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Comments 130351 to 130400:

130351. Mizimi at 01:34 AM on 20 January 2009
        It's not bad
        Millions of years ago, climate conditions were such that plant life grew rapidly on a global scale. CO2 and WV levels were high enough to sustain this growth and during this period much of the FF's we now burn were laid down. Plant life sequestered CO2 and locked it up as FF, thereby reducing the CO2 levels, although at times, 'natural' events such as vulcanic erutions/forest fires would have temporarily offset this sequestration. The end result is that CO2 levels hit (possibly) an all time low of around 200ppm and stayed there. As this level is close to the minimum C3 plants can tolerate, further growth and investment of new habitat were resticted. At this time, only C3 plants existed (fossil records of C4 plants indicate their emergence around 8mya) and C3 plants, in order to prosper, require CO2 levels higher than 200ppm. If the levels fall below this figure, then growth effectively halts as does sequestration. One can argue that the emergence of C4 plants was 'caused' by persistent low levels of CO2 - an adaptation of metabolic process to environmental pressures - and since they are more efficient in their use of CO2,(they had to be) they began to colonise and modify habitats where C3 plants could no longer compete effectively. C4 plants are grasses, and include the cereals. The rise of civilisation was made possible only because of these plants and man's ability to husband them, so we actually owe our existence to low levels of atmospheric CO2. Current concern is directed at enhanced CO2 levels through burning FF's, and the (modelled) effects this may have on climate, and the consequent impact on man's habitat. The current level of around 380ppm, whilst nearly double that during the period C3 plants were dominant, is still towards the lower level of tolerance for them. It can therefore be argued that further increases of CO2 will be beneficial to this class of plants and not detrimental to C4's until levels exceed 1000ppm; in other words, our CO2 emissions are helping C3 plants, and quite possibly helping (in some small way) to offset the losses incurred by de-forestation. Yes, they may be disadvantages to mankind and his preferred lifestyle/habitat from CO2 enhancement, but there are benefits to the biosphere at large.
130352. Patrick 027 at 16:18 PM on 19 January 2009
        Arctic sea ice melt - natural or man-made?
        In a quasigeostrophic approximation: In isobaric coordinates x,y,p: Following the air as it moves: As mentioned in comment 411, the change in vertical wind shear driven by momentum (wind) advection by geostrophic wind shear (Let's call this 'momentum forcing' - MF, in this context) is the opposite of the change in geostrophic wind shear driven by the Laplacian in the horizontal (sum of second derivatives in horizontal dimensions - aka 'curvature') of the temperature change driven by temperature advection (let's call this the 'thermal forcing' - TF, in this context). Both TF and MF make equal contributions to ageostrophic vertical wind shear: MF by changing the wind shear, and TF by changing the geostrophic wind shear in the opposite direction. The relative vorticity (RV) is the vertical component of the curl of the wind velocity vector, equal to the Laplacian of the streamfunction in the horizontal plane (horizontal being along an isobaric surface in x,y,p coordinates). And so the same is true for the variation of RV over height (over p in isobaric coordinates): Both MF and TF create equal ageostrophic vertical RV variation - MF by channging the vertical RV variation, and TF by changing the geostrophic vertical RV variation in the opposite direction. BUT One can add to MF the effects of advection of planetary vorticity - north/south winds in the presence of nonzero beta, and frictional/viscous torques. One can add to TF diabatic heating. Thus, the total MF is from the vertical variation (vertical derivative) of the sum of: the advection of RV, the advection of f, and the curl of viscous acceleration. And the total TF is from the Laplacian of the sum of: the temperature advection and the diabatic heating. For quasigeostrophic balance, vertical derivative of RV = -G/f * Laplacian of q where G = R/p * T/q where R is the gas constant for air, And for a given p, T/q = (p/p1000)^(R/cp) where p1000 = 1000 mb (a reference pressure level) and cp is the specific heat of air at constant pressure For the purposes of a simple scale analysis, this relationship can be written roughly in terms of a height scale H (Hp, in pressure coordinates), and length scale L, as RV/Hp ~ G/f * q/L^2 where the negative sign was dropped by assuming Hp is measured upwards (the direction of decreasing pressure). (~ can be read: "scales as" and/or "is of the same scale as") The change in vertical variation of geostrophic RV due to advection of q (proportional to the advection of T as a function