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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 125501 to 125550:

  1. 1998 DIY Statistics
    #3: I made up the values using 0.2cos(At)cos(Bt). A and B were calculated to give periods of 4 and 8 years, and I chose an amplitude of 0.2 because peak to peak swings of 0.4C seem to have been observed before. Eg 1996-98 was a 0.4C swing in HadCRUT3 and I think it's reasonable to assume most of that was ENSO related.
  2. 1998 DIY Statistics
    neilperth, there are some problems with your procedure. You cannot use unadjusted data, if by unadjusted you mean the raw data. There are several reasons and tons of papers on the need to adjust the raw readings. You can use a single station to look for the trend; although the statitstical significance of the results will probably be rather poor. Neverthless you can try. Or, you might want to look at global averages. In this case you can not simply pick up a random and rather limited selection of stations. You need to homogenize the time series first and check for the geographical distribution, the random selection criterion do not apply in this case. A final statistical test must be applied for the significance of the result. In other words, you must make a choice local vs global (or regional), then use the right data and the appropriate procedure.
  3. What ended the Little Ice Age?
    batsvensson, what you call bandwidth (i'd call it variability) is not known a priori but can be extracted from the measurements. The signal, again, is not know a priori but can be extracted from the measurements. In practice, take the temperature data, smooth with the algorithm of your choice, take the residuals. The standard deviation of the residual is the bandwidth, the smoothed line is the signal.
  4. Climate's changed before
    As a total layman I can follow the arguments in my simple way to the point where I see that GHGs amplify warming and cooling periods, so more co2 in the atmosphere increases amplification. But when I look to see what the science says about what initiated pre-industrial inter-glacial warm and cool periods i get a bit stuck in debates about solar activity, a plethora of weather oscillations between negative and positive and now feeback loops and planet earth knowing and adjusting its own temperature because it is conscious of an energy imbalance. Global warming doesn't get any easier to understand.
    Response: Hang tight, I'm at this moment working on a post on the whole ice age/interglacial mechanism, the emphasis on making it easy to understand. Hopefully online within a day or two.
  5. 1998 DIY Statistics
    #6 & #7, global warming seems to be most easily evidenced by nighttime temperatures The above post is about trends in averages; the post I linked is about trends in record temperatures. They're really quite different things.
  6. What ended the Little Ice Age?
    RSVP and SNRatio, My comment is not considered about how well models are at making a curve fit with actual measurement or why the measured curve has the shape it has. What I am asking about is how well our understanding is of the behavior of the actual measured signal. There is no rocket science involved in this really and no reference need to be done to reality for this, but just a couple of standard test. Bern , Why do you think it is meaningful to compare variations in global mean with variations in temperatures for local weather?
  7. 1998 DIY Statistics
    neilperth: Why are only "unprecedented" temperatures seen as being significant? Which data set(s) did you use? How many stations were in the data, total? How far back did your data go? Why select 20 stations out of N? How was your "random" selection done? What results do you get if you looked for "unprecedented" readings across all stations, and what % of hits (highest value in that 10-year window) would you consider significant to prove your hypothesis? For that matter, what was your hypothesis? You can access temp graphs and a bunch of other energy and climate graphs on a page I put together: http://www.grinzo.com/energy/graphs_v3_beta.html The temp graphs my page loads (all from NASA GISS) show a pronounced upswing beginning around 1975.
  8. 1998 DIY Statistics
    What concerns me is the following : I took unadjusted data for a “randomly” selected set of weather stations around the globe up to around the year 2000, and looked at the data. I looked at the data for 20 stations and asked myself : “from the data is it seen that the temperature in any of the last 10 years of data is unprecedented”. In only one of the stations ( Hawaii ) was the highest ever recorded temperature in the last 10 years of data. I have been told that the earth is suffering from “unprecedented global warming” as a result of man-made CO2 emmissions since about 1970. But from this simple and quick investigation of mine, I don’t see that.
