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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 101201 to 101250:

  1. The 2nd law of thermodynamics and the greenhouse effect
    damorbel at 00:00 AM Ned has already said it, but i realize on reading what i wrote how it may be interpreted, the lapse rate, may be due to density/gravitational compression(which also effects path length), but the energy contained is due to energy in vrs path length out. As can be seen in the graphic in NEDs post. The stratosphere is an entirely different kettle o fish, it absorbs UV through O3, and is optically thick for UV, but is relatively transparent to LW, so CO2 cools it, But UV heats it from the top down, there is a thread on it here at the moment. In which there has been a bit o a discussion about the relevance of radiation to the lapse rate and convection.
  2. The 2nd law of thermodynamics and the greenhouse effect
    Also, for what happens to the upper level photons, the graphic at jg's (meant for explaining stratospheric cooling) is useful. And dont forget DLR is measured, something damorel struggles to explain.
  3. It's albedo
    Here's a link to that paper /news.php?n=481&p=2#34079
  4. It's albedo
    #19, I recommend Climate modeling through radiative-convective models (Ramanathan 1978) equation 16 (absorption and scattering of solar radiation) which integrates over wave number, angle of incidence, etc.
  5. It's albedo
    Hi, Rovinpiper. Sorry to have missed your first question: What is "s" in your equation for energy emitted? It should be a "sigma" ... it's the Stefan-Bolzmann constant. Since it's constant, the equation tells us that emitted energy at a given wavelength is a function of just the object's temperature and its emissivity (fraction) at that wavelength. [...] he states that we must integrate over the whole spectrum. Must integrate over the whole spectrum to do what? What's he "skeptical" about? The spectral distribution of incoming solar radiation is very different than the spectral distribution of outgoing longwave radiation. The former is almost entirely at short wavelengths (probably > 99% of it is below 3 micrometers) , while the latter is almost entirely long wavelengths (definitely > 99% of it longer than 3 micrometers). The latter is why the Earth doesn't glow in visible light (lava flows and forest fires excepted...). So you don't really need to integrate across the entire spectrum (or integrate anything, really) to answer the questions you were talking about earlier in this thread. Changing the visible-wavelength albedo of an object will change how much it absorbs, without necessarily implying a corresponding change in the efficiency with which it emits longwave radiation. In that case, the object will warm up or cool down until it reaches a new equilibrium. Dunno if this helps at all.
  6. An Even Cloudier Outlook for Low Climate Sensitivity
    Yep...Spencer is definitely saying clouds are initiating ENSO in that exchange. The mechanistic sequence is not really explained though. Nature paper there if he can convince anyone...
  7. Human CO2 is a tiny % of CO2 emissions
    I think I understand the basic science quite well and am familiar with the details of the Keeloing curve. I am certain without knowing the details that I can visualize what is hapeening at the ocean-atmosphere interface. One of my current interests is to try to bridge the severe communication problem between scientists and nonscientists. I have at every opportunity made myself available to speak or write about the aspects of this probelm that I think I understand well. As part of this effort I turned to the Skeptical Scientist for guidance and the first thing I came upon was this thread and the figure (7.3) from the IPCC that seems to me to undercut the effort. In this figure a cycle involving 300+ GT of CO2 to and from the ocean is "given" - nothing to indicate the time span (although one could surmise a year) but more importantly nothing to indicate distance. The arrows in the figure suggest vary large distances but in what sense does one know (or feel qualified to suggest) that 300+ GT of CO2 move from point A to point B on the earth? My point is that the quoted 300+ GT of carbon (or CO2 - not even that is clear)are meaningless and these numbers only serve to confuse an already confused situation. If you are inclined to respond please know that I know how much CO2 humans are producing, how much of it is going into the atmosphere, how much CO2 (and bicarbonate and cardonate) are dissoled in the ocean, I understand heterogeous equilibria, and etc. I just want to know why figure 7.3 was the first response of many possible to the original query, and would like to have people acknowledg or refute my assertion that the figure is bad science and therefore bad communication.
  8. An Even Cloudier Outlook for Low Climate Sensitivity
    HR, This should be obvious in their exchange: http://geotest.tamu.edu/userfiles/216/emailExchange.pdf http://www.realclimate.org/index.php/archives/2010/12/feedback-on-cloud-feedback/
  9. Human CO2 is a tiny % of CO2 emissions
    Here is link to an image of the CO2 flying carpet showing spatial and temporal variability combined.
  10. It's albedo
    I am facing that most intractable of global warming deniers, the old physicist. Faced with what we just discussed about Kirchoff's Law he states that we must integrate over the whole spectrum. How do you do that?
  11. Ocean acidification isn't serious
    Glad someone has the patience and time to post those images! "So anyone who says 'atmospheric CO2 increase is solely due to ocean outgassing' is all wet." On that we should be able to agree. Physical and chemical considerations as well the evidence from stable isotopes, physical measurements, times series of pH and pCO2 pattern/trends are in agreement and unequivocal.
