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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 127351 to 127400:

  1. How we know global warming is happening, Part 2
    There is a potted history of the(apparent) ocean cooling found in 2007 here: http://earthobservatory.nasa.gov/Features/OceanCooling/ It seems there was bad data from the XBT floats and theArgo floats, one giving consistently high results the other consistently low. Cross checking with ERBES data ( which are not consistent with CERES) and correcting the float data gave a very different picture of ocean heat content. Also there is extensive info on Argo float position and coverage etc plus data at: http://wo.jcommops.org/cgi-bin/WebObjects/Argo.woa/wa/
  2. How we know global warming is still happening
    RSVP: You have not read those sites carefully enough. The experts do agree with each other. And the other issues you just now raised are dealt with in those sites, as well as here on the Skeptical Science site. (Click on "View All Arguments" at the bottom of the thermometer at the top left of this page.) You need to read those sites. All the way through. It won't take long, even if you read thoroughly. Hold your questions until you've read all that material.
  3. How we know global warming is still happening
    Revising wording from above... ...it should be a no brainer to explain how exactly the Earth comes out of an ice age, and what keeps it from warming to a point so hot that it becomes inhospitable to life???? Please use delicate sunlight balance theory.
  4. How we know global warming is still happening
    To Tom Dayton... I have gone to the sites you posted and these bring a lot to the table. Almost too much, in that there is an overriding sense when reading it that even the experts cant agree with each other. For instance, the bit on whether IR absorption saturates, and inacceptance of extensive and laborious computer modeling, etc. At any rate, what I find all this quibbling really points to is that the effect of CO2 on global warming is not violent in the way volcanic eruptions have plunged the Earth into ice ages. In fact, with all the endemic global warming you can imagine from CO2, the effects of a single volcanic eruption could leave us all freezing and starving to death from lack of vegetation within a growing season. Given the theory that average temperatures depend on such a fragile balance of the sunlight's heat, (and with so many experts abounding), it should be a no brainer to explain how exactly the Earth comes out of an ice age without going past a point so hot that it becomes inhospitable to life???? as there seems to be hard feedback mechanisms that take the Earths temperature up from ice ages and hold it steady past this point and others that are ignored when referring to the effects of CO2. Or is CO2 in charge of everything? My last little word would be that it might make some sense that CO2 concentrations as discovered in ice core samples correlate not because CO2 drives temperatures around, but because living organisms that produce CO2 do better when things warm up.
  5. How we know global warming is happening, Part 2
    Is the 0.77Wm-2 supposed to be averaged over the whole surface of the Earth? The graph seems to be referring to oceans on their own. The graph covers 6 years which equals to 6*365.25*24*60*60 seconds = 189345600 seconds(A) Eyeballing the graph it looks as though the six year period has seen an ~1.5*10^8 Jm-2 increase.(B) Dividing B by A gives us ~0.79W-m2(pretty close to the 0.77) storage in the oceans, but the oceans are only ~70% of the Earth's surface. This gives us 0.56Wm-2 averaged over the surface of the Earth. I wonder if we're comparing apples to oranges. Cheers, :)
  6. Some Skeptical Science housekeeping
    Yes, great work John, thank you. A small suggestion. You might watch out for sock puppets if you don't already. I have a gut feeling there may be just one denialist hiding behind several aliases here. But then I have always had a nasty suspicious mind!
  7. How we know global warming is still happening
    "Thinking of it this way also shoots down all the silliness about the 2nd law of thermodynamics that some throw in for more confusion." Absolutely...It is the surface that warms the atmosphere. Earth's average surface temperature at 288K is some 33K degrees warmer than the equilibrium black body temperature of Earth as viewed from space at 255K. The 255K emission is on average given from high in the troposphere (~16,000'), without an atmospheric greenhouse effect the 255K emission would come from the surface. The stronger the greenhouse effect the higher in the troposphere is the 255K emission. The atmosphere does not warm the surface because it is warmer than the surface (it isn't), it does so by inhibiting cooling of the surface. The loss of thermal energy continues outward toward space on average, a cooler atmosphere is not radiatively warming a warmer surface which would violate the Second Law. Sorry if this seems off topic.
  8. Philippe Chantreau at 05:40 AM on 2 October 2009
    How we know global warming is still happening
    Good reminder Weather Rusty. I think the best, shortest, clearest description was given on RC by one of the contributors: the greenhouse effect impairs the cooling of the surface. Increased GH effect means higher equilibrium temperature. It's rather simple. Thinking of it this way also shoots down all the silliness about the 2nd law of thermodynamics that some throw in for more confusion.
  9. There is no consensus
    "So from what you are saying,variations in those natural factors which affect temperature ( sun, El Nino etc )are as likely to affect cyclones, sea-level changes, polar ice-melting etc as man-made CO2 emissions?" That's not really correct. The natural factors generally result in fluctuations around a trend which under normal circumstances is flattish (on the multi-decadal timescale). In a world warming under an enhanced anthropogenic greenhouse forcing, the natural factors result in fluctuations around a rising temperature. It is the rising temperature that causes the sea level rise, ice sheet melting and so on. Of course if an El Nino occurs on a rising temperature trend, this will supplement the warming producing a short pulse of excess heat which temporarily would accelerate warming onsequences like ice sheet melting. A La Nina will provide a slight brake on these warming-induced consequences. However these don't have much long term effect since these are very short lived phenomena. It's really only changes in solar output that potentially have significant long term consequences that could compete with anthropogenic-induced warming, but analysis of long term solar output indicates that solar variations are rather small in their effects on earth surface temperature.
  10. How we know global warming is still happening
    Just for the sake of clarity and proper conception of what is going on when greenhouse gases absorb IR radiation, it must be stated that nothing is trapped as is commonly stated. The radiation absorbed ceases to exist, having been converted to kinetic energy of the molecule. This energy is then emitted again by the molecule as IR radiation or the newly acquired kinetic energy is transfered to adjacent molecules, O2, N2 etc.. The atmosphere is warmed. Adjacent greenhouse gas molecules again absorb the proper resonant radiation countless times and emitted in all directions, some up and some back down. If the atmosphere were transparent to IR it all would escape from the surface to space unimpeded, but due to greenhouse gases the energy is slowed in that escape by countless repeated absorptions and emissions of IR. Nothing is trapped, the flow of outward energy is constant but slowed by countless repeated absorptions and emission.
  11. How we know global warming is still happening
    RSVP, the history of the discovery of CO2's effect answers a couple of the questions you've asked here, and anticipates questions that you'd likely ask next. See Spencer Weart's The Discovery of Global Warming, the section The Carbon Dioxide Greenhouse Effect. I think your time in asking individual questions would be saved by reading some short overviews that answer many of those questions at once and in context. A excellent one is cce's The Global Warming Debate. In that particular site, the section 1. Primer and History covers CO2's absorption of radiation, with links to online versions of the sources of that info; in some cases you'll want to go to the links on those linked sources to see the actual scientists' publications. But I strongly recommend you read the entire site, not just section 1. See also A Saturated Gassy Argument, which is a posting on RealClimate. Another good resource, though not as integrated as cce's site, is RealClimate's Start Here section.