  9. Climate's changed before
    Quietman. Even if we ignore the impact of past climate change on animals, look what slower-less extreme-warming events had on human civilizations. Two come quickly to mind-the Anasazi & The Khmer Empire both died out because they failed to adapt to a relatively small warming of the planet during the Medieval Warm Period. Another thing-the feedbacks may not be boundless, but evidence of past climate suggests the situation could get very bad if we let it. Throughout much of the pre-Quaternary period, the planet was a good 4-8 degrees warmer than what it was at any point in the Quaternary period. Is it mere coincidence that this higher temperature was at a time when CO2 levels were 10 times higher than today? I seriously doubt it.
  10. 1998 DIY Statistics
    Here's another point worth considering. Look at the data from AMSU-A, comparing the temperature of mid-July, at roughly 2-year intervals, for the last 11 years & you get the following results: 1999: -14.35 2001: -14.29 2003: -13.98 2005: -14.00 2007: -14.06 2009: -13.65 Though the numbers bounce around a little bit, what we see is a definitive +0.7 degree warming trend at 1km above the planet's surface (the so-called "near surface layer). Looking at other parts of the year shows similar trends. Again, that this has occurred during a period of a record solar minimum just beggars belief-unless you accept greenhouse gas theory. Also, the fact that these measurements are occurring at 1km above the Earth's surface must surely discount the myth that any differences are due to the placement of weather stations!
  11. 1998 DIY Statistics
    If I use GISS data & plot it against the year, I still come up with a trend line of y=+0.0102x for the period of 1998-2008. For 2000-2009, the trend line is y=+0.012x. Also the average temperature anomaly for 2000-2009 is +0.515, compared to +0.32 degrees for 1990-1999. That the first decade of the 21st century is a clear 0.18 degrees *warmer* than the 1990's-in spite of falling solar irradiance-suggests to me that CO2 is playing a *very* important role in increasing the underlying temperature of the planet.
  12. 1998 DIY Statistics
    Well written, Mark, thanks. Out of curiosity, what data source did you use for your ENSO values in Figure 1? Made-up values, or real ENSO data? Your solar cycle looks like a nice 11-year sine wave... :-)
  13. It's freaking cold!
    @djb95054 Watts' attempt isn't much of a debunking. Everything he mentions is addressed in the original paper. I mean what do you think is the more robust analysis, a weatherman's report of the records across a few dozen states or the actual record from 2000 stations over decades. See the y-axis above that's 5e+05! 500,000 measurements! Watts' plots show maybe 50 self-reported measurements. The statistical error on that alone is > 10%. Ask Watts to put this in excel and tell us the error on the slope. And he says things like there were 10 lows and 8 highs in 1930s or something like that. Do yourself a favor, read the original paper--you'll find the analysis 5e+05 times more robust.
  14. 1998 DIY Statistics
    Nice explanation, bookmark, bookmark!
  15. 1998 DIY Statistics
    Good, simple explanation. I tried a similar thing here last year.
  16. What ended the Little Ice Age?
    We must never forget that 'sensitivity' is _not_ well-defined as the net result of a complex of mechanistic processes. It is just the expectation value of something that may be considered a stochastic process. We will eventually get to know what the realized value in our current experiment will be, but we may not know exactly how close a second, more or less identical, experiment would come in. As most estimates of pdfs for the sensitivity seem to have rather fat upper tails, we might expect the observed results to differ quite a bit from case to case - but we will never be able to repeat the current experiment even approximately. This is not a weakness of AGW theory, it is a strength. And one consequence, is that if somebody should come up with an analysis showing another decomposition in natural and anthropogenic components than Meehl's estimate presented here, it would actually -in principle- strengthen the case for AGW. The more models consistent with physics and with the observations, the more robust the paradigm. Surely, the denialosphere will be thick with statements about "debunking" whenever an alternative reconstruction is introduces (just see what happened to Knorr's paper). But that will be like someone triumphantly saying: "Got you! Yesterday, you tried to tell me that nine is six plus three. But now, I can prove you wrong. Here I have obtained conclusive evidence that NINE IS FOUR PLUS FIVE."