  12. Human CO2 is a tiny % of CO2 emissions
    Hfranzen "but in what way is a dynamic exchange of CO2 a cycle?" As noted, there is a lot more spatial variability implicit in that image than can be presented effectively. Also a cycle as used in earth science also implies transitions between different states (inorganic/organic, aqueous/gaseous) that can occur in a single space. That's just the usage.
  13. Human CO2 is a tiny % of CO2 emissions
    #87: "in what way is a dynamic exchange of CO2 a cycle?" To use a familiar illustration, here is a 'dynamic exchange' of CO2 in/out of the biosphere. The result is a regular 6-7 ppm peak to trough cycle each year. It is superimposed on the long-term increase of ~2ppm per year due to anthropogenic CO2. The annual peak is in April, at the start of the growing season in the northern hemisphere; the annual trough is in September-October, aka 'fall'.
  14. Human CO2 is a tiny % of CO2 emissions
    Hfranzen Most of that annual cycle has to do with seasonal cycles in carbon stored in terrestrial organic matter as biomass that builds up in spring and is later decomposed. For this reaons the annual cycle gets progressively less obvious as one moves from northern latitudes (with large proportion of surface area as land mass), to southern latitudes (where most of the surface area is covered by ocean). Biomass can accumulate on land because plants are more complex and there is a lag between formation and decomposition of organic matter (those processes also show lagged seasonal cycles). Plants in the ocean are largely single cells and get quickly eaten or decomposed. So even though there is almost as much photosynthesis in the ocean as on land, it is impossible to store much carbon in biomass in the ocean. Therefore, net CO2 flux into the ocean on the short time scale tends to be driven by abiotic factors (pCO2 in water and air, water temp, wind, currents, upwelling/downwelling). As for how these numbers are measured, I think that is covered in the IPCC AR4. In both terrestrial and oceanic systems there are areas than act as sinks and sources. We know the ocean is a net sink because it is acidifying as CO2 invades (in fact, becasue of that you can say that we actually know the net flux there better than the gross fluxes back and forth!) We also have calculated maps of CO2 flux based on physical/ biological controls that are consistent with a net influx under current conditions. Those are pretty good, but are improving all the time. Land use and biomass inventories suggest that overall the land is a net source due to deforestation - but regional reforestation has meant that some areas have been CO2 sinks over the last century. Uncertainty on the inventories is large but getting better - an active area of research. There are also biophysical models of primary production and decomposition that are driven by satellite data and physiological constraints. These are groundtruthed against long term plots used in the inventory studies. One can cross check both land and oceanic net flux estimates against changes in pCO2 as air masses pass over water bodies and land as constrained by known physical constrains on exchange. That can be done on the small scale (eddy diffusivity measurements in forest or grassland plots) or the very large scale (over Amazonia or the Southern Ocean) using so called inversion techniques which infer exchange rates -- essentially a complex regression whose fit is constrained by physical considerations. So basically on the budget side the focus has been on measuring net exchange in many ways rather than following individual molecules or plumes of CO2 (although that is interesting in and of itself). You can infer how far a typical molecule of CO2 travels in the atmosphere, but that turns out to be a consequence of the measurements and does not affect them. Hope that helps...
  15. Ocean acidification isn't serious
    Lovenduski's Fig 4 captures in time series format the changes going on south of 35S latitude. For 'natural flux', the trend turned from - (sink) to + (source) in the mid 80s; a warming sign? But when she adds in 'anthropogenic' to create the 'net flux', the long term trend is driven downwards towards a stronger sink. Hence this patch of southern ocean is, on balance, soaking up CO2 and acidifying. But the picture changes in other parts of the world: --from Lamont Doherty --from NOAA PMEL So anyone who says 'atmospheric CO2 increase is solely due to ocean outgassing' is all wet.
  16. Human CO2 is a tiny % of CO2 emissions
    Many thanks,I am fully aware of the point of your second paragraph -I have developed a power point discusing the CO2 atmospheric balance and detailiong the physical chemistry of its effect upon the earth. Does anyone want a copy? As regards your first paragraph, that may be the way they are thinking, but in what way is a dynamic exchange of CO2 a cycle? If I take a bottle of soda water in and out of the refrigerator and think about doing it a rediculously huge number of times am I then justied in calling what I envision a carbon cycle and putting 300+ GT arrows in my drawing of the soda bottle? I.e. a dynamic exchange of that charater may justifiably be considered a microcycle but it has no relavance to the type of macrocycle one thinks of when one considers, for example, the water cycle during which water is moved thousands of kilomters in periods of weeks. My major point is that a cycle means movement and to discuss movement in terms of quantity alone is, in this case for sure, meaningless. What is needed is quantity a distance and a time and the figure gives only a quantity. It is very poor communication at best and very poor science at worst.
  17. Ocean acidification isn't serious
    As for whether clouds are trickier than oceanic CO2 exchange, you'd have to say the Luvenduski paper does an outstanding job of reproducing the mesocale SST variability across the Southern Ocean (fig 2). I have pretty good confidence in their prediction of the underlying physical variables that largely constrain CO2 flux. Clouds are WAY more difficult, I think.
