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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 59451 to 59500:

  1. Alberta’s bitumen sands: “negligible” climate effects, or the “biggest carbon bomb on the planet”?
    Thanks Andy for this insightful article. There is one thing that I would like to point out. Discussion of this paper has largely centered around Figure 1, and inferred that it is a comparison of oil-sands to other fossil fuels, and in this context that oil sands are not too bad. In fact this was not the intention. If you read the text of SW12, we calculate that North American usage of the tarsands would lead to massive per capita carbon footprints, although this point is barely reported anywhere (including here). We never state anywhere that tarsands emissions are "negligible", but rather the opposite, with statements like "The eventual construction of the Keystone XL pipeline would signify a North American commitment to using the Alberta oil-sand reserve, which carries with it a corresponding carbon footprint [ of 64 tonnes / person ]." But recognizing that North Americans only comprise 5% of the global population we then state "...many other sources of fossil fuels will also be needed if growing Chinese, and indeed worldwide, energy demand is to be met through the exploitation of fossil fuels." We calculate the potential for warming of other resources to compare them with the 2°C 'guardrail', not necessarily with each other . That is, we recognize that people in other parts of the world do not have tarsands themselves, but if they follow the Albertan example on hydrocarbon exploitation for energy, they will extract what is locally available to them. I believed this to be important because in and of themselves, the tarsands cannot take us over 2°C, BUT large scale extraction of fossil-fuels globally could lead us to exceed that limit many-fold. In other words, the message is "if we do this in Canada, we should expect that others globally will follow our example, in which case the warming will be large". This is discussed in detail at our website. -Neil
  2. ABC documentary demonstrates the how and why of climate denial
    Anna Rose penned a brief rebuttal article. “Climate change isn't a plot, it's science”, Sydney Morning Herald, Apr 27, 2012
  3. ABC documentary demonstrates the how and why of climate denial
    It's difficult to comment because, being in the UK, I've not seen the show. However it seems to me that if, as Dana says, only 3 from Anna Rose's side got to speak against 5 from Minchin's, then the whole balance basis for the show was blatantly skewed. Also, from this clip, it seems like only the 'expert guests' did much speaking, so -- given that your average 'don't know' viewer doesn't really know what the 'experts' are talking about, then it seems that the whole take home message must be that there's a big disagreement about whether climate change is real. The lesson for all climate scientists must be: don't agree to appear on any programme unless you know for certain that the producers are -- at the very least -- neutral; or that it's a debate being transmitted live. Giving a 'Martin Durkin'-type 'sceptic' producer permission to make fast and loose with the scissors on your interview is a recipe for disaster.
  4. Alberta’s bitumen sands: “negligible” climate effects, or the “biggest carbon bomb on the planet”?
    Ryan, thanks. You can find what you are looking for in the Supplementary Information for Swart and Weaver's paper which, I believe, is open access. The Matthews et al paper has more background on the delta T calculation methodology.
  5. Alberta’s bitumen sands: “negligible” climate effects, or the “biggest carbon bomb on the planet”?
    Excellent Article. Where do you get the numbers for converting bbl oil to gtC and TtC to deltaT? I've been looking for a sourced database of these constants for awhile.
  6. ABC documentary demonstrates the how and why of climate denial
    People looking for the missing Admiral Titley or Naomi Oreskes segments could have a look at their "web extras" page I assume they will work outside of Australia...
  7. ABC documentary demonstrates the how and why of climate denial
    Well I am not the first to say it, but democracy is incapable of dealing with climate change. And the ABC removed any lingering doubts.