  17. Is the airborne fraction of anthropogenic CO2 emissions increasing?
    The network of in-situ CO2 measurement stations ( http://gaw.kishou.go.jp/wdcgg/ ) provides a good record of global and coarse-scale variation in atmospheric CO2 over time. Satellite measurements provide information on finer spatial scale (regional) variation in CO2 over time. There really is no question about any of the following three statements: (a) human activities (fossil fuels and land use) are adding CO2 to the atmosphere, (b) natural biogeochemical sinks are removing some but not all of that excess CO2 from the atmosphere, and (c) because only a fraction of the anthropogenic CO2 emissions are removed, the CO2 concentration in the atmosphere is increasing over time. All of this is very well understood, and not even remotely controversial. With all due respect, the comments made in this thread by ralphiegm give a quite misleading picture of uncertainty in an area where no such uncertainty exists. [If he/she has been relying on the work of EG Beck, that is quite understandable....]
  18. Is the airborne fraction of anthropogenic CO2 emissions increasing?
    I'm sure ralphiegm very well knows that almost all the instruments around the world need to be calibrated, just a few exception. As an engeneer he's also able to read a graph and understand the meaning of numbers and he also knows that almost all measurements are indirect throgh some physical effect. There's more in what he say that is contradictory but just this shows that he's trying to fool people. This site is to talk about science and there's no point to discuss with one with such an attitude; WUWT would be a better choice.
  19. Is the airborne fraction of anthropogenic CO2 emissions increasing?
    I see what you are getting at...but what you are talking about doesn't discredit at all that atmospheric CO2 concentrations have been increasing in recent years or our ability to detect it. The NASA AIRS CO2 map which on the scale had it from about 364 to 382 ppm showed the distribution of the CO2 in the atmosphere at a particular date. I only just saw this but it is pretty amazing. The variation that got climate scientists so excited is only of the order of 1% in the "concentration of mid-tropospheric carbon dioxide". (I myself would have been frowning if it was on the order of 20% as long term trends would be difficult to compare,but it is not) Watch the video here over different months: http://svs.gsfc.nasa.gov/vis/a000000/a003500/a003562/index.html You are correct in asserting that CO2 is not as well mixed in the atmosphere as previously thought (1%variation) but I cannot see how you would infer that the satellite measurements are unreliable, or discredit the long term trends in atmospheric CO2 concentrations. Chahine et al 2008 has used the satellite derived CO2 data track weather patterns. Which is fantastic as we see an even better picture of how CO2 moves around the globe through sources and sinks and "mixes" as other people have been saying! Satellite remote sounding of mid-tropospheric CO2 Chahine et al 2008 http://www.ess.uci.edu/~jranders/Paperpdfs/2008GRLChahineetalAIRSCO2.pdf
  20. What ended the Little Ice Age?
    batsvensson: the natural variation is very large - look at the range of daily temperatures, and look at the variation from day to day, week to week, season to season. The sensitivity being discussed here is about the climate, which is pretty much defined as long-term average conditions. If you're considering an analogy of a signal varying about a centre (as I understand your comment), then, yes, the radiative forcing is affecting the position of that centre, and the sensitivity is the amount of change of that centre when subject to a given radiative forcing. The variability about that centre may stay the same, or it may shrink, or increase, quite separately from the shift in the centre. As I understand it, that's where climatology varies from meteorology - climatology concentrates on the centre, while meteorology looks at the day-to-day variation about the centre. They are quite different aspects of temperature. Weather forecasts are rarely given beyond a few days to a week, and the accuracy falls off dramatically the further out you go - primarily because weather seems to be a chaotic system with almost unpredictable behaviour. But when you look at longer term averages, that unpredictable variation is smoothed out, and we're dealing with much more predictable systems - heat comes in, heat goes out, the difference says what the long-term temperature average will be. The hard part that seems to be occupying climatologists' time now is figuring out exactly *where* heat goes - the satellite measurements seem to clearly indicate that heat is being retained by the earth - and what effects that will have, in terms of sea levels & potential weather patterns (which will both determine whether that beach-front property was a good long-term investment or not).