  12. Models are unreliable
    model B is the relevant one Neil. It corresponds most closely to what has happened emissions-wise in the real world. The data in the paper I cited goes up to 2005. That's why I stopped at 2005. Why wait until 2030? The simulations have done a very good job of predicting reality for almost 20 years. So we can say that the real world has "evolved" in a manner that is consistent with our understanding of the greenhouse effect as it stood some 20 years ago. That seems a rather good indication that even 20 years ago we understood the basic elements of the climate system with respect to radiative forcings and heat retention. Obviosuly we know a whole lot more now and we expect our current models to be considerably better (not to mention the vast improvements in computational speed, efficency and data storage and analysis). You need to make up your mind about what you think constitutes a long enough period to assess a computational projection into the future! If you consider we won't "know the "truth" until about 2030", how can you possibly say that "it should be apparent already that to date the real data is diverging from Hansen's more likely scenarios A and B"! Those are trwo mutually exclusive notions. In reality, as i said in my post #118, a projection cannot simulate contingency (giving rise to much of the "noise") in the climate system, and therfore we expect considerable short term divergence of simulated and real word data. That's obvious I would hope! We can see that this is the case by inspecting Hansen's simulated projection (Figure 2 here: http://www.pnas.org/content/103/39/14288.abstract and observe that despite the overall good correspondence between scenario B simulation and real world temperatgure evolution, that there are very large short term deviations (e.g. 1974-1976; 1992-1994; 2008 etc.). We can understand these in hindsight since we kbnow what contingent events (volcanic eruptions; El Nino's etc.) caused them. Since these events result in temporary perturbation of the surface temperature evolution, the temperature response recovers and the long term temperature evolution remains driven by the anthropogenic increase in radiative forcing despite short term fluctuations...
  13. How we know global warming is still happening
    Chris wrote: "I can't think why anyone would attempt to make arguments that are completely opposed to basic physics and empirical and theoretical consideration!" When a train on an east west rail starts or stops, its change in velocity affects the Earth's rotation. That is what the physics says. No one is concerned with this problem because the mass of the train next to the Earth is minute. The argument is quantitative, not qualitative. Aside from my bad joke about cola, I will admit that I expressed my self poorly when I made that reference to a lossy system. (Perhaps if you are non skeptic, it wont matter.) What I was trying to say was that if CO2's job conceptually was to trap the Sun's energy, and any energy that it did not trap was considered a loss, I would agree that the energy trapped would be in direct proportion to the increase in CO2's numeric concentration, no matter how small its concentration was. But, as we know, there are many more factors that cause the Sun's energy to be retained, including the rest of air's chemical components. In fact, when CO2 is produced through combustion, oxygen is removed or displaced in this reaction. What do you think CO2 is warming up anyway? It is passing heat convectively to the nitrogen and oxygen that surround it. I am not denying that CO2 is a contributor to Global Warming, however I would like to see meaningful data before concluding that it is the main culprit to this problem. The kind of testing I described above would be a good starting point.
  14. How we know global warming is still happening
    RSVP re: "..... but doesnt it make you a little suspicious that CO2 levels have been tracked for the last 100 years somewhere on the top of a volcano in Hawaii? Nothing wrong with this in general, but I get the feeling its as if someone out there needs to justify the data taking, and if we were into Global Cooling, someone would be making an argument that the cooling was due to CO2." Knowledge is the scourge of suspicion RSVP, and if one is really interested in atmospheric CO2 measurements one should know that Mauna Loa is only one of a large number of sites for monitoring of atmospheric greenhouse gases. Analysis of atmospheric CO2 data from many different parts of the world gives a very consistent measure of this atmospheric gas: http://gaw.kishou.go.jp/wdcgg/wdcgg.html Additionally, one should know that atmospheric CO2 levels are continuously monitored remotely by satellite, nd these measures are entirely consistent with atmospheric CO2 measured at Mauna Loa and elsewhere: http://photojournal.jpl.nasa.gov/jpegMod/PIA11194_modest.jpg Of course no informed individual "would be making an argument that the cooling was due to CO2", since CO2 is well understood to be a greenhouse gas, the increased concetration of which drives the Earth's surface temperature towards a higher equilibrium value (all else being equal of course). I can't think why anyone would attempt to make arguments that are completely opposed to basic physics and empirical and theoretical consideration!
  15. How we know global warming is still happening
    Tom Dayton wrote: "The amount of trapping is not just theoretical. For more than a hundred years, scientists have been filling tubes with various mixtures of gasses, sending IR radiation through those gas-filled tubes, and measuring how much gets through to the end of the tube." Would you know of a link that points to these results? What I have seen are graphs comparing IR absorption between gases, but I have never seen a graph that shows steady state temperature vs. concentration around the values of CO2 that we are talking about. With a fixed IR source in a controlled environment, I would assume this would be very telling. My expectation is that any measurable increment in temperature will be directly proportional to the incremental percentage of CO2 with respect to the nominal steady state temperature, which of course would always be smaller for higher temperatures. --------------------------------------------- Moving on... Another way to look at the issue of CO2 is to invert the concept of a lossy system. Imagine that the only energy trapped by the Earth was due to CO2. If so, then the doubling of CO2 in the atmosphere regardless of the concentration would most likely double the heat retention. We know however that CO2 is NOT the only thing that holds onto heat. Heat is stored in the oceans, mountains, buildings, and 98% of the gas that you and I breath everyday. I am getting ahead of myself without the data from the test I described above, but doesnt it make you a little suspicious that CO2 levels have been tracked for the last 100 years somewhere on the top of a volcano in Hawaii? Nothing wrong with this in general, but I get the feeling its as if someone out there needs to justify the data taking, and if we were into Global Cooling, someone would be making an argument that the cooling was due to CO2. Here's my real theory... There is a correlation between soda pop drinkers and those that believe in global warming. The extra CO2 is lodging between their brain cells and causing their body temperatures to rise ever so slightly.
  16. Models are unreliable
    Chris, We are talking about basically the same thing in relation to Hansen's scenario C. You are saying that Scenario C is the imaginary situation that greenhouse gas emissions were stopped in 2000. I am saying that it is an imaginary situation in which the CO2 emission's growth was drastically reduced ( as you point out,it represents the case that growth actually stopped ) in 2000. In your comparison above, why did you stop at 2005, when data is available at least up until 2008? As you say, "Of course what happens over very short time periods (a few years) is of little consequence in comparing climate simulations with reality". Therefore to my way of thinking, we will not know the "truth" until about 2030. But it should be apparent already that to date the real data is diverging from Hansen's more likely scenarios A and B.
  17. There is no consensus
    Chris Well thanks at least for confirming some very important points - that there is not a simple relationship between CO2 increase and temperature rise. And that natural forces can affect climate and sometimes, at least, over-ride any perceived temperature increases due to increased CO2. This was one of the areas that I was trying to understand as the IPCC reports and the media frequently talk about recent or possible future catastrophic events such as cyclones which are said to be due to man-made CO2 emissions. So from what you are saying,variations in those natural factors which affect temperature ( sun, El Nino etc )are as likely to affect cyclones, sea-level changes, polar ice-melting etc as man-made CO2 emissions? I can see you are knowledgeable on the subject of global warming. For the record, I do believe in global warming ( that the temperature is presently rising ), but then again the climate never has been and never will be static.
