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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 75301 to 75350:

  1. apiratelooksat50 at 23:59 PM on 14 September 2011
    Climate Communication: Making Science Heard and Understood
    My Environmental Science classes are studying Climate Change. Once again they are going to present a survey that will be sent to all students and faculty in our school and perhaps the district. I posted a link to our survey from last year and was roundly criticized for it's design because the results contradicted some of the ideals held by visitors of this site. This year if any of you would like to design the survey, I will gladly post it. It needs to be 10 questions long and neutrally worded. It will be posted on www.survymonkey.com If you are interested please contact me at mikemacdonald64@yahoo.com Thanks, Mike
  2. Medieval Warm Period was warmer
    Fitz1309, like many 'skeptic' arguments this boils down to arguing that climate science has failed to do the impossible; 'They have not compared 300 years of AGW warming to the 300 years of the MWP'... obviously AGW hasn't been going on for 300 years and thus the data to perform such a comparison does not exist. 'They have not compared the 10 hottest years of AGW (thus far) to the 10 hottest years of the MWP'... proxy data resolution is not detailed enough to identify what the 10 hottest years (globally) of the MWP were with any confidence, let alone to generate a map of global variations for such a small time period. In the realm of things which might be possible; A comparison of the last 50 years to ~1026-1075 would show less pronounced differences than the maps above, but the overall conclusion would be the same. A few small parts of the world were slightly warmer back then, but the vast majority of the globe is much warmer now.
  3. Dikran Marsupial at 23:02 PM on 14 September 2011
    Medieval Warm Period was warmer
    Fitz1309 The argument that a 300 year average is bound to appear colder than a 10 year average is bogus. A 10 year average will have greater variability than a 300 year average because there is less data, however that would be equally likely to make it colder than the "true" temperature as warmer. Picking the warmest 10 years in the MWP would indeed be cherry picking, if someone used such evidence to claim that the MWP was warmer than now that would be bogus. However it would be a good way to show that current temperatures are warmer than the MWP, if it were the case even though you cherry pick the data that minimises the evidence in favour of the hypothesis. Having said which, if you look at the magniture of the difference, I rather doubt cherry picking a ten year period in the MWP would make much of a difference anyway.
  4. Medieval Warm Period was warmer
    Fitz, see Daniel Bailey @ post 20 of this thread. You're looking for a graph, and Daniel has a few for you.
  5. There is no consensus
    Roh: "And in the Oreskes report he took a poll in 'refered journals'. There has been rejection of skeptic papers in the journal as it 'goes againt the consensus'." Roh, you really don't understand how journals work, do you? You assume there's pressure on journals to adhere to the consensus. Why? What's the mechanism? If anything, there's pressure not to adhere to the consensus. Who would want to reject a paper because it "blows a hole" in the dominant theory? That's the kind of stuff that Science and Nature salivate for. In reality, though, there's simply pressure to get the science right, whatever it might mean for our understandings. Don't you agree?
  6. Medieval Warm Period was warmer
    I've just read an argument claiming that the maps you display above comparing the MWP to the last decade anomaly isn't repersentative as you're comparing 300 years to 10 so it's bound to appear colder. Perhaps a map of the 10 years at the height of the MWP would be more repersentative, but then I guess you have the problem of which years to pick as you'll be accused of "cherry picking" which ever you do.
  7. IPCC is alarmist
    lancelot, no the Wikipedia article does not attribute Pachauri's position to the IPCC. In any case, it hardly matters whether 'you' or 'your interpretation of the Wikipedia article' are incorrect... the position stated (by whomever) is not accurate. You also still haven't given ANY reason for the claim that 350 ppm is "crying wolf"... which is certainly your own claim rather than anything in the Wikipedia article. It needs to be understood that the primary difference between Hansen's 350 ppm estimate and the more common 450 ppm estimate of 'safe' CO2 levels is the timeframes involved. If we look only at 'fast' (e.g. within 100 years or so) feedbacks then we could likely go up to about 450 ppm. However, if you take the long term view then going over 350 ppm would eventually cause significant warming and flooding of major coastal cities around the world. The relevant questions then become how soon would major consequences from exceeding 350 ppm manifest, and would that allow us enough time to get back down below 350 ppm. Is 350 ppm a reasonable target to get back down to within 500 years? I'd say yes... if we switch away from fossil fuels in the next several decades and then work on technologies to pull CO2 out of the atmosphere that seems entirely possible. Could we get back to 350 ppm within 50 years? Certainly not... but then we shouldn't be seeing major problems (e.g. large sea level rises, major agricultural disruptions, millions of deaths) in 50 years unless we continue to push CO2 levels higher.
  8. Hockey stick is broken