of pressure: q = T*(p1000/p)^(R/cp)) is opposite the change in vertical variation of RV due to RV advection - this can be written advected RV /Hp ~ - G/f * advected q /L^2 ... Assume H = Hp for the rest of this comment: ... Well, without dragging everyone through the algebra, this implies (with conservation of IPV, where IPV/g = AV*S, S being del(q)/del(p) and AV = RV + f), where total (RV advection + f advection + curl of viscous acceleration)/H = W * RV advection/H Thus total MF = W * MF from vertical variation of RV advection and similarly, total TF = Q * TF from Laplacian of q or T advection: --- The balance equation and relationship between MF and TF can be solved for vertical motion: in terms of q advection, qad: vertical motion ~ (Q+W)*G/f * H^2/L^2 *qad } / [ G/f * H^2/L^2 * S + AV ] and in terms of RV advection, RVad: vertical motion ~ -{ (Q+W)*RVad*H } / [ G/f * H^2/L^2 * S + AV ] Vertical variation of vertical motion in pressure coordinates, in a hydrostatic approximation, requires horizontal convergence and divergence. This is the secondary adiabatic ageostrophic circulation. The Laplacian of vertical motion changes the Laplacian of q by moving q surfaces relative to p surfaces (adiabatic cooling and warming). The horizontal convergence and divergence changes AV (and thus changes RV, since, after a 'time step'**, f doesn't change because at an instant the air doesn't move and f is fixed at a given location) while conserving IPV; vertical stretching reduces S. This secondary adiabatic ageostrophic circulation (SAAC) brings the actual RV closer to geostrophic RV, both by (at least when assuming both W and Q are positive) reducing the RV changes forced by MF and reducing the q changes forced by TF. Notice that if W and Q are of the same sign, MF and TF cause SAAC of the same direction. If both changes in RV and q are reduced, it is possible for the net changes to be zero. But one effect could be said to 'win' if it is not zero. Substituting the vertical motion back into the balance equation: FOR Ross = G * H^2/L^2 * S/(AV*f) : balanced change in RV ~ RVad * [ W - (Q+W) / ( Ross + 1 ) ] balanced change in q ~ qad * [Q - (Q+W) / ( 1 + 1/Ross ) ] AND balanced change in IPV/g (where S is a basic state value) ~ RVad * S * ( W - Q / Ross ) Thus, for positive W and Q, the effect of RVad 'wins out' over qad in both balanced RVad, qad, and IPV changes, when Ross >~ Q/W whereas qad wins when Ross <~ Q/W Of course W and/or Q could be negative as well, in which cases ... - etc. It might seem odd that the change in IPV is determined by the spatial scales of MF and TF, but the IPV advection can be calculated from the TF and MF effects without SAAC, and it is the same, which is not surprising since the conservation of IPV during SAAC was used in the algebra (IPV may not be conserved during MF and TF because of viscous and diabatic contributions). And MF and TF forced IPV changes are affected by H and L because: forced change in S by TF ~ Q*qad / Hp and of course, forced change in RV by MF ~ W*RVad ~ - Hp * W * G/f * qad /L^2 NOTICE, Ross = G * Hp^2/L^2 * S/(AV*f) Thus sqrt(Ross) = Hp/L * sqrt[(G*S)/(AV*f)] If Ross = 1, L is proportional to the internal Rossby radius of deformation for a given Hp.
130353. Patrick 027 at 14:52 PM on 19 January 2009
        Volcanoes emit more CO2 than humans
        It also occurs to me that Spencer's analysis could be capturing some aspect of the annual cycle.
130354. Patrick 027 at 12:11 PM on 19 January 2009
        Volcanoes emit more CO2 than humans
        3 and 4 in last comment - What I mean - Spencer refers to striations and spirals. Are those spirals predominantly clockwise or counterclockwise? (And does it vary by the size of the spiral? Etc...) It may be that the method for figuring out climate sensitivity that Spencer is criticizing is actually not a very good method, for perhaps some of the same reasons that Spencer's own method seems lacking. But this is just one piece of the puzzle (which might have been helpful but unnecessary? - There is a lot of other evidence out there). For example, Spencer mentions use of this method on climate models. But the most clear cut way to evaluate climate model sensitivity is to have multiple runs in response to various forcings and compare. ------------ "The curve was rejected and is now accepted by the consensus" Could you show me where it is accepted?
130355. ANTILiberal at 11:54 AM on 19 January 2009
        We're heading into an ice age
        I heard about this on the radio last month, and this would prove that we are not the cause of climate change, and that industrialization is not harmful. Unfortunately, many people are still advocating global warming since they have their money on it. This seems to be the strategy for defense of these advocates: "if any part of the earth gets warmer during the industrialized age, industrialization is to blame. If the earth gets cooler, of course, industrialization is a bad thing anyway. Heads, I win. Tails, you lose!