  21. Is the airborne fraction of anthropogenic CO2 emissions increasing?
    "Significant Findings from AIRS Data 'Carbon dioxide is not homogeneous in the mid-troposphere; previously it was thought to be well-mixed 'The distribution of carbon dioxide in the mid-troposphere is strongly influenced by large-scale circulations such as the mid-latitude jet streams and by synoptic weather systems, most notably in the summer hemisphere 'There are significant differences between simulated and observed CO2 abundance outside of the tropics, raising questions about the transport pathways between the lower and upper troposphere in current models 'Zonal transport in the southern hemisphere shows the complexity of its carbon cycle and needs further study" Yocta - I have been saying that CO2 is not well mixed in the atmosphere. I have been getting rebuked here for that position. But the AIRS scientists agree with me judging from their notes I pasted above. I expect that after many, many years of this remote sensing we may finally find get a handle on the global mass of CO2 and whether it is actually rising over time. I am happy to wait till the data is perfected.
  22. Is the airborne fraction of anthropogenic CO2 emissions increasing?
    RE: ralphiegm post 62 The same historical article you referenced continues to chart the need for future satellites to complement and add to the existing data away from the middle troposphere not because AIRS is no good. ralphiegm:...This device is not measuring CO2 - it is measuring infrared light and "calibrating" it in the lab back on earth... By “ground station” I am to understand that you just mean it as a place to process the raw data downloaded from the satellite. The AIRS people are not calibrating the data with anything. The mixing ratio of trace gases in the atmosphere is directly calculated from the data from the AIRS data (Chahine et al 2006 page 921) . This is then checked against other independent detection systems including a ground based FTR and aircraft flask measurements. This paper also links to the details of how the mixing ratios are calculated from specta, and links to others (i’m hoping you have access?) Chahine et al 2006 http://trs-new.jpl.nasa.gov/dspace/bitstream/2014/40298/1/05-0324.pdf ralphiegm:...You imply the device is a spectrograph...fancy calibrating. It is a spectrograph and it happens to be sensitive to IR radiation. It doesn’t matter if it is 830 miles away as long as it has a lens capable of resolving it at that distance (think Hubble or other IR astronomical devices that can measure spectra from interplanetary bodies). It has been pre-calibrated on earth by NIST, which is about as fancy as you can get. Then the accuracy and sensitivity was tested again to better than 1 part in 105 and is tested regularly for drift and long term stability whilst in flight. The only calibration is done on the equipment before flight. Chahine et al 2006 continue to state: The radiometric accuracy and stability of AIRS radiances has been confirmed by several fundamentally different types of comparisons, including 1) the results of the daily measurements of sea surface temperature (SST), 2) direct spectral radiance comparisons from aircraft observations, and 3) low temperature surface radiances from Antarctica. This paper is pretty good, it also deals with the cloud cover issue you were raising.
  23. Is the airborne fraction of anthropogenic CO2 emissions increasing?
    Ian - as to your thermometer analogy - try reading the thing 830 miles away with an infrared detector.
  24. Is the airborne fraction of anthropogenic CO2 emissions increasing?
    Ian - if you check how a satellite measures CO2 you will begin to see the pitfalls: Clouds, ground reflections, wind, water vapor, atmospheric pressure, strata, turbulence, aerosols. It is not perfected by any stretch. And since the clouds appear more frequently over the southern hemi and the ocean the CO2 from those areas are not as well represented. I think the current data is too weak to make sweeping judgments about the fate of the planet. And Gordon - the 200 ground stations actually represent 1 million square miles of area per ground station. And that is just one strata. That may be enough data for you but NASA thinks we need a lot more CO2 data and so do I (they are trying to get a new satellite up there that works - and new data coming soon anticipates that the atmosphere is not well mixed at all - as I have said). Some folks wanna jump the gun on CO2 - I'd rather wait until there was real data synched with temperature and land use. What's the hurry? Gordon -
  25. Is the airborne fraction of anthropogenic CO2 emissions increasing?
    Ii don't understand how 200 or 300 stations are not enough to show whether CO2 is evenly mixed. If that many stations, located around the world, show consistency over time, what is the likelihood that another station, or another million stations, will show mixing, or any kind of inconsistent distribution? Furthermore, if you want me to accept clouds as an appropriate comparison, you will have to explain to me how the stationary stations do not show significant variation over any time period. You know,the way my eyes measure the presence of clouds in the morning, and their absence in the afternoon, although i have hardly changed my position? Soory, if there was any significant mixing, and wind effect, even a single station could reveal that.