    Roh234, as others have pointed out, the 'hockey stick' has been confirmed by numerous subsequent studies by different groups of scientists, and even 'skeptics', all over the world using several different data sources. Alot of this is also detailed in the article above. On McIntyre's specific claim about 34 tree ring data sets... have you heard of the divergence problem? Basically, over the past century many trees have shown very low growth even as the temperature has increased. This is believed to be due to environmental toxins and other factors. However, what it means is that the rings on these trees are not accurate proxies for RECENT temperatures. Thus, McIntyre essentially went out and found recent tree rings (from a completely different study BTW) that did not match ACTUAL temperatures and is claiming that Briffa should have factored them in. In short, he is criticizing Briffa for not using INCORRECT data. That McIntyre is wrong should be obvious to any thinking person who looks at the graph. The red and black temperature lines essentially match up until the last 50 years or so. Then the black line plummets downward while the red shoots up. Now let's engage basic reasoning for a moment... What have actual temperatures done over the past 50 years? Has it gotten significantly colder? If not, then the black line is wrong. Ask yourself how 'skeptical' you are being when you blindly accept the validity of a graph which is at odds with observed reality.
  9. Dikran Marsupial at 22:03 PM on 14 September 2011
    IPCC is alarmist
    lancelot wrote: "In general: Do you think 350ppmv is a realistic global target? If so, when do you think it might be achievable? " This is pretty off-topic for this article, if you want to discuss it in detail, please find a more appropriate thread. From a scientific perspective, the natural environment is currently taking about 1.6GtC per year out of the atmosphere. 40ppmv is about 19GtC, so it would take the natural environment at least 12 years to get back down to 350ppm if we cut emissions to zero today. That gives an approximate lower time limit. So of course it is achievable, however I am rather cynical about those in public office and those that elect them. Both are generally too focussed on short term self-interest to act for the long term good of us all. Thus 450ppmv is a more realistic stabilisation point (the politics being the limiting factor not the science), and we will have to put up with the consequences, which will generally be worst in those parts of the world least capabale of adapting and who generally will have been least responsible for creating the problem.
  10. Dikran Marsupial at 21:48 PM on 14 September 2011
    IPCC is alarmist
    lancelot wrote: "I am quite familiar with the science. " Very clearly this is not the case, otherwise you would not have seen any contradiction in the idea that 350ppm is a "safe" stabilisation concentration yet not having observed a "tipping point" given that we had already past that level. The reason there is no contradiction has already been explained to you, and yet you have not accepted it, nor refuted it. This is not encouraging. A more realistic safe upper limit argument would be to say that the safe upper limit for dietary intake would be 2500 calories per day. However if on one day you eat 4000 calories at a banquet, the fact you didn't have a heart attack or stroke on that day does not mean that 2500 calories is not the long term safe upper limit. The 350ppm is a safe LONG TERM stabilisation figure, not a limit on the safe SHORT TERM transient concentration. If you think it is just that the Wikipedia article is badly worded, why are you discussing it here, rather than at Wikipedia (I suspect the chaps at Wikipedia would point out the error in your position much as I have)?
  11. IPCC is alarmist
    Dikran and CBD, hello. I am quite familiar with the science. I did not 'improperly conflate' RKP and J Hansen with IPCC. Wikipedia does. Don't shoot the messenger! RKP, in his highly public position, should not say things 'off the cuff'. No-one in such a position should. How is whether the figure appears in IPCC reports relevant to the impact of public statements made 'off the cuff'? Have you heard of the 'Media'? CBDunkerson you wrote: "the 'tipping point' comment... it didn't come from either of the two scientists" I didnt say that it did. The Wiki article appears to. Safe upper limit: If an engineer says that 100 lbs per sq ft is a safe upper limit for loading an elevator, he means exactly that. He does not mean that is a limit 'just in case' someone were to walk in carrying another 100 or 200 lbs or whatever. He means it the safe upper limit as would be generally understood in any other field I can think of. If it is not that sort of limit in climate science, what exactly is it? - this seems to be turning into a game of words. I have simply pointed out how the Wiki quote could be (mis)understood by the average reader. Take that up with Wikipedia perhaps? In general: Do you think 350ppmv is a realistic global target? If so, when do you think it might be achievable?
  12. Santer et al. Catch Christy Exaggerating
    Thanks for the pointer, CTG! I'll give it a good look, and maybe get a reprint of Santer too. If it turns out to be useful I'll try and write it all up as a resource.
  13. CO2 limits will harm the economy
    Well this site mostly deals with the science. Climate Progress is one place to discuss the political solutions.
  14. CERN - Saying Nothing About Cosmic Ray Effects on Climate