  8. Global Warming Causing Heat Fatalities
    Chip (#51) says, "I am not an economist". I think I knew that. Neither am I but, unlike you, I do not second-guess genuine experts in any field. I acknoweldge that 'the marketplace of ideas' is a dangerous fallacy; and that climate change is not a hoax, a false alarm, or a potential benefit to humanity: http://lackofenvironment.wordpress.com/2012/04/27/worlds-biggest-watermelon-found-in-washington-dc/
  9. Michael Whittemore at 17:18 PM on 27 April 2012
    Shakun et al. Clarify the CO2-Temperature Lag
    The stopping of the AMOC would have caused considerable warming, but very little of its effects would have been able to cause a global forcing as CO2 does. Without a prolonged global forcing from added CO2, the AMOC would have come back on after cooling of the north had reduced melting. This would have simply had caused the Earth to go back into the LGM as short lived GHG dissipated. Its seems so logical to see CO2 is the control knob of climate.
  10. Levitus et al. Find Global Warming Continues to Heat the Oceans
    anthony the rate at which the ocean warms tells you what the earth imbalance is, not the forcing. You're confusing the two terms, they may look the same but they're not. The forcing gives you the imbalance produced by an agent (sun, GHG, etc.) while keeping the temperature constant and allowing no action by the feedbacks. The former tells you the actual energy imbalance while the system evolves. For example, immagine to apply a instantaneous constant forcing. At time t=0 the imbalance equals the forcing. At later times the planet warms and the imbalance gets smaller untill it's zero when the new equilibrium is reached. The 1.6 W/m2 from 1750 is the forcing and it would also be the imbalance if you magically prevented the planet to warm and the feedback to operate. But the planet has obviously warmed and the feedbacks operated; Levitus' imbalance tells you what is left to reach equilibrium. This is what someone call the warming in the pipeline.
  11. Levitus et al. Find Global Warming Continues to Heat the Oceans
    trunkmonkey @19, autumn temperatures keep on rising after the peak of the summer sun has passed because they are still cooler than the equilibrium temperature for the current (autumn) insolation. When the equilbrium temperature for the current insolation drops below the actual temperatures, temperatures start to decline. That the ocean continues to warm therefore proves that the Earth has not reached its equilibrium temperature for the current forcing. The rise in insolation from the purported "grand solar maximum" is so slight that the Earth passed the equilibrium response to that increase long ago, and hence the reduction of insolation since the 1980s does not result in continued warming due to thermal inertia, but instead partially compensates for the increasing anthropogenic forcing.
  12. Levitus et al. Find Global Warming Continues to Heat the Oceans
    One would expect the oceans with their massive heat capacity to continue warming after a diminution of "forcing" just as autumn temperatures lag the departure of the Summer sun.
  13. ABC documentary demonstrates the how and why of climate denial
    bill @24 - indeed, the entire premise of the show was a bad idea. Minchin was quoted in the Sydney Morning Herald yesterday as saying that the documentary was a “terrific opportunity to convey to an ABC audience that there remains a significant debate." So he flat-out admits that just by ABC airing the show he wins because it creates the impression of a "debate" where one does not exist. Apparently the program showed 5 'experts' from Minchin's side and 3 from Anna Rose's. If it were realistic, Anna Rose should have had 33 experts to Minchin's 1. Though Minchin's "experts" were a pretty sorry bunch. But the bottom line is that the audience comes away thinking there's a debate on the subject, so Minchin is right that he (meaning his agenda of sewing doubt and delaying action) automatically wins.
  14. Levitus et al. Find Global Warming Continues to Heat the Oceans
    anthony @16, predictions of the equilibrium climate response include the Planck feedback function which you describe (and which is explained in more detail by Chris Colose here). So your argument amounts to the claim that a prediction which incorporates the Planck feedback cannot be realized because of the Planck feedback. I still remain mystified as to why self describe "skeptics" think that simply citing a well known physical effect which is incorporated into all Global Circulation Models (GCMs) (as both the Planck feedback and Beer's Law) will show the predictions of those GCMs to be false, without any need of calculation on their behalf. It is as though they thought yelling "But E=mc^2" would disprove the special theory of relativity.