  26. Is the airborne fraction of anthropogenic CO2 emissions increasing?
    Ralphiegm said:
    This device is not measuring CO2 - it is measuring infrared light and "calibrating" it in the lab back on earth.
    So you don't believe in liquid in glass thermometers since they don't measure "temperature" but measure changes in volume of a liquid which are then "calibrated in the lab"? You have obviously never worked in, or have knowledge of what goes on in an analytical lab. Nothing actually measures what they are reporting but measure some proxy which is then, through calibration and running of standards, converted to actual measurement of the material in question.
  27. Is the airborne fraction of anthropogenic CO2 emissions increasing?
    "What AIRS does is measure the infrared light emitted by carbon dioxide molecules. Carbon dioxide in the air absorbs infrared emitted by the surface, and then re-radiates it at a slightly lower energy level (which is why it acts as a greenhouse gas). The exact frequency that gets emitted depends on temperature. So Chahine can take the infrared data AIRS sends back to Earth and use a mathematical inversion process to turn it into temperatures." I think the above quote from the NASA website http://airs.jpl.nasa.gov/story_archive/Measuring_CO2_from_Space/Measurement_to_Science/ explains my concern. This device is not measuring CO2 - it is measuring infrared light and "calibrating" it in the lab back on earth, which I assume, is a ground station (what else could it be?) In fact, NASA is trying to send more satellites up to see if they can measure CO2 - if the AIRS was so good why do we need another one? My guess because it is not so good. You imply the device is a spectrograph but it sounds like something else - but whatever it is - it would take some fancy calibrating to assure me that it is reading accurately the CO2 variations in the air column or reading the total weight of CO2 in the air column.
  28. It's the sun
    If it was only the troposphere & near-surface that was showing warming, then I might-just might-be prepared to accept that something other than GHG was the cause of the last half-century of global warming. What concerns me, though, is that the Stratosphere has been COOLING over that same period of time (minus a few spikes due to a few huge volcanic eruptions). If the sun were the cause of the warming, then the warming would be spread throughout the entire atmosphere, yet instead the warming simply *stops* at the tropospheric level. This suggests that long-wave radiation is being trapped in the troposphere by.....Greenhouse gases!
  29. Is the airborne fraction of anthropogenic CO2 emissions increasing?
    In keeping with the site’s ethos I’ll make sure to keep to the science in my comments. RE:# Ralphiegm commment 59 ralphiegm: And there is no "global" data back from those satellites yet. So how can you use that argument against my position? I am bringing to your attention that there are satellites launched with the primary purpose to measure and map CO2 more effectively, and, as a bonus, the measurements it has performed are consistent with what is known of the atmosphere. ralphiegm: You make it seem as though all these climate scientists have accurate satellite data on CO2 for years. NASAs Aqua satellite launched in 2002 has an Atmospheric Infrared Sensor onboard. This is one of 6 instruments on board the satellite but given it is a highly accurate infrared spectrograph it makes a very handy tool for measuring CO2 concentrations in the atmosphere, and I believe across different altitudes. Just because the satellite wasn’t primarily designed to measure CO2 concentrations (like GOSAT and the unfortunate NASA one that crashed) doesn’t make it ineffective at all or mean that climate scientists have never had satellite data to use. AIRS http://airs.jpl.nasa.gov/AIRS_CO2_Data/About_AIRS_CO2_Data/ See John’s post on how the earlier IRIS satellite from 1970 and the Japanese IMG Satellite in 1996 was used in comparison with AIRS. There is also a good paper that discusses the results (Harries 2001). http://www.skepticalscience.com/empirical-evidence-for-global-warming.htm ralphiegm : As you may know satellites do not measure CO2. They try to measure CO2 but must be calibrated from - you guessed it - ground stations. This is where I am confused by what you mean. AIRS has a spectrograph on board. It measures the spectrum of CO2 directly and hence the concentration. It was calibrated prior to its flight through the National Institute of Standards and Technology (NIST) which in metrology is the appropriate thing to do. Prelaunch and in-flight radiometric calibration of the Atmospheric Infrared Sounder (AIRS) http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=1196044&tag=1 I am assuming when you say ground stations you mean ones that are used already to measure atmospheric CO2. Please tell me (with links perhaps) as to why you believe the Satellite data is calibrated from ground stations?