  18. Ocean acidification isn't serious
    Muoncounter - "How is it possible for oceans to simultaneously absorb and emit CO2?" Actually a simple source of confusion may be the separation of natural and anthropogenic CO2 that is made the Luvenduski paper. It helps to know that net flux of CO2 into the ocean really reflects the balance between CO2 influx and outflux, just like temperature of the ocean reflects a net energy balance. So there can be a net flux of anthropogenic CO2 in (as all of it is in the atmosphere), but a net total flux of CO2 out due to local imbalances between pCO2 in water and air. It can be hard to parse that out in words without being confusing, as that text you quote makes quite clea! But fig 3 does a good job. The complex pattern of "natural" CO2 influx and outflux (Fig 3b)reflects upwelling of CO2 rich water, temp changes, downwelling (well constrained) as well as sea surface exhange and phytoplankton growth/sinking (both less well constrained) on the CO2 balance. The contemporary pattern differs in that influx of CO2 has increased regionwide due to anthorpogenic CO2. The spatial pattern of that increase is shown in Fig3c. That's the shift toward sink state I mentioned. One big unknown in all of this is if the biological pump in this region may respond to changing CO2 in this region. People are working on various aspects of that as we speak.
  19. A new resource - high rez climate graphics
    This NOAA graph of CO2 and global temperature should be used more often when communicating to the public.
    Moderator Response: [Daniel Bailey] Link here: http://www1.ncdc.noaa.gov/pub/data/cmb/images/indicators/global-temp-and-co2-1880-2009.gif
  20. Human CO2 is a tiny % of CO2 emissions
    #82: "how do I reconcile several hundred GT changes in the atmosphere with the ca. 5 GT annual change of the Keeling curve?" I may be oversimplifying it a bit, but I visualize the '~330 Gt up/down' as being an equilibrium cycle. Even if we released zero anthropogenic CO2, that cycle would still be there. Add in the CO2 we release from fossil fuel consumption -- on the order of 30 Gtons annually in recent years -- and you get the annual change in average atmospheric CO2 concentration (+1.5-2.5 ppm by volume). It is not difficult to work out how this excess mass of CO2 in Gtons converts to +2ppm by volume in the atmosphere, as long as approximately 50% of this mass is taken from the atmosphere by land/ocean sinks. You can actually trace the increasing rate of atmospheric CO2 concentration from increasing annual CO2 emissions; data are available here.
  21. Human CO2 is a tiny % of CO2 emissions
    #83: "the sign of this flux is spatially and temporally heterogeneous." Is it ever. We're trying to decipher some of this at Ocean acidification.
  22. A new resource - high rez climate graphics
    Or (thanks to Wolframalpha.com) ~~ 5.6 × 2003 estimated energy in world's total fossil fuel reserves (~~ 3.9×10^22 J )
  23. A new resource - high rez climate graphics
    I think it'd be good to put chart 2 into units people understand for more visceral impact. A couple of options. Based on my calculations, the energy gain of the earth has been the equivalent of detonating 52 Million x 1 Megaton atomic bombs. That is 100 x 1 Megaton atomic bombs every hour, for the last 60 years. Another way of looking at it is that over 60 years, the planet has been warmed by the energy equivalent of 62x of the output all of the world's power plants (2010 power plants), operating for 60 years. DOE says total worldwide electricity generation in 2010 was 16,385 Billion Kwh. My calculations: 1 joule 0.0002778 watt hours 1.00E+21 joules 2.78E+17 watt hours 2.20E+23 Joules total earth energy gain 6.11E+16 KWh 60 years 525600 hours 1892160000 seconds 1.16E+11 kW net gain (assuming linear over 60 years) 1.6358E+13 Annual electrical energy production Kwh (per DOE) 1,867,351,598 Electrical power generation worldwide KW (average) 62.27 Energy gain of planet vs current electricity production 1 Megaton atomic bomb 4.184E+15 Joules 5.26E+07 Atomic bombs energy equivalent 1.00E+02 Atomic bombs every hour over 60 years
  24. A new resource - high rez climate graphics
    I think Inkscape might convert pdf to SVG?? It's a free open source drawing package.
  25. Human CO2 is a tiny % of CO2 emissions
    Thanks for the answer (and rest assured I am definitly on the side of the IPCC. But,how far does the CO2 have to travel from source to sink to be inclded? Clearly CO2 is entering and leaving the ocean everywhere at all times, but to get a number to put on the quantity one has to define the transport as being between two points. How does one decide upon the two points? It seems to me that that decsision would be totally arbitrary i.e. one could get any number up to some meaningless maximum for which the CO2 travels only a millimeter or a micron. What am I missing here?