    Research into the climatic impacts of solar cycle variability is certainly worth pursuing. Its just a whole different kettle of fish to suggest that this can meaningfully translate into impacts on climate trends! Thats the point. Its a Cycle! And the important thing to remember is that Solar cycles produce a range of changing phenomena, not just GCR levels on the Earth. Assuming that any solar cycle influence on climate is mainly due to one possible impact of only one of these phenomena changes is unreasonable. Particularly when that is based on studies of correlations only. Off the top of my head here is a list of potential or real influences that the solar cycle 'could' have on climate variability. - Overall solar energy flux from the sun varies a fraction of a percent over the solar cycle. This is well known - Higher energy parts of the solar spectrum, UV and up vary by more than this - 1 to 2% over the cycle. Since UV is absorbed preferentially in the stratosphere, this could have an impact. Also UV is actually involved in the creation of Ozone in the stratosphere. And research in recent years has suggested that the Ozone hole over the Antarctic is having an observable impact on Antarctic weather, resulting in the continent becoming more isolated from weather systems in the rest of the world. - Methane conversion to H2O and CO2 happens mainly in the stratosphere an depends on the availabilty of OH radicals. UV changes could impact on this reaction pathway. - One major source of aerosols that are known to impact on clouds, sulphates, is phytoplankton in the ocean. Changes in TSI and/or UV levels could impact on the rate of aerosol formation by the plankton. - Changes in Solar wind and the magnetosphere don't just impact GCR's, they could impact weather in the Ionosphere for example. - Similarly changes in the degree to which the Earth is shielded from solar influences, solar wind etc could also impact on rates of deposition of interplanetary dust etc onto the Earth. As this falls through the atmosphere it could impact on cloud formation. - Fluctuations in GCR's are also thought to possibly impact on charge separation in clouds. The tops and bottoms of clouds have a significant charge separation and fluctuations in this could impact cloud optical properties and precipitation rates. This pathway of GCR's impacting on the charge searation of existing clouds seems to need fewer hard steps to have an impact than Svensmark's hypothesis. - Then their is Svensmark's theory which is plausible as a possible minor contributory mechanism, but implausible as a substantial or dominant mechanism. Are none, some, all of these mechanisms possible (as well as others we haven't thought of). Yep. Are they proven? No. Hence broad research is worth while. But it is research into cyclical variability, not underlying trend because we know that the cycles involved are too short to explain the observed trends.
  15. Hockey stick is broken
    It would also by nice if you provided a link back to your sources. You are aware of various non-tree ring proxy reconstructions as well?
  16. Renewable energy is too expensive
    Very balanced view on Renewables. Often supporters of Renewables overlook the production costs at present. With increased efficiency and improved materials,solar energy will be cheaper in the coming years especially CSP. Dr.A.Jagadeesh Nellore(AP),India Wind Energy Expert E-mail: anumakonda.jagadeesh@gmail.com
  17. CO2 limits will harm the economy
    Two things: 1. I have a very high level of confidence in climate models, and am not the least but skeptical about AGW. You folks do a bang-up job of demolishing every quibble put into your path. Forgive me if I do not have the same confidence in economic models ... all the whizziest of the math whiz kids out of MIT didn't go into climate science when they could make ten times as much working on Wall Street, and not a one of them managed to predict our current economic debacle. 2. So far, I haven't seen a single mention of just how much good any of the proposed laws would do in terms of reducing the effects of global warming ... to me, a furry-minded layman, they all seemed much too little, and much too late. I would love to see comment on this. P.S. I realize politics are verboten on this thread (although that seems to be subject to considerable wiggle room). What bothers me most of all is that real live scientists are winning the arguments here, and on sites like it, but losing dismally outside them ... the 3% of GW skeptics seem to have swayed more than half the population with garbage arguments. I think we really do need to take a somewhat different approach to the problem if any public action is to be taken.
  18. Hockey stick is broken
    Roh234 - the world has moved on from 1998, but Mc Intyre hasn't. The rebuttal to future hockey sticks remark is amusing, but in all seriousness the evidence is overwhelming that present temperatures surpass that of the Medieval Warm(ish) Period. For starters: 1. Glaciers were advancing in North America during the MWP. See SkS post: Icing the Medieval Warm Period 2. The North American cordillera snowpack was much heavier during the MWP - indicating that it was colder back then. See: The Unusual Nature of Recent Snowpack Declines in the North American Cordillera - Pederson (2011) 3. Atmospheric circulation patterns match the paleoclimate proxies - See SkS post: The Medieval Warm(ish) Period in Pictures 4. Paleoclimate reconstruction below:
  19. It's Urban Heat Island effect
    Roh234 - read the Intermediate version. Noone doubts that urban heat island exists - thats why the effect is removed by comparisons with rural stations in the global records.
  20. There is no consensus
    77/79 is a 97% out of 0.77% of climate scientists. I assume we are using the Doran study. A 30% turn-out may be typical in internet polls but 70% of views are not here. 70% is too large. I'm not claiming that the 70% are skeptics but when 70% don't show up it is not legiminate. And in the Oreskes report he took a poll in 'refered journals'. There has been rejection of skeptic papers in the journal as it 'goes againt the consensus'.
    Response:

    [DB] As a new participant here, please take the time to acquaint yourself with the Comments Policy.  Posting comments here at SkS is a privilege, not a right. 

    Please take the time to review the policy and ensure future comments are in full compliance with it.  Thanks for your understanding and compliance in this matter.

  21. It's Urban Heat Island effect
    Counties in Calafornia have shown evidence of the heat island effect. (-Snip-)
    Response:

    [DB] Posting just a graphic (please restrict widths to 450 pixels or less) without demonstrating the significance of it helps no one.  And therefore proves nothing.

  22. Climategate CRU emails suggest conspiracy
    I got a 60 page report with ove 228 points of legiminate criticism (with propoer citation) why the trial and questioning may be fuzzy. http://thegwpf.org/images/stories/gwpf-reports/Climategate-Inquiries.pdf
    Response:

    [DB] If you want to be taken seriously, dispensing denialist literature with a sweeping hand-wave does you no favors.

    A focus on the science is best.

  23. Hockey stick is broken
    Hey I'm new to this fourm but Steven McIntyre has got a rebuttal to his rebuttal and a rebuttal to any new hockey sticks. here is a reconstruction showing Briffa's exclusion of data and what it really is supposed to be. From the Keigwin 1996 study. I will debate the Heat Island Effect on the specific section which I challege the graphs provided here.
    Response:

    [DB] A better thread for the tree ring discussion is probably Climategate: Hiding the Decline?

    As you are new to this forum, you may want to read it before proceeding further.  Respondees to this, please take it up there.

    The hockey stick challenge Roh234 issues is fair game here.

    Take heat island comments to the It's Urban Heat Island effect thread.  Please read both the Basic and Intermediate tabs to prepare yourself.

    For the record, please in the future also indicate the paternity of your sources for furnished graphics.  Ex:

    Graphic 1 above:  http://joannenova.com.au/globalwarming/hockey-stick/rcs_chronologies1v2.gif

    Graphic 2 above:  http://wattsupwiththat.files.wordpress.com/2009/09/rcs_chronologies_rev2.gif?w=420&h=360

    Graphic 3 above:  http://www.friendsofscience.org/assets/documents/FOS%20Essay/seasurface.GIF

    Graphic 4 above:  http://www.friendsofscience.org/assets/documents/FOS%20Essay/Mann%201998%20+%20Corrected.gif

    Congratulations, no peer-reviewed primary sources used.