130356. Patrick 027 at 11:45 AM on 19 January 2009
        Volcanoes emit more CO2 than humans
        The problems I saw in Spencer's approach: 1. he was looking at climate sensitivity based on Temperature and radiative fluxes (top of atmosphere (TOA)) over rather short time periods. This is not an equilibrium climate sensitivity at all. (PS if a period of 5 years is sufficient, then why isn't 40 or 100 years of warming sufficient?) 2. conceivably there could be some net global cloud feedback, as well as the ice-albedo and and water vapor feedbacks and others, to forcing of climate from CO2, etc. Over short time periods (this is part of concern 1, actually), any water vapor feedback and other feedbacks, etc., would be limited by thermal inertia of the oceans. In addition, CO2 would generally only be a feedback over longer time periods. What is the cloud feedback to cloud forcing? 'Internal Radiative Forcing' is a feedback to some other internal effect, and will react to itself... 3. If one of the graphs could be shown in enough detail, one might judge to what extent temperature fluctuations are driving radiative fluctuations and vice-versa - obviously both happen - they must, that's the physics. 4. On that note, there can be some correlation, perhaps with some lag in time or not, between cloud radiative feedback and temperature, or temperature changes, that is not entirely due to a direct forcing of temperature by clouds OR a direct forcing of clouds by temperature. The short term variability may involve fluctuations in cloud type, amount, and distribution, and in temperature and wind, etc, that are of a different nature than that of longer term changes. 5. Spencer's description of how the IPCC, etc, estimate sensitivity is not descriptive enough for me to judge what it means. ------- FROM http://www.drroyspencer.com/research-articles/satellite-and-climate-model-evidence/ "And it appears that the reason why most climate models are instead VERY sensitive is due to the illusion of a sensitive climate system that can arise when one is not careful about the physical interpretation of how clouds operate in terms of cause and effect (forcing and feedback)." This seems to set aside any work that goes into trying to realistically model clouds based on observations of clouds and weather on smaller spatial scales (relative to global) - I think 'they' do that. " The allure of models is strong: they are clean, with well-defined equations and mathematical precision. Observations of the real climate system are dirty, incomplete, and prone to measurement error. " Well, I guess we should trust the models, then, eh Spencer? :) (I just found that particular passage to be very ironic, and not just within the context of this paper.)
130357. Steve L at 07:38 AM on 19 January 2009
        Latest satellite data on Greenland mass change
        Oh dear, I missed that Mizimi was writing about Iceland and not Greenland. Mizimi, please answer Ian's questions about where you're getting your info. Looks unreliable!
130358. Quietman at 07:19 AM on 19 January 2009
        Volcanoes emit more CO2 than humans
        Sorry, I missed something that you said. The Fairbridge curve and the Solar Jerk are two different hypotheses. The curve was rejected and is now accepted by the consensus while the solar jerk still has not been accepted. They are unrelated subjects.
130359. Patrick 027 at 09:59 AM on 18 January 2009
        Arctic sea ice melt - natural or man-made?
        CORRECTION to 408: third paragraph (the one that starts: "In contrast, for the eddy thermal fluxes that would cause a decrease in the geostrophic u," ) ... "The adiabatic MMC caused by this is in the same direction as that described by the previous paragraph." The exact opposite is true. The same point was made and implied correctly in other parts of comment 408. BUT often, the two MMCs are in the same direction, with the u'v' and v'T' effects making opposite contributions to the net change in IPV and balanced wind distributions. In particular, the vertical variation in RV advection and the horizontal curvature (Laplacian) of temperature advection (following the motion of the air) tend to have opposite effects, when advection is mainly by geostrophic winds, as described previously (comments 319 - 323). Whether the RV advection or the temperature (T) advection dominates in the IPV tendency depends on length and height scales, stability, AV and f, some other things - in a relation that is very similary to the relationships in the formula for the Rossby radius of deformation. More on that later... PS the example of an SSW in Holton, p.416, (estimated from a graph) shows (in terms of zonal averages) a warming of the polar stratosphere at the 50 mb level (PS sea level pressure averages ~ 1013 mb; 1 mb = 100 Pa = 100 Newtons/square meter), most of it in about 5 days, greater than 10 K (10 deg C, 18 deg F) north of ~ 65 deg latitude, greater than 30 K at ~ 80 deg latitude; with a reduction in the zonal wind of over 10 m/s north of ~55 deg latitude, becoming easterly north of ~61 or 62 deg latitude. Holton p.415: the warmings can be as much as 40 K. An SSW involves distortion and breakdown of the westerly circumpolar vortex in the stratosphere. Enhanced planetary (Rossby) wave propagation from the troposphere, of mainly zonal wavenumbers 1 and 2 (when a wavenumber is given without units, in this context it refers to the number of wavelengths that fit around a circle of latitude; zonal wavenumbers 1 and 2 are the longest of zonal wavelengths) is "essential" (Holton p.415) to produce an SSW.
130360. Quietman at 08:47 AM on 18 January 2009
        Volcanoes emit more CO2 than humans
        ps This is spencers site. Articles and links to peer reviewed papers. http://www.drroyspencer.com/
130361. Quietman at 08:46 AM on 18 January 2009
        Christmas cartoon on melting North Pole
        Sorry, Are we in another La Nina now?