  26. It hasn't warmed since 1998
    A really nice temp chart is here at NASA Earth Observatory
  27. The 2nd law of thermodynamics and the greenhouse effect
    damorbel - By George, I think you've got it! Even if you don't recognize it. The surface of the Earth (e) radiates greenhouse gas IR bands proportionally to T(e)^4. If there were no greenhouse gases, that would go straight to space (s), which has a temperature of ~3K. Instead, we have an atmosphere (a) with greenhouse gases, which emits IR at those wavelengths proportionally to T(a)^4. Summing radiative energy transfer in those bands (as per your post): - No GHG's -> (T(e)^4 - T(s)^4), T(s) = 3K - GHG's -> (T(e)^4 - T(a)^4), T(a) = 287K Note that 287K >> 3K, and that in the GHG case much less energy leaves the surface of the Earth in those bands - lowering emissivity. The effective emissivity (proportion of energy emitted versus a black body) of the Earth has dropped, and to radiate the same incoming solar energy with a lower emissivity the temperature will go up.
  28. The 2nd law of thermodynamics and the greenhouse effect
    There is no logical connection between this paragraph: This would be fine if the temperature in the troposphere was a function of the radiation but it isn't. DT/dz in the troposphere is about the same over the poles as it is over the equator, this temperature gradient is called the lapse rate and it has nothing to do with radiation. and the preceding paragraph, to which it is presumably intended as a response. Nobody said that the lapse rate is determined by radiation. That is a complete red herring (something that should be no surprise to readers of this thread, or the preceding one). Raising altitude of emission (due to GHGs), and keeping the lapse rate constant (not due to GHGs), implies warming of the surface. If you're unwilling to listen to people here, and you're unwilling to read Science of Doom, and you're unwilling to look at a textbook or talk to an expert, there's probably nothing I can do that would help. But for others who might be interested, there's a very good explanation of the underlying physics of the greenhouse effect over at Chris Colose's blog. Here's a simple graphic from Chris's post, explaining how raising the height of emission while keeping the lapse rate constant (the slope of the diagonal line in this figure) implies a warming of the surface: The Y axis is altitude, the X axis is temperature. Since the temperature at the new height of emission has to increase, the constant lapse rate means that all temperatures at lower altitudes must increase, too. Here's Chris's summary:
    So…review: Because of energy balance, the planet must get rid to space as much energy as it receives from the sun. Averaged over the Earth, taking into account the albedo and geometry, this is about 240 W m-2. In the absence of an atmosphere, this flux of radiation is lost by the surface by \sigma T^{4}_{s}. With an atmosphere, this flux of radiation is allowed to emanate from upper, colder layers of the atmosphere, say on average at some altitude H. Increasing greenhouse gases increases the altitude of H, a height in the atmosphere which depends on wavelength, and characterizes a level of mean emission to space. Because the atmosphere is now emitting from colder levels of the atmosphere, the OLR has decreased, and the result is that the planet must warm to re-establish radiative equilibrium.
    I have no expectation that damorbel will learn anything from this, but others might find Chris's discussion useful. I highly recommend his blog, though he only posts very sporadically.
  29. Human CO2 is a tiny % of CO2 emissions
    hfranzen writes: Furthermore if the time is for one year, how do I reconcile several hundred GT changes in the atmosphere with the ca. 5 GT annual change of the Keeling curve? Re: the ocean/atmosphere CO2 exchange, the sign of this flux is spatially and temporally heterogeneous. In one area and one season, the ocean will be a CO2 sink, while at some other place and time it will be a source. Integrating over the globe and the seasons gives a total upward flux of 332 Gt, and a downward flux of 338 Gt. This doesn't show up as a huge swing in the Keeling curve because the two processes are occurring simultaneously and thus mostly but not entirely cancel each other out. At least that's my understanding.
  30. The 2nd law of thermodynamics and the greenhouse effect
    Re #239 you wrote:- "its the altitude at which energy can effectively escape however, that is responsible for the T gradient, which is necessary for the transport of energy to this altitude... " How can this be when the temperature rises steadily in the stratosphere? So the lower atmosphere is already largely opaque to some wavelengths, but the path length shortens with altitude, so by adding more opaque molecules, it raises the height that radiation can effectively escape, so its necessary for this new altitude, to heat enough that it is emitting the incoming, and next layer down must heat enough that it is able to transport this energy up to this height, etc etc.. This would be fine if the temperature in the troposphere was a function of the radiation but it isn't. DT/dz in the troposphere is about the same over the poles as it is over the equator, this temperature gradient is called the lapse rate and it has nothing to do with radiation.
  31. The 2nd law of thermodynamics and the greenhouse effect
    Re #245 SteveS you wrote:- "I've seen this statement a number of times and it makes no sense to me. If the GHGs absorb the downward radiation, they would still have to re-emit some of it again, some of which would again be downward. Only if there were a layer of GHGs next to the surface that somehow magically didn't re-emit any radiation downward could this mean that none of the downward radiation reached the surface." The layer just above the surface has about the same temperature as the surface so, with a very small temperture difference there is almost no radiative energy transport. By far the greatest transporter of energy from the surface to the atmosphere is the evaporation/condensation cycle of water (rainfall!) Don't forget that radiative transport is proportional to (T1^4 - T2^4) where T1 is the surface temperature and T2 is the destination temperature; whereas evaporative transport works for the order of a few degrees. BTW, when calculating radiative transport, where is the destination, so that its temperature can be known - the troposphere is very thick and has a very variable temperature?