  30. Is the airborne fraction of anthropogenic CO2 emissions increasing?
    dhogaza - I am not aware of a model that accounts for wind but maybe there is one out there. I have never seen wind, clouds or air turbulence mentioned in any of the many papers I have read on climate studies. I could be wrong but if you can point out to me that someone, somewhere has considered wind in their model I would happily read about such a model and report back to you - if you can find one. Good luck trying - I gave up looking. And the reason why wind is not considered is the same reason why clouds are not considered in climate models - it's beyond human ability to model the world. Its just too complicated.
  31. Is the airborne fraction of anthropogenic CO2 emissions increasing?
    Yocta - As you may know satellites do not measure CO2. They try to measure CO2 but must be calibrated from - you guessed it - ground stations. And there is no "global" data back from those satellites yet. So how can you use that argument against my position? You make it seem as though all these climate scientists have accurate satellite data on CO2 for years. But the satellites were launched just a year or so ago and are barely working even today. And the American satellite crashed after launch. So what are they climate scientists using for CO2 data?
  32. Is the airborne fraction of anthropogenic CO2 emissions increasing?
    "Where does the CO2 go you ask? - it blows away in the wind - which, sadly, I have yet to see a climate model account for (wind that is)." I'll bite, Ralph. How many model sources have you read (I know you haven't read the Hadley Centre's, theirs is proprietary ...) My guess is you haven't seen a climate model account for anything because you've not studied a single climate model.
  33. Is the airborne fraction of anthropogenic CO2 emissions increasing?
    ralphiegm: "I am using numbers taken from a variety of sources". Care to share those "sources" with us so we can see how reliable they are? You cannot have the variation of a well mixed gas (100% miscible, yes gases are all 100% miscible) with those kind of variations. Of course, if your sources are taking samples from the top of a chimney then they will show higher results than the global average. However, that would not be considered science.
  34. Is the airborne fraction of anthropogenic CO2 emissions increasing?
    RE# ralphiegm You stated earlier (post 31) that you didn't trust that satellites actually measured CO2. Well they do. GOSAT is a Japanese one launched recently that has amongst other things a Fourier Transform Spectrograph. And if you don't trust the validity/accuracy of spectroscopy, then you can throw out most of atomic physics, astrophysics for the last 50 years or so. Look at the references here for more info on the satellite's specs: http://en.wikipedia.org/wiki/Greenhouse_Gases_Observing_Satellite My Japanese isnt too good but in the brochure it lists the satellite with the ability to measure over 56,000 data points. Not quite the zillion that you expect the poor scientists to deliver but if you can't accept that this is good enough then you are wasting everyone's time. GOSAT: Greenhouse Gases Observing Satellite "IBUKI" http://www.jaxa.jp/pr/brochure/pdf/04/sat02.pdf Also, preliminary results have already been released that show CO2 is within the range of 360 to 390 ppm. Initial Analysis of Observation Data from GOSAT http://www.gosat.nies.go.jp/eng/result/download/GOSAT_L2_20090528_en.pdf When scientists talk about considerable variation in the atmosphere it is on the order of 3ppm not the crazy numbers you seem to be claiming. Aircraft observation of carbon dioxide at 8–13 km altitude over the western Pacific from 1993 to 1999 http://www3.interscience.wiley.com/journal/118916481/abstract?CRETRY=1&SRETRY=0
  35. Is the airborne fraction of anthropogenic CO2 emissions increasing?
    Ian - I am using numbers taken from a variety of sources. I have no wish to support or diminish this Beck fellow. Jeez - Is the only purpose for this site to squeeze out verbal revenge against skeptics? As to the content of my post which is really the only point I care about - atmospheric CO2 appears to range from 250 to 425 ppm. Is that data wrong too? Where does the CO2 go you ask? - it blows away in the wind - which, sadly, I have yet to see a climate model account for (wind that is).