  24. Republican Presidential Candidates vs. Climate Science
    Here's a searchable database of the environmental policy votes in the current US Congress. Relevant to this thread because Bachmann is a serving Representative and much of this will actually come to pass if more Repubs are elected. "This is the most anti-environment House in history," said Rep. Waxman. "The House has voted to block action to address climate change, to stop actions to prevent air and water pollution, to undermine protections for public lands and coastal areas, and to weaken the protection of the environment in dozens of other ways." The database offers details on each vote, including the bill or amendment number and sponsoring member, a brief summary of the bill or amendment, the vote outcome, and additional relevant information. The votes are searchable by bill number, topic, affected agency, and affected statute. Canada may not be far enough; I hear Finland is nice.
  25. CO2 is just a trace gas
    Eric @ 100, Well I'll have to say I'm sorry for my terse reply to your comment. Sorry. Based on intuition (I'm a tech, not a scientist ;) I would guess that effectively zero of the principle CO2 IR band photons emitted at ground level make it to space directly. I had to look it up, but see the figure here, from wiki: http://en.wikipedia.org/wiki/File:Atmospheric_Transmission.png The grey area along the CO2 spectrum shows that it maxes out at several absorption bands. The following description of the detectors used for water vapor images on GOES satellites says they are tweaked for sensitivity at a water absorption band or channel, (6.5-7.4 micron), which makes sense if you're interested in water vapor. http://cimss.ssec.wisc.edu/goes/misc/wv/wv_intro.html If you check that band against the figure at my first link, you'll see that 6.5-7.4 microns (on the logarithmic x axis) is where water absorbs strongly, and not much else does. (CO2's strongest absorption band is more in the 13-17 micron range.) So the black on the water vapor image, aside from being an assigned translation of the IR signal to a visible representation, and not an innate property, indicates lack of water vapor, not lack of absorbance/emission by CO2. Thanks your considered reply to my previous comments. Cheers.
  26. CERN - Saying Nothing About Cosmic Ray Effects on Climate
    gpwayne#27: "why is Kirkby looking for a mechanism" The original its cosmic rays thread has the history. Blame the fascination with Svensmark's earlier work, suggesting a correlation between CR flux and cooling episodes; Nigel Calder hyped this to no end (still does). What I've noted is that they've lost any connection at all to the paleo record of CR-produced isotopes (such as Be10) and their correlation with cooling events. By the time rebuttals of Svensmark were published, the CLOUD funding was approved. It is an interesting academic question with valid theoretical support - ionizing radiation does indeed make 'clouds' in saturated environments (ie, cloud chambers). High energy particle physics projects take a long time to get going and tend to live for a while; look at the number of secondary authors on their papers. Once the detector is built, secondary beam time (they are not using the LHC's main beam) is relatively inexpensive. One could also suspect that the LHC administration was anxious to produce some results while waiting for the Higgs to show up.
  27. Climate Communication: Making Science Heard and Understood
    Poynter.News University offers a free, 4-hour, online, self-directed course, “Covering Climate Change.” To access it, click here.
  28. SkS Weekly Digest #15
    pbjamm: that is a delightful article. Thanks for sharing it. I hope others follow the link. I got obsessed with exoplanets a year ago because the science of detecting gases in explanet atmospheres is a logical extension of understanding our own planet's greenhouse effect. jg
  29. OA not OK: Booklet available
    “Stanford University researchers have gotten a glimpse into an uncertain future where increasing levels of carbon dioxide in the Earth's atmosphere will lead to higher levels in the ocean as well, leaving the water more acidic and altering underwater ecosystems.” Source: “Oceans' increasing acidity likely to hurt biodiversity” by Louis Bergeron, R&D, Sep 13, 2011 To access this in-depth article, click here.
  30. Climate Denial Video #6: Past climate change
    "I am curious though and from what I can gather, you are saying that the physics of a GHG MUST always result in warming, but there could be counter scenarios that will itself counteract the resulting warming." Well the obvious one is where the increase in GHG is also accompanied by an increase in aerosols with a similar magnitude of forcing. However, aerosols are shortlived in the atmosphere compared to CO2, so if the GHG is CO2, then warming results as aerosol declines. As to what happens in the ice reversal, well see the appropriate thread, but when solar declines in NH, albedo increases, cooling starts, and the feedback mechanisms for GHG (methane sources freeze and then as ocean cools, CO2 is absorbed, etc) work in reverse to amplify cooling.
  31. CERN - Saying Nothing About Cosmic Ray Effects on Climate
    "Both solar magnetic field strength and the number of cosmic rays reaching Earth have been flat over the past 50+ years..." I'm quite puzzled by this CERN experiment. When I first heard about it, I took a look at the sun's output and found the same thing - not much going on in TSI, field strength or rays. So my question is this: why is Kirkby looking for a mechanism that correlates cosmic rays with climate change, when the catalyst for the 'forcing' has been notably absent during the most dramatic increase in global temperatures?
  32. Climate Communication: Making Science Heard and Understood
    Susan, one program a group like yours could/should set up, is workshops (online?) (preferably, accompanied by some dedicated funding) for people from small nonprofits whose missions are threatened by climate change, to equip these communicators with the most important & misunderstood concepts & points so they can (& will be motivated to) communicate the basic information needed by their communities.
  33. Santer et al. Catch Christy Exaggerating
    Kevin - Bob Grumbine did a post on this a while back. He came up with 20 years as the minimum length, although 17 years is probably about long enough. There are several factors you need to consider.