  18. How we know global warming is still happening
    RSVP wrote: The reason I do not believe the greenhouse theory even after attending Al Gores seminar live, is that CO2 comprises such a small fraction of the mass of our atmosphere, something like .04%. I have a very hard time believing that such a small fraction of the total atmospheric mass could possibly contribute to runaway greenhouse warming. Answer Part 1: You shouldn't focus on the fraction of the atmosphere that CO2 comprises, because it is not relevant all by itself. You need to combine that fraction with the number of molecules of all kinds that are in the atmosphere, and with how much volume they fill in between the ground and outer space, to come up with the number of CO2 molecules sitting in front of a long-wave IR photon leaving the ground headed toward outer space. The bottom line is the probability of a long-wave IR photon hitting a CO2 molecule before making it from the ground to outer space. (Okay, it's also important how close to this CO2 molecule, are the other CO2 molecules that could capture the photon emitted by this molecule, but that doesn't change the essence of the answer to your question.) For example, Mars has a much higher fraction of CO2 than Earth does, but the total number of molecules of all kinds in the Martian atmosphere is so much smaller than in the Earth's atmosphere, that far fewer CO2 molecules sit between the Martian ground and outer space, than between Earth's ground and outer space. So the Martian atmosphere traps far less long-wave IR emanating from the ground, than the Earth's atmosphere does. That's one reason Mars is much colder than Earth. So contrary to your intuition, the fraction of the atmosphere that CO2 comprises is in fact sufficient to trap long-wave IR enough to cause significant warming. The amount of trapping is not just theoretical. For more than a hundred years, scientists have been filling tubes with various mixtures of gasses, sending IR radiation through those gas-filled tubes, and measuring how much gets through to the end of the tube. They've also measured IR transmission in the atmosphere at multiple heights. You might wonder that if the fraction by itself is not relevant, why do climatologists talk about CO2's level in the atmosphere in terms of parts per million (PPM)? That's a convenience that suffices because the other factors that I wrote in my first paragraph are, for practical purposes, constant for the Earth. Answer Part 2: With regard to global warming, it's not even the absolute number of CO2 molecules currently present that is important. Rather, the change in number of CO2 molecules is important, because it's the change in the temperature that is the problem. The change in CO2's PPM since the 1800s is huge--an increase of one third! The change in the amount of heat trapped by that extra CO2 is correspondingly large (though not exactly the same amount of change--its more complicated than that). Answer Part 3: The greenhouse warming on Earth is not and will not be "runaway." Probably you were using that term loosely to mean "increasing at an increasing rate." But you shouldn't use that term, because it really means increasing at an increasing rate due to positive feedbacks that feed back at ratios greater than 1. The Earth's CO2-caused greenhouse effect instead always stops feeding back, because the feedbacks (e.g., CO2 causes warming which causes more water vapor which causes more warming which causes more water vapor,...) cause increases smaller than the increases that triggered them. The feedbacks cause the temperature increase from adding a unit of CO2, to be larger than the temperature increase just from the CO2 itself. But that amount of heating due to a unit of increase of CO2 is finite, not infinite. You can think of the feedbacks as a finite amplifier of CO2's heating effect. The reason the temperature keeps increasing year after year is not that the feedbacks run away, but that we keep adding CO2 to the atmosphere year after year.
  19. How we know global warming is still happening
    RSVP: Of course I am not implying that all IR emitted by Earth is absorbed by CO2! It doesn't matter that not all of it is absorbed. What matters is that enough is absorbed to make a difference.
  20. How we know global warming is still happening
    RSVP wrote: "A lot of the incident energy coming from the Sun is also IR. How does this energy make its way down to the Earths surface if it is blocked by CO2 in the upper atmosphere?" Answer: The radiation blocked by CO2 is mostly long-wave IR, not the full spectrum of IR. The radiation coming from the Sun is a lot of wavelengths other than long-wave IR, which make it past the CO2 on the way down. Those other wavelengths of radiation from the Sun are absorbed by the Earth and the energy contained in those wavelengths is re-emitted by the Earth as long-wave IR, which the CO2 blocks (well, absorbs and re-emits, actually).
  21. How we know global warming is still happening
    To Tom Dayton: Are you implying that all IR emitted by Earth heat resonates with IR absorption wavelenghts? I dont think you are, and I have seen the aborption spectrum of IR which is relatively narrow. To Stevel L: I started my entry saying that energy cannot be destroyed. I hold my ground. The atmosphere accumulates energy from all people in all nations carrying it all around the world. The first place you will notice Global Warming is in the Artic and the Alps. That does not mean that it started there. Next time you get to a stoplight, if you turn off your engine, you will help delay Global Warming. About as long as it takes the light to turn green.
  22. Measuring Earth's energy imbalance
    Yep, I'm pretty sure. Why don't you cite a competing estimate (complete with uncertainty) if you think it really challenges the estimates published by the IPCC?
  23. How we know global warming is still happening
    RSVP -- don't you think that if human exothermic activities were responsible, the warming would be greatest near the largest sources of those activities? Instead the Arctic shows the most warming and alpine glaciers are melting. As for something in low concentrations having a large effect, think of DDT, CFCs, ozone, stratospheric sulfur, etc.
  24. Philippe Chantreau at 04:25 AM on 1 October 2009
    How we know global warming is still happening
    RSVP, it does not add up. There is not enough energy emitted by human made exothermic activities to achieve what's been observed. By far.