  36. Is the airborne fraction of anthropogenic CO2 emissions increasing?
    Ralpiegem, can you please explain where the CO2 comes from so that its concentration doubles in the very short periods of time shown in Beck's paper. Also, please tell me where it suddenly disappears to after it reaches its high points. The paper you are using is nothing but garbage, and what is worse, if you are an engineer as you have stated, you probably know it is garbage but will use it to support your denier claims.
  37. What ended the Little Ice Age?
    To batsvensson: Reading your comment, I can only assume you have a background in electrical engineering. The problem with this is that you have a high level of math skills, mathematical intuition, systems analysis and computer modeling abilities and wish to actually approach the eco-system as a sincere scientist. I applaud your question. Unfortunately, we are talking about many non linear and dependent relationships that probably are not being accurately modeled. I dont think anyone is to blame, nor in a position to answer your question. It almost seems like there is a limit to what we humans can know, predict, and control. I am sorry for sounding so pessimistic, yet on the lighter side, I think we should also be grateful for the margin of error that Divine Providence at least so far has allowed mankind. My guess is that since 2/3 of the planet is water, there is a self imposed restriction as to how much damage we can actually do to ourselves.
  38. Predicting future sea level rise
    rajpe, to be in topic i will consider just #1 and 2. During the last interglacial sea level was several meters (4-8) above current level and Greenland was about 3 °C warmer and with less ice than today. That makes sense. What does not make sense is to assume that we are naturally heading there again. Indeed, sea level has been almost constant in the last 2000 years and from about 7 to 2 thousands years ago it rose only a little and very slowly. There is no indication at all that we were heading toward the same state as the last interglacial. Maybe you are right and it's too late to save the Maldives whatever we may try to do starting from now. But it could be worse, much worse than just the Maldives.
  39. Is the airborne fraction of anthropogenic CO2 emissions increasing?
    Riccardo -I think that CO2 ranges from 250 to 425 ppm globally based on the literature. So it is amazing that (some) climate scientists are in a panic over this issue.
  40. Is the airborne fraction of anthropogenic CO2 emissions increasing?
    ralphiegm, you have local and global mesurements; you also have the physics and simulations that match the experimental data locally and globally (by the way, not all natural systems are too complicated to be described quantitatively). Putting completely arbitrary minimum requirements to belive in the data indicates that you simply (and dogmatically) do not want to. It's ok for me, your choice. But do not pretend to judge thousands of (irresponsible ..) scientists (and many more common people) on this basis.
  41. Is the airborne fraction of anthropogenic CO2 emissions increasing?
    TerryG, do not make the mistake made by ralphiegm, not any kind of pollutant, molecule or particulate behave the same. It is well known that the global circulation tends to separate the two emispheres, but it changes with season and it's not "perfect". If you have a very stable (chemically inactive) and long lived specie it will first mix vertically through the whole troposphere (and beyond) and then mixes globally in the atmosphere. You may also notice that the seasonal cycle is much less pronounced in the southern emisphere; this is because there's much less land (vegetation) and there's no enough time for the northern emisphere CO2 to mix. So it's just a matter of giving the CO2 time to mix and it will.
  42. Is the airborne fraction of anthropogenic CO2 emissions increasing?
    Jim - Are you saying that CO2 can only be in concentrations ranging from 360 to 380 ppm?
  43. Is the airborne fraction of anthropogenic CO2 emissions increasing?
    It seems Ralph is getting some of his ideas from Herr Beck's paper in Energy & Environment. http://www.realclimate.org/index.php/archives/2007/05/beck-to-the-future/ That explains much.
  44. Predicting future sea level rise
    Please excuse me, but am I missing something? Does not most of the discussion on sea level rise miss the most important point? As the Koop article in Nature, 17DEC09, points out, the maximum sea level during the previous interglacial was about eight (8) meters above the current sea level. Does this not suggest the following: 1. Future sea levels will likely be 8 meters higher than we have now - with no help from man. (Things are NOT different, this time.) 2. Don't worry about the Maldives, etc. They will be gone, whatever we do. 3. Don't waste current resources (yen, eruos, dollars, etc.) on wishful-thinking projects. 4. With regard to Climate Change, do only science and do no politics, i.e., if you are a politician, butt-out. P.S. Please don't think that fast climate change must be man-made. Don't believe me, read "The Two Mile Time Machine".