  15. ABC documentary demonstrates the how and why of climate denial
    Bill's point at #24 is pretty much the fact of the matter. As much as I admire Anna Rose's enthusiasm, the fundamental premise of the program was to use evidence to convince the opposing party of the error of their interpretation - to wit, "I can change your mind about climate". However, the actual exchange largely did not involve a critical analysis and subsequent discarding of the invalid material cherished by the denialists, and I (unsurprisingly) saw no consensus science refuted by the denialists, nor any acknowledgement of this fact. There were moments where refutation of denialist points did occur, but they were rare (when they should in fact have been the meat of the venture). Instead, Minchin and his agents were allowed to replay their fouls after a few minutes in the sin bin. If there had in fact been an impartial, objective analysis of the truth and the myth of climate science, each lie and inaccuracy would have been sequentially identified, examined, shown for its invalidity, and then not be permitted to be used again. Where such were raised after refutation, there should have been a red cross superimposed on the scene, with a reference to the refutation... heck, Skeptical Science's numbered points could have been used as a resource here... One of the most serious injustices of the show was that Anna and the producers allowed Minchin to frame the putative correct position to lie in the middle between two 'extremes'. There is no half-pregnant truth about scientific fact, and the IPCC summary that most use as a basis for discussion is a very conservative summary of the evidence. Further, the results of warming are not a single point in time and space: the longer and the more than humans continue to pollute the atmosphere with excess CO2, the closer we drive the final condition to the 'extremes' that (real) science unavoidably indicates will occur. As a follow-on from the previous paragraph, it's interesting to note that Minchin denies that he is denying science - he refers to himself as a sceptic (when he is in fact denying rather than exercising genuine scepticism) - whist simultaneously referring to scientists as "warmists". The term "warmists" is a propaganda-based one, calculated to convey the impression of people who are ideologically attached to the idea of human-caused warming of the magnitutde predicted by science. However the fact is that the conclusion simply emerges from the scientific evidence: it is not an emergence of ideology or of political inclination. Minchin is simultaneously trying to have his semantic cake and eat it. Changing the subject, vrooomie, be my guest! Just remember to account for the late-night mislabelling that I corrected at #15.
  16. ABC documentary demonstrates the how and why of climate denial
    bill @ 24: I wholeheartedly agree. The whole call for "debates" is only ever going to result in a win for the deniers. Just like scientists no longer 'debate' creationists because it's like playing chess with pigeons, or mud wrestling a pig - however it goes, the other camp will always declare themselves the winners. Plus, the British style of debating is one of the most vile inventions I have ever had the misfortune to come across; purely antagonistic, noting is ever resolved, and in the end it all comes down to charisma, not facts - in other words the domain of demagogues.
  17. ABC documentary demonstrates the how and why of climate denial
    The deniers won this debate the moment it was announced. There's a debate - so; there's a debate! Then all of the above. Can we please stop being so bloody naive about this? When you come from a political campaign background watching folks - no matter how earnest or charming - taking careful aim at their own feet gets very frustrating... Consider some truths of the world of campaigning. If you don't have the numbers - don't hold a rally! Do something creative and eye-catching instead. 20 people who know what they're doing can be far more effective than 2000 standing around with placards. If you do have a rally and you're likely to get 2000 people along - don't ever say you'll get 5000! Say 1500 and be thrilled that 'turn out was higher than expected'. Deploy the high estimate and News Limited will announce 'organiser's were disappointed with the low turnout'. Don't let the work-experience kid near a microphone, and establish a media policy that ensures only people who've been briefed on what to say speak to the media. Your media people are getting a message to the public and should dress and speak accordingly - that is, in a professional manner. Don't give the 'hostile' media cameras an opportunity to just hone in on the 'ferals' in order to represent the group. These are all things people I've worked with over the years will tell you they've learned from bitter experience. (Who knows, maybe some day our side will realise that sitting at home being right isn't going to be enough, and then these tips may be useful!) After the string of fiascos, such as 'debating' Monckton - kudos to Peter Hadfield for being the only antagonist to have worked out how to clearly demonstrate that he's all mouth and no trousers - here's some other suggestions: Send only your heavy-hitters to deal with the other side. Give them PR training just as every other public performer has to get. Don't set yourself up to be in a defensive position responding to a Gish Gallop welter of claims. Don't let vital points - such as 'it hasn't warmed for 15 years' or 'it's the volcanoes' - go unchallenged; this was so obviously going to come up, how could it possibly have got through? Don't let your position be represented by someone who's chief interest may well be a political defence of their institution, not the science. Make sure the 'live science' response blog will work! :-) And, most of all: Don't allow a scientific debate to be miscast as a rhetorical debate in the arena of infotainment.