  32. The 2nd law of thermodynamics and the greenhouse effect
    damorbel writes: "But don't GHGs also absorb the downward radiation? Surely they absorb the downward radiation from the upper atmosphere long before it gets to the ground" As SteveS has pointed out, this is pure nonsense. Let's say the atmosphere was 100% greenhouse gases. In such a circumstance every photon of IR in the impacted wavelengths would be absorbed immediately after leaving the ground. It would then be re-emitted... possibly back down to the ground or possibly upwards... where it would immediately be absorbed by another molecule of greenhouse gas and then re-emitted... possibly back down to the previous 'just above the surface' molecule and from there either up again or back down to the surface. Continue ad infinitum. With less than 100% atmospheric greenhouse gases the process works the same way except that most photons travel past several molecules of other types (e.g. Nitrogen) before being absorbed by another greenhouse gas molecule. Yes, the further up a photon gets the less likely it is for that energy to eventually be transmitted back to the ground... but we are talking about ridiculously large quantities of energy. Even 0.00000000001% is a tremendous amount of heat. The question also ignores everything below the "upper atmosphere"... as if photons magically teleported from the surface to the upper atmosphere without having to pass through all the space in between - with its much higher probabilities of the energy being 'bounced' back down to the surface. Also: "...few seem to recognise that, if the outgoing radiation exceeds the incoming, then the temperature cannot rise." If outgoing radiation exceeds incoming then we've violated the law of conservation of energy.
  33. An Even Cloudier Outlook for Low Climate Sensitivity
    Albatross (#83), I was incorrect in #80 (answering your #77). I read the paper body (p. 1525) and forgot about the caption where Dessler only plotted ECMWF, not MERRA. When I looked them up originally I found the MERRA tech report which explained assimilation very nicely so I used that. I need to find a similar reference for ECMWF. Both "reanalyses" (i.e. models with data assimilation) are used in the same way for his conclusion (the models with real world data matches the models without). My argument is that the cloud parameters are internal (at least in MERRA) and therefore depend on the radiation, convection and cloud process equations plus an assortment of parameters which are determined by fitting the model to the real world data. I think my argument will apply to ECMWF, but I will have to look that up to find out their model details, particularly for clouds. Sorry about the confusion (starting with my #16). Obviously I need to look at Spencer next. I am pretty sure that you are correct that his model is too simple and that his model assumptions are what creates his result independently of the real world measurements. I'll also try to evaluate how he states and tests his hypothesis. Dessler was quite clear about his.
  34. Ocean acidification isn't serious
    Muoncounter - How is it possible for oceans to simultaneously absorb and emit CO2? The temperature of the ocean is heterogeneous too. Generally the flux of CO2 to the atmosphere originates from the tropical regions where the ocean is warmer and CO2 less soluble. The uptake is occurring in the larger region of cooler waters where CO2 is more soluble. Much more complicated than that of course, as others have already pointed out, but why over-complicate matters?. The overall effect of human fossil fuel combustion is to increase CO2 dissolved into the oceans at a rate that is unprecedented. Papers are practically screaming that the oceans are sucking up CO2 to what will become dangerous levels (at least to plankton) in not very many years. From McNeil and Matear 2008 The Arctic Ocean is projected to reach aragonite (more soluble form of calcium carbonate) undersaturation within a decade, meaning the waters will be corrosive to calcifying marine organisms that make their shells from aragonite. Imminent ocean acidification in the Arctic projected with the NCAR global coupled carbon cycle-climate model "Aragonite undersaturation in Arctic surface waters is projected to occur locally within a decade and to become more widespread as atmospheric CO2 continues to grow. The results imply that surface waters in the Arctic Ocean will become corrosive to aragonite, with potentially large implications for the marine ecosystem, if anthropogenic carbon emissions are not reduced and atmospheric CO2 not kept below 450 ppm." It amazes me how little attention is being given to such a serious issue. It will have profound effects for life on Earth, and the changes to ocean chemistry are pretty much irreversible for many ten of thousands of years.
  35. The 2nd law of thermodynamics and the greenhouse effect
    "But don't GHGs also absorb the downward radiation? Surely they absorb the downward radiation from the upper atmosphere long before it gets to the ground" I've seen this statement a number of times and it makes no sense to me. If the GHGs absorb the downward radiation, they would still have to re-emit some of it again, some of which would again be downward. Only if there were a layer of GHGs next to the surface that somehow magically didn't re-emit any radiation downward could this mean that none of the downward radiation reached the surface. Imagine if things worked the way you think they do, then wouldn't the same be true for the radiation going upward? All of the reflected radiation would be absorbed within a few mean free paths of the surface and never make it to the TOA, let alone into space. The layer next to the surface would become extremely hot since all the reflected IR never leaves that layer.
