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Unforced variations 3

Filed under: — group @ 21 October 2010

Here’s an open thread for various climate science related discussions, to prevent more off-topic clutter everywhere else. We have some good posts coming up, but if you want to discuss something you read in the media, saw in a press release or just wanted to ask about, this is the time.

Some interesting things we’ve seen recently include discussions on the epistimology of climate modelling, Andy Dessler’s adventures in debate land and his new paper on water vapour trends, and a review of trends in the Columbia glacier. Have at it.

Addendum: Kevin McKinney has beaten us to the mention of this, but another recent article of importance is a thorough review of the state of knowledge of drought, past and future, by Dai.  The article is open access here.


573 Responses to “Unforced variations 3”

  1. 1
    dlharman says:

    “Unforced Variations” I believe.

    [Response: That indeed was an unforced variation. How neat is that? - gavin]

  2. 2
    Robert says:

    I was wondering if anyone could perhaps help me to understand the mechanism through which the AMO (Atlantic Multidecadal Oscillation) could have effects on global temperatures. A recent paper has found that it is contributing to the current warming (termed IMP) by the paper.

    ftp://www.iges.org/pub/delsole/dir_ipcc/dts_science_2010_main.pdf

    I know there are a lot of climatologists out there who are not so big on the AMO but it seems that there is a plethora of evidence out there that it is a dominant driver outside of just the North Atlantic.

  3. 3
    TimTheToolMan says:

    If the models were to be shown to be specifically deficient in some area and need significant rework what impact would you see that having on the thousands of papers that have relied on them to this point and of climate science in general?

    [Response: And if the moon were made of green cheese, what impact would that have on space science in general and on the astronauts who walked on it? Please don't play games. - gavin]

  4. 4
    David B. Benson says:

    Robert @2 — Thanks for the interesting link. Is there a published paper for which you can provide the citation?

    I’m certainly an amateur at this. It seems that the AMO is a index for MOC rate variation (amoungst other things). So the AMO gives some guide as to the interaction between the deep ocean and the rest of the climate system.

  5. 5
    AJ says:

    I am interested in citations for the seminal works in radiative transport through the atmosphere, as well as a link to any documentation on the most widely used transport models.

    Thanks and best regards.

  6. 6
    Arrow says:

    I was curious if anyone was following the GCM discussions on Jeff Id’s blog:

    http://noconsensus.wordpress.com/2010/10/21/456345/

    Nick Stokes also chimes in on his blog:

    http://moyhu.blogspot.com/

    I’ve been finding the discussions interesting, even if some of the claims might be a bit heavy on the rhetoric.

  7. 7
    Harold Pierce Jr says:

    ATTN: Gavin
    I misspelled my first name in the name box: It should “Harold” How do I fix this?

  8. 8
    TimTheToolMan says:

    Gavin says “And if the moon were made of green cheese, what impact would that have on space science in general and on the astronauts who walked on it? Please don’t play games. – gavin”

    Whether the recent discovery of a possible deficiency in the models turns out to be significant or not, this is a legitimate question to be asked and answered. Think of it as disaster mitigation needed for science. We do it for business, I don’t see why science should be exempt when science has tied itself more closely with results based funding than ever.

    [Response: Coyly hinting at some super-secret deficiency you think you've discovered or read about, but not actually saying what it is, is just playing games. If you want to talk about something specific, do so. - gavin]

  9. 9

    I was sent a link to an article (see below) that makes me wonder how “bad” is “bad? Do we really know if we are headed for “catastrophe”? How do we know?

    How do we know things are “urgent” and we must put limits on fossil fuel use? How urgent is urgent?

    When you read it focus on how bad things could get – i.e. catastrophe and not on the other junk in this article. The remarks about climategate or the hockey-stick are pretty irrelevant to what I am concerned about.

    If we can’t convince people on how serious things are they won’t support any kind of regulation. Is there any proof we are headed for “disasters”. Suppose we do implement some form of regulation… will that really put a dent in curbing the progress of global warming?

    I am sorry to sound so down but that article made me ask these kinds of questions.

    http://blogs.forbes.com/warrenmeyer/2010/10/15/denying-the-catstrophe-the-science-of-the-climate-skeptics-position/

    Thanks,

    David

  10. 10
    Fred Moolten says:

    Because water vapor trends are critical to the issue of positive feedbacks, the Dessler et al paper indicating that four out of five reanalyses show positive trends with warming is an important step in providing a realistic perspective. The one deviant, the NCEP/NCAR reanalysis, was the one effort that utilized only radiosonde data without availing itself of the newer and more accurate satellite based methods. The downward trend in that dataset has been analyzed by Yang et al, with evidence indicating that each downward step followed a change in intrumentation that diminished what were previously upward biases. In that sense, some of the mystery surrounding the spurious trend appears to be resolved. The link is: NCEP Reanalysis

  11. 11
    Dan H. says:

    Robert,
    The AMO and its cousin the PDO (pacific decadal occillation) have shown good correlations with the sinusodial type oscillations in the 20th century temperature profiles. I will to describe them in a nutshell. Both oceanic indices are termed positive when warmer water flows poleward, and negative when the warmer water flows towards the equator. The indices become more positive (negative) as the water becomes warmer towards the poles (equator). As warmer water flows poleward, it warms the winds that sweeep over the ocean, and warm the nearby land regions. During the periods of greatest positive indices, the land masses show higher temperatures (relative to recent negative indices). These indices tend to remain in one particular mode for extended time periods (decades). The PDO affects the ENSO events; positive PDOs lead to greater El Ninos and lesser La Ninas, and negative PDOs lead to the opposite. Positive AMO values lead to greater melting of Arctic sea ice. Some oceanographers claim that the these cycles are responsible for most of the observed warming. Prof. Latif has postulated that the switch to negative AMO indices will lead to 2-3 decades of cooling, followed by warming. I do not have the link handy.