  18. Two Centuries of Climate Science: part one - Fourier to Arrhenius, 1820-1930
    Excellent article in the new issue of American Scientist about William Herschel's experiments with infra-red. He quickly realized (in 1800) that he'd have to isolate his thermometers from the effects of conduction and convection in order to study radiation. That's a lesson that many more modern would-be Galileos haven't figured out! Unfortunately, this article requires a subscription at the moment.
  19. Levitus et al. Find Global Warming Continues to Heat the Oceans
    anthony - "Given this for CO2 forcing to continue to have a temperature effect must it increase at a greater than linear rate as well?" CO2 is increasing faster than exponentially, according to Tamino's analysis, meaning that forcing is increasing faster than linearly. Even linear forcing means the climate is in a constant state of catch-up - faster than linear forcing is not good news.
  20. Levitus et al. Find Global Warming Continues to Heat the Oceans
    Yes, I saw Tom's comment. There are 2 issues here; the forcing and the heat accumulation as a proxy for the delayed temperature stabilising effect which is the equilibrium sensitivity. In this respect is CO2 forcing mitigated by Stefan Boltzmann and Beers Law effects to such an extent that further increases in CO2 at a linear rate do not have further temperature increases, or at least only minimal ones. The reason for this is that Stefan Boltzmann effects are non-linear: From 200K-250K radiated energy increases from 91-222 W/m^2 – an increase of 131 W/m^2. From 300-350K radiated energy increases from 459-851 W/m^2 – an increase of 392 W/m^2. This is a result of T^4. Given this for CO2 forcing to continue to have a temperature effect must it increase at a greater than linear rate as well? And does this explain Levitus's finding of a reduced forcing for extra CO2?
  21. ABC documentary demonstrates the how and why of climate denial
    Q&A show was disappointing, considering the panel participants. I'm especially disappointed with the attitude of Dr Megan Clark from CSIRO. With many myths fying around, she did not even try to correct any of them. For example, one question from the audience directed at her stipulated: "How do we know our CO2 emmitions are the largest? There are other CO2 emmission sources, i.e. volcanoes...". Megan knows for sure how misleading the last sentence is, so she should be able to debunk it with scientific facts and some hard numbers. But instead she's choosen not to give any facts but to repeat her cliche statement: "we are here to provide the research and not engage in policy discutions", as if she was told not to engage in any controversy because she must "stay neutral". However by staying neutral she kept silent when both panel members and an audience made incorrect claims. IMO, that's not responsible attitude of a sicentist, the only scientist in that panel.
  22. ABC documentary demonstrates the how and why of climate denial
    It appears that Nick has not learned a thing from the encounter, considering this commentary on The Age site. He even trots out the old "no warming since 1998" rubber duckie. And while his bias is so entrenched, he has the gall to accuse the ABC of being "not renowned for its balance on this subject". How very boring this is getting; I'm off to battle the Expanding Earthers.
  23. Levitus et al. Find Global Warming Continues to Heat the Oceans
    anthony @14 - I would direct you to Tom Curtis' comment in the link you provide (the second comment), which points out where the argument Stockwell and Pielke are making is completely wrong.
  24. Lessons from Past Predictions: Vinnikov on Arctic Sea Ice
    #7 Chris - what you say reminds me of a paper I saw where the researchers used something like the average latitude of the Arctic ice edge to estimate retreat rates. This cleverly gets around the problem of Asia and Canada being 'in the way'. IIRC, one interesting conclusion was that winter retreat is also rapid as the ice edge creeps northwards, but it does not show up so well in extent measures as the area of ice involved is smaller. Unfortunately I cannot recall enough about the paper (authors, title) to locate it for you, or remember specific details, strengths and weaknesses of the paper.
