no canna fix 'em). [mc] Aargh - should work now.
  26. Deep ocean warming solves the sea level puzzle
    Concur with zinfan94, I too calculate the same heat flux into the deep (deeper than 700m) ocean as the upper (less than 700m deep) ocean. I also find interesting the phase shift between the model and the data, which only has some small discussion on page 9. sidd
  27. A Swift Kick in the Ice
    Norman... Remember, we're trying to look at climate, not weather. Your choice of the most recent 10 years as a base line is wrong on many levels. 1) It's not statistically significant (too few years). 2) Comparing the past year to the most recent decade tells you absolutely nothing. Stick with a 30 year baseline.
  28. Deep ocean warming solves the sea level puzzle
    Thanks for the feedback Zinfan, I am pretty busy right now, which means that I cannot devote as much time to this as I would like. Yes, it will be interesting to hear Trenberth's thoughts on this, and I'd be curious to know what Pielke Snr's and other contrarians' spin will be on this. Ari, I realise they do not have any new observational data for the deep ocean, but surely their model calculates deep water temperatures, b/c they do calculate the contribution from the deep water to the SSL? Then again, a closer read of zinfan's post suggests that the deep water contribution to SSL was determined as a residual.... Anyways, if zinfan's maths is correct then this paper is very exciting indeed, at least in terms of trying to close the planetary energy budget.
    Moderator Response: (DB) My first read-through yielded the same interpretation as Zinfan.
  29. Deep ocean warming solves the sea level puzzle
    Albatross #8 Ari Jokimaki #9 and Ken Lambert #10 I read the paper last night, and found it very interesting. They used gridded satellite altimeter data for sea level and compared this to gridded ocean bottom pressure (OBP) from GRACE. They then took the upper level (700m) ocean heat content (OHC) info from XBT/ARGO and translated that into a steric sea level (SSL) contribution. The contribution of eustatic rise from ice sheet and glacier melt is removed, leaving the SSL contribution from the deep ocean heating in each particular grid cell. In these two paragraphs from the paper, they explain the deductive reasoning: [30] So far, we have mostly assessed the upper ocean (0–700 m) data, satellite SSH and OBP data, and compared them with the model. In this section we focus our attention on the deep ocean. Figure 12 shows the model deep ocean SSL below 700 m. Note that the seasonal variability in the deep ocean SSL is rather weak, particularly for the annual amplitude. This is consistent with the previous data assessment, suggesting that deep oceans contribute very little to the seasonal variability of the sea level. However, the story is different for the regional trends. The model suggests a significant deep ocean warming trend, particularly in the North Atlantic and along the Antarctic Circumpolar Current (ACC). The warming features appear closely related to the oceanic circulation and dynamics. As such they may provide an explanation as to why altimetry SLR cannot be adequately explained by the sum of upper ocean (0–700 m) SSL and ocean mass change calculated from GRACE (discussed in section 3). [31] In order to verify a possible hypothesis that connects the deep ocean warming to the missing part of the sea level budget closure, the following two conditions should be fulfilled: (1) The model deep ocean warming should be consistent with available bottom water measurements, and (2) its combination with the in situ upper ocean SSL and GRACE data should explain the altimetry SLR in both global mean and regional trends. In the following we discuss these two conditions in more detail. They estimate that eep ocean heating contributes about 1.1 mm of the observed 3.1 mm per year of sea level rise (SLR). The paper also shows significant regional deep ocean warming variation, with the Southern Ocean and portions of the Atlantic warming much faster. The authors compare the regional results with other studies and discuss many similarities and a few discrepancies. Although not discussed in the paper, this amount of SLR should translate into the deep ocean acting as a heat sink with a rough estimate that the deep ocean is taking as much as 70 x 10^20 J per year of the planetary energy imbalance, roughly the same as the upper 700m level. In essence, this would close the planetary energy budget, and confirm the planet is heating about 0.9 W per square meter, the estimated top of atmosphere (TOA) imbalance from AGW models (and roughly confirmed by measurements of outgoing longwave radiation). Dr. Trenberth has published extensively on the planetary energy imbalance, and it will be interesting to hear his views on the Song and Colberg results. This paper may go a long way in helping resolve the famous “Trenberth Travesty”.
  30. A Swift Kick in the Ice
    Norman: Don't you think a comparison of what happened last month to what happened in the last 10 years has a major sample bias issue? Like comparing what happened yesterday with what happened last week? For further discussion of recent surface temperatures, go to Global warming stopped in ...
  31. Deep ocean warming solves the sea level puzzle
    This new paper or Purkey & Johnson do not depend on the 0,64 W/sq.m figure. It's just used in Purkey & Johnson to compare their result. This new paper doesn't seem to use it in any way.