  36. The 2nd law of thermodynamics and the greenhouse effect
    Re #238 KR - The temperature of any object,... ..(physical changes), etc. Agreed. - Under the conservation of energy... ...equilibrium is reached when incoming = outgoing again. Agreed - Outgoing energy in a vacuum ... ...a change in temperature can change outgoing energy until it balances incoming energy. Agreed "- The atmosphere is quite transparent to visible light (from the sun), hence the incoming energy is fairly constant." The incoming energy - agreed (the atmosphere is not transparent to solar infra red) "- Outgoing energy to space leaves the Earth as thermal IR, to which the atmosphere is partially transparent." Agreed (you are refering to the IR window) But what follows is unclear:- "- Greenhouse gases absorb IR, re-radiating it in all directions, including back to the ground, which re-absorbs most of what hits it." But don't GHGs also absorb the downward radiation? Surely they absorb the downward radiation from the upper atmosphere long before it gets to the ground And:- " This means that less IR goes to space at any particular temperature, and the Earth has a lower effective emissivity to space due to greenhouse gases." For me this is unclear. How does the downward radiation mean "less IR goes to space"? You said (above) "Greenhouse gases absorb IR, re-radiating it in all directions" - care to explain? You write "The thermal mass of the atmosphere is irrelevant." Not true, the atmosphere, with or without CO2 is a very important contributor to climate because it is a major distributor of heat between equator and poles. As such the mass and mean temperature are very important since they determine the thickness, from the thickness and the lapse rate you can determine the surface temperature This statement of yours is too vague:-> "Therefore the greenhouse effect means that the Earth must have a higher temperature than it would in the absence of the greenhouse gases in order to radiate away the energy it's receiving from sunlight. Don't be misled by convoluted side-tracking arguments." -> to dispute. When making claims about planetary temperature and climate change, all effects that may influence the temperature must be taken into account. Many posters here recognise that incoming radiation adds energy to a given location, few seem to recognise that, if the outgoing radiation exceeds the incoming, then the temperature cannot rise.
  37. Ocean acidification isn't serious
    michael sweet #41 "stop speculating about processes you do not understand" Thanks for answering my question. In reading 41, 42, 43, and 44 it becomes clear that the problem is not simple.
  38. An Even Cloudier Outlook for Low Climate Sensitivity
    HR the coefficient of determination need not be high; if the dependent variable depends on many factors you won't get a high r^2 anyways. As Dessler says "This does not mean that ΔTs exerts no control on ΔRcloud, but rather that the influence is hard to quantify because of the influence of other factors". Having said this, I'm sure no one is "satisfied" with a non statistically significant result, but what a scientist must do is to obtain as much informations as possible from the available data. Dessler conclude that the feedback is probably positive, a large negative feedback is very unlikely and that models do a decent job. This can be said even with a low r^2.
  39. An Even Cloudier Outlook for Low Climate Sensitivity
    HR, "when things start dropping below this we're worrying about reproducibility. r^2 of 2%, and being satisfied with that, are beyond my comprehension." Dessler is clearly not "satisfied with that" as you claim, please read the quote again carefully. The climate system is obviously not the controlled lab setting with which you are familiar. Although, I agree that 2% is extremely low, even for 120 data points, and even in the realm of feedbacks when r^2 tend to be relatively low. Then again, one doesn't need to change cloud cover much to have a marked impact on the energy budget of the climate system. And remember, that low r^2 applies to anyone working on this problem (including Spencer) and trying to extract a signal from noise in the system.
  40. An Even Cloudier Outlook for Low Climate Sensitivity
    I obviously need to get some sleep. Murphy and Forster (2010) was written to address problems with Spencer and Braswell (2008), not Spencer and Braswell (2010). Sorry. With that said, it looks like Spencer and Braswell (2010) used the same, or similar, simple model used in Spencer and Braswell (2008).
  41. An Even Cloudier Outlook for Low Climate Sensitivity
    Oops, sorry, hit return too soon. You also say that "The difference is that the MERRA AGCM assimilates the GEOS satellite data so the model numbers match reality" Both ECMWF-interim and MERRA assimilate satellite data, which includes data from the GOES sounders, and other satellite platforms. Above I said "GOES-5", which should have been "GEOS-5"-- they are even confusing me with their acronyms. For what it is worth, ECMWF-interim is considered to be the Rolls-Royce of all the reanalysis products (e.g., NCEP, NCEP-DOE, JMA etc.), although it would be nice if they could match the 0.5 degree grid spacing used in MERRA. I'm surprised that it does into bother you that Spencer and Braswell used a much, much more simplistic model in their recent paper on feedbacks in JGR. In fact, it did bother Murphy and Forster, so much so that they wrote a paper, Murphy and Forster (2010) back in September 2010, in which they summarize some serious problems and consequences related to Spencer and Braswell using that simple model. Murphy and Forster conclude: "This paper shows that Spencer and Braswell overestimated the difference. Differences between the regression slope and the true feedback parameter are significantly reduced when 1) a more realistic value for the ocean mixed layer depth is used, 2) a corrected standard deviation of outgoing radiation is used, and 3) the model temperature variability is computed over the same time interval as the observations. When all three changes are made, the difference between the slope and feedback parameter is less than one-tenth of that estimated by Spencer and Braswell." The outlook for those trying to argue for a marked negative cloud feedback gets cloudier and cloudier.