130362. Quietman at 07:11 AM on 18 January 2009
        Volcanoes emit more CO2 than humans
        Spencers argument is specifically about sensitivity to CO2. Look under Arguments, the Pacific Decadal Oscillation (at this site). I posted a link to a draft he did that they have refused to publish. I would prefer to be wrong about all this as I much prefer a warmer world but I fear that Spencer may be right. I am sure that Fairbridge was as the last two winters have been showing. The test is 2007 through 2011. Halfway there.
130363. Quietman at 07:00 AM on 18 January 2009
        Christmas cartoon on melting North Pole
        John and Phillipe In all honesty, I sincerely hope that I am wrong and that you are correct. I have lived in temps up to 140F and down to -60F and believe me I prefer heat to cold. But I simply can't believe all that science pointing to another glacation is wrong and that we are attempting to encourage it's start. La Nina is not affecting this winter and that article was posted yesterday. I have not personally experienced any warming since the Plains Blizzard of 1996. 1998 was a freak rewarming due to El Nino. The warming trend was just a weather cycle IMO, the true trend is cooling, hopefully slight.
130364. Patrick 027 at 12:17 PM on 17 January 2009
        Volcanoes emit more CO2 than humans
        In that work of Spencer we've discussed, his argument was not abotu CO2 forcing but about climate sensitivity. There is no flaw in the fundamental sense. There is uncertainty. Spencer's argument seemed ill-concieved to me - the logic isn't quite there.
130365. Patrick 027 at 12:10 PM on 17 January 2009
        Volcanoes emit more CO2 than humans
        "the average length of an interglacial BTW" Average, perhaps. Not all. Once every few interglacials, one is longer - although this is too long of a pattern to have been repeated much in the last several hundred thousand years, but there was at least one extra-long interglacial. Based on astronomical forcings, this interglacial could be one of the extra-long ones, perhaps lasting another 20,000, 30,000, or 50,000 years, even without AGW. "t won't cause a rise in sealevel because it is expanded (frozen) water that is also displacing sea water at present. " Yes, of course. Yet, the sea level is rising; Greenland is losing land-based ice (potential point of confusion: the base of the ice is below sea level in many parts, and in Antarctica too (West Antarctica in particular), but the height of the surface of the ice is such that most of the weight of the ice is not supported by the water - it will raise sea level when it melts). Antarctica may also be losing ice in total even though some parts may be gaining ice mass. "Sea level rise is within the Fairbridge curve; ie. normal or "expected"." But if it is expected, what is the expectation based on? (Fairbridge's argument about Solar jerk was based on cycles dominated by Jupiter and Saturn, but the actual forces (tides on the sun) would be dominated by Jupiter and Venus, then Earth and Mercury, before any other gas giants - and I showed earlier these would be exceedingly exceedingly small effects.) I'm really not at all convinced that the Fairbridge curve was/is based on a solid body of evidence. "I like the way you calculate out the CO2 forcing" Thank you - but actually, I only explained how it is calculated, and the physical principles on which it is based, which are as sound as the inverse square law. "but I still agree with Spencer." Spencer doesn't really make a durable point, though.
130366. Patrick 027 at 11:50 AM on 17 January 2009
        Volcanoes emit more CO2 than humans
        Regarding the P/T extinction: The concept as I understood it: There was a long ice-house period (with some significant ice, sometimes more (ice ages)) in the late Paleozoic. I've not been clear just when that ended, whether that was part of the P/T extinction or not. If it had ended but only just recently, that might have left species more vulnerable to any further warming. It was a time of continental collision - the formation of Pangea. One version: So then this Siberian trap flood volcanism starts up and persists for ~ a million years (more?), pumping CO2 into the air at a faster than typical rate. (Aerosols too, but those don't accumulate.) Eventually there is a lot more CO2. The Earth warms - maybe 5 degrees C - some extinctions occur (more on land??) The warmth causes CH4 release from the oceans. Sudden burst of warming. A total of 10 deg C more than before the flood volcanism? More extinctions. Oxygen doesn't dissolve as well in the oceans because of higher temperatures. Anaerobic bacteria that produce H2S become more commonplace. H2S in oceans, maybe some in the air. More extinctions.
130367. Philippe Chantreau at 10:40 AM on 17 January 2009
        Christmas cartoon on melting North Pole
        People have become so used to not have a winter that they're surprised when there is one.
130368. Philippe Chantreau at 10:39 AM on 17 January 2009
        Christmas cartoon on melting North Pole
        There is no such thing as weather anymore?