    Climatologists tend to dismiss these explanations as they minimize the CO2 affect on temperature.

    The unanswered question is what causes these indices to change. Some speculate that they are tied into solar variations.

    I hope this helps.

  12. 12
    Jim Groom says:

    I hope you folks don’t find this one too far off the usual topics on RC, but I found it to be of great interest. On Oct 7th the following news was released.

    Spire Semiconductor LLC has claimed achievement of the world efficiency record for a concentrator photovoltaic (PV) solar cell.

    The Hudson, NH based company, said its cell was measured by the U.S. Dept of Energy’s Natl Renewable Energy Lab to have a peak efficiency of 42.3% at 406 suns AM1.5D, 25C (42.2% at 500 suns).

    Spire Semi said this came about after it won a $3.7 million dollar subcontract from the agency in early 2009 to develope high efficiency triple junction, gallium arsenide solar cell (GaAs). A typical roof-top solar installation today has an efficiency of about 12%.

    ‘In less than 18 months, we were able to validate and incorporate our new concept into a production-ready cell design with world-record efficiency,’ said Ed Gagnon, general manager of Spire.

    Gagnon said the higher efficiency cell platform is now commercially available to concentrator systems providers. This advance will help ‘to move solar energy ever closer to the goal of grid parity.’

    The above news release seems to me to be big news. I’ve not read a thing in the MSM for reasons that I can’t understand. Does anyone have any additional information or comment on the above?

  13. 13
    Chris Colose says:

    Richard Kerr’s article on the AMO is a very nice introduction (sorry to those w/o full text access)
    http://www.sciencemag.org/cgi/content/summary/288/5473/1984

    You always have to be careful saying this because there’s a lot of people waiting to distort, but a lot of researchers do feel some recent warming in the North Atlantic in particular has a lot to do with internal variability. There’s a lot of research into understanding the high frequency and multi-decadal departures of the Northern Hemisphere mean temperature from a uniform warming trend. This is particularly important for the attribution of hurricane trends and also decadal prediction. Note that there’s really no evidence for the long-term warming trend to have any significant component from internal variability

  14. 14
    Robert says:

    Chris Colose at 13,

    Try running a multivariate regression between Temperature (Y) with CO2 and the AMO (x-variables).

    The predicted values versus the actual temperature values are pretty shocking and obviously flawed somewhere…

    My understanding is that the AMO has an impact on global temperatures in themselves. The paper showed above (it is peer reviewed, the link to the journal is somewhere else) seems to say that the IMP or AMO variability is a dominant signal in current warmth on a global scale.

    Furthermore, research from the following presentation
    http://meetingorganizer.copernicus.org/EGU2010/EGU2010-13508.pdf

    Indicates a predominantly positive AMO during the MWP, negative during the LIA and currently positive.

    I am certainly not a skeptic but I am interested in how much the AMO is influencing global temperatures. It would be interesting to get some feedback on the mechanisms. I have my theory it has a somewhat solar origin over long time scales. Any ideas?

  15. 15
    TimTheToolMan says:

    Gavin says “If you want to talk about something specific, do so. – gavin”

    It looks like me being specific was just moderated into oblivion. Sooner or later we’re likely going to have to deal with the point I raised and I think it would be better to do it in a planned controlled fashion rather than in damage control.

    [Response: Spare us. Models are used because they work, not because they are some pure deified output of our reasoning. No supposed deficiency takes away from the already demonstrated skill - how could it? Can they be better? Sure, but your imaginings of some huge looming crisis is simply fantasy. - gavin]

  16. 16
    Septic Matthew says:

    The fifth Mojave Desert giant solar project (600+MW from Stirling engines) has been approved by the Feds. The next CA State hearing will be Oct 28. Here are some nice photos from one of the organizations that opposes it.

    http://basinandrangewatch.org/CalicoSolarApril.html

  17. 17
    Dean S. says:

    (Comments by TimTheToolMan)

    It seems to be common contrarian argument that somehow EVERYthing measured and researched and evident is somehow all dependent on modeling, which is ironic since the truth is it’s very much the other way around…?!

    It’s difficult to understand sometimes how apparently not EVERYone has learning in recognizing classic logical fallacies, corrupted media, and simply unreasonable reasoning.