  34. We're heading into an ice age
    Dana, The question is: did man change the climate 5,000 years ago to prevent the change to an ice age or was the climate not changed until the last 100 years? ASFIK that question is still under debate. With the current carbon in the atmosphere the next several ice ages have been prevented. As we emit more carbon the time until it will be removed by natural causes keeps getting longer and longer.
  35. We're heading into an ice age
    I was directed from another thread to this topic. From what I have been able to gather, the addition of man in the climate equation, has created a new hypothesis: That man contributing CO2 levels in the atmosphere have altered the climate in such a way as to prevent future ice ages from happening. The reason behind this being that CO2 is a forcing that far exceeds any counter negative feedback. If true this is a whole new direction of thought.
    Moderator Response: Click the Intermediate tab. Then read.
  36. Climate Denial Video #6: Past climate change
    Dana69, unfortunately no... you haven't made yourself clear. Why do you have a problem with orbital forcing driven CO2 increases stopping when the orbital forcing does? That would seem self-evident... yet in #21 you appear to hold it out as some sort of 'obvious flaw'. I can't figure out what you think is 'wrong' with it. If you look at the ice core CO2 records of past glaciation cycles you will see that CO2 'quickly' (~10,000 years) rises from ~180 ppm to ~280 ppm and then slowly drifts back down. Looking more closely at the current cycle CO2 levels had been at 280 ppm +/- 10 for a few thousand years prior to the industrial revolution. In short, CO2 levels had not changed significantly for a long time and thus were not causing any additional warming of the planet. As the orbital forcing reverses we would then see cooling from that... which would result in a decreasing atmospheric CO2 feedback and thus more cooling. Obviously the 'recent' large human CO2 emissions have changed this, but the point is that CO2 levels from natural emissions had leveled off... and perforce warming from them had done so as well. There wasn't any 'ongoing warming' to prevent cooling from the orbital shift. CO2 feedback effects do not self perpetuate ad infinitum... otherwise the planet would have burned to a crisp long ago.
  37. Republican Presidential Candidates vs. Climate Science
    Here’s another article similar to Dana’s. This one, however, includes quotes by the candidates on both climate science and evolution. “In Their Own Words: GOP Candidates And Science” by Corey Dade, NPR, Sep 8, 2011 To access this article, click here.
  38. Climate Denial Video #6: Past climate change
    Dana: "I am ok with this, but what I cannot wrap my tweener brain around is how to explain the opposite affect. Meaning, there must be a point where temperature reverses and starts to decline, but CO2 levels MUST be higher, YET do not affect this reversing trend of the earth falling back into an ice age. Unless the new hypothesis states that since man is contributing all this additional CO2 there will be no new ice age, and that man has permanently altered this process through the increase in man-made CO2 levels." Move this to the ice age thread.
  39. CERN - Saying Nothing About Cosmic Ray Effects on Climate
    Esop#23: "should put a rather sizeable dent in Svensmarks theory. " You're correct; this apparent contradiction should dent Svensmark right out of the park. The solar minimum was indeed accompanied by a max in GCR flux in 2009. So there should have been beaucoup clouds and much cooling. But the people who buy this 'theory' also believe warming stopped in 1998. I suppose this proves that if you believe in two simultaneous falsehoods (warming stopped and GCRs cause climate change), that makes them true.
  40. Climate Denial Video #6: Past climate change
    DSL, Let me answer your question first then ask a follow up question that has bugged me. 1) Yes I agree that humans are the source of the most recent and rapid rise of CO2 in the troposphere (not sure if the distinction is relevant) 2) Yes, I do accept that CO2 is a positive forcing on temperature. Now my main point of incongruity is from this site itself. Note: "When the Earth comes out of an ice age, the warming is not initiated by CO2 but by changes in the Earth's orbit. The warming causes the oceans to give up CO2. The CO2 amplifies the warming and mixes through the atmosphere, spreading warming throughout the planet. So CO2 causes warming AND rising temperature causes CO2 rise." I am ok with this, but what I cannot wrap my tweener brain around is how to explain the opposite affect. Meaning, there must be a point where temperature reverses and starts to decline, but CO2 levels MUST be higher, YET do not affect this reversing trend of the earth falling back into an ice age. Unless the new hypothesis states that since man is contributing all this additional CO2 there will be no new ice age, and that man has permanently altered this process through the increase in man-made CO2 levels. No matter what you label me, this is something that sticks out in my head. If this is true, there seems to circumstances which appear to counteract the conclusion that CO2 is ALWAYS a forcing. Also, I read GMB post#10 at 16:57 PM on 27 December, 2007 under CO2 lags Temperature. It was a much different take on the subject, but I notice no one answered when he states: "This idea that Malinkovitch needs CO2 feedback to do the job is clearly false. Since it relies on a WATTS-PER-SQUARE-METRE model which is a light-and-air-only model. "If we allow for the accumulation and decumulation of joules in the planet and the oceans then it is the factor of TIME ALONE that needs to be taken into account and not this sideshow of CO2-feedback. We ought to be looking at a model which relies on STRATA AND HEAT BUDGETS." I pray that I have made myself clear, because I hate all these denier labels and I know you feel these might be sophomoric questions. Thanks in advance, and oh by the way, I have read the IPCC reports, and for one in search of knowledge they are no help.
    Moderator Response: [Dikran Marsupial] you write "No matter what you label me", please can you avoid this sort of thing, SkS works best when everybody concerned keeps everything on a calm impersonal scientific basis. This sort of statement comes across badly (it implies that the other parties in the dicussion are looking to label you, which is unfair to them).