130369. Quietman at 09:46 AM on 17 January 2009
        A Great Science Fiction Writer Passes - Goodbye Dr. Crichton
        An interesting piece with a little insight: Scion of Frankenstein Michael Crichton, novelist and policy provocateur Ronald Bailey | February 2009 http://www.reason.com/news/show/130852.html
130370. Quietman at 09:36 AM on 17 January 2009
        Christmas cartoon on melting North Pole
        1-16-2009, MSNBC News: By Friday morning, cities and towns in 13 states reported temperatures well below zero, among them: -50 in Big Black River, Maine, in what could be a new state record -46 in Embarrass, Minn. -42 in Island Pont, Vt. -42 in Necedah, Wis. -39 in Berlin, N.H. -38 in Monticello, Iowa -36 in Sterling, Ill., possibly tying a state record -35 in Paradox, N.Y. -26 in Stambaugh, Mich. -20 in Valparaiso, Ind. -19 in Lawton, Pa. -16 in Snowshoe Mountain, W.Va. -14 in Dayton, Ohio In upstate New York, meteorologist Dave Sage said areas near Lake Erie were walloped by snow, with 2 inches falling per hour in some areas on Friday morning. As Ricky would say - Splain This Lucy
        Response: The question of specific instances of cold weather is answered here. More generally, recent cooling across 2008 was due to the cooling effect of La Nina and to a lesser extent, the solar minimum.
130371. Quietman at 07:17 AM on 17 January 2009
        Volcanoes emit more CO2 than humans
        Sea level rise is within the Fairbridge curve; ie. normal or "expected". The Arctic is the obvious problem which is why I did not mention it. But outside of Greenland it won't cause a rise in sealevel because it is expanded (frozen) water that is also displacing sea water at present. Add to that the increased sea and glacial ice in Antarctica despite the small area near S.A. and there is no reason for additional sea level rise. The planet went through a brief warm spell, a large part caused by ocean cycles but some was abnormal. The anomally clearly shows which areas and they are decidely not global. I like the way you calculate out the CO2 forcing but I still agree with Spencer. There is a fundamental flaw somewhere. Be the one to find it.
130372. Patrick 027 at 06:37 AM on 17 January 2009
        Volcanoes emit more CO2 than humans
        Here's the thing(s) about that: " Eastern Canada and the N.E. U,S, are not the only places on earth that have cooled while population centers warmed and it is from population centers that most data comes from. Why was this cooling ignored? " No, not really. The Arctic has warmed, the oceans have warmed (Aside from other data, sea level has been rising - that has to be mainly a combination of melting or temperature inceases - melting involves some of the heating occuring without temperature changes, of course). "South America, Antarctica and Africa have not experienced the same changes as Europe and PARTS of Asia. " ... " South Atlantic and Antarctic deep water is notably getting colder." The point being, you have to put all those together. It's still global warming, in the sense that there is more heat coming in then going back into space. "Glaciers in sunny california are GROWING because of the extra moisture off the Pacific." And why is that happening? "All of this climate change can easily be explained without super powerful CO2 forcing that historically does not seem to very powerful at all." It could be explained without CO2, but with strain and guessing. Much or most can be explained very very very very very very very very easily with a net forcing that is the sum of contributions from the changes in CO2, somewhat smaller from the rest of GHGs, a sizable likely negative aerosol contribution, rather small contributions from episodic volcanoes and solar radiation, and also, some other effects of ozone depletion (that doesn't explain the general global warming, etc, but it has effects). Etc.
130373. Philippe Chantreau at 16:07 PM on 16 January 2009
        Arctic sea ice melt - natural or man-made?
        You need to stop insinuating that the cites are some ploy to try to convince people of something or some way to establish a "consensus." It is a tool that researchers can use to access more information. Accessorily, it helps to determine the relevance and usefulness of a paper. The example I gave in post #394 is about diabetes and genetic, no suspicious consensus problem in this now, is there? You've spent too much time reading conspiracy BS on so-called skeptic sites,IMO.
130374. Quietman at 09:09 AM on 16 January 2009
        Arctic sea ice melt - natural or man-made?
        Phillippe Actually I do spend a lot of time at both PLos Biology and PLos ONE. Granted I am only lookong at Paleontology and Evolution related papers. I check the references but I have never noticed a "number cited" but you may be right, I may have overlooked it as I don't consider consensus important. I look to see WHO is referenced as there are authors I trust and others I do not.
130375. Quietman at 08:49 AM on 16 January 2009
        Volcanoes emit more CO2 than humans
        Also you might want to read Peter Ward's work on the PT extinction (not the media coverage that assume CO2). While Ward does not recognize the importance of the Antarctic impact, he does cite the Siberian Traps that it created as releasing METHANE and poisionous gas. While the gas may have caused a GH condition, the GHG did not cause the extinction event, which (as he points out in Gorgon and elsewhere) was a two stage extinction. First the oceans died (90% of all ocean species) and was followed by land species (70%). What most forget when reading about the PT extinction is that the Pennsylvanian-Permian Ice Age had just closed and the planet had warmed (naturally) prior to the extinction event, just like right now after 12000 years of interglacial (the average length of an interglacial BTW).
130376. Quietman at 08:38 AM on 16 January 2009
        Volcanoes emit more CO2 than humans
        ps Glaciers in sunny california are GROWING because of the extra moisture off the Pacific. I have posted links to all of these articles that describe what I have said. All of this climate change can easily be explained without super powerful CO2 forcing that historically does not seem to very powerful at all.