  18. 18
    Hunt Janin says:

    For my introductory survey on sea level rise, I’m about to draft a few pages on possible impacts on Chinese coastal cities. I’ve run through all the Google entries on this subject I can find but want to know if any list members can further enlighten me on it. If so, please do so off-list at huntjanin@aol.com

  19. 19
    Hunt Janin says:

    If anyone knows a good deal about the likely impacts of sea level rise on Chinese coastal cities, I’d be grateful if they could contact me off-list at huntjanin@aol.com.

  20. 20
    Marco says:

    Gavin,

    Tim refers to the new meme in parts of the deniosphere. See e.g. Jeff Id’s blog:
    http://noconsensus.wordpress.com/2010/10/19/momentary-lapse-of-reason/

    No need to post this.

    [Response: I know what he is referring to, I'm 'Gavin' on that thread. But what I object to are coy hints of some looming issue that everyone is running scared from. That is simply spin for the unwary. This is not as exciting as the authors claim, and the response to their earlier claims is full of very good reasons why. - gavin]

  21. 21
    Dean S. says:

    re:Comment(s) by TimTheToolMan:

    It’s become a popular contrarian argument to propose that EVERTHING that is measured, researched, and evident relies on modeling, which is ironic since in reality it’s very much the other way around…?!

    It’s difficult sometimes for me to understand how not EVERYONE has learning on how to recognize classic logical fallacies, media bias and corruption, and simply unreasonable reasoning. I guess what some say about our education system failures is true after all…of course they also say “you can lead a horse to water…” The difference there is, of course, that if you stop pushing the horse will soon realize it’s thirsty and stop being stubborn proud and take a drink…

  22. 22
    Chris Colose says:

    Robert– I’m only skimming this paper but I’m not getting out of it what you are, and I also don’t see the utility in your multi-regression approach. Keep in mind that AMO refers to detrended SST anomalies. This is hard to do because there’s not really an easy way to decompose the signal and the residual (you need a model that provides a control, no anthropogenic forcing). But you should read this post from RC several years ago on this issue of the AMO since I’m not too well-acquainted with this stuff (maybe Dr. Mann can chime in)
    http://www.realclimate.org/index.php/archives/2006/09/tropical-ssts-natural-variations-or-global-warming/

  23. 23
    TimTheToolMan says:

    Gavin says – “Can they be better? Sure, but your imaginings of some huge looming crisis is simply fantasy. – gavin”

    This is why I’ve explicitely tried to dissassociate this discussion from any work on models.

    So am I to assume that you dont think it would be a worthwhile discussion because you believe that the models will always be “valid” no matter what is discovered about them or the earth’s climate processes in the future?

    And consequently any papers that use today’s models and come to conclusions based on the model’s results are equally going to be always valid into the future?

    [Response: That is a ridiculous false dilemma, implying that if I think that models have been skillful, they therefore must be perfect and, presumably, incapable of improvement. What is wrong with 'yes, models have been shown to be skillful, and yes, they can be improved, and will be in the future'? Obviously, this means that some results from today might be changed, but as I stated, where models have already shown skill, that doesn't go away. And where models support conclusions from data, that isn't going away either. So climate sensitivity is still around 3 deg C. Sorry. - gavin]

  24. 24
    Chris Colose says:

    TTTM (on models)

    Part of the reaction toward you is based on your history, so don’t act surprised, but your question makes absolutely no sense. We have come to learn that the world we live in is governed by the laws of physics. A large component of climate models is built on these basic physical laws (conservation of mass, momentum, energy, etc). This provides us with great diagnostic and predictive power which has repeatedly proven to be incredibly useful. Perfection is not the goal.

    We can understand key features of the atmosphere (including the climate and the sensible weather) just from these really basic principles. For example, if you have more divergence of fluid in a column of atmosphere at the top than at the bottom, then you have to move air upward in line with pure physical intuition and conservation of mass. For synoptic-scale meteorology, I can then tell you this rising air will probably mean a cloudy day over you. If the air is sinking, the skies will be clear.

    If you create a horizontal temperature gradient (say between the equator and pole) then through basic manipulation of momentum and hydrostatic equations we can deduce that the wind speed must increase with height in the atmosphere. This happens, manifested as jet features. You can see it if you rotate a tank of fluid no bigger than your table (MIT has excellent experiments in rotating tank lab online). If you pour dye into the tank you will see a circulation that looks like a Hadley cell. Turn up the rotation and you’ll see that energy is transferred by eddies and waves instead of a nice overturning cell, as what occurs in the mid-latitudes.

    Operational satellite meteorology heavily relies on radiative transfer, and the theory and relationships used in models being useful. Spectral features and lapse rate effects is how we see into the atmosphere and distinguish between the surface and the top of a cloud. Stellar astrophysicists use these same principles to find out information about stars.

    Why am I rambling about all of this and throwing factoids around? There are many, many examples of simple physical lines of argument that give incredible insight into how atmospheres work. I encourage you to take some quantitative-level classes in climate or meteorology to really convince yourself (and fascinate yourself) with how much physics works. GCM’s take this physics, countless pieces of it, and provide us with invaluable information. That models are all wrong is just not possible. It’s a hypothesis, but easily demonstrated to be false. That said, that models are imperfect is also easy to demonstrate. The goal of the scientists now is to show if these deficiencies matter (which is certainly dependent on the question of interest, the radiative forcing for CO2 for example has nothing to do with a small deficit in model precipitation over western Wisconsin). Furthermore, what matters scientifically may not be interesting enough to matter for policy.