    Now if the IPCC reports are not much help, that probably means you need to start with something a little more basic (e.g. Houghton's book).

    Lastly, if there is something you don't understand, or you want to ask a question, it is best simply to ask a direct question without the extensive quoting or digressions.
  41. Climate Denial Video #6: Past climate change
    Just a note on Dikran's moderator comment to #17... I presume that the second to last sentence, "BTW, the observed rise is 100% anthropogenic", is referring to the rise in CO2 rather than the rise in temperature. I make this assumption because otherwise Dikran would be incorrect, and that just can't be the case. :]
    Moderator Response: [Dikran Marsupial] Yes, absolutely correct. The rise in CO2 is 100% anthropogenic, the rise in temperatures is not.
  42. Climate Denial Video #6: Past climate change
    Dana, do you accept that humans are the source of the recent and rapid rise of atmospheric CO2? And do you accept that increased CO2 is always a positive forcing on temp (whatever else is going on)? It's important that we establish something, or else we end up like middle-class sophomore philosophy majors: all talk and no performance--all theory and no practice. No one has the patience for that here. Most of the discussion on this site is now in the realm of determining the influence of various forcings and feedbacks beyond GHGs. The science reflected in the IPCC-supported sensitivity models is robust, and there are hundreds of links on this site that you can follow to get a feel for that robustness. Note that there is no "other side." There is no comprehensive alternative theory widely supported by some "other side." If you tried to create a physically consistent model out of all of the attacks on the theory of AGW, you'd fail miserably. That's why SkS isn't set up on an "us vs. them" either-or framework. If you want to understand sensitivity, there are plenty of other articles and threads on SkS where you can do this (with semi-live people willing to take part).
  43. Climate Denial Video #6: Past climate change
    I am not sure why it repeats, I am truly not trying to do that. Please forgive me.
    Moderator Response: [Dikran Marsupial] No problem, it has happened before. It is probably becuase you are using the reload button, or the forward and backward buttons to navigate, which in some circumstances can resend the post.
  44. Are you a genuine skeptic or a climate denier?
    From an article in CounterPunch recently by Michael Brenner (International Affairs at the U of Pittsburgh: "Of course, this last is a feature of contemporary American political culture in general. Facts are taken to be infinitely malleable, the very notion of truth is denied, speaking honestly is viewed as a life style choice, and communication is more a matter of self affirmation than an attempt to convey knowledge, emotion or intention to somebody else. We have externalized navel gazing to a remarkable degree. All the demonstrative primping and preening suggests self-licking ice cones looking for an audience. One consequence is that public discourse is not anchored by common standards of honesty. It is a maelstrom of raw opinion, emotive outbursts, mythology and primal screams. Accountability, therefore, ceases to exist. There is accountability only where there are benchmarks of veracity, a reasonably rigorous monitoring of what is said and done, and a dedication on the part of some at least to ensuring that these requirements for a viable democracy are met. The abject failure of the media to perform these functions to any reasonable degree is a hallmark of our times. The think tank and academic worlds are little better." The piece was on Obama, but this section seemed awfully relevant to the work being done at SkS.
  45. Santer et al. Catch Christy Exaggerating
    Note: The keys for Figures 6A and 6F are vitually unreadable due their tiny size. Clicking on them will generate a screen showing the complete set of graphs, A thru F, in a slightly larger size. The keys are readable on the pop-up page.
  46. Climate Denial Video #6: Past climate change
    Guys, [inflamatory snipped] "From the available evidence it is quite clear that human emissions are the main cause of the increase of CO2 in the atmosphere. There is a small influence of temperature on this increase, as warmer oceans emit some CO2 (but warmer land absorbs more CO2 in vegetation!). But the influence of temperature is limited: based on the variability of the CO2 increase around the trend, the short-term (1-6 months) ratio is about 3 ppmv/ºC (based on the 1992 Pinatubo and 1998 El Niño events). The very long term influence of temperature on CO2 levels (Vostok ice core) is about 8 ppmv/ºC. Thus at maximum, the influence of temperature on the current increase is 0.7 ºC x 8 ppmv/ºC = 5.6 ppmv of the about 100 ppmv increase since the start of the industrial revolution. There are only two fast main sources of CO2 to the atmosphere, besides the burning of fossil fuels: oceans and vegetation. Vegetation is not a source of CO2, as the oxygen deficiency (in 5.5) showed. Neither are the oceans, as the 13C trend (in 5.3) and the pCO2/pH (in 5.6) shows. This is more than sufficient to be sure that human emissions are the cause of most of the increase of CO2 in the atmosphere of the past 1.5 century. Thus we may conclude: All observed evidence from measurements all over the earth show with overwhelming evidence that humans are causing the bulk of the increase of CO2 into the atmosphere. But... That humans are the cause of the recent increase of CO2 doesn't tell anything about the influence of increased CO2 on temperature! Humans may be responsible for (a part of) the temperature increase. How much, that is an entirely different question, as that mainly depends of the (positive and negative) feedbacks that follows any increase of temperature..." Seems like everything is contained in here and gives credit to both sides. No denying, same physics, yet diverse conclusions.
    Moderator Response: [Dikran Marsupial] Please do us a favour and go and read the technical summary to the IPCC WG1 report. You will find there that not all of the observed warming is attributed to AGW, so you are arguing against a position that nobody is actually taking.