130377. Quietman at 08:35 AM on 16 January 2009
        Volcanoes emit more CO2 than humans
        Patrick You may recall that when we started talking about Bertha we took note that tropical storms had been forming farther east, meaning a change in air currents. Eastern Canada and the N.E. U,S, are not the only places on earth that have cooled while population centers warmed and it is from population centers that most data comes from. Why was this cooling ignored? South America, Antarctica and Africa have not experienced the same changes as Europe and PARTS of Asia. In fact, it has been noted that most warming has been on the western coasts of the Americas and Europe. If you check the ocean threads here you will see that overall the oceans have not warmed but there ate definate warm currents and hot spots. South Atlantic and Antarctic deep water is notably getting colder. Referring to this as "climate change" is quite accurate, but it is by no means "global warming".
130378. Philippe Chantreau at 18:44 PM on 15 January 2009
        Christmas cartoon on melting North Pole
        Sure, he's OK if you carefully pick what years to compare with. NSIDC put things in perspective: http://nsidc.org/arcticseaicenews/ Of course, we're not considering volume here...
130379. Tanuki at 12:45 PM on 15 January 2009
        Water vapor is the most powerful greenhouse gas
        Help please! I have not be able to find the paper disclosing the physics of the carbon dioxide and water interactions. Here I see only references to climate models and empirical studies, I would prefer to see the description of the actual phyical chemistry.
130380. Mizimi at 01:32 AM on 15 January 2009
        Water vapor is the most powerful greenhouse gas
        Chris; the paper is Santer 2007 noted above. And you didn't answer the question....how do climate models incorporate the heat emitted from life which is independant of IR ? Also, as you have previously averred, the WV content of the atmosphere is dependent on P~T, (subject to availability)so when it is removed during photsynthesis it is readily replaced..returning to "equilibrium"; so WV emitted by air breathers adds to the atmospheric content.
130381. Patrick 027 at 15:44 PM on 14 January 2009
        Arctic sea ice melt - natural or man-made?
        EP Flux AND SSWs - TOGETHER AGAIN (FIXED EARLIER PROBLEM - corrections to comments 403-405): If the zonal wind is slowing down in geostrophic balance, this implies decreasing stability (warming below, cooling above) on the poleward side and the opposite on the equatorward side. Deceleration by u'v' flux, taken in isolation, first causes an ageostrophic decrease in u (the zonal wind), which is then acted on by the coriolis effect, causing poleward displacement, which is balanced by adiabatic sinking below and rising above on the poleward side (vertical stretching) and the opposite on the equatorward side, which causes an adiabatic temperature change pattern as described in the last paragraph; it reduces the initial change in u but balances the remainder with a change in the mass distribution. The meridional circulation is the momentum-flux forced adiabatic MMC; the coriolis acceleration of the poleward part of the MMC increases u; thus reducing the initial change in u. A similar MMC (the VMC) would occur in response to a reduction of u forced directly by friction. In contrast, for the eddy thermal fluxes that would cause a decrease in the geostrophic u, taken in isolation, they first cause an increase in the ageostrophic u (by directing the temperature changes in the same direction as described two paragraphs previously). The adiabatic MMC caused by this is in the same direction as that described by the previous paragraph. It reduces the temperature changes but the coriolis acceleration of the equatorward part of the MMC causes a decrease in u to balance the remainder of the temperature changes. ----------- The two MMCs are in the opposite direction. For the mechanism of SSWs, the adiabatic MMC forced by the u'v' flux divergence must be dominant, or else the DMC caused by the temperature changes must be able to act fast enough to have a 'sudden' effect. (The changes in temperature tend to shift radiative fluxes so as to diabatically cool the adiabatically-warmed areas, etc, and the adiabatic circulation which occurs in response to the diabatic processes would cause poleward drift at the level of the EP flux convergence. However, I'd guess this process isn't fast enough for something 'sudden' (how sudden is sudden? - will report back).) THIS is because, while if both u'v' and v'T' make contributions to EP flux convergence, the resulting temperature changes are correct for an SSW, an SSW also involves poleward drift at and around the level of the EP flux convergence. ----------- Seperating the DMC from it's adiabatic MMC response: The diabatic process doesn't by itself cause any vertical motion in x,y,p coordinates. It just moves the isentropes. In x,y,q coordinates, this looks like vertical motion relative to fixed isentropes. The adiabatic MMC response to the diabatic changes reacts by moving the isentropes part-way back (but not all the way back) to their earlier positions, but in so doing requires vertical motion in x,y,p in the same direction as that which occured in the DMC in x,y,q. Vertical stretching and compression in x,y,p change the stability part way, but not all the way, back to the pre-DMC values, while the corresponing horizontal convergence and divergence, while conserving the DMC-generated IPV changes, cause changes in AV and thus RV (tending to be in the same direction as the diabatic IPV change) so as to balance the remaining portion of the pressure, temperature, and stability changes. ----------- A question that may come up - as the EP flux convergence propagates downward in response to changing wave-propagation properties (more later on why that happens), shouldn't the temperature changes that occured below the EP flux convergence reverse themselves as the level of EP flux convergence shifts downward? I don't know - apparently it doesn't, at least not fully. Perhaps it