    If we fix a cloud parametrization and get better droplet formation or something, then does Joe down the street really care? If we improve hurricane track forecasts though, people will probably care. For climate change, there’s lots more (regional precip changes for example) that people care about which can be improved, but what do you think is going to change about CO2′s role in temperature change? Do you think some magic stabilizer which has never worked in Earth’s history, that models don’t develop, that no observations have ever seen, etc is going to suddenly turn on and save us? That’s a bit more far-fetched than the moon made of cheese I think.

  25. 25
    Terry says:

    Gavin, on a “perhaps” related topic to #15 above, I have been looking at the eqns in the CAM3 description related to moisture and convection to get a better handle on it. I am not a modeller, but my question is pretty basic. Do most of the current models use similar procedures for entrainment/detrainment in convective air masses as used in CAM3?

  26. 26
    Jerry Toman says:

    Since nobody at Realclimate seems to have much faith or enthusiasm for the potential of the Atmospheric Vortex Engine as a technology for mitigating or arresting climate change,in spite of the existence of natural “models” for it in nature, perhaps someone here might suggest here the name of a researcher or company or “Angel” who might have both the interest and budget (~$100,000) to actually build a captive waterspout about 50 feet in diameter, for which I have developed a simple design.

    I trust that if one could be built that exhibits impressive results, I could get one or more of you on board, along with myself and Don Cooper of Australia, as an official Endorser this potentially “Messiah” technology as one that at least merits even further developmental efforts–if not by “our” government, by the one who is currently eating our breakfast, lunch and dinner (you know–the one who now emits as much greenhouse gas as we currently do).

    Just askin’.

  27. 27

    I heard a rumor that a paper to explain why Potential Dependence of Global Warming on the Residence Time (RT) in the Atmosphere of Anthropogenically Sourced Carbon Dioxide by Robert H. Essenhigh
    http://pubs.acs.org/doi/full/10.1021/ef800581r#references
    is wrong where on it’s way… however that was some time ago, any one have news on that?

    I wrote about it briefly here:
    http://uppsalainitiativet.blogspot.com/2010/04/swedish-television-goes-oreskes-on.html

  28. 28

    Robert 14,

    when I regress dT on ln CO2 and AMO index for 1880-2007 I get 76% of variance accounted for by CO2 and another 12% by AMO. So AMO is an influence on the variance, but not as big as greenhouse gases.

  29. 29
    Ray Ladbury says:

    Tim the Toolman,
    OK, Tim, ‘splain me this: Where on Earth did you guys get the idea that if somehow the models were found to be flawed, the climate crisis would go away? Do you think temperatures would somehow miraculously return to pre-industrial levels, that the glaciers would come back, that the pH of the oceans would be restored, and that all the extinct species would come back?

    There is an astounding amount of evidence that global temperatures have risen rapidly in the past 40 years. It is happening. There is overwhelming evidence that CO2 is a greenhouse gas, and that the climate’s sensitivity to it is more than 2 degrees per doubling (or do you think Arhenius used a computer model?) Indeed, climate models are instrumental in placing an upper limit on climate sensitivity! Without this upper limit, there would be even more reason to slam the brakes on CO2 now.

    Now, there is no evidence that climate models are seriously wrong. None. However, I’ll never understand why the denialist contingent thinks their being wrong works in their favor. Uncertainty cuts both ways, and the blade is a whole helluva lot sharper on the high-sensitivity side than on the low.

  30. 30
    Ray Ladbury says:

    Dan H says, “Prof. Latif has postulated that the switch to negative AMO indices will lead to 2-3 decades of cooling, followed by warming. ”

    Not working out too well so far, is it?

    Dan H: “Climatologists tend to dismiss these explanations as they minimize the CO2 affect on temperature.”

    No, they dismiss them because they don’t explain the evidence and fail in predictive power. Evidence–there’s more to it than tropospheric temperatures.

  31. 31
    The Ville says:

    Tim the Tool said:
    “If the models were to be shown to be specifically deficient in some area and need significant rework what impact would you see that having on the thousands of papers that have relied on them to this point and of climate science in general?”

    This seems like a a leading question and you know the answer you want.
    The science would continue in whatever direction, like science always does.
    However you seem to be searching for a result that satisfies your views, which isn’t exactly unusual in business.

    I question whether you are interested in the science or are more interested in outcomes.

  32. 32
    Christoffer Bugge Harder says:

    It sure appears as Dessler pretty much demolished Lindzen. However, I would like to hear if somebody could elaborate more about the uncertainties in the four feedback “components” in the classic sensitivity equation he showed. (water vapour, lapse rate, ice albedo and clouds). Dessler showed nicely how water vapour was positive and did a very nice (the best I have ever seen) demonstration of how Lindzen is highly unlikely to be right with the cloud feedback (80% likely to be positive, most probable value 0,15, uncertainty intervals -0,04 to +0,34). This gives pretty much the sensitivity intervals around 1,7-4,5C.