  32. A Swift Kick in the Ice
    The interesting thing about the GISS anomaly map above is the choise of base=line (1951-1980). This was a relatively cooler period of time and to use that to show Arctic warming may distort what has recently been going on. I went to the GISS page (At this time I do not know how to paste a map on a post so I can only send a link) and put in this last decade for the baseline. The Global temp for January is lower than the last decade and the Arctic warming does not look too severe except around Greenland. Going to the Arctic sea ice page this is explaine by a negative Arctic Oscillation: Quote from the page "Arctic sea ice extent for January 2011 was the lowest in the satellite record for that month. The Arctic oscillation persisted in its strong negative phase for most of the month, keeping ice extent low." The negative phase kept parts of the Arctic warmer but created much colder weather in other areas as this cold air was able to move much further south. GISS Arctic temp map using 2000-2010 as the baseline.
  33. A Swift Kick in the Ice
    As someone else has eluded to, for the last 4 years the arcitc sea ice level has been well below 2SD deviations from the 1979-2000 mean. This means all things being natural variation that there has been a 1:100 year at least event in the arctic every summer for the last 4 which would be a rarity I'd of thought. It is most likely from sea ice extent estimates and arctic temperature reconstructions that the arctic hasn't had this little ice in the summer and this high a temperatures since the thermal maximum if not longer and the trend for temeprature change in keeping with the Northern hemisphere insolation averages was for a slow cooling until 100ppm of CO2 was dumped into the atmosphere in a very short period, when the arctic temperature suddenly started to rise again. The arctic really should be cooling all things natural! Due to natural variation 2010 should have been on the cold side, unless of course the recent paper in nature saying the solar max and heat in put min. is correct. However if it is correct then there is no accounting for the LIA cooling other than the very slight drop in CO2 at the that time, which would mean CS to CO2 is very significant, so lets maintain that low sunspot activity means lower general earth temperatures, thus the none activity from 2008-2010 should have been a signifcant cooling effect of about 0.1-0.15C from the mean, La Nina (which was strong) and El-Nino (which wasn't strong in early 2010 until May) somewhat cancle each other out but still overall a cooling effect! Do wonder if the earth has slipped into a new phase with a higher median temperature with 2010 representing a low year in the natural variance? Would be in keeping with chaos for the climate to start to do jumps or leaps from one phase of being to the next. Anyway it is more likely that despite being much warmer in the pliocene and previous inter-glacials that the arctic ocean was still only free of ice in the summer. Virtually ice free summers do seem inevitable by 2050 at the latest, this is sobering stuff, for it will accelerate warming locally as water will warm up alot more than it did basking in the long summer sun and will release this heat in the Autumn. Lots of amplification potential and less latent heat exchanges which mean the artic winter to summer temperature differential will be amplified. Interesting times, new weather patterns to emerge, extreme events to witness and new arctic tourist industry to set up. Swim with the, ?who knows? Lets face it CO2 emissions aren't seriously going down any time soon so what were does leave us?
  34. Climate Models: Learning From History Rather Than Repeating It
    Way back in December 2006 I attended a lecture on "climate change" at the Perimeter Institute for Theoretical Physics where the presented stated that "all climate models predict warming" and only differ on the point of no return. I just stumbled onto this lecture which can be viewed by clicking the following link: From here to eternity: Global Warming in Geologic Time
  35. Monckton Myth #13: The Magical IPCC
    The MWP is is alive and well and it is shown in AR4. Northern hemisphere temperature variations from AR4 Figure 6.10c are shown below. I have deleted the instrumental temperature from HadCRUT2v data so that only proxy records are compared. Note that there is a distinct MWP comparable to the current warming period.
    Moderator Response: [Daniel Bailey] Yes, if you hide the incline (wherein we've equalled the maximum temperatures reached in the Holocene Altithermal), then a regional temperature excursion like the MWP does become more evident. Do you have a point with this exercise?
  36. A Swift Kick in the Ice
    Tom Curtis (RE: 41), "RW1 @33, in 30 you quoted 0.2 w/m^2 per degree centigrade of global warming. That would mean the effect of polar amplification is 0.6 w/m^2 at 3 degrees of global warming, or 3.6% of the total effect. Of course, the figure you quoted is that derived from models which are underestimating the extent of sea ice loss in the arctic. Based on observation, the net forcing for the ice and snow loss to date is 0.62 w/m^2, and we have not yet experienced a full degree of global warming. That suggests the total effect could result in 7 to 10% additional warming, or up to an additional degree centigrade by the end of the century." Not really. There becomes less and less ice to melt, and you'll never melt it all because half of the year the Artic is dark and the ice grows back. Also, as more ice melts, you get closer and closer to North Pole, which means lower and lower insolation. Furthermore, increasing temperatures can lead to increases in evaporation, which can lead to increasing snow accumulations, which in turn increase the earth's surface albedo and have a cooling effect, which in turn can cause more ice to grow back.
