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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 67551 to 67600:

  1. Updating the Climate Big Picture
    mace @24, you need to quote the section of the main article which calls something settled science and the equivalent claim from the IPCC which is called "very likely" (>90% likelihood). Otherwise your sentence is post is meaningless. As it stands I cannot find anything called "settled science" above which the IPCC only calls "very likely".
  2. Updating the Climate Big Picture
    This is an excellent piece of work, thanks. It is probably the most important information that this site puts out because it will do most to convince those who are confused by the opposing views that they are presented with in the media, yet becoming sufficiently worried about it to seek better information. On a technical note, I would like to see more emphasis on the projected sea level rise and its likely non-linear progression (re. Hanson and Sato). For instance, the U.K. government in its infinite wisdom is spending an absolute fortune, which it can ill afford, on the Olympic Games in a city that is vulnerable to sea level rise. The time will likely come in the not too distant future when the chosen site for the games will only be suitable for water-sports, which will, of course, work wonders for real estate values. Long before then, Canute like, there will need to be a new Thames Barrier unless they, the powers that be, wake up and take London to high ground, which won’t be cheap! (And they think that the current financial situation is bad.) It is amusing to read current plans for a new London airport in the Thames estuary, which, I assume, will be designed to accommodate modern versions of Sunderland and Catalina flying boats. Virtually all coastal cities are vulnerable in their own way. A potential three meter rise in sea level from the collapse of the West Antarctic Ice Sheet should concentrate the minds of many, especially of those that can’t swim. On a practical note, errors in proof reading will, in the minds of some, reflect errors in the science it discusses, which is a pity, considering the effort that has clearly gone into compiling it. Though having done some proof reading on my own publications, you have my deepest sympathy. I found the following: ‘theory?". Well’ ‘Unfortunately there is a there is a very vocal’ ‘Th good news’ ‘not to immeditately take’
  3. Updating the Climate Big Picture
    JamesWilson - "Can we get back to discussing science?" Yes, indeed. Like for instance who is taking the NASA dating apart and correcting mistakes? " If you want to convince a Global Warming skeptic" SkS does not attempt to convince fake-skeptics. The evidence for man-made global warming is overwhelming, and yet they still resist the evidence, throwing up one illogical objection after the other.Trying to convince those people is a futile exercise. Our objective is right at the top of the home page: Explaining climate change science & rebutting global warming misinformation
  4. Updating the Climate Big Picture
    JamesWilson#23: Your objections to BEST make no sense; that data set was gone over with a fine-toothed comb. See the several existing BEST data threads. What NASA data are you referring to as 'more scientifically defensible' and how does this differ from BEST? Please be sure to cite your sources for these assertions; this is science we're talking about, not hearsay. In case you hadn't noticed, there are hundreds of posts here discussing specific aspects of science. No one is 'sweeping science away.' Many people think having one 'big picture' thread is a very good idea. If you are looking to discuss a specific point, find the thread that deals with it - and read the posting.
  5. Updating the Climate Big Picture
    iPCC use the phrase 'very likely' rather than settled. We should stick to the consensus view. Mankind adding gases to the atmosphere that cannot be naturally balanced is settled, but the link between this and global warming is 'very likely', rather than settled. Terminology is important.
  6. Updating the Climate Big Picture
    The choice of graphs seem a little questionable. BEST for example is a much poorer source of land data than NASA. Both have known bias but NASA has a lot more external people pulling the data apart and correcting their mistakes. This is likely to produce more accurate data. But more importantly: NASA produces more scientifically defensible data. This article really isn't going to convince *anyone* skeptical of the science behind Global Warming of *anything*. It also makes so many claims that it difficult to even discuss the science behind it. Can we get back to discussing science? If you want to convince a Global Warming skeptic that is the way. Sweeping science away in "the Big Picture" is what makes people skeptical of Global Warming theory in the first place.
  7. Updating the Climate Big Picture
    Thank you Rob
  8. Foster and Rahmstorf Measure the Global Warming Signal