    However, I would like, just for the record, to see some uncertainty intervals around the values he showed for water vapour (+0,6), lapse rate (-0,3) and ice albedo (0,1). If anyone can point me to such material, then I would much appreciate it.

    [Response: Try Soden and Held. - gavin]

  33. 33
    Urs Neu says:

    Robert,
    When discussing the AMO you first have to keep in mind what the AMO is: It is simply the detrended SSTs of the North Atlantic. Therefore it represents a priori the evolution of temperature itself and not any physical process which influences temperature. If you detrend global temperature you get pretty much the same pattern as the AMO. This pattern of global temperature can be explained by a combination of different influencing factors over time (increasing solar activity plus moderatly rising greenhouse gases until 1940; cooling through strong increase of aerosols / fading of solar activity increase / still moderate GHG rise until 1970; strong increase of GHG emissions / reduction or inversion of aerosol increase and the related cooling after 1970). There is no reason which a priori suggests that the temperature evolution in the North Atlantic should be significantly different from the global one. If there is a high correlation between temperature in the North Atlantic (NA) and global temperature, this can be due to a reaction of both geographical entities on the same external influence (which seems not unlikely…), due to an influence of the NA on the global scale, or due to influence of the global evolution on the NA. There is a paper (Elsner 2007: myweb.fsu.edu/jelsner/PDF/Research/Elsner2007.pdf) suggesting that an influence of global temperature on NA temperature is more likely than the other way round.

    Nevertheless, there is some evidence that the AMO, i.e. in fact NA SSTs, might be influenced by variations in the Meridional Overturning Circulation (MOC) of the ocean (Delworth and Mann 2000, Vellinga and Wu 2004, Knight et al. 2005, Latif et al. 2004). Climate models produce natural variations of Atlantic SSTs due to MOC variations at a similar timescale as the AMO, but with a wide range of frequencies (50 – 130 years), compared to the AMO frequency of 50-70 years. The subtraction of the greenhouse warming effect calculated by climate models from global temperature exhibits a geographical pattern, which is similar to the one attributed to the AMO (Kravtsov and Spannagle, 2008). Furthermore, Baines and Folland (2007) have shown that a number of signals over the globe can be attributed to North Atlantic cooling (an thus NA SST variation). Thus it seems likely that there is some signal related to MOC variations, which seems to have an influence on natural variations of the global temperature.

    However, these natural variations linked to MOC mainly explain residual natural variability which is superposed on greenhouse warming and do not in any way represent an alternative explanation of ongoing global warming. Furthermore, there is no observational evidence that the observed AMO (and recent NA SST increase) is actually linked to real MOC variations, since we don’t have any useful observations of recent decadal MOC behaviour so far. The suggested link is only based on a rough similarity of frequencies of two signals without the possibility to position the modelled variation on a real time scale.

    In view of all this, I won’t give much on any predictions related to the AMO. There are less than two AMO cycles in the instrumental period (which makes the frequency band estimation very uncertain), and reconstructions (e.g. Delworth and Mann 2000, Gray et al. 2004) show similar substantial frequency variations (40–150 years) than the models (50-130 years). If we don’t know if the next AMO cycle starts after 40 or after 150 years I won’t bet on a cooling during the next decades.

  34. 34
    Dan H. says:

    David,
    I read the article to which you linked. I think it describes the position of those who believe that CO2 is partly responsible for the observed warming, but that other factors were also involved. Warren Meyer divided global warming into two theories (although I think this was more to make his point than that the theories are seperate). The first is that the additional CO2 in the atmosphere will lead to warming due to chemical and physical properties of the gas. This is generally believed by all (except for a few deniers), and often referred to as the “consensus.” The second part is that feedbacks dominate the climate systems such that the increased CO2 will lead to catastrophic warming. This is were the skeptics and alarmists differ. In fact, there is a wide range of opinions within the skeptics and alarmists as to the actual feedback effects. I have seen many people err in assuming that the first “consensus” can be transferred to the second. I have also seen the most fervent believers in global warming refer to those who subscrribe to theory #1, but not #2 as deniers, when in fact, they believe that CO2 has contributed to the observed warmer, but not that it will accelerate to create a catastrophe. From my encounteres, skeptics are usually better informed scientifically than either the deniers or the alarmists.

    This is good reading for those who do not understand that there is a difference between those who “deny” global warming, and those to refer to themselves as “skeptics.”

    [Response: Sorry, but this is simply an attempt to reframe the 'center' of the debate. The mid-range of climate sensitivity is around 3 deg C - it might be a little less, it might be a little more - but this is what you get if you actually look at how climate has changed in the past. It also happens to be the mid-point of what the climate models suggest - though you are welcome not to pay attention to that if you want. The idea that 1.2 deg C is the midpoint and only 'alarmists' think it is bigger is nonsense. A sensitivity that low makes it impossible to explain ice ages, hothouse climates, etc. So no, this is not the difference that defines 'skeptics'. People who are in denial that there is plentiful evidence for net positive feedback are just the same as those who deny the evidence for rising GHGs, or the existence of the greenhouse effect, or the existence of internal variability, etc. etc. - gavin]

  35. 35
    Mitch Lyle says:

    Dan H. (11): Actually no oceanographers claim that the AMO/PDO cause ‘most of the observed warming’. I would suggest that you read Latif before quoting him. Essentially all oceanographers believe that AMO/PDO are important decadal modulations of the global warming trend. The magnitudes of the temperature change caused by these modulations are on the order of 0.1 deg C vs a trend of about 0.8 deg C.