  25. Models are unreliable
    re #117 Not really Neil. You should really familiarize yourself with the data before attempting to trash it! You can read about the Hansen scenarios and the models here [*](see Figure 2 and accompanying text). Scenario C is the imaginary situation that greenhouse gas emissions were stopped in 2000 Scenario B described as "the most plausible", is a scenario with moderately increasing greenhouse gas concentrations and some volcanic eruptions, much as we've observed in reality. Scenario A is a model used to bracket the high end of likelihood with rapid exponential increase in anthopogenic emissions and no volcanos. If one compares the models with reality based on 2005 data, the results are: predicted temp rise 1998-2005, relative to 1951-198 mean: model A: 0.59 oC model B: 0.33 oC model C: 0.40 oC real world measurement: land suface: 0.36 oC land-ocean surface: 0.32 oC That seems a pretty good prediction (a 17 year projection into the future). The most plausible scenario has been almost smack on. Of course this is a rather lucky observation, since the models cannot predict the noise in the climate system which is rather large especially on the decadal time scale. So one can hardly claim a model hasn't been a rather good predictor of future when it's made a prediction that's very close to real world observations! Of course what happens over very short time periods (a few years) is of little consequence in comparing climate simulations with reality, since as is very obvious, a climate simulation cannot predict as yet contingent events like El Nino's, La Nina's, volcanic eruptions, changes in solar output and so on. So a succesful simulation is expected to produce the broad progression of temperature rise while the fluctuations around the trend is expected to be completely discorrelated with real world observations. [*] http://www.pnas.org/content/103/39/14288.abstract
  26. How we know global warming is still happening
    "Swanson and Tsonis [**] It's worth looking at the most recent paper on his subject by these authors. They analyze 20th century surface warming and attributons to "tease out2 anthropogenic greenhouse forcing contributions and natural variation. The conclude that the anthropogenic forcing has been (and continues to be a monotonic, accelerating warming during the 20th century). This has been modulated by natural contributions, especially ocean current effects on surface temperature, the net contribution of which to 20th century warming has been close to zero. These authors remark on the possibility that natural variation might result in a suppression of surface warming for a period. However they also point out that "However, global warming could likewise suddenly and without any ostensive cause accelerate due to internal variability.". I think the point is that GW has (most likely) already accelerated due to internal variability from the late 70s to the late 90s and is now decelerating. IMO, the most likely cause for this is the shift in PDO regimes. Cheers, :)
  27. How we know global warming is still happening
    RSVP wrote: "A lot of the incident energy coming from the Sun is also IR. How does this energy make its way down to the Earths surface if it is blocked by CO2 in the upper atmosphere?" Answer: The radiation blocked by CO2 is mostly long-wave IR, not the full spectrum of IR. The radiation coming from the Sun is a lot of wavelengths other than long-wave IR, which make it past the CO2 on the way down. Those other wavelengths of radiation from the Sun are absorbed by the Earth and the energy contained in those wavelengths is re-emitted by the Earth as long-wave IR, which the CO2 blocks (well, absorbs and re-emits, actually).
  28. There is no consensus
    Not really Neil. You were the one that quoted the IPCC. I'm pointing out that you’re out of date since you resorted to a quote from an old IPCC report. If you wish to use an isolated IPCC statement to attempt to make a point, you can hardly complain if I use a more scientifically accurate IPCC presentation to address the same point! If you don't consider that the IPCC reports have merit, why bother to quote from them in the first place? Anyway you seem rather hung up with the IPCC, if I may say so. It's not the IPCC that have shown that it's not possible to reproduce 20th century warming using known natural contributions and their amplitudes, and that this can only be reproduced by incorporating the anthropogenic greenhouse component. That's the work of a large number of scientists published in a significant body of scientific papers. The IPCC merely collate and summarise scientific data and present rather conservative interpretations. The attributions of contributions to 20th century temperature evolution doesn't come from modelling. We know, for example, that solar contributions can have made only minor contributions to 20th century warming since direct empirical analysis of the sun informs us so (e.g. [*]). We know that ocean current changes have made a negligible net contribution to 20th century warming, because empirical and theoretical analysis informs us of that (e.g. [**]). And so on... we can incorporate this empirical and theoretical knowledge into a model. But we don't need modelling of the sort you’re talking about to know that known natural contributions can't have made much of a contribution to the warming of the last 100 years. It is a pretty clear cut case that >CO2 means >temperature. There's lots of empirical data that indicates that the earth tends towards a new equilibrium temperature that is around 3 oC warmer (2-4.5 oC at 95% confidence) for each doubling of atmospheric CO2 [***]. That's not to say that there is "a simple relationship between CO2 increase and temperature rise." Since the anthropogenic component is mixed in with natural variation, sometimes natural variation temporarily opposes CO2-induce temperature rise and sometimes it temporarily enhances it. So during the last couple of years the position of the sun smack at the bottom of the solar cycle, and La Nina conditions, have temporarily suppressed surface temperature. As the sun “moves” towards the solar cycle maximum during the next 4-5 years its contribution will enhance anthropogenic greenhouse warming. So the IPCC reports (not “studies” since the IPCC don’t do the studies Neil – they collate, summarise and report the science) are obviously quite right in stating that we expect a “noisy” temperature rise in an enhanced anthropogenic greenhouse warming world. [*] Lean JL, Rind DH (2008) How natural and anthropogenic influences alter global and regional surface temperatures: 1889 to 2006 Geophys. Res. Lett. 35 L18701 http://www.agu.org/pubs/crossref/2008/2008GL034864.shtml [**] K. L. Swanson, G. Sugihara, and A. A. Tsonis (2009) Long-term natural variability and 20th century climate change. Proc. Natl. Acad. Sci. USA (in press) http://www.pnas.org/content/early/2009/09/09/0908699106.abstract [***] Knutti R, Hegerl GC The equilibrium sensitivity of the Earth's temperature to radiation changes Nature Geosci. 1, 735-743 http://www.nature.com/ngeo/journal/v1/n11/abs/ngeo337.html
  29. How we know global warming is still happening
    One of my very first science lessons from the school yard was that you couldnt create or destroy matter. Then at some later point in time, I learned that the same applied to energy. If you cant destroy energy, where does all that excess heat from human activities go? Thanks to God, heat radiates into outter space, (and by the way, the rate of blackbody radiation is nonlinearly proportional to temperature. This helps us stay cool globally speaking, but it is very possible for some heat to accummulate, all depending on overall comparative rates. I agree with this article that the oceans would be the ultimate storage area for this excess energy given the associate volume, fluidity and heat capacity. Furthermore, probably the best way to know if there is Global Warming is to track ocean temperatures. That said, I find myself in the skeptics camp as far as believing that Global Warming is due to CO2. I believe that Global Warming is real, not only because of the type of data presented in this article, but as I am 50 years old, I have noticed the effects of climate change directly in a variety of locations around the world. In most ways, these changes have been for the worst, however it may be just a matter of maladaptation. I cant imagine more prosperity coming from an ice age. The reason I do not believe the greenhouse theory even after attending Al Gores seminar live, is that CO2 comprises such a small fraction of the mass of our atmosphere, something like .04%. I have a very hard time believing that such a small fraction of the total atmospheric mass could possibly contribute to runaway greenhouse warming. The greenhouse theory as purported by Al Gore is that the full spectrum of radiative solar energy makes its way through the atmosphere warming objects on the Earth. These objects on the Earths surface later radiate heat back in the form of IR. CO2 in the atmosphere then absorbs the IR warming it such that the incremental CO2 due to fossil fuel burning is causing what we are perceiving as Global Warming. For one thing, since the 1970s we were supposedly going to run out of fossil fuels by the year 2050. Not sure why then this is a problem?? But that is besides the point. It turns out that a lot of the incident energy coming from the Sun is also IR. How does this energy make its way down to the Earths surface if it is blocked by CO2 in the upper atmosphere? I do not deny IR can be absorbed by CO2 at groundlevel, however this effect should be compensated in kind by 1) the same mechanism in the upper atmosphere blocking IR coming from the Sun. 2) a general increased rate of cooling up there due to the nonlinear nature of black body radiative mechanisms. But what seems to weigh against CO2 as the ultimate culprit for Global Warming is simply the compartively small percentage that CO2 represents in terms of its overall mass next to other atmospheric gaseous components. So what is causing Global Warming if it is not CO2? That appears to be the million dollar question. I for one (skeptic) believe it is simply the increased rate of human activities (generally speaking exothermic) on top of any possible fluxuation that may be due to nature.