    The links to AERONET and GAW that I posted are to networks of ground-based passive optical instruments that use direct sun readings to measure the atmospheric attenuation at specific (narrow range) wavelengths. The filters can be in the UV, visible, or near-IR portions of the spectrum, and are usually selected with particular types of analysis in mind (i.e., particular types of atmospheric aerosols). These sorts of instruments have several characteristics: - the direct sun reading does not tell you whether the attenuation is the result of absorption or scattering or both. - the direct sun reading does not tell you where in the atmosphere the aerosol is. It represent an atmospheric total. - the initial measurement tells you Total Optical Depth. Data analysis accounts for attenuation due to Rayleigh scattering. Depending on the wavelength, other adjustments are made for absorption by other known gases - e.g. ozone, water vapour, etc. The remainder becomes the Aerosol Optical Depth, and it is wavelength-specific. - depending on the purpose, wavelengths will be selected to avoid certain absorption bands, but you can also target them if you are trying to measure a particular gas (e.g., ozone). - how Aerosol Optical Depth varies with wavelength can tell you a lot about the aerosols - e.g., size distribution. - some instruments (AERONET in particular) take readings away from the sun. This allows identification of many other optical properties of the aerosols, including whether they are mainly absorbers (e.g. soot) or scatterers (e.g. dust). - clouds also have optical depths. Thin ones are measurable, but thick ones absorb everything and optical depth becomes infinite (mathematically). To get aerosol optical depth, analysis includes some sort of cloud screening, so that cloud doesn't get confused with aerosols. - all of this will allow some determination of what type of aerosol is present, and perhaps where it is in the atmosphere (e.g., volcanic dust in the stratosphere). There are other methods of measuring aerosols, such as aircraft sampling, or LIDAR. LIDAR is a laser-based active sampling method that sends light beams into the atmosphere, and measures the return signal. They are capable of creating atmospheric soundings of various optical properties. A quick Google search led me to this European network: EARLINET. I hope this helps clarify some of the characteristics of measuring aerosol optical depths.
  9. Updating the Climate Big Picture
    Michael - the figure is around 20,000 visits per day IIRC. And no where near 7 billion people have access to the internet. Billions are currently starving, so blogging is way down the list of their priorities.
  10. Models are unreliable
    JamesWilson -"Oddly the Jason-2 site shows the change and drop starting in 2010 but...... See SkS post: Sea level fell in 2010 And the latest update from AVISO
  11. Updating the Climate Big Picture
    At the risk of being off-topic here goes on big picture: - CO2 cumulates and incremental emissions have an atmospheric life of tens thousands of years [This is so if one assumes the sinks are cleaning up CO2 from many decades ago - the right way to look at it given the impending feedbacks]. - The general public and most politicians thinks CO2 is a smelly Fart that dissipates quickly once we reduce CO2 emissions. Governments are not interested in informing them otherwise. - Nevertheless this means paleoclimate comparisons are valid given CO2 is the main driver of global temperature for a constant solar irradiance. However, given that the rate of CO2 increase is now 10,000 times quicker than in paleoclimate Newton would not hesitate to claim the transition to Pliocene paleoclimate conditions will also be much much quicker. Basically 25m sea level rises for the 2C target and lots of other nasties. http://www.giss.nasa.gov/research/news/20111208/ http://www.youtube.com/watch?v=hK8BbOnvGJU - This wonderful website of yours gets 2 to 3 thousand users a day in a world of 7bn. It has done great work and is a fantastic resource. - But how can we change the understanding of the public to motivate the politicians ? Or is this off topic ? Best wishes.
  12. Models are unreliable
    James Wilson#441: CFC's are indeed greenhouse gases, but measured in parts per trillion, they don't do much. As the figure shows, CO2 and CH4 are the big kahunas of GHGs.
  13. The End of the Hothouse
    Causation is a fundamental tenet in science. True randomness is very hard to find. Even what is called "unforced variation" still happen because of causes. These are of fundamental importance to say weather-forecasters or ocean dynamic modellers but not so much for climate since they are energy-bound. For CO2 drop, you cannot simply expect CO2 to disappear. A process must be operating that takes it from atmosphere and changes one or more the carbon-cycle fluxes. These are all governed by physical and chemical laws. You can believe in magic but I find science more useful. Obligatory XKCD
  14. Foster and Rahmstorf Measure the Global Warming Signal
    Sorry, wrong link for Sato et al., 1993.
  15. Foster and Rahmstorf Measure the Global Warming Signal
    #73 skept.fr: "So, if I correctly understand the methods, the AOD measure is not limited to volcanic activity signal, but to all aerosol's changes including the anthropogenic sources." I may be wrong, but what I understand from this study is that AOD here stands for stratospheric AOD, which really is a measure limited to volcanic activity signal, and which influence used in FR2011 seems detailed in Lean&Rind 2008 (finally the equivalent study with the same exogenous factors, but in the opposite path) : "Volcanic aerosols in the stratosphere are compiled by [Sato et al., 1993] since 1850, updated from giss.nasa.gov to 1999 and extended to the present with zero values." Moreover, the study result of FR2011 called "true global warming signal" corresponds to an estimate of the net anthropogenic forcing : "including greenhouse gases, landuse and snow albedo changes, and (admittedly uncertain) tropospheric aerosols." Just to be sure to agree on the fact that it doesn't represent the filtered GHG global warming signal, but the whole AGW signal.
  16. Models are unreliable
    JamesWilson - "CFCs are also much more of a GHG than CO2. Lending them actually higher credibility" Higher credibility with whom? Random bloggers on the internet? CO2 is a powerful greenhouse gas. Note the relationship between CO2 and global temperature from the ice cores: Because of fossil-fuel burning (mainly) atmospheric CO2 is now at its highest concentration in at least 15-20 million years. See Tripati (2009). The satellites also observe CO2 trapping more heat. See SkS post: How do we know more CO2 is causing warming? And finally, CFC's are discussed in this SkS post: It's CFCs The heat-trapping ability of CO2 does not simply disappear because man-made chemicals can also trap a small amount of heat. And if you wish to comment further on CFC's, do so on that thread. Thanks.