  25. michael sweet at 09:20 AM on 27 April 2012
    Weird Winter - March Madness
    Jeff Masters referred to the "winter in April" theme TOP started today on his blog "At least 36 of the roughly 400 major U.S. cities that maintain automated weather sensors at their local airports (8%) have set or tied all-time April high temperature records so far this month; no all-time April cold records have been set. The U.S. has been on an extraordinary pace of setting high temperature records so far in 2012. During March 2012, an astonishing 32% of all the major airports in the U.S. set all-time March high temperature records. For the year-to-date, there have been 184 new all-time monthly high temperature records set at the major airports, and 6 all-time monthly low temperature records. Not surprisingly, the period January - March this year has been the warmest such period in the U.S. since record keeping began in 1895." This did not include the past 24 hours of records which had at least 6 monthly all time highs (but no low records). I cannot imagine why the press is not trumpeting all the cold! There is still 4 days left in April, perhaps we will have one cold record for the month.
  26. Levitus et al. Find Global Warming Continues to Heat the Oceans
    Forcing is not a product of time; with a temperature response to a sustained forcing over time, as is supposed by increases in CO2, the temperature response is itself a negative feedback to the continued forcing via Stefan Boltzmann effects. This would mean a measure of the effect of a forcing after that forcing has been active for some time should show a lessor temperature response which would be reflected in turn by a reduced forcing. In this respect Levitus's finding seem to be confirmatory. The other ramification is that this decline in forcing will mean that the predicted Equilibrium Climate Sensitivity temperature response in a few centuries time will not occur. David Stockwell is discussing this point here: http://landshape.org/enm/levitus-data-on-ocean-forcing-confirms-skeptics-falsifies-ipcc/
  27. Renewables can't provide baseload power
    It's worth noting too that Australia didnt go through NZ-style economic reforms in 80s, 90s so things are done differently. With economic "drys" in command in both parties over that period, NZ is a different place. I dont buy the idea that generation isn't built without a deal. If no generation is build, electricity price would soar - if a company doesnt move to catch that profit, then a competitor will. A variety of companies are building new generation.
  28. Global Warming Causing Heat Fatalities
    Chip @62 uses an analogy of wolves killing sheep, and argues for protecting the sheep. A better analogy to global warming is a case where your neighbour is breeding wolves, and it's his wolves that are killing your sheep, not the one's nature left running around in the woods. It would appear that Chip thinks having the neighbour breeding wolves is good for your sheep farm, because it will force you to adapt and improve your defences against all wolves, including the small number that existed naturally. Why Chip doesn't think that stopping your neighbour from breeding wolves is a good idea, I can't say, but that's the analogy to his position on heat stress.
  29. ABC documentary demonstrates the how and why of climate denial
    A suggestion re the debate between both positions on climate science. Sceptics normally want to have the two positions defended with equal numbers and of course they argue that the 97% of climate scientists believe in ACC is flawed. So why not suggest that a panel of 20 climatologists debate it. The participants could be chosen at random. This would surely show that the vast majority of climate scientists do indeed support the IPCC position. The point should be apparent that the reason 2 v 2 in a debate is inappropriate is that it would be unrepresentative!
  30. ABC documentary demonstrates the how and why of climate denial
    Minchin failed to acknowledge the CSIRO position relying on standard evasive cliches bordering on lies. From the audience Matt England comprehensvely refuted Minchins comments on warming in the last decade, the IPCC models and UEA. Within minutes Minchin bounced back all smiles as if nothing had happened. I think the general public switches off technical issues and looks for certainty.