  30. There is no consensus
    Chris, there is considerable skeptisism regarding the claim made by the IPCC that man-made CO2 emissions are causing catastrophic global warming. That is why websites such as this exist and why you and I and others are discussing this issue. Therefore your quoting the IPCC's viewpoint on this as being the "truth" is rather cirular logic. A bit like a Christian arguing that the Bible is true because the Bible says it is true. Your satement that : "It's not possible to reproduce the temperature evolution using known climate contributors without incorporating anthropogenic greenhouse forcing" carries little weight with me, I assume you are referring to the IPCC's computer models and predictions based on these models. Models are models, they are not reality. In any event, the model averages plotted in many IPCC diagrams result in a smoothing of the simulated natural variations that are present in individual GCM model runs.In fact most model runs actually show short periods of cooling over periods of say 10 years. Thus some infer from this that the lack of warming since 1998 is caused by a natural cooling forcing of sufficient strength to temporarily  overcome the assumed longer‐term carbon dioxide‐forced warming. However, the IPCC has argued that the climate system possesses only limited internal variability, which is why carbon dioxide forcing came to assume special importance in the first place. Therefore even the IPCC's own studies show that there is not a simple relationship between CO2 increase and temperature rise. The IPCC itself admits that temperature can vary due to several factors including natural factors which can overome man-made temperature rises at least for periods of say 10 years. So it is not a clear cut case of > CO2 means > temperature.
  31. There is no consensus
    re #161 re your question: "Why did you send me information regarding how graphs should be presented in a scientific journal. When the graph I mentioned was never made to be presented in a scientific journal?" The answer is that this statement in the "Instructions to Authors" of a scientific journal simply reiterates what all scientists know already, namely that in presenting scientific data in graph form, one should allow the data to fill the available space. It's only those that have something to hide that would present the ludicrous graph that you drew to our attention! as for: "If it does not clearly show the IPCC's "catastrophic" temperature increases of 0.5 degrees or so, that is because the graph is not designed to show that." That's silly 'though isn't it. If the temperature rise is 0.5 oC (or whatever) that should certainly be apparent in a graph designed to present the temperature rise! Otherwise someone is trying very hard to present a dishonest depiction of the data. Of course if you're an Earth Science scientist with 40 years experience and as someone who has written technical papers and reviewed others, you surely know that...
  32. There is no consensus
    Neil, if one is going to cite the IPCC (or science in general!) one should recognise that knowledge and understanding advances. Rather than refer to 10 year old science in a report prepared 9 years ago and published 8 years ago, it makes sense to address the most up to date IPCC report (if one wishes to obtain the IPCC position). This can be found here: http://www.ipcc.ch/publications_and_data/publications_ipcc_fourth_assessment_report_synthesis_report.htm a good starting point is the Summary for Policymakers which can be found here: http://www.ipcc.ch/pdf/assessment-report/ar4/syr/ar4_syr_spm.pdf and the relevant information can be found on pages 5 and 6. This indicates that even the presentation of the rather conservative IPCC are quite consistent with my statement that: It's not possible to reproduce the temperature evolution using known climate contributors without incorporating anthropogenic greenhouse forcing. Of course that's simply a statement of fact. One can address this further by going back to the original scientific literature, particularly the science published in the last few years since the 2007 IPCC report urled just above.....
  33. How we know global warming is still happening
    Robbo: You said "The surface temperature record shows cooling to 1975, warming to 1998 and cooling since. This is apparent in the monthly anomalies in any of the records." I would disagree with this. For example if you look at the GISS record you can not pick a starting point in 1998 that gives you a slope of less than 0.098 C/decade (increasing). Also, but I am not sure I followed your comments about the IPCC projections for warming trends. However, as Deep Climate shows here the trends are actually quite accurate. Regards, John
  34. How we know global warming is still happening
    Oh well Robbo, in order to make your point you have to tell porky pies. Two lies now. First you took a paper whose observations and analyses are completely at odds with your non-scientific position...and inserted a phrase into the abstract to pretend that the paper agreed with your false analysis. And now you say that: "The addition '1976 to 1998' is relevant and placed in brackets to indicate that I added it." But that's obviously not true as inspection of your post #3 clearly shows. You put the entire (nearly) two sentences in brackets two signify that the section was a direct quotation (which it almost is as can be seen from my reproduction of what Trenberth and Fasullo actually wrote). You didn't place your sneaky and false addition in a seperate bracket to indicate that you added it, at all. Surely if you have to tell porkies to attempt to shore up a position, there is something seriously wrong with your point of view...at the very least it's not a scientific one. Just to be very clear the paper that you have attempted to misrepresent (Trenberth and Fasullo) analyzes models to determine the attribution of warming from 1950 through to the end of the 21st century. They find, in complete contradition to your false assertion, that during the period 1976 to 1998, the absorbed solar radiation (ASR) has decreased, and thus this has ofset some of the anthropogenic greenhouse-induced warming. This is largely the result of enhanced aerosolic screening. This situation is expect to persist up to around 2020-2040 after which absorbed surface radiation will increasingly dominate accumulating surface warming in greenhouse-enhanced world. Note that the published evidence indicates that the oceans are continuing to take up heat as expected in a warming world [see papers cited in the top article and also the von Schuckmann et a (2009)] paper in my post #5. Note also that you've misunderstood Swanson and Tsonis and Keenleyside, both of whom are pretty mainstream with respect to scientific understanding of the earth's response to enhanced athropoenic greenhouse forcing. The world is going to get a whole lot warmer in both of their analyses. To be specific: Keenlyside et al. [*] These authors use a model that incorporates analysis of sea surface temperatures and estimates of ocean current effects to make hindcasts and forecasts. They project (see their hindcast/forecast in their Figure 4) that a rather marked surface warming of around 0.5 oC in the period 2010 and 2025. Swanson and Tsonis [**] It's worth looking at the most recent paper on his subject by these authors. They analyze 20th century surface warming and attributons to "tease out2 anthropogenic greenhouse forcing contributions and natural variation. The conclude that the anthropogenic forcing has been (and continues to be a monotonic, accelerating warming during the 20th century). This has been modulated by natural contributions, especially ocean current effects on surface temperature, the net contribution of which to 20th century warming has been close to zero. These authors remark on the possibility that natural variation might result in a suppression of surface warming for a period. However they also point out that "However, global warming could likewise suddenly and without any ostensive cause accelerate due to internal variability.". None of this contradicts our understanding of the earths temperature response to enhanced greenhouse forcing, although recent analyss does reinforce the expectation that the time progression of warming is modulated by natural fluctuations. [*] N. S. Keenlyside et al. (2008) Advancing decadal-scale climate prediction in the North Atlantic sector Nature 453, 84-88 http://www.nature.com/nature/journal/v453/n7191/abs/nature06921.html [**]K. L. Swanson, G. Sugihara, and A. A. Tsonis (2009)Long-term natural variability and 20th century climate change. Proc. Natl. Acad. Sci. USA (in press) http://www.pnas.org/content/early/2009/09/09/0908699106.abstract
  35. There is no consensus
    Chris. Regarding your point 1 above "1. It's not possible to reproduce the temperature evolution using known climate contributors without incorporating anthropogenic greenhouse forcing." As I understand it, the authors of chapter 1 of "Climate Change 2001 - The Climate System : An overview" wrote : " The fact that global temperature has increased since the late 19th century and that other trends have been observed does not necessarily mean that an anthropogenic effect on climate has been identified. Climate has always varied on all time scales, so the observed change may be natural".