  17. Models are unreliable
    The Graph of Sea Levels according to Jason 2 is out of date. This is the Nasa site. Oddly the Jason-2 site shows the change and drop starting in 2010 but I can't find a link to that at the moment. http://climate.nasa.gov/keyIndicators/
  18. Models are unreliable
    "Noone has created a general circulation model that can explain climate's behaviour over the past century without CO2 warming." This isn't true regardless of the veracity of Qing-Bin Lu's claim that CFCs actually more closely model Global Warming trends than CO2: It is a model that shows the trend without using CO2 as the driver. CFCs are also much more of a GHG than CO2. Lending them actually higher credibility as the driver of Global Warming. From a scientific perspective you need much less of them to cause a problem.
  19. The End of the Hothouse
    @ doubtingallofit
    "The moderator response to "The level of CO2 drops for no particular reason" was that this is positing magic. It is unclear how magic and lack of a particular reason are equal."
    CO2 does not rise nor fall without causative physical reasons/mechanisms. To posit that it simply "drops for no particular reason" is to betray either a lack of knowledge about those physical, causal mechanisms (unfortunately for TIS, he is very aware of those mechanisms but conveniently omits them) or to just make a comment that is intended to waste the time of others. I.e., trolling. For more info on CO2, I recommend watching this video on why CO2 is the biggest climate control knob in Earth's history.
  20. The End of the Hothouse
    What the moderator is saying is that there will always be a reason for drop in CO2 - the idea that something happens without a cause is in fact magical thinking. Moreover, particularly large changes of the sort referred to can only be caused by a limited number of mechanisms, which we understand very well. In many cases we know enough to determine if those mechanisms could or couldn't be acting. I don't see how your cancer cluster example is relevant. That is simply a case of being properly rigorous in statistical analyses of data so that we don't try to explain a phenomenon that does not actually exist. Such false phenomena can actually happen for no particular reason, because they are a figment of our imagination. While quantum mechanics seems magical to the unitiated, it has proven to be very predictive - so it classifies as a particular reason for lot of stuff that happens. It would be magical thinking if we concluded instead that the phenomena explained by quantum mechanics happened for no particular reason.
  21. Foster and Rahmstorf Measure the Global Warming Signal
    skept.fr#73: "aerosols have been decreasing in the 1980s and 1990s" Numbers are always nicer than 'probablies' and 'summaries.' Here are some from Hatzianastassiou et al, as presented at 2009 EGU: On a global basis ... the AOT has slightly increased (by about 4%) over the two-decadal study period, mainly in the Southern Hemisphere. Consequently, the magnitude of aerosol DREsurf has also increased by 0.38±0.1 W m-2 (or by 6%) indicating thus an aerosol solar dimming from 1984 to 2001. ... Although on a global basis the contribution of aerosols to GDB can be exceeded by the effects of other radiative components such as clouds, aerosols are found to significantly contribute to GDB at the regional scale Here AOT = aerosol optical thickness, GDB= global dimming and brightening, DREsurf = direct radiative effect on solar radiation at the Earth's surface The problem will be in the last sentence of the quote: these effects are regional. How do you propose to include that in an analysis such as FR2011, which is a decomposition of temperature record into components and not a forward model?
  22. doubtingallofit at 04:48 AM on 24 December 2011
    The End of the Hothouse
    #23 The moderator response to "The level of CO2 drops for no particular reason" was that this is positing magic. It is unclear how magic and lack of a particular reason are equal. Isn't this how we get statistical anomalies entrenched as the truth? For example, cancer clusters that aren't real? A whole lot of quantum physics seems pretty magical, so would that not be science? Please clarify how magic and no particular reason are the same.
  23. Updating the Climate Big Picture
    John Brookes @17 & 18, globally averaged it is 6 *10^-6 W/m^2, so no. Specifically with regard to ocean heat content, that measured in units of 10^22 Joules for convenience for the upper 700 meters.
  24. Foster and Rahmstorf Measure the Global Warming Signal
    #71 Bob : thank you. So, if I correctly understand the methods, the AOD measure is not limited to volcanic activity signal, but to all aerosol's changes including the anthropogenic sources. Furthermore, the direct effect (reflectance in clear sky) can be accurately estimated, but not the indirect effects of aerosols (total cloudiness and optical property of clouds). If this a correct, FR2011 probably underestimate the trend (or the slope of the warming signal). As mentioned in 57, it is widely considered in the literature (see this 2009 review for example) that aerosols have been decreasing in the 1980s and 1990s (warming trend, not fully accounted in FR2011 for the indirect effects by AOD) then stabilizing and slightly increasing in the 2000s (cooling trend with same problem, not fully accounted for the indirect effects by AOD). So, it suggests a full account of aerosols would likely produced a higher warming signal in 2000s than in previous decades.
  25. Updating the Climate Big Picture
    Believe me, Daniel Bailey, it was there in the original post.
    Response:

    [dana1981] Oh yeah sorry, I just went ahead and made the suggested change.  Probably should have made a note - it's been a busy day.

  26. Updating the Climate Big Picture
    Sorry - 10^17 Joules, not 10^20.
  27. Updating the Climate Big Picture
    A quick question. Looking at sea levels from 2010 to 2011 shows a drop of ~8mm. Assuming that all this water ends up on land at an average elevation of ~5m gives this water a raise in potential energy of ~ 10^17 Joules. This energy will be converted back to heat as the water returns to the sea. Is 10^20 Joules a significant amount of energy in the atmosphere - upper ocean system?
  28. Roy Spencer on Climate Sensitivity - Again
    Tom, I used table 2 from my link in #62 which says "Jan 1979–Dec 1998" so I went through Dec for the trend from woodfromtrees. There are other problems with this method such as the basic difficulty of estimating what the effect of the old errors would be on new trends. Would their estimate in 2011 be only 1/4 of the actual trend today if they had not made the 1998 and subsequent corrections? Can't say for sure.
  29. Roy Spencer on Climate Sensitivity - Again
    Eric (skeptic) @62, I considered using that method, but to do so correctly you must ensure the trends are taken over the same period, to the month. As Spencer and Christy do not always state the final month in the trends in various publications, that is not always convenient. It is not clear to me that you have done that, particularly with the 1998 date (which was published in 1998 but may have included no data later than 1997).
  30. Updating the Climate Big Picture
    To show how even more unreliable is your source, I show how the piece I linked before ends: "U.S. Economy at a Crossroads: Ironically, the communist nation of China is making energy decisions based on capitalist principles , while the United States of America is floundering with a non-energy policy that most closely resembles a variation of European Socialism ." This page has also the following intro: "This page contains facts and figures about U.S. coal resources that every American should know. If you dislike America or capitalism you should not read this page. Go instead to this page: http://www.greensocialist.org.uk/ags/" (a british socialist page called Alliance for Green Socialism) This statements that want to accuse proponents of action against climate change of being politically biased towards socialism and communism are likely an example of projection: a trasfer the sub-conscient sense of guilt to your adversary. (-Snip-)
    Response:

    [DB] Please refrain from remarks about politics and ideology (snipped).

  31. Updating the Climate Big Picture
    Mr mace: You should be careful with the sources of information you use. Your source is called "Plant Fossils from West Virginia" (http://www.geocraft.com/WVFossils/Articles1.html) This innocent-looking site do not just question the science of global warming. It also has this section: "America has the Worlds Largest Coal Supply" where, in a few words, the following is sustained: 1:America is the "Saudi Arabia" of Coal 2:The Petroleum Dilemma 3:Coal is the Key to Affordable Energy 4:China Chooses Coal 5:Renewable Energy Requires Coal 6:Liquid Fuels from Coal 7:U.S. Economy at a Crossroads It a series of half-truths that fall in one category of writing: propaganda. This shows that whoever wrote this page is on the side of the most dirty fossil fuel industry: coal. Obviously this is not a reliable source.
  32. Updating the Climate Big Picture
    GrahamC, the term 'conclusively prove' appears nowhere in the above article.
  33. Roy Spencer on Climate Sensitivity - Again
    A simple estimate of the corrections is to use current UAH data with up-to-date corrections and compare the trend for an early part of the data to the trend calculated in an old paper with uncorrected or less corrected data. The corrected trend for Jan1979 to Apr2002 is 0.26C or 0.11C per decade, see http://woodfortrees.org/plot/uah/from:1979.0/to:2002.33/plot/uah/from:1979.0/to:2002.33/trend The corresponding trend from the paper in Tom's post 51 above is 0.06C per decade. So about one half of the corrected trend for that period is from corrections and the other half is from warming over that interval. Looking back a little farther, there is 0.23 trend from 1979 through 1998 or 0.115 per decade in current corrected data. The corresponding paper http://journals.ametsoc.org/doi/pdf/10.1175/1520-0426(2000)017%3C1153%3AMTTDCA%3E2.0.CO%3B2 indicates a 0.03 per decade trend corrected to a 0.06 per decade trend (+/- 0.06). Although the "peak" in their underestimate of TLT trend may have occurred earlier than 1998, the correction made at that point seems to be the most significant in magnitude (comparing the error in the trend to the trend itself). Also the comparison above does not mean that the current corrections are complete.
  34. Updating the Climate Big Picture
    This is a great article. Just one niggle. Would you consider replacing the term 'conclusively prove' (in the Humans are Increasing Atmospheric Greenhouse Gases section) with something else? Lots of the non-scientists who resd this will interpret that as implying 100% certainty, and seeing the term used here makes them susceptible to the skeptics demand that they shouldn't believe anything unless it's 'proven'.
  35. Updating the Climate Big Picture
    mace, The geocraft CO2 history has been debunked many times. See this CO2 was higher in the past thread. Once again, the best advice is to read and learn, rather than make decisions from unsubstantiated claims.
  36. Bert from Eltham at 10:46 AM on 23 December 2011
    Foster and Rahmstorf Measure the Global Warming Signal
    Yes Tom Curtis I am sorry if I went off half cocked. I fully realize it is not helpful. I am just an older retired Physicist and we are used to being correct! skept.fr is at least logical and his analysis is sound if his assumptions are real. The real problem I have is that full picture is difficult to comprehend. Flying a light aircraft solely on instruments is something you all should try. If you do not cross correlate all the information or rely on one instrument indication you will crash. We are all biased by our life histories. None of us is immune. Again I will think more carefully before posting next time. Bert
  37. Updating the Climate Big Picture
    "I think what's clear is that mother earth's been around billions of years, and we need at least 50,000 years to see the signal emerge from the climate noise." Nope. The temperature signal shows two things: 1/ internal variability (eg ENSO) which is unforced variation due to distributing heat around a water-covered planet. 30 years appears to more than enough time to account for this. 2/ forced variability from natural forcings (eg sun (milankovitch and solar output variation), volcanic aerosols; and longer time scales - variation from continent arrangement and GHG variation due to biochemical factors. To claim that you need a longer time to sort natural from anthropogenic would require some evidence that there is natural variation that is not yet linked to a natural forcing. As it stands - no evidence that I am aware of. We can account for past variation from past forcings and we know the strength of current forcings. Natural forcing alone do not account for current climate (eg Meehl 2005 or the summary in the IPCC report). Furthermore, there needs to some magic that counteract the effect of the known physics of GHGs. So far the modelled effect of increased GHG is being reflected the observations. Ignoring that and praying for some natural variation fairy to let us off the hook is imprudent to me.