    Since it is clear that you don’t actually have contact with climatologists, why do you claim that they tend to dismiss this oscillations?

  36. 36
    Mitch Lyle says:

    Don H. (11): Essentially all oceanographers believe that AMO/PDO are important modulations on a long term global warming trend. You should actually read the Latif paper you quote.

    AMO/PDO cause decadal variations on the order of 0.1 deg vs the 0.8 deg C temperature trend.

    Why do you claim that climatologists are trying to cover things up–who do you think are making these observations?

  37. 37
    Alexandre says:

    Suggestion for future posts: regional climate change. Pick some example and go deeper about risks, likely consequences, uncertainties. Amazon, southern Europe, Africa, US would all be interesting subjects.

    And thanks for the time and attention you dedicate to this forum.

    [Response: Good suggestion on a very important topic and thank you for the compliment; it is appreciated.--Jim]

  38. 38

    9 (David Palermo),

    …but that article made me ask these kinds of questions.

    I don’t see how it could. The article itself is just a morass of denier tripe. I don’t see how you can separate out the “catastrophe” talk from the rest of it, because its all tangled together into a mess of misinformation.

    The basic point seems to be (1) even if AGW is true, “they” are exaggerating how large the temperature change will be and (2) “they” are exaggerating what the effects will be by attributing every disaster to AGW.

    We’ve all seen this tired stuff before and it doesn’t even merit any further discussion. In a nutshell:

    (1) No, the evidence for climate sensitivity (2˚C-3˚C per doubling CO2) is very strong, and a lot of different lines of reasoning all lead to the same conclusion, while “hoped for” denial lines of reasoning have all been repeatedly debunked. The claim that warming will be limited to 1˚C because the positive feedbacks will not materialize is unsubstantiated wishful thinking which is quickly swallowed by the willfully, eagerly ignorant. You can’t help those people. If they were told that the Flying Spaghetti Monster would never allow the planet to warm more than 1˚C, they’d abandon Christianity in a blink, at least as far as AGW goes.

    (2) The attribution of disasters to climate change, or rather the lack of clear, justifiable attribution of noteworthy events to climate change, is a recent, common denial tactic (and that’s all it is, a tactic).

    First, everyone who understands the problem knows that we are talking about the impacts 30 to 100 years down the line, with the understanding that if we don’t get the problem reasonably under control now, it will be too late for the next generation.

    Second, no one with any credibility is saying that warming to date or in the near future is going to create category 6 hurricanes or melt all of the ice in the Arctic year round. Exaggerations like that are sometimes made by the media or deniers themselves, by quoting the end points of ranges from scientific statements, but this is a combination of media hyperbole and the willingness of deniers to highlight those end points to try to ridicule the science (and it works with the willfully ignorant).

    Third, many of the scientific references to attribution to current events are merely studies. They are just scientists who are saying “this is interesting, I wonder if this is caused by warming, and if so, is there any scientific way to prove it?” The fact that someone initiates such a study does not mean that such attribution exists or is provable. It’s just useful science to perform at this point in time.

    So what you have is a falsehood (that warming will be held to 1˚C), a distraction (pointing to the extremes in ranges, or media hype, or new studies interested in determining attribution), and a misdirection (trying to convince people that a long term problem should be ignored because they don’t see the effects yet).

    Of course this is all capped with the last denial meme, that the proposed solution is to destroy the global economy, which is absolutely not the case. All we need is moderation, and to get started in a meaningful way on the problem now. The only way it will destroy anything is if we wait twenty years to do anything at all about it.

  39. 39
    harvey says:

    So as I understand it the AMO, PDO, ENSO are all just ways that the ocean re-distributes its heat. Thus they influence the Weather in land masses near them. Global warming on the other hand is the increase in the TOTAL heat content of the ocean and the land masses. The increase in the TOTAL heat content of the oceans may affect the strength and periods of the ocean heat redistribution networks.

  40. 40
    Didactylos says:

    TimTheToolMan’s fantasy ties into a discussion I had recently about scientific upheavals.

    For Tim’s benefit, here is the bottom line:

    Yes, sometimes the text books are rewritten. But this is very rare, and when it happens, we don’t throw out everything that came before. Classical mechanics may be “wrong” now we know about relativity. But classical mechanics still serve us well – Newton is taught every day in schools, and classical equations are constantly used by engineers for real-world problems.

    So what if a fundamental problem is found with climate science? No scientist can rule this out with 100% certainty, because that’s not how science works. But if a problem is found, then we will need new explanations for many, many questions that are already neatly answered by our current integrated, self-consistent understanding of climate. Questions such as what causes ice ages, why the planet is not an icy snowball, or where all the carbon we burn disappears to will suddenly have no answer. Are you really so arrogant that you think that climate science got absolutely everything wrong?