  36. There is no consensus
    Any graph can be made to emphasise what the maker of the graph wants to show. The IPCC is particularly good at this, even going as far as shading in the green ( good ) bits and the red ( bad ) bits on some of their graphs. The graph example I gave simply shows the data from a different perspective. I assume you have no problem with the actual data plotted on the graph, only the way it is presented? In terms of what the graph is designed to show, it is correct. If it does not clearly show the IPCC's "catastrophic" temperature increases of 0.5 degrees or so, that is because the graph is not designed to show that. There are many other graphs which show that. Anyone interested in AGW will no doubt look at many graphs and hopefully he/she will understand what is shown on each graph and understand how it has been presented. Why did you send me information regarding how graphs should be presented in a scientific journal. When the graph I mentioned was never made to be presented in a scientific journal.
  37. How we know global warming is still happening
    The addition '1976 to 1998' is relevant and placed in brackets to indicate that I added it - I obviously have to spell everything out or take the risk of silly and irrelevant comment. This is the only period of surface warming in the last 50 years - and the warming was associated with decreasing cloud from 1984 to 1998 as shown in the ISCCP records - about 3.7W/m2 increase of shortwave radiation from 1984. The surface temperature record shows cooling to 1975, warming to 1998 and cooling since. This is apparent in the monthly anomalies in any of the records. So we have had 22 years of net warming in the 50 year record. It is simply a fact of life. The IPCC is explicit is attributing most of the warming in the last 50 years to anthropogenic influences - and very little to natural variability. There is no strong heating or cooling in the ARGO record. These records are subject to endless revision despite which the evidence for heating and cooling is still not definitive. To claim that the evidence shows continued warming is nonsense. The conclusion is inescapable - there is no evidence of continuing ocean warming (or cooling) within the limits of error. However, there is an expectation of ocean heating and cooling in line with the scientific evidence for cyclic ocean states. You guys can continue to deny cyclic ocean states for as long as you like - it takes strength of character or an extreme foolishness not susceptible to evidence. Anything that shows complexity and uncertainty and challenges Chris' simplistic understanding is confidently labelled cheery picking. Some warming, of the oceans in particular, from 1975 to 1998, comes from changes in clouds. Amy Clements et al describe this as a positive global warming feedback. It has turned around however and is consistent with established patterns of multidecadal ocean cyclic states. Multiple lines of evidence rather than a stubborn refusal to accept evidence of anything that suggests a lower climate sensitivity to greenhouse gases. I am not skeptical at all - the question is how much warming was due to AGG and how much is natural variability. The only sensible way of approaching this problem is to consider net warming over a full cycle of 20 to 30 year warming and 20 to 30 year cooling. For the 1945 to 1998 period - this is a net warming trend of 0.08 degrees C/decade from all other factors - less than half of what is assumed by the IPCC. 20 to 30 years of an ocean warming record is not sufficient to disentangle natural cyclic variation on multidecadal timeframes from AGW. This is simply a scientific and statistical truth. Pointing to ocean warming in a rising phase and insisting that this proves something is nonsense. The lack of recent strong ocean warming is not consistent with climate forcing as determined by the IPCC. Surface warming has not been 0.2 degrees C/decade over the last decade as predicted by the IPCC - you can rabbit on about natural variability without being specific at all - and project vastly increased warming in future decades - or you can look for the causes of natural variability operating now and in the recent past and consider rationally the implications for AGW theory. This is why the lack of recent ocean and atmospheric warming falsifies IPCC theory – it is simply not consistent with the Earth energy budget with the theorised forcing – it is a problem that requires reanalysis of the forcing rather than pillorying of anyone who has the temerity to suggest that the emperor’s clothes are in tatters. It is entirely reasonable to expect – as with Swanson and Tsonis, Keenlyside etc – a lack of global ocean or atmospheric warming for 20 to 30 years from 2000.
  38. How we know global warming is still happening
    As well as the growing number of recent papers that demonstrate a continuing uptake of heat into the worlds oceans, the following paper has just been published: K. von Schuckmann F. Gaillard and P.-Y. Le Traon (2009) Global hydrographic variability patterns during 2003–2008 J. Geophys. Res. 114, C09007, doi:10.1029/2008JC005237 abstract below [***] This analysis indicates that if ocean heat content to a depth of 2000 m is assessed, that there has been a rather larger continued uptake of heat into the oceans (compared to, for example, the Levitus data that analyzes heat in the upper 700 m of the oceans; see Levitus data here) [***]abstract: Monthly gridded global temperature and salinity fields from the near-surface layer down to 2000 m depth based on Argo measurements are used to analyze large scale variability patterns on annual to interannual time scales during the years 2003–2008. Previous estimates of global hydrographic fluctuations have been derived using different data sets, partly on the basis of scarce sampling. The substantial advantage of this study includes a detailed summary of global variability patterns based on a single and more uniform database. In the upper 400 m, regions of strong seasonal salinity changes differ from regions of strong seasonal temperature changes, and large amplitudes of seasonal salinity are observed in the upper tropical and subpolar global ocean. Strong interannual and decadal changes superimpose long-term changes at northern midlatitudes. In the subtropical and tropical basin, interannual fluctuations dominate the upper 500 m depth. At southern midlatitudes, hydrographic changes occur on interannual and decadal time scales, while long-term changes are predominantly observed in the salinity field. Global mean heat content and steric height changes are clearly associated with a positive trend during the 6 years of measurements. The global 6 year trend of steric height deduced from in situ measurements explains 40% of the satellite-derived quantities. The global freshwater content does not show a significant trend and is dominated by interannual variability.