  37. Deep ocean warming solves the sea level puzzle
    Ari Jokimaki #9 & zinfan94 #7 If the above paper is using Purkey & Johnson quoting Lyman 2010 viz: "From 1993 to 2008 the warming of the upper 700 m of the global ocean has been reported as equivalent to a heat flux of 0.64 (±0.11) W m–2 applied over the Earth’s surface area (Lyman et al. 2010)." - then it is probably wrong. The 0.64W/sq.m is derived from linearizing a step jump in OHC over the 2002-04 period which has been extensively discussed elsewhere on this blog.
  38. A Swift Kick in the Ice
    @17 HPB “From what I can see and knowledge of history, like everything else on this planet it goes in cycles. One minute we are hot another cold. One minute theres ice and the next there is not. I can remember as a child rivers (salt) freezing over in southern England that you could walk on.” We have had some slight variations in the climate in historical times, for instance the Medieval Warming Period and the Little Ice age, but you shouldn’t compare f.i. a time in which it was possible to ice skate on the Thames in Winter (the little ice age) with a time in which the whole of Europe was covered in an ice layer 2 kilometers thick (a genuine Ice Age). Likewise, the worst case scenario: triggering a runaway greenhouse effect would have consequences that cannot in the least be compared to the medieval warming period. It is true that drastic climate changes have taken place in a more distant past due to natural causes so strictly speaking the current warming is not unprecedented in the entire history of the earth. But you have to understand that these past climate changes have led to mass extinctions, and a virtual standstill of the evolution for millions of years (look up for instance “snowball earth” or the “perm-trias mass extinction event”). The argument that sea ice melt or temperature trends have occurred in the past is in itself not comforting at all. I think this is a major problem with most people. They still think that climate change means we’re going to have a climate comparable to the south of France (at least that’s what people in Belgium think ). They even welcome the thought. We also know that the arctic regions were once fertile and that Mammoths were frozen in situ as they grazed these areas. In Roman times grapes tropically grown fruit was being farmed in Scotland and CO2 level were supposedly higher then than now as well as temperatures higher than now. Average global temperatures are currently higher than during the MWP, and still rising. CO2 levels have never been this high in historical times. They are the highest in 800000 years and very likely the highest since the origin of mankind, 3 million years ago. We are creating conditions on this planet that have not prevailed since the dawn of mankind. The consequences are difficult to predict, but knowing from the past how strong the earth’t climate may react to different conditions, we should prepare for the worst.
  39. Meet The Denominator
    #611 Thanks Muoncounter, I no longer need to read any more of this car-crash of a thread.
  40. A Swift Kick in the Ice
    One pretty strong argument you can use in the discussion with the deniers is that even gas and oil companies believe that the arctic ice is disappearing (although it is still unclear whether this means that they endorse AGW). In every case they are in full battle for the rights to drill for oil and gas in the Arctic Sea.
    Moderator Response: [Daniel Bailey] Even Shell Oil Company, to their credit, is on record as accepting the findings of the IPCC AR4.
  41. A Swift Kick in the Ice
    Thanks for going to all the trouble to ensure that the public are as well informed as possible. A prodigious output for a one man site. Unfortunately, for every day that action is delayed because the public is presented with conflicting information, a lot of it unsupported, or supported in a misleading way, vote-seeking politicians have an immediate need to hang fire. As things stand, to quote Bob Dylan, the 'sceptics' are 'winning the war while losing every battle' (Bob Dylan).
  42. The Dai After Tomorrow
    Marcus #28 Ill be back. An idea might be what RC do and allow an open thread for no holds barred discussion on anything. More on topic Im in New zealand we have just had our hottest January - Febuary on record. Ive been having an intersting lengthy debate wth some political hacks using SC as a reference source. Im Gandalf. http://www.nzherald.co.nz/climate-change/news/article.cfm?c_id=26&objectid=10701558&pnum=2
  43. Philippe Chantreau at 18:23 PM on 19 February 2011
    Meet The Denominator
    How can I sample results that I do not have and cannot obtain? Why will you not disclose your sampling method? The method matters little or not at all. Why can't you make up your own? You're not good enough with Google Scholar?