    Can climate science be overturned like this? No. Any new revolution will be like Relativity, building on what came before. And most actual changes will be small, and within existing uncertainties.

    It’s like a jigsaw. There may be missing pieces still, but we can already see the big picture. Therefore, we can be absolutely confident that most of the pieces are in the right place.

  41. 41

    #9–David, I’m afraid I can’t give much credence to an article that says:

    Further, few skeptics deny that man is probably contributing to higher CO2 levels through his burning of fossil fuels, though remember we are talking about a maximum total change in atmospheric CO2 concentration due to man of about 0.01% over the last 100 years.

    Any reasonable person would think that .01% referred to CO2, not total atmospheric content! For “atmospheric CO2 concentration” the correct (ie., “non-misleading”) number would be 30%+.

    But as to how do we know we have problems:

    1) Climate sensitivity has been much-studied by multiple methodologies–modeling, paleoclimate analysis–and keeps coming out at about 3C, plus or minus 1.5. Some basics:

    http://en.wikipedia.org/wiki/Climate_sensitivity

    Your article basically ignores this science.

    2) This summer saw weather disasters that cost tens of thousands of lives and tens of billions of US dollars. We can’t definitely attribute the specific events to AGW, but they are just what we may expect to see more of, according to multiple studies. And it remains a real possibility that these events might not have happened without the effects AGW. So it’s possible, but unprovable, that we just experienced a couple of “climate catastrophes.”

    3) Coincidentally, we just yesterday were taking note of this study on another RC thread:

    http://www2.ucar.edu/news/climate-change-drought-may-threaten-much-globe-within-decades

    Look at the Drought Index figures carefully. You will note that the forecasted values in many instances are considerably more severe than those experienced in the infamous “Dust Bowl” years, commonly called the “Dirty Thirties.” Those years triggered a massive internal migration in the US, reflected in works such as “The Grapes Of Wrath,” “Of Mice And Men,” and a good deal of the work of Woody Guthrie. (NB-A great-uncle and great-aunt of mine were among those “droughted out” of Saskatchewan–after about 20 years of back-breaking labor to establish their homestead. It must have been heart-breaking to have to return East and beg family assistance.)

    This article puts the number of US citizens displaced at 2.5 million:

    http://en.wikipedia.org/wiki/Dust_Bowl

    The future will look worse, if the predictions Dr. Dai considers are realized.

    Is that bad enough for you?

  42. 42

    Oh, I should have mentioned the Gwynn Dyer book “Climate Wars,” which considers security implications of CC. Another denialist tactic is to carefully avoid thinking about second-order consequences (or “knock-on effects,” in the British idiom the linked article uses.) But the “real world” has no such compunctions about its actual workings.

    I reviewed “Climate Wars” here, in a piece which will give the gist:

    http://hubpages.com/hub/Climate-Wars-A-Review

  43. 43
    Steven T. Corneliussen says:

    “[I]f you want to discuss something you read in the media, saw in a press release or just wanted to ask about, this is the time.” Apologies if this has been covered at RC already and I missed it, but I’d be grateful to learn RC’s take on that Wikipedia climate-science stuff that the Wall Street Journal was crowing about the other day in an editorial headlined “WikiPropaganda.” The editors praised Wikipedia for what the editors characterized as editorially disempowering energetic opponents of climate skeptics. I haven’t seen coverage elsewhere, so I can’t even tell what actually happened. Setting aside the WSJ editors’ views, I wonder if RC scientists think that Wikipedia has acted properly, sensibly and fairly. Thanks.

  44. 44
    Dan H. says:

    Gavin,
    I do not know where you got the idea that someone thought the midrage for climate sensitivity was 1.2! Neither my post nor David’s article made that claim. The midrange of the models is 3, but with a rather wide range, moreso than just “a little.”

    I fail to see how the article was attempted to “reframe the center of the debate.” It was an attempt to define the group referred to as “skeptics” as somewhere between the deniers and the alarmists. The idea that anyone who thinks the climate sensitivity is less than 3 is a denier is akin to calling everyone who is not a liberal democrat a “teapartier.” There are many staunch believers in global warmer who claim that the climate sensitivity is between 2.3 and 3. But you are free to call such people “deniers.”

    btw, how does climate sensitivity relate in any way to the ice ages?

    [Response: the temperature of the planet at equilibrium is expected to be a function of the drivers of climate change (CO2 sure, but also other GHGs, ice sheet extent, solar input, aerosols etc). So at any past equilibrium (such as the last glacial maximum) the drivers and temperature are related by the climate sensitivity - see kohler et al (2010) for an up to date calculation. The bottom line is that it is impossible to explain how cold the ice ages were if sensitivty is small. - gavin]

  45. 45
    Jeff N says:

    My wife and I have spend the last 25 years converting (actually letting it convert itself)our 10 acres of open field to native deciduous forest. I’m just curious about how much total carbon we have “captured” to this point and how much our little forest captures each year. Can anyone point me to some links that will help me do these calculations? Thanks.