  31. ABC documentary demonstrates the how and why of climate denial
    It was disappointing that the ABC gave sceptics greater freedom (in the subsequent QandA the scientists were in the audience) but for most people the important issue is that there exists a debate and they are free to participate. The fact that the debate is over a known, like the earth is round not flat, appears to be irrelevant. I wouldn't mind seeing the Admiral Titley clip too, why they cut that while leaving in Marc Morano is odd. But no less odd than Minchins position, which he is still standing by, that he is unconvinced etc
  32. Renewables can't provide baseload power
    Realist, you keep insisting on this. You seem to have taken an a priori position that electricity must be subsidized to provide a particular price and are uninterested in other evidence. NZ companies are building new generation to meet demand and do so because they believe they can make a profit in the current market. Demand is increasing, there is no price control so why not. The government does not do deals. Your insistence that does without a scrap of evidence is not convincing.
  33. Lessons from Past Predictions: Vinnikov on Arctic Sea Ice
    For that matter, Arctic ice is somewhat constrained on maximum by Canada, Siberia, and Greenland. So, the higher values used in calculating the Arctic 12-month mean are somewhat clipped, and in the Antarctic, the lower values within a 12-month mean are likewise clipped. I'm thinking that in a hypothetical world, without land boundaries, the slopes of the ice extent at the two poles would both be different. If you clip high values within a mean, then a change in mean over time will be mostly a function of minimum extent, and vice versa, if you clip low values within a mean, any change over time is mostly a function of maximum extent. I have not sorted out in my mind if this is a bias that can be corrected, or if it is forever going to be an apples and oranges comparison. Dana, ah, that would be a working explanation.
  34. Lessons from Past Predictions: Vinnikov on Arctic Sea Ice
    Chris @5 - I think they ran the model for 250 years even though the figure only showed 150 years. I can't recall off the top of my head though, and don't have the paper on-hand.
  35. Lessons from Past Predictions: Vinnikov on Arctic Sea Ice
    In Figure 1 caption "~250 years"; should be ~2050-1900~=150 years? I'm feeling a little conflated between Antarctic and Arctic, max and min extent. IIRC, Antarctic min bottoms out near zero. The Arctic still exists within an all positive range. When comparing the two as 12 month averages, as in Figure 5, there is a comparison between Arctic, which I believe has seen more of a drop in minimum than maximum, and has not seen a flooring of minimum, with Antarctica, which does experience a flooring. If I'm right, there is a bias in the comparison.
  36. ABC documentary demonstrates the how and why of climate denial
    Minchin's regurgitation of a meme (and incorrectly too) "No warming for past 15 years" was not pounced on by anyone. Amazing. I point out to people that deniers regularly abuse the intent and meaning of scientific statements. Probability and appropriate time scales in science are difficult for laypeople to understand. I ask them to consider the calculated odds of a football team (2/3rds through a season) placed 2nd on the ladder (representing a pretend 90% confidence level) playing a team on the bottom of the ladder. The football expert predicts that based upon past form and current injury levels, home ground advantage, weather etc that the top team is expected to win by 6 goals. Now 1/4 into the match, imagine that after a bit of scoring from both sides that the scores are such that the predicted winning team is only winning by 1 goal. The deniers would be screaming that "The prediction is wrong. The expert should be sacked." This serves to illustrate a number of points (pun intended): (1) Even the best predictions of a football game and climate science are never certainties. (2) It is respectful and appropriate to not dismiss a prediction until an appropriate time period is reached (Waiting till the fat lady sings is ok) (3) Scores go up and down throughout a game and you cannot gauge a teams performance from watching a short time interval. (4) Unforeseen things can occur (a major injury to a key player) which can change the outcome but does not dismiss the basis for prediction.
    Moderator Response: TC: All caps modified to comply with the comments policy. Please read it and comply. Failure to comply with the comments policy can result in text simply being snipped, or posts simply being deleted.