    Your statement that "That humans are the cause of the recent increase of CO2 doesn't tell anything about the influence of increased CO2 on temperature!" is also a non-sequitur. The influence of CO2 on temperatures is established by physics (theory, experiment and observation), and remains true whether we are emitting CO2 or not.

    BTW, the observed rise is 100% anthropogenic. I'll happily discuss how we know that to be true on a more appropriate thread.
  47. SkS Weekly Digest #15
    Not sure this is exactly ontopic but it seemed like as good a place as any to link to an article about climate change and the scientific method. Diamond planets, climate change and the scientific method: "And yet the diamond planet has been hugely successful in igniting public curiosity about the universe in which we live. In that sense, for myself and my co-authors, I suspect it will be among the greatest discoveries of our careers. Our host institutions were thrilled with the publicity and most of us enjoyed our 15 minutes of fame. The attention we received was 100% positive, but how different that could have been. How so? Well, we could have been climate scientists."
  48. Santer et al. Catch Christy Exaggerating
    Could somebody tell me if I'm interpreting Santer's Figure 6 correctly, particularly 6A and 6E? He took model outputs, which include hindcasting for most years, and projections for the last few years since AR4, and compared the model ensemble average TLT to the observations. Figure 6A shows the model average (hindcast + projection) differs from the model observations by just a little less than 2 standard deviations. Figure 6E (click on Skeptical Science graph to get the full graph) seems to confirm this by showing that the "weighted pf value (OBS vs 20CEN/A1B trends" is about 0.07. In other words, whether the model average TLT trend is significantly different than the observations depends upon whether one chooses 90% or 95% confidence interval.
  49. Climate Denial Video #6: Past climate change
    Yes, Dana, given the current Earth system and the likelihood of its persistence, GHGs must result in warming. Other things might overwhelm that warming, but GHGs will STILL be acting to warm. It's all about the net effect of all forcings and feedbacks.
  50. Climate Denial Video #6: Past climate change
    Dana69 - I'll have to ask you to excuse my interpretation, but you appear to be hunting for reasons to deny CO2 warming. While the epistemology of math is an interesting subject in itself, epistemology is quite a different realm from the accumulated physical evidence, and I must view your introduction of it as a red herring. The direct effect of doubling CO2 is ~1°C warming. Feedbacks look to amplify that to a climate sensitivity of ~3°C. There is essentially zero evidence for sufficient negative feedback to suppress that forcing. Please read that link for a discussion of the evidence in this regard.

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