  39. There is no consensus
    re #159 Goodness Neil, that really is junk! I assume that the graph at the bottom left of the page that you refer to is to illustrate how one can "magic" the disappearance of real changes in observables, and thus remove essentially all information from the reader! The data in a graph should pretty much fill the space available. After all the point of presenting a graph is to inform the reader, and (I'm sure you know this as someone who has written and reviewed technical papers) this is best done by allowing the data to fill the graph (i.e. don't show unnecesary empty space by having axes that extend way beyond the actual data). In fact as I'm sure you know, this is standard practice in presenting scientific data. I've reproduced a paragraph on data presentation from the "Instructions to Authors" of a scientific journal below (The Biochemical Journal as it happens, 'though one could choose many examples) which emphasises this very obvious point [***] The other point of course, is that a graph is never the only bit of information a reader will see, and there will always be some context. So for example a presentation of 20th century temperature evolution and atmospheric CO2 rise might be accompanied by the following relevant information: 1. It's not possible to reproduce the temperature evolution using known climate contributors without incorporating anthropogenic greenhouse forcing. 2. The temperature rise observed during the last 100 or so years is aproaching around 1/6th of the total temperature rise during the 5000 years of the last glacial to interglacial transition. 3. The very large rise in atmospheric CO2 since the pre-industrial age (around 115 ppm) is already larger than the CO2 rise during the entire 5000 years of the last glacial to interglacial transition, and has taken atmospheric CO2 levels to a concentration not reached during the last million years at least. 4. Current understanding of the relationship between earth surface temperature and greenhouse gas concentrations indicates that doubling of atmosphere CO2 results in an equlibrium temperature rise of the order of 3 oC. 5. The equilibrium temperature rise expected from levels of atmospheric CO2 that will be reached by mid 20th century, are similar to those exisiting during the last interglacial period when sea levels were around 4 metres higher than now... etc. etc. [***] from the "Instructions to Authors" (my highlights):
    Figures will usually be reduced in size to occupy a single column (width 8.5 cm) or less unless a larger format is necessary for clarity. All lettering and symbols should be produced to be at least 1.5 mm, but not more than 3 mm, after reduction. All curves and lines should be drawn clearly, and of a line thickness that allows for the reduction in size on final printing. Axes should not extend appreciably beyond the curves, and it is often unnecessary for an axis scale to start at 0; only the part of the scale relevant to the curves should be given.
    pretty standard stuff..
  40. How we know global warming is still happening
    re #3 Oh dear Robbo…that’s a horribly cherrypicked selection. Let’s have at one of your assertions “Trenberth and Fasula” (sic). Let’s compare what they said with what you said they said: Here’s what Trenberth and Fasullo said[***]:
    Global climate models used in the Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report (AR4) are examined for the top-of-atmosphere radiation changes as carbon dioxide and other greenhouse gases build up from 1950 to 2100. There is an increase in net radiation absorbed, but not in ways commonly assumed. While there is a large increase in the greenhouse effect from increasing greenhouse gases and water vapor (as a feedback), this is offset to a large degree by a decreasing greenhouse effect from reducing cloud cover and increasing radiative emissions from higher temperatures. Instead the main warming from an energy budget standpoint comes from increases in absorbed solar radiation that stem directly from the decreasing cloud amounts. These findings underscore the need to ascertain the credibility of the model changes, especially insofar as changes in clouds are concerned.
    Here’s what Robbo pretended they said:
    I refer also to Trenberth and Fasula who suggest that the ‘main warming between 1976 and 1998 from an energy budget standpoint comes from increases in absorbed solar radiation that stem directly from the decreasing cloud amounts. These findings underscore the need to ascertain the credibility of the model changes, especially insofar as changes in clouds are concerned.'
    For some reason you’ve added the tiny phrase "between 1976 and 1998" to their abstract…..??? In fact Trenberth and Fasullo are commenting on the results of global climate models and their observations highlighted in their abstract relate to late 21st century effects. In fact (according to Trenberth and Fasullo) the absorbed solar radiation (ASR) has decreased through the middle to late 20th century (due to aerosolic effects amongst other things including clouds) and this has countered the enhanced greenhouse-induced warming to date. It’s expected to continue to do so through to about 2040 after which there is a marked increase in ASR that drives rather significant further warming through to 2100 [***] K. E. Trenberth and J. T. Fasullo (2009) Global warming due to increasing absorbed solar radiation Geophys. Res. Lett, 36, L07706 (abstract in blockquote above)
  41. How we know global warming is still happening
    How We Know that the Planet isn't Warming Your first egregious error - as shown by Harrison and Carson – is that 20 to 30 years of increase in ocean heat content is not sufficient to determine longer term trends in systems with inherent multidecadal variability - such as has been shown repeatedly and consistently in ocean/atmospheric interactions. ‘Is the World Ocean Warming? Upper-Ocean Temperature Trends: 1950–2000 D. E. HARRISON NOAA/Pacific Marine Environmental Laboratory, and Joint Institute for the Study of the Atmosphere and Ocean, and School of Oceanography, University of Washington, Seattle, Washington MARK CARSON Joint Institute for the Study of the Atmosphere and Ocean, and School of Oceanography, University of Washington, Seattle, Washington JOURNAL OF PHYSICAL OCEANOGRAPHY (Manuscript received 25 July 2005, in final form 10 January 2006) ABSTRACT Subsurface temperature trends in the better-sampled parts of the World Ocean are reported. Where there are sufficient observations for this analysis, there is large spatial variability of 51-yr trends in the upper ocean, with some regions showing cooling in excess of 3°C, and others warming of similar magnitude. Some 95% of the ocean area analyzed has both cooled and warmed over 20-yr subsets of this period. There is much space and time variability of 20-yr running trend estimates, indicating that trends over a decade or two may not be representative of longer-term trends. Results are based on sorting individual observations in World Ocean Database 2001 into 1° _ 1° and 2° _ 2° bins. Only bins with at least five observations per decade for four of the five decades since 1950 are used. Much of the World Ocean cannot be examined from this perspective. The 51-yr trends significant at the 90% level are given particular attention. Results are presented for depths of 100, 300, and 500 m. The patterns of the 90% significant trends are spatially coherent on scales resolved by the bin size. The vertical structure of the trends is coherent in some regions, but changes sign between the analysis depths in a number of others. It is suggested that additional attention should be given to uncertainty estimates for basin average and World Ocean average thermal trends.’ The second error is in opportunistic evaluation of recent ocean heat content. Warming or cooling since 2003 in any of the studies mentioned is not significant. It is like saying that 2005 in the annual GISSTEMP record warmer than 1998 when the 2 results are well within error bounds. Scientific nonsense in other words – intended only to mislead and deceive an unsuspecting and naïve public. Physical oceanic evidence suggests cyclic warming and cooling and this has been linked to Hale periodicity in solar output. Please note especially the comment on amplification of weak solar signals. As an example – Solar Physics (2004) 224: 455–463 C _ Springer 2005 HALE CYCLICITY OF SOLAR ACTIVITY AND ITS RELATION TO CLIMATE VARIABILITY O. M. RASPOPOV1, V. A. DERGACHEV2 and T. KOLSTRO¨M3 Abstract The periodicity of climatic processes along the Russian Arctic Ocean coast has been studied by analyzing the tree-ring chronologies for the regions close to the northern timberline. The wavelet analysis of annual series of conifer tree rings for the period 1458–1975 has revealed climatic oscillations with periods of 20–25 years. The amplitudes and periods of climatic oscillations in the region of Russian Arctic Ocean proved to exhibit appreciable changes. Especially strong climatic variations in comparison with the recent ones were found to occur during the Maunder minimum epoch when the period of oscillations increased from 22–23 years to 24–29 years, and oscillations with periods of 15 years appeared. After the Maunder minimum, the periods of oscillations and their amplitudes again decreased, and the 15–16-year maximum disappeared. Analysis of solar activity based on of radiocarbon (14C) concentration in annual tree rings has revealed a similar pattern in changes of periodicity before, during, and after the Maunder minimum. This suggests that quasi-bidecadal climatic oscillations and variations in solar activity can be connected with each other. A possible solar forcing of periodic climatic processes and its nonlinear influence on the atmosphere-ocean-continental system are discussed. The intense quasi-bidecadal climatic oscillations can be, in all probability, interpreted as resulting from amplification of a weak solar signal in the atmosphere-ocean system that has its own noises whose frequencies are close to the 22–23-year solar cycles. It would be astonishing on other lines of evidence if the oceans were warming at all strongly. Observations (see Project Earthshine) show an increase in Earth albedo since 1999 of about 1% - or 2 W/m2. This followed a decline in albedo from 1984 to 1998 - equivalent to additional shortwave forcing of 3.7W/m2. It has been suggested that the amplification mechanism involves clouds – either as amplification of small changes in solar irradiance or in response to variation in atmosphere ionisation by cosmic rays. I refer also to Trenberth and Fasula who suggest that the ‘main warming between 1976 and 1998 from an energy budget standpoint comes from increases in absorbed solar radiation that stem directly from the decreasing cloud amounts. These findings underscore the need to ascertain the credibility of the model changes, especially insofar as changes in clouds are concerned.' How do we know that the planet isn't currently warming? Because neither the atmosphere or oceans are currently warming at all - a result that is utterly inconsistent with IPCC reporting regardless of the time period.