  38. Updating the Climate Big Picture
    4, mace, That's a wonderful find!!!! You should now look and see how the site you posted absolutely, undeniably and maliciously tricked you and anyone else who visits it. Concerning the "modern temperature record" they used, the recent temps (1979-2001) are supposedly from "Satellite stratospheric data," but since stratospheric temperatures (a) are not in any way indicative of surface temperatures and (b) have been cooling for the last 30 years (in accordance with GHG theory expectations), I think they really meant "tropospheric temperatures." Beyond this, however, if you compare the different measures, you'll find that comparing ground temperatures to tropospheric temperatures is apples and oranges. Concerning the temperature data from 1871 to 1979, why in the world did they use Southern Hemisphere data, of all possible global data sources? One has to scratch one's head at that choice. They may argue that it is similar to the Vostok ice core data (by at least being in the same hemisphere), but that sort of points out how wrong it is to compare any of that to the global mean satellite data. Concerning the temperature data from 1871 back... the temperatures at the poles change substantially more than the global mean temperature. This was true then and it's true now. It's called polar amplification. But the temperature swing in the Vostok data before 1871 is less than 2 degrees from the mean. The temperature swing today at the South Pole is more than 3. At the North Pole it's more than 4.5. So... they used three wildly disparate sources that show entirely different things that can't be compared, in particular a comparison of temperatures at one specific, extreme location in the past (one everyone knows will show more variation) as compared to the global mean temperature in the present (using a metric that everyone knows will show less variation in comparison, and yet it is by far the more important and more sensitive number). Quite a wonderful load of denial misrepresentation you've found! And let it be a lesson to you. Look into the data, and understand what you are looking at, before you accept what they are trying to sell you.
  39. The Media & Global Climate Science Communication
    Shoe – may I add to John Hartz’s directions Under each chart in article you will see reference to the figure numbers of charts in the study from which they were directly copied. They combine information from two separate charts in study to make them more comprehensive in detail. If you are now confident about the data collection methodology feel free to share.
  40. Ocean Acidification Is Fatal To Fish
    Mace @ 19 - we don't know enough about the Cambrian (some half a billion years ago) to be absolutely sure about the ocean pH back then, and it can't be calculated from atmospheric CO2 alone. There is huge uncertainty about atmospheric CO2 concentrations that far back, and the estimates come from models, with few actual proxies. An additional consideration is that slow changes would allow the ocean to mix CO2 (and the resulting chemical changes) down to the deep ocean, diluting and therefore minimizing the drop in pH at the ocean surface. All-in-all it's a big question mark. The fact that life was actually blossoming at this time (the Cambrian Explosion) suggests the oceans can't have been inhospitable to life. In relation to the fake-skeptic canard of higher levels of CO2 in the past, I'm writing up the basic/intermediate/advanced versions of that rebuttal. Simple version = rapid rises in atmospheric CO2 lead to ocean acidificaton, whereas slow changes do not. Of course none of this has any bearing on species living today, especially the two fish species investigated here. They die when pH drops significantly, that's an observation - no modelling or interpretation of fossils required. This is a concern given the current rate of change in atmospheric CO2 is 5-27 times greater than the Paleocene-Eocene Thermal Maximum (as pointed out by the moderator above) and around 18-30 times faster than the Permian extinction (around 250 million years ago) also known as the Great Dying because over 90% of life on Earth went extinct. None of this means we are going to see a repeat extinction event, but at the very least it does suggest a monumental struggle for species to survive. Many will simply not make the grade. I suggest you avail yourself of the OA is not OK series to gain a better understanding of this rather ominous threat.
  41. Updating the Climate Big Picture
    I think what's clear is that mother earth's been around billions of years, and we need at least 50,000 years to see the signal emerge from the climate noise. I think those ice core charts are a brilliant attack against deniers when they claim a few not so hot years are the sign of a cooling trend.
    Response:

    [DB] "we need at least 50,000 years to see the signal emerge from the climate noise"

    Um, no.  That is the entire point of the Foster and Rahmstorf Measure the Global Warming Signal thread.  A thread which you have already commented upon..

  42. Updating the Climate Big Picture
    Sorry guys, I think this one's the one I meant to post:- CO2 v Temperature over last 50K years *Blush*
    Response:

    [DB] Rather than promulgating fake-skeptic graphs from dubious blogs, use rather the scientific sites, like this one from NASA:

    http://climate.nasa.gov/evidence/

  43. Updating the Climate Big Picture
    I think the scientific understanding of carbon-cycle feedbacks has reached a point where it warrants a line or two in "the big picture." Significant, ongoing releases of CO2 and methane from melting permafrost imply that, at best, emissions must be cut more aggressively than previously estimated to stop the rise in atmospheric CO2. At worst, it could mean that we initiate a process in which even a completely carbon-neutral society sees CO2 levels continue to rise for centuries. Without wishing to distract attention from the central problem of human emissions, I think carbon cycle feedbacks are important enough to be included in a review like this one.
  44. Roy Spencer on Climate Sensitivity - Again
    Chris @59, Thanks for the citations. Here is another important one by Prabhakara and Iacovazzi (1999), their abstract is worth a read. At the end of the day Spencer and Christy were wrong and Wentz and Schabel (1998), Hurrell and Trenberth (1997, 1998) and Prabhakara et al. (1998) were correct. But when first notified of the errors in their data by Hurrell and Trenberth in 1997, Spencer and Christy were quick to dismiss them and did not take the critique at all seriously, this from March 1997: "There isn't a problem with the measurements that we can find," Spencer explained. "In fact, balloon measurements of the temperature in the same regions of the atmosphere we measure from space are in excellent agreement with the satellite results." And in February of 1997 they said this: "Spencer and co-author Dr. William Braswell of Nichols Research Corporation have great confidence in the quality of their satellite data. "We've concluded there isn't a problem with the measurements," Spencer explained. "In fact, balloon measurements of the temperature in the same regions of the atmosphere we measure from space are in excellent agreement with the satellite results." "Instead, we believe the problem resides in the computer models and in our past assumptions that the atmosphere is so well behaved. " Note how quick they are to blame the models. more noteworthy though is their reliance on the balloon data is intriguing and convenient, because even back then it is well established in the literature that there were also serious issues/biases with the balloon data (see Luers (1997), Parker and Cox (1995), and Gaffen (1994) et cetera.) A summary paper by Randel and Wu (2005) can be found here. So when Christy claims that "When problems with various instruments or processes are discovered, we characterize, fix and publish the information", that is not entirely true and not what the literature and history show and does not credit or acknowledge the errors pointed out to them by other researchers. Additionally, when Christy claims that "Indeed, there have been a number of corrections that adjusted for spurious warming, leading to a reduction in the warming trend" that is not entirely true either as shown by Tom's research shown above. In the same blog post Christy says, "The notion in the blog post that surface temperature datasets are somehow robust and pristine is remarkable." Interestingly back in March 1997 Christy said: "Over Northern Hemisphere land areas, where the best surface thermometer data exist, the satellites and thermometers agree almost perfectly", said Dr. Christy of UAH." So in March 1997 he agreed that there was good agreement between the satellite and surface (land) thermometer data. Ironically, it is now in 2011 that the evidence that the surface temperature record is robust is strongest, but Spencer and Christy are still choosing to questioning that and casting doubt on the land temperature record. I strongly suspect that they in their heart or hearts know that the surface record is robust, but prefer to be merchants of doubt. Someone should write a book on this sad saga, maybe titled "Satellite temperature illusion".
  45. Updating the Climate Big Picture