  45. Is the airborne fraction of anthropogenic CO2 emissions increasing?
    Catprog - see the problem is you are assuming CO2 is well mixed. You have no way of ever proving that assumption unless you take the zillions of measurements necessary to prove such a thing or if you had a dispersion / diffusion model that explained how CO2 can populate the atmosphere on its own. It appears that climate study is based on the super smooth mixing of CO2 in the atmosphere. It appears that CO2 can range from 250 to 425 ppm looking at 5 year smoothed data. And diurnal cycles in CO2 varying by 50 ppm. And seasonal variation from 350 to 415 ppm (all nos. rounded by me from the literature for illustrative purposes). So how can anyone have such faith in the CO2 well-mixed assumption given the crazy variations in CO2. It does not make sense to take a dogmatic position on CO2 being uniformly distributed through the atmosphere.
  46. Is the airborne fraction of anthropogenic CO2 emissions increasing?
    Have been following this web site for a while. I have some observations and questions. Of the CO2 we produce the northern hemisphere produces what percentage? 90%,85% or 80% It is then stated, in this thread that the CO2 then evenly mixes through the atmosphere. But on this web site it's a tale of to hemisphere's: http://www.livescience.com/environment/080930-chemical-equator.html The Chemical equator as they decribe it, where the poluted air is in the north and the south is considerably cleaner. Now I have seen CO2 readings from Cape Grim, Tasmania, Australia. http://www.esrl.noaa.gov/gmd/ccgg/carbontracker/co2timeseries.php (Go to: Site CGO_01d0) and as you can see they indicate CO2 levels at 385ppm at present time. The point is I'm finding it hard to believe that northern hemisphere CO2 is the cause of ppm levels to rise in the southern hemisphere.
  47. Is the airborne fraction of anthropogenic CO2 emissions increasing?
    @ralphiegm not to disrespect any scientist - but do you believe there are enough data points throughout the entire shell of the atmosphere to accurately model CO2. Show me one station that shows a big difference then the other and I will be more inclined to believe the CO2 needs to be measured more finely. Why does the Antarctica CO2 graphs show a similar annual increase to all the others if CO2 is not distributed relativity evenly. I think a particulate can be an indicator of mixing in the atmosphere. If you get a bunch of small neutrally buoyant pieces (Particulates),some red food dye(CO2) and water(Atmosphere) and mix them all together by stirring. The red food dye will be distributed evenly while the pieces will all collect together underneath the mixer. ground CO2 data at grid points of 5 miles Why 5 miles and not 1 mile. If you really believe that CO2 is not mixed evenly go out and buy a CO2 meter. on your daily travel look at the readings. if you find a big variation then look around for a big emitter of CO2(and make sure you are measuring the outside not the inside). If you can't find one then look up how to get a science paper published because you have found something no one has found before.
  48. What ended the Little Ice Age?
    "Meehl 2004 is also confirmation that past climate change tells us how sensitive climate is to radiative forcing." I acknowledge this as an possible interpretation of data. However, using words like “sensitive” is misleading when there is still no clear picture about what the bandwidth of the natural variation actually is. What “sensitive” suggest is that there exists a certain (known) signal with a certain (known) bandwidth and that due to “radiative forcing” the center and/or shape of the bandwidth has changed. Is such interpretation supported by the analysis in the report? If not, another interpretation could be that the signal is very noisy and the bandwidth is great which can be put in other words as climate is able to vary fast over time.
  49. What ended the Little Ice Age?
    I went to the "hockey stick page" but the graphs don't show the MWP. They only go back to 1500 except one which is only Northern Hemisphere. I think the MWP is instructive in this debate.
  50. What ended the Little Ice Age?
    Why don't the graphs on this site go back to 1000 AD? It appears the warming shown is something new without a little more historical context.
    Response: More context is always a good thing. For discussion of temperatures going back 1000 years, see the hockey stick page. For temperatures going back 450,000 years, see "CO2 lags temperature". For temperatures going back 540 million years, see "CO2 was higher in the past".

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