  44. Deep ocean warming solves the sea level puzzle
    dorlomin #1: I didn't see mention of aquifers in this study. dorlomin #2: Read the Purkey & Johnson mentioned above. They seem to suggest that Southern Ocean plays a large role (by circulation) in the deep ocean warming. Andrea Silverthorne #3: Methane has not risen much during the study period of this paper (1993-2008). Atmopheric methane concentration has been quite steady since 1999 (although it has been rising again since 2007). There's also Dlugokencky et al. (2009), who say that "Near-zero CH4 growth in the Arctic during 2008 suggests we have not yet activated strong climate feedbacks from permafrost and CH4 hydrates." By the way, there's a new paper out that gives satellite measurements of methane concentration. actually thoughtfull #5: It seems to me that the amount of warming discussed in Purkey & Johnson might not be enough to close that budget, but it would be nice to see actual analysis on that. Here's a relevant quote from Purkey & Johnson: "From 1993 to 2008 the warming of the upper 700 m of the global ocean has been reported as equivalent to a heat flux of 0.64 (±0.11) W m–2 applied over the Earth’s surface area (Lyman et al. 2010). Here, we showed the heat uptake by AABW contributes about another 0.10 W m–2 to the global heat budget." Albatross #8: They didn't calculate deep ocean OHC in this paper. They used an ocean model to determine the deep ocean situation, so they don't actually have any new observational data.
  45. A Swift Kick in the Ice
    Albatross @40, yes, I love the fact that Arrhenius got it so right so long ago. The one area in which he slipped up was Antarctica, which was a virtual unknown at the time. The first attempt to reach the South Pole did not even set out until four years after his paper. SFAIK, there are three crucial distinctions about Antarctica. The first is that rather than sea ice, it has ice sheets which cannot melt to bedrock in a season, or even in a hundred years; thus side stepping the mechanism of polar amplification. The second is the uninterrupted ocean of the Antarctic ocean allows circumpolar currents and winds that drastically reduce heat transfer between the tropics and the antarctic. The original mechanism identified by Arrhenius only works because the polar regions recieve a significant amount of heat from the tropics, and as the Antarctic receives much less than the Arctic, the effect is much weaker there. The third is the unusual fact that due to the extreme cold of Antarctica, especially in winter, sometimes there is an inverted lapse rate over the continent. The surface temperature in these circumstances is actually colder than the tropopause. When that happens, the effect of increased greenhouse gases is to cool the continent rather than to warm it. It is uncertain what the net effect of this is. I believe most models predict much reduced warming, though at least one has predicted cooling for Antarctica.
  46. A Swift Kick in the Ice
    RW1 @33, in 30 you quoted 0.2 w/m^2 per degree centigrade of global warming. That would mean the effect of polar amplification is 0.6 w/m^2 at 3 degrees of global warming, or 3.6% of the total effect. Of course, the figure you quoted is that derived from models which are underestimating the extent of sea ice loss in the arctic. Based on observation, the net forcing for the ice and snow loss to date is 0.62 w/m^2, and we have not yet experienced a full degree of global warming. That suggests the total effect could result in 7 to 10% additional warming, or up to an additional degree centigrade by the end of the century.
  47. The Dai After Tomorrow
    Re: TOP (29) 1. Thank you for your perspective. 2. The study discusses in exquisite detail, replete with sourced references, the entire field of drought in a warming world up to the present day even before it attempts to look at what the future may bring. Could you explain what you mean by:
    "The computer models just charged on into the far distant future with no correlation to actual future events."
    Suggesting that we must wait until after a speeding train hits us before deciding if we should have gotten out of the way seems logically impoverished to me. As do BP's ramblings on past conditions, which occurred under far different circumstances than today. 3. Models used in the study were the 22 coupled models used in the IPCC AR4. 4. On pages 13-14 of the study, that is discussed. Essentially, India gets progressively wetter though increased precipitation (which in its case is expressed as more frequent precipitation, as opposed to more precipitation when it does rain): FIGURE 10 | Multi-model mean changes from 1980–1999 to 2080–2099 under the SRES A1B scenario in annual (a) precipitation (mm/day), (b) soil moisture (%), (c) runoff (mm/day), and (d) evaporation (mm/day). The stippling indicates where at least 80% of the models agree on the sign of the mean change. (Meehl et al 2007) The Yooper
  48. A Swift Kick in the Ice
    Tom @14, You are right, the framework which he used to make those calculations was in fact a simple model. In my original post I was thinking more in terms of the sophisticated and complex models (i.e., AOGCMs) that we are familiar with today, and not communicating very eloquently (my own lapse) that in fact there are some very basic (yet solid) physics are at play. Fascinating that Arrhenius predicted current events so very long ago.
  49. Deep ocean warming solves the sea level puzzle
    Zinfan94, I was wondering how this translates into OHC. Have yet to look at the paper, but I'm wondering if they calculated OHC? If yes then it sure would be nice to see those data; if not, their data could probably be used to calculate OHC.
  50. Meet The Denominator
    "You have still failed to disclose your sampling methods." I'm sorry I didn't notate the process. Make up your own. It won't make an appreciable difference in the results.

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