  42. An Even Cloudier Outlook for Low Climate Sensitivity
    79 NewYorkJ If that's all it takes to get published in JGR then I guess we should all have a go. "I think clouds cause ENSO" Can you quote from Spencer's paper where he makes or infers this? (it's linked in the article) In fact he states the following as the drive behind the paper. "The central issue we will examine is that satellite measurements of variations in radiative flux contain a mixture of forcing and feedback and the presence of one will affect the identification and estimation of the other. Our specific interest is a better understanding of the impact that unknown levels of time‐varying radiative forcing have on feedback diagnosis and what that might mean for the estimation of climate sensitivity." Maybe we could also discuss what Spencer is trying to do here rather than what you (or Dessler) think he is doing. From the Spencer paper I couldn't actually see any estimate of short term feedback.
  43. An Even Cloudier Outlook for Low Climate Sensitivity
    78 Albatross Thanks, part of the problem is this is a Science article which means much of the detail is omitted, not even any SI. r^2 = 2%. I work primarily with well controlled laboratory experiments. r^2 is generally well over 90%, when things start dropping below this we're worrying about reproducibility. r^2 of 2%, and being satisfied with that, are beyond my comprehension. I know why it's happening, this is a complex, uncontrolled experiment, I just don't understand what that does to the certainty behind the result.
  44. Human CO2 is a tiny % of CO2 emissions
    Questions about Fig 7.3 IPCC AR4. I find it necessary , in order to think about climate relevant properties or quantities, to know the time span and area to which they relate. As regards the 338 GT down arrow and the 333 GT up arrow on Fig.7.3: 1. What is the relevant surface area? If it is a whole earth average, it seems to me, the only meaningful arrow is a net downward 5 GT arrow. Furthermore if the time is for one year, how do I reconcile several hundred GT changes in the atmosphere with the ca. 5 GT annual change of the Keeling curve? In short, what is the meaning of the up and down arrowa and how were the quantities determined? If this is simply a way of saying that the CO2 in the ocean goes into and out of the aqueous phase then it is misleading because that is true for any solution-vapor coexistence and is irrelevant to the net changes in the quantity of significane in climate change, namely the amount of CO2 in the vapor. Fritz
  45. An Even Cloudier Outlook for Low Climate Sensitivity
    Eric @80, Not to be a pain, but you originally referred to the the "top chart in the post". That figure is Fig. 2 in Dessler (2010), and the figure caption makes no mention of MERRA: "Fig. 2. (A) Scatter plot of monthly average values of DRcloud versus DTs using CERES and ECMWF interim data. (B) Scatter plot of monthly averages of the same quantities from 100 years of a control run of the ECHAM/MPIOM model. In all plots, the solid line is a linear least-squares fit and the dotted lines are the 2sigma confidence interval of the fit." The model at the heart of the ECMWF interim, is IIRC, a similar version of their operational global NWP model. So I do not know why you are focusing on MERRA and the AGCM used in the GOES-5 data assimilation system.
  46. Ocean acidification isn't serious
    Ah, I see your problem. The simple (probably non-informative answer) answer is that the ocean is heterogeneous. Depending on where you are it can be a source or a sink for CO2. What increasing atmospheric CO2 concentration has done is to shift that balance uniformly toward the sink side of things. Still, there are large areas where upwelling of deep, CO2 rich water and limited phytplankton growth (often due to relatively low Fe availability) results in surface waters that are supersaturated with CO2. This is particularly true in the Eastern Equatorial Pacific because the cold CO2-rich waters warm significantly after reaching the surface, making them even more supersaturated. It's the largest natural source of CO2 on the planet. In the Southern Ocean things are more complicated because the deep water upwells vigorously there and can be subducted beneathe warmer, light water after moving northward, or can sink to great depths if it gets particularly cold and salty after moving south. I need to read the paper when I have time, but the quote you cite seems to have something to do with the fact that under positive SAM and steady state CO2 conditions, vigorous upwelling brings CO2 rich water continually to the surface where it can lead to net evasion of CO2 on the whole. However, in some places there may net uptake of CO2, or net evasion depending on initial CO2, the evolution of water temperature and mixing with surrounding waters. Under higher atmospheric CO2 levels, though, the net flux would be into the ocean across the Southern Ocean because, while the atmopsheric concentration is changing, the concentration in the upwelled water stays constant because it reflects past atmospheric conditions 200-1000 years ago. If that difference is high enough, then the same vigorous upwelling during SAM could actually enhance net storage of CO2 by continuously bringing new undersaturated water to the surface across the entire region where it can soak up CO2 and then sink to depth again.