  37. Global Warming Causing Heat Fatalities
    While perhaps not a totally analogous, this discussion reminded me of a documentary I saw recently on the hunter gatherer method of 'persistence hunting' where hunters would chase prey who could run much faster than the hunters could. The narrator explained that the hunters could catch their prey because the speed that the animals were running at prevented the prey from panting, their only method of reducing body heat. The last scene showed an antelope, standing, unable to move because of heat stress, while the hunter walked up and killed it with a spear. High "Wet bulb" temperatures seem to have the same effect for people, inhibiting or preventing the cooling produced by the evaporation of sweat.
  38. Why Are We Sure We're Right? #1
    Sphaerica, OK, sounds good. Moderators, can you move my deleted comments to the climate sensivity thread? I would do it myself, but I didn't copy them and don't have them anymore. Thank You.
  39. Global Warming Causing Heat Fatalities
    Thanks to adaptation our grandchildren will have to live inside in a fully air conditioned city? What a wonderfull world!
  40. ABC documentary demonstrates the how and why of climate denial
    Bernard @12: BEST exposition of the issues, using humor and pointed facts! TEN thumbs up! As an earth scientist, I'm always striving to explain this extremely complex science to laypersons, and I will utilize your concise statement..with proper attribution, natch...;)
  41. Lessons from Past Predictions: Vinnikov on Arctic Sea Ice
    IMO opinion the term "death spiral" is properly applied to the September sea ice extent. There is a very real possibility that we will have ice free periods at the North Pole within 10 to 20 years. In contrast, an ice free Arctic requires an Arctic Ocean warm enough that ice cannot form over 6 months of without sunlight. That is not likely this century. The extended survival of winter ice will also likely result in a radical slowing in the rate of loss of summer ice in the near future. The situation will arise where each season of summer melt will need to melt one winter season of ice to become ice free, with at which time the mean reduction in summer ice will match the mean reduction in winter ice. That will still leave us with the North Pole being frequently ice free, and occasional ice free summers (no water in the Arctic with more than 15% sea ice).
  42. Lessons from Past Predictions: Vinnikov on Arctic Sea Ice
    pauls @1, yes it depends how you define "death spiral". We're talking ice free after just ~200 years of anthropogenic influence, which as John Mason @2 notes, from a geological perspective certainly is "a flash". The Arctic may or may not be ice free by 2030, but I think it's fair to characterize what's happening as a 'death spiral', personally.
  43. KeefeandAmanda at 02:20 AM on 27 April 2012
    Global Warming Causing Heat Fatalities
    To address that some posters may seem to be confusing thermometer temperatures with wet bulb temperatures (my apologies if I read them wrongly): This is not about heat killing people and animals that need evaporative cooling to survive, but a combination of heat and humidity killing people and animals that need evaporative cooling to survive - this is not about the heat, but about the heat index, a measure of heat and humidity. Over the very long run, with the atmosphere containing more and more water as the planet accumulates more and more heat energy, it may be harder and harder for the thermometer temperature to go up and up. But we will see at the same time the heat index - the wet bulb temperature - continuing to go up and up. This simply reflects the facts of what we see: For instance, in the US, in humid environments like Florida we see high thermometer temperatures being almost always no higher in the summer than in the 95 degree F range, but in the dry climates in the southwestern US the thermometer temperatures can reach well over 110 degrees F. Yet the heat indexes - a measure of heat and humidity - can be the same, overwhelmingly uncomfortable if not yet high enough to be deadly to everyone. The online heat index calculator I linked to at #11 shows that even with just thermometer temperatures of 100 and 105 degrees F, which are thermometer temperatures that humans and animals experience today and survive just fine, we would see heat indexes of 150 and 176 degrees F respectively with just a relative humidity of 75%, deadly to humans and some animals even just within hours. The wet bulb temperature that would be deadly within hours to all humans and some animals talked about in the article is 35 degrees C and 95 degrees F, a heat index of 170 to 196 degrees F according to Huber. Side note to address that some seem to think that all will be well no matter what: I don't think that civilization can survive no one being able to go outside without being killed in just hours, but that's just me. But even if with super high technology in some science fiction future in a few hundred years global civilization could barely handle with extreme stress billions of people in the equatorial regions living in such summertime death zones, what about the wild animals? Whole continents in the middle parts of the planet would become dead zones, essentially devoid of all wildlife - killing off essentially all birds and mammals in these areas would disrupt the food chain so much that the whole ecosystem in these regions would collapse entirely. This impending mass extinction on so much of wildlife including on the pinnacle of evolution, the mammals, does not bother the fake skeptics? They talk as if they care only about humans. For clarity, to avoid confusion, what we need are not just graphs covering the last 50 years that show the global thermometer temperature increase, but graphs that show the global wet bulb temperature increase - graphs that show the global heat index increase. I'd bet that given that water vapor has increased by 4% over just the last 40 years, these global wet bulb temperature or global heat index graphs would uncover trends that we otherwise could not see. (And I think that it would be a good idea to break down the global data on the heat index to include comparisons of trends in heat indexes with respect to nighttime vs. daytime, summer vs. winter, and arctic vs. the equator. We should all know that globally, nighttime temps rising faster than daytime temps, summer temps rising faster than winter temps, and arctic temps rising faster than equatorial temps have been happening and are possible only with a significant increase in greenhouse gas activity.)