    Response: So 30 years of warming oceans is not sufficient to establish a warming trend and yet alleged ocean cooling (which is doubtful considering all the evidence) over the last few years is sufficient to disprove IPCC reporting?
  42. How we know global warming is still happening
    Manuel, Are you implying the AGW warming is insignificant compared to the sun? When was the last time the sun managed to heat the earth at a rate of 0.9W/m2?
  43. Measuring Earth's energy imbalance
    Steve, "We're not talking about a field with competitors legitimately claiming greater certainty" Are you sure? I am not.
  44. Models are unreliable
    The real data up to 2008 shows that global temperatures are tracking below Hansen's (1988) scenario C since about 2005. As I understand the predictions of Hansen's models, scenario C relates to a drastic REDUCTION in the increase of CO2 growth. Yet in reality CO2 emissions have continued to INCREASE. So real temperatures are tracking even lower then Hansen's most optimistic prediction based on a drastic reduction in CO2 emissions. If I compare real data to Hansen's scenario B (assumed to represent CO2 emissions frozen at 1988 levels ), the real data is now about 0.4 degrees below that predicted by Hansen. This may not seem a lot, but these are the sort of anomlalies which the IPCC is describing as catastrophic. I would argue that Hansen’s model is not validated by real-world data and I think that as time passes, it is likely that Hansen's 1988 predictions will diverge even further from real world temperatures. Arguably, real temperatures should be compared to Hansen's scenario A ( continued growth in CO2 emissions ). If such a comparison is made, Hansen's prediction is about 0.6 degrees above reality.
  45. Measuring Earth's energy imbalance
    My point is that (a) the value of information provided is relative to what else is available (you'd lose clients because others in your field could provide more certainty in their estimates, but we're not talking about a field with competitors legitimately claiming greater certainty); and (b) they have a very good idea what the anthropogenic radiative forcing is -- it is positive and nowhere near zero.
  46. How we know global warming is still happening
    John, Great post. It really puts us humans in perspective, does it? If .9 W/m2 translates into 190,000 GW power plants, the more than 340 W/m2 of total solar irrandiance is a pretty big number.
    Response: Don't fall into the "sun big, me small" trap. As far as the sun and climate is concerned, it's solar variations that make a change to our climate. If the sun is shining away at a steady 340W/m2 without changing and the climate was in equilibrium, then the Earth's global temperature wouldn't change - the energy coming in from the sun would equal the energy radiating back out and the planet would be in energy balance. However, if solar activity changes (eg - the sun gets hotter), then the energy coming in is greater than the energy out. The planet is in energy imbalance and starts accumulating heat. As it gets hotter, the energy it radiates back into space increases until it's back in equilibrium.

    The amount that solar activity changes is relatively small. The amplitude of the solar cycle is about 1 W/m2. This translates to a radiative forcing of about 0.25 W/m2 and is estimated to have an effect of around 0.1C on global temperatures over the 11 year cycle. Similarly, the long term changes in solar activity are relatively small - upper limits of radiative forcing from the Maunder Minimum until now place it at around 0.23 W/m2.
  47. Measuring Earth's energy imbalance
    Steve, Examples and analogies usually cause problems, as already mentioned in this thread. Anyway. My point is that if I were to tell my clients that I really have no idea of what is the market value of their companies, I would lose them.
  48. Measuring Earth's energy imbalance
    Chris, Thank you very much for your highly detailed answers. Unfortunately, I am unable to access most of the papers you cite. "It turns out that this net radiation does have a generally linear relationship with the change in the earth's surface temperature." I fear that this is precisely what I was suggesting. Does the linear relationship you mention correspond to a proven consequence of physics laws? or is it an observed phenomenon? Unfortunately, I do not have access to the paper you cite. With respect to the degrees of uncertainty. I understand that there is a normal distribution involved, but I still maintain that the degree of uncertainty is too high.
  49. It's the sun
    "most retroreflective signs use glass beads" Thanks, Hank.
  50. Models are unreliable
    "While there are uncertainties with climate models, they successfully reproduce the past and have successfully predicted future climate change". As someone who has built computer models based on natural data, I can make some comments on this. The models I build are based on spatial data rather than time-based data, but I suppoose the methods are similar. It is not surprising that the IPCC's climate models reproduce the past because I would think that the models are based to a large extent on past data. When I build a model I start with the basic ( past ) data values and come up with a mathematical formula which will model how these values change from place to place in 3 dimensional space. Then the formula is used to predict hundreds of "hypothetical", estimated values within the physical model limits. After doing this it will be apparent that in some places within the physical model, there are places where there exist an original (real) data value and a nearby estimated value in close proximity. The real and estimated values can then be compared to see how well the formula predicted reality. The formula can then be "tweaked" if necessary to give a better fit between real and etimated data values. This process is known as cross-validation. I assume the IPCC builds its models using historical data and carries out similar cross-validation techniques. Therefore of course the IPCC models can predict the past in a general sense. With regard to predicting future climate change, only time will tell. I think we would have to wait a minimum of say 30 years to see how the IPCC model's future predictions compares to reality. So I think it is premature to say that the IPCC models predict the future accurately. We do not know yet. However, I understand the IPCC produces lots of predictions based on its computer climate models and these show a large range of possible outcomes ( correct me if I am wrong ). Therefore, if this is the case, which IPCC model do we take as its prediction of future climate ? Therefore in summary, with regard to your claims quoted above, my responses are : 1. Yes the IPCC models would reproduce the past - that is what the models are based on. 2. It is too early to tell if the future prediction of climate change is correct, but which prediction are we talking about, there are many.

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THE ESCALATOR

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