    [Response: Jeff, email me some more details and I'll see what I can do.--Jim]

  46. 46
    Vince Belovich says:

    I’ve seen some of the future-climate predictions showing some areas around the world will be getting drier, while others may be getting more rain fall. I’m wondering if anything can be said about average wind speed. With more internal energy in the environment, due to higher temperatures, is it possible that average wind speed around the world, or in a given area, may be going up as well?

    This has a practical implication for those of use who live in a relatively low-wind area. The economics of putting up a windmill in my area of Ohio are borderline, but still cheaper than solar panels (at this time). If I thought average wind speed were going to be a little higher in the future (it wouldn’t take much), it might be enough for me to do it now.

  47. 47
    Maya says:

    David @ 9,

    Others have pointed out the fallacies in that Forbes article, so I won’t recap here, although I have to point out that what he said regarding Hansen’s predictions is tripe, all things considered: http://www.realclimate.org/index.php/archives/2007/05/hansens-1988-projections/

    When you consider the reality that’s staring us in the face – 3 degrees C, not 1 degree – and the consequences we are already experiencing from the 1 degree we already have, then yeah, I think we’re looking at a dyed-in-the-wool climate disaster. That kind of warming will have a huge impact on the polar ice mass (both, not just the Arctic), further rise of sea levels, rainfall pattern effects, etc. Now add in the ocean acidification and the effect it’s having on the shell calcification of critters that are at the base of the food chain, and 100 other things you can find on this site and elsewhere. Add in a healthy dose of human nature and consider the things that we’ve fought wars over during our entire written history – land, resources, and food – and you have the potential for some catastrophic effects on society. That’s not even going into the long-term effects on the millions of other species with which we share the planet.

    We don’t “know” this, we can only make our best estimates, and try to deal with it. As far as taking action to curb the progress of global warming, I think we can, I just don’t think we will. But, that’s only my opinion, of course, and hopefully I am wrong.

  48. 48
    Maya says:

    Not sure where to report this, but one of your wiki links is going to a “page not found”. The link is http://www.metoffice.gov.uk/corporate/pressoffice/myths/3.html and it’s the last one on this wiki page http://www.realclimate.org/wiki/index.php?title=Modern_changes_simply_part_of_natural_cycle

  49. 49

    35 (harvey),

    So as I understand it the AMO, PDO, ENSO are all just ways that the ocean re-distributes its heat.

    I would rephrase that to say that they are patterns of the periodic redistribution of heat in the ocean, not actual ways to redistribute it. They aren’t mechanisms, they’re temperature observations, or rather, repeating patterns detected in those observations.

    And that’s the first two mistakes in any effort to attribute warming to these measurements.

    First, without a mechanism, without understanding what’s going on, all one is doing is correlation without causation. I could just as easily argue that warming is caused by the sky being blue, because the sky has been blue since I can remember, and the world has been warming in that same time frame. [And as a proper skeptic, I have no evidence that the sky was actually blue before I was born, so you can't fool me with tree ring proxy studies which falsely demonstrate the color of the sky prior to 1960.]

    Second, as their names imply, they are oscillations. They have an up phase and a down phase. An oscillation in and of itself is not going to get you anywhere. It would be like getting on the swing in the backyard as a way to get to work and beat the traffic.

  50. 50
    Dan H. says:

    Kevin,

    I am glad to see that you are familiar with some of the great literature about the 30s. I am not sure how UCar came up with their future drought index, but appears to contradict the idea that water vapor and precipitation will increase due to warming. According to the graph, it looks like >90% of the planet will experience drought conditions by 2100. This sees rather implausible, especially considering that warmer times on this planet has consistently led to wetter conditions. Personally, I would not put much faith in these type of predictions. Also, to what weather disasters are you referring that cost the U.S. tens of thousands of lives? Are you referring to the Russian heat wave, Pakistani floods, and South Aerican freeze? The 2.5 million displaced U.S. citizen amounted to about 20% out the population of the affected states (Texas north to the Dakotas). Many studies have not shown an increase in droughts during the recent warming period, but that drought conditions are affected largely by ENSO conditions. This may tie into the posts about PDO and AMO.

    http://water.washington.edu/Research/Articles/2008.global.continental.drought.pdf

    I agree that Warren Meyer was misleading with his assertion that CO2 only rose 0.01%. While accurate in that the atmospheric concentration increased from roughly 0.03 to 0.04% (a 0.01% increase), many uninformed readers would assume that he meant a percentage increase.

    [Response: A little bit of learning goes a long way here, and the IPCC report is your friend as far as that is concerned. If you read the relevant section of the AR1 report (chapter 10.3) , you will find that projected increases in continental drought (i.e. decreases in soil moisture) are far more widespread than changes in precipitation alone might suggestion (see figure 10.12 of that section). This is primarily because warmer soil and vegetation evaporate/transpire greater amounts of moisture into the overlying atmosphere, leading to drying. Remember, drought isn't purely a function of the flux of water from the atmosphere to land (i.e. precipitation) but the difference between that flux, and the flux of water from the land into the atmosphere. That imbalance can easily become negative (i.e. drought) due to warming alone, irrespective of changes in precipitation. -mike]


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