has something to do with changes in pressure and stability with height? -------------- What is the EP flux and what isn't it? I think the adiabatic MMC response to diabatic processes must be included in the DMC, or else it wouldn't make sense to show a DMC (residual MMC) circulation on the graph in Holton (in log-p coordinates - not isentropic coordinates) However, a long term average for a stable climate must assume there is no net movement of isentropes, so the vertical motion of diabatic processes must automatically appear in log-p coordinates, although this includes the adiabatic response AND something else... Holton doesn't explicitly note a VMC but that may just be because it's small. Or maybe it is included by approximation with the DMC just because the DMC was calculated by assuming VMC = 0 (an approximation). All adiabatic MMCs (inluding those in response to diabatic and viscous processes) also produce momentum, temperature, and IPV fluxes directly by advection, but they are, as I understand it, small in comparison to those fluxes in the EP flux and the sources and sinks directly from diabatic and viscous processes. Since additional MMCs would have to react to such processes, it is useful approximation to set them aside (at least for the purposes in Holton Ch. 10). Ealier I described how it would be possible to have (at least over a shorter time period ??) adiabatic zonal average vertical motion without vertical displacement of average q. However, in that case, there would be zero average adiabatic cooling or warming. Just something to keep in mind.
130382. David Horton at 12:32 PM on 14 January 2009
        Climate's changed before
        This The_skeptic_who_came_in_from_the_cold.html is an attempt to answer, for a skeptic (not denialist) friend, his proposition that since climate had changed before there was nothing to either explain or worry about. It is an attempt to distinguish between genuine skepticism and malign, planet-hating, denialism. The comment from tommybar "even if C02 is contributing, which it may have/be, a lot has been shown that it's 'greenhouse' ability is a logarithmic function, and that it has already contributed as much as it can" is interesting because it has suddenly started cropping up, in blogs around the world almost simultaneously. Could it be the latest talking point provided for the denialist anti-environment lobby? Funny how they all sing to the same tune (ice caps on Mars, Antarctic ice growing, planet now cooling) at the same time with each new attempt to stack the card deck, shuffle the pea, while distracting the punters.
130383. Patrick 027 at 12:13 PM on 14 January 2009
        Arctic sea ice melt - natural or man-made?
        "author A cites author B on a point, checking the citation you find B hasn't done the experiment and is instead citing author C. Checking author C you discover that like author B he has not done the experiment but is instead citing another author but this time it is author A from an earlier paper." That could actually make sense many times. If C had some insight about A's earlier work that A and B did not have by themselves, and B did some more work on it or commented about it and made some key point in the process, than it makes sense that A would reference those points in additional work if it applied... Note that additional work is not necessarily an experiment. There's math and logic, analysis, etc, to do, and also, comparing multiple experiments to each other...
130384. Wondering Aloud at 09:20 AM on 14 January 2009
        Arctic sea ice melt - natural or man-made?
        A circular citation is very common, though it depends on the field and the publisher,it works like this author A cites author B on a point, checking the citation you find B hasn't done the experiment and is instead citing author C. Checking author C you discover that like author B he has not done the experiment but is instead citing another author but this time it is author A from an earlier paper. The circles tend to have 3-5 members but I've learned if I don't find the original actual experiment in the first 2 or 3 steps the author is faking. Peer review is only one step in the scientific method, I've seen it work well and I've seen it fail totally. If for instance you have failed to isolate the variable than the fact that the reviewer doesn't notice either is not a great help. I think you were trying to make a different point and I was picking on you for something minor but as you already know I think poor scientific method, especailly drawing conclusions too broad for the data available is a large problem. Unless you want it privately I really don't want to enter into specific examples our legal system is not the same as yours and this is a public forum and I am not really anonymous.
130385. Quietman at 06:45 AM on 14 January 2009
        There is no consensus
        ps I'm not a believer in consensus. The greatest minds in history all went against consensus. It just happens to be the topic of this thread and John wants us to try and stay on topic, hence most of my arguments and links are in the appropriate threads. Just click on "arguments" for the full list.
130386. Quietman at 06:41 AM on 14 January 2009
        There is no consensus
        Yes I do have something better. Tree farming. CO2 is doing as much as a GHG it can right now. But it can do more if we let it. Better management of our forrests will help make the planet more productive. Unfortuantely most states have no green acreas laws. If you wan't to help the environment get your state to pass one. Those states with green acres laws make it a minimum of 2 acres of property per house. Even if they only grow grass it's better than asphalt. This produces O2 and frees up nitrates which combined with CO2 aids in plant growth. One visable truism about past periods of high CO2 concentrations is giganticism. Plants and animals grew much larger than today and covered the entire earth. We don't have much chance of achieving this kind of growth but we could at least increase food production and free up land that is currently incapable of supporting life.