  47. A new resource - high rez climate graphics
    mbayer - John mentioned he prepares the graphs in Excel. I don't think Excel does SVG, though I believe there are add-on programs that will do it for you (SVGmaker comes up on a Google search, though I haven't looked any further than that).
  48. Stratospheric Cooling and Tropospheric Warming
    mars @241, whether the 2nd effect is over ridden by other factors is a complex issue, involving, as I see it, four factors. 1) With the addition of extra CO2, the amount of CO2 leaving the troposphere is reduced by two effects. First, because of increased optical thickness, the average altitude of emmission increases and hence becomes cooler. On an emmission spectrum, this means the trough around 15 microns (due to CO2) will be deeper. Second, because of a variety of factors, that emmission/absorption band will also be broader, as shown in figure 2 in the revised article. Both effects reduce the amount of energy escaping the atmosphere around 15 microns, requiring more to escape at other wavelengths to maintain equilibrium, which in turn requires the Earth's surface to heat. However, the emmission/absorption band of CO2 in the stratosphere is much narrower than that in the troposphere due to its low partial pressure. The stratospheric emmission band can be seen as the small spike at the center of the tropospheric emmission/absorption band in the graph below. Because the stratospheric emmission/absorption band is so narrow, broadening of the tropospheric band has no (or almost no) effect on amount of IR energy absorbed by CO2 in the stratosphere. Therefore, Bob's seoond mechanism is entirely a function of the first effect (increased altitude of emmission), and how strong it is depends on the relative strengths of the two effects I have just described. Unfortunately, I cannot tell you what the relative strength is. The first factor describes completely the initial responce to the addition CO2 to the atmosphere. However, after that addition, the atmosphere adjusts bringing in factors that act as negative feedbacks to Bob's second mechanism. Consequently, Bob'second mechanism will undoubtedly cool the stratosphere initialy, but may not do so in the final state. Indeed, it is possible it will slightly warm the stratosphere in the steady state. Dealing with these feedbacks, we come to: 2) As the atmosphere responds to the greenhouse effect, the surface warms, and with it all altitudes above it in the troposphere. This increases the temperature at the effective altitude of emmission, reducing the effect of Bob's second mechanism. 3) Further, warming the atmosphere drives a water vapour feedback. The enhanced greenhous effect due to the water vapour feedback will also increase the temperature at the effective altitude of emmission, again reducing the effect of Bob's second mechanism. 4) Finally, as you mention, the lapse rate feedback (the reduction of the lapse rate due to the presence of additional water vapour) will also reduce the temperature at the effective altitude of emmission. How these factors play out is beyond my means to calculate. If only factors 2 and 4 were involved, then I could confidently state that they do not eliminate the second mechanism in the steady state, for if they did so, net radiation from around the 15 micron band would not have reduced, meaning there was no increase in the greenhouse effect. However, because of the broadening of the band (factor 1) it is possible that factors 2, 3, and 4 could result in a net increase in temperature at the altitude of effective emmission while still reducing outgoing IR radiation because of line broadening. This is one reason I would like to see comments by someone who was genuinely expert on this topic (eg, Gavin Schmidt). Finally, there is at least one positive feedback on both mechanisms. Specifically, as tropospheric temperatures increase, a greater proportion of CO2 will be found at a higher altitude, thereby increasing optical thickness. I suspect it is a miner effect compared to the others mentioned.
  49. How to explain Milankovitch cycles to a hostile Congressman in 30 seconds
    Finally, Ben Santer did beat the crap out of Pat Michaels. Very great video :-)
  50. Ocean acidification isn't serious
    #42: "outgassing from a warmer ocean affects atmospheric CO2 concentrations significantly" I'm not referring to RSVP's mathiness. Papers are practically screaming that the oceans are sucking up CO2 to what will become dangerous levels (at least to plankton) in not very many years. From McNeil and Matear 2008, Southern Ocean acidification via anthropogenic CO2 uptake is expected to be detrimental to multiple calcifying plankton species by lowering the concentration of carbonate ion (CO3-2) to levels where calcium carbonate (both aragonite and calcite) shells begin to dissolve. ... Southern Ocean wintertime aragonite undersaturation is projected to occur by the year 2030 and no later than 2038. On the other hand, the language of outgassing is very complicated, as in Lovenduski et al 2006: In contrast, there is a simultaneous anomalous uptake of anthropogenic CO2 during a positive phase of the SAM in the southernmost regions of the Southern Ocean, due to increased upwelling of deep, older waters and their subsequent exposure to higher atmospheric CO2 levels. The anthropogenic uptake only slightly mitigates the natural outgassing from the Southern Ocean, so that a positive SAM is associated with anomalous outgassing of contemporary CO2. In a future characterized by higher atmospheric CO2, however, positive phases of the SAM may be associated with a greater oceanic uptake of anthropogenic CO2. And they say clouds are complicated beasts?

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