    Mace - your confusion will not be alleviated by reading fake-skeptic blogs, like the one you just linked to. Peer-reviewed scientific literature is what you should be reading.
  46. Climate's changed before
    I would say the modern agriculture would have a very hard time coping with climate change that happened as fast as the YD. However, no agriculture existed. Human's even as hunter-gatherers apparently did indeed struggle Pleistocene changes, with populations surviving in enclaves, driving migration. Fortunately, rapid climate change events are associated with the ending of ice-ages not interglacials. As to deeper time, time resolution becomes a problem unless the event can be interpreted from a single sequence. Rates of change far less than present are associated with the great extinctions in the paleo record.
  47. The Debunking Handbook: now freely available for download
    Thoughts: I happen to have degrees in cognitive psychology and computer science; I'm familiar with a common misconception that human memory works like computer memory. It is not, at all. When you write to computer memory, it is like flipping a switch; whatever information was there before is erased and the new information is put in its place. There is no "memory" of what was there before. However, brains are organic by nature; memory works as associations between neurons and these have to be "grown". I've been out of the field for some time, but, to my knowledge, there is no mechanism to erase prior associations. Whatever the strongest association is becomes "the memory", and whatever weak ones may be present become some barely conscious addenda. It takes some repetition and active processing to develop a new connection to the point where it is stronger than the old one. I think that using this as a working model of brain behavior might help with understanding and predicting how it can be difficult to change someone's mind about an issue. For instance, with the one-myth, many-facts scenario, you have one strong pattern of association, and the multitude of weak associations never receive enough processing resources individually to overcome the strong one. The loudest demon metaphor comes to mind. I suspect that it applies to more that just our perception neurons. Changing a set of firmly entrenched, interwoven beliefs, can be like trying to create a paradigm shift. Sometimes it takes a traumatic event to cause such a shift. For example, young people often have the sense that nothing bad will happen to them because nothing really bad has ever happened to them before. Often, nothing short of something like getting in a car wreck, breaking a leg, or getting arrested and thrown in jail will convince them otherwise. I have some curiosity to look up other works by Professor Lewandowsky. The term "belief perseverance" comes to mind. (references available through Google). One of the more effective ways to overcome this is to get the other person to try to imagine as if some bit of information were true, and then build an logical argument from there. I think it is important to remember that the other person is likely to honestly believe the incorrect information, and refrain from accusations otherwise.
  48. Updating the Climate Big Picture
    Thanks both. Sorry, I get confused with the baselines for these anomalies from time to time. I've come across this which plots CO2 against temperature for the last 50 years which I think is pretty conclusive. http://www.geocraft.com/WVFossils/last_500_yrs.html
    Response:

    [DB] As Rob says below, it is better to relay on actual source material rather than just some blog.  Data from the primary sources, placed in context, shows clear relationships between CO2 & temps difffering from the portrayals of your source:

    Click to enlarge

    Click to enlarge

  49. The Media & Global Climate Science Communication
    Shoe: According to the study that Brian Purdue's article is based upon: "positive" means that an article was positive towards the proposed carbon policy; and, "negative" means that an article was negative towards the proposed carbon policy. The methodology employed by the study is set forth on pages 21 thru 23 of the report, "A Sceptical Climate: Media coverage of climate change in Australia 2011: Part 1- Climate Change Policy." To access a PDF of this report, click here.
  50. Climate's changed before
    mace, This is always a sobering graphic to ponder. Two degrees C on a global average is a lot - especially if it occurs quickly. Just be sure to note the non-linear time scale.

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