  44. Lessons from Past Predictions: Vinnikov on Arctic Sea Ice
    Pauls, I guess that depends on what you mean by "a flash" - that has quite different connotations depending on what sort of timescales are being contemplated i.e. wrt human generations, human history, recent (Quaternary) or longer geological ones....
  45. ABC documentary demonstrates the how and why of climate denial
    catamon #11. Seemed pretty obvious to me from the program content that [Minchin's] position is based entirely on an economic / political perspective and the science is pretty much not an issue for him. Well, if he was allowed get away with such an incoherent position, then the programme was an uter farce. Clearly, Oreskes was not letting him off that lightly. Again, it looks like the editor's strove for a "balance" that is completely not there in the science. It would have been much more honest and productive to have started with "Look, global warming is happening. What is your solution on how to handle it?" If Minchin wanted to argue for a "Do Nothing" position, well and good, but it looks as if the programme did not even get to that in the interests of giving airtime to a complete charlatan like Morano.
  46. Lessons from Past Predictions: Vinnikov on Arctic Sea Ice
    I find it amusing when "skeptics" try to "falsify" the models by comparing with global temperature observations. If they really wanted a falsification comparing with Arctic sea ice trends would give them much clearer grounds. Do you think references to a death spiral are supported by the published literature? My impression, particularly from this recent RealClimate guest post, is that most scientists don't see it. I guess it depends how you define 'death spiral', but my impression of the phrase is that it describes something going out of control into oblivion. However, I think the published literature tends to suggest the presence of Arctic Ice is relatively stable - i.e. it will respond to persistent GHG forcing but won't simply disappear in a flash.
  47. ABC documentary demonstrates the how and why of climate denial
    Dagnabbit. "Ms AGW" in the penultimate paragraph of my last post should have been "Ms Ecology" Cooee nice mods?
  48. Levitus et al. Find Global Warming Continues to Heat the Oceans
    It's definitely a confusing issue. What we're talking about here is basically the amount of unrealized warming, whereas the radiative forcing tells you the total net energy imbalance since your choice of start date (the IPCC uses 1750). So they're not directly comparable figures. The unrealized warming has been fairly constant over the past ~50 years whereas the radiative forcing increases the further back in time you choose your initial point. So if you look at the unrealized warming starting at any date from 1950 to 2010, it will be a fairly constant number. But the radiative forcing from 1950 to 2010 is larger than the forcing from 1990 to 2010, for example. Hopefully I got that right.
  49. Anne-Marie Blackburn at 01:34 AM on 27 April 2012
    Two Centuries of Climate Science: part one - Fourier to Arrhenius, 1820-1930
    Nice read, thanks for that - look forward to the rest of the series. I'd definitely recommend Spencer Weart's book and website. A very interesting read.
  50. ABC documentary demonstrates the how and why of climate denial
    Definitely should be aired. All guns firing I say...

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