130387. usa1 at 05:00 AM on 14 January 2009
        Christmas cartoon on melting North Pole
        Looks like Santa is OK. http://www.ijis.iarc.uaf.edu/seaice/extent/AMSRE_Sea_Ice_Extent.png Ice coverage is above the levels in 2005, 2006, 2007, and 2008. I wonder if we will hear about this in the media... don't count on it. Now if the levels were low... look out!
        Response: I'll direct you to the page that poses the question Is Arctic ice-melt manmade or a natural cycle?
130388. Tanuki at 04:59 AM on 14 January 2009
        Water vapor is the most powerful greenhouse gas
        Chris: I have difficulty some points you have mentioned. "Water Vapour as a positive feedback" If this were true, then what prevents the water from providing it's own feedback into what is essentially a thermal runaway? As well, it's a well documented fact that carbon dioxide dissolves in rain water, resulting in a typical pH of 6.5. So how can the lifetime of CO2 be so large if it's readily washed out by rain fall?
130389. Risky at 22:12 PM on 13 January 2009
        There is no consensus
        Re: #121 Quietman, where is that well-honed skepticism you keep telling us about? You can be quite dismissive of the IPCC ("Sorry, but my view of anyone who has not left the IPCC by this point is someone that can not think for themselves. Sheep going along for the ride with what they view as "the winning team". Lots of BS and outright lies fudging numbers and skewing results to get funding. "). Yet you uncritically post a link to a story that is no more than the annual reheating of that old chestnut, the Leipzig Declaration. I am sure there are some genuine scientists in climate-related fields are among the additional 250. Some of them might even be climate scientists, with published, peer reviewed science to back their skepticism, but the liberal padding of the numbers with T.V. weather reporters and other interlopers does not inspire confidence. If the skeptics genuinely feel they have a good basis for refuting scientific consensus here, why would they need to pad out the list? Obviously they don't feel their scientists are reputable enough, or the science is strong enough. Your basis for skepticism seems to change depending on the discussion - one minute, a believer in CO2 emissions as the only way to forestall a catastrophic ice age, the next minute dismissive of the very idea of ACC (see above 'BS and outright lies fudging of numbers blah blah blah...'). This is not skepticism, it's advocacy. Any argument to avoid deep cuts to emissions will do - even contradictory ones. Any skeptical scientist will do, even the ones who are not scientists, or not even skeptics. As for the story itself: "In fact, the total number of scientists represented in the report is 12 times the number of U.N. scientists who authored the official IPCC 2007 report." A bit of a nothing statement. Kind of like saying that all of our scientists outnumber some of theirs. The site posted does not list an author, but if you are interested, look up Marc Morano. Quietman, as a genuine skeptic, surely you have something better than that?
130390. Patrick 027 at 14:47 PM on 13 January 2009
        Arctic sea ice melt - natural or man-made?
        "VMC" - actually, Holton identifies the friction itself as a direct forcing of the zonal wind. Which makes some sense, of course. But the result by itself won't be a balanced wind (then again, near the surface, the wind is generally less (subgeostrophic) and directed partly from high to low pressure...
130391. Patrick 027 at 12:28 PM on 13 January 2009
        Arctic sea ice melt - natural or man-made?
        "But that is what happens. So I must have goofed-up something before...(?)***" Well, after "SO, I think this is essentially what's happenning.", I forgot that the EP-flux related zonal wind accelerations were due to the sum of the coriolis effect acting on the adiabatic MMC AND the momentum flux convergence. Still, however, the result should be in geostrophic balance with the IPV rearrangement, so I'm still missing something...
130392. Patrick 027 at 12:21 PM on 13 January 2009
        Arctic sea ice melt - natural or man-made?
        ... Those diabatic effects: relative to isentropes, there will be upward motion where there is heating and downward motion where there is cooling. Where there is heating above cooling, air is being pulled out of isotropic layers - the stability is increasing, tending to produce cyclonic IPV; by itself this leaves an ageostrophic wind shear such that there is a vertical minimum in cyclonic ageostrophic RV; thus there will tend to be a vertical maximum in convergence (or minimum in divergence), increasing cyclonic RV the most at that level and decreasing the stability until the horizontal variation in stability and vertical variation in vorticity are balanced for the new IPV. And so on for the opposite: cooling above heating. Thus the diabatic vertical motion across isentropes drives horizontal motion; diabatic vertical stretching tends to drive horizontal convergence (or a vertical minimum in divergence), etc...(it is because of geostrophic or gradient wind adjustment that this would occur, as opposed to vertical stretching in pressure coordinates, which, in a hydrostatic approximation, requires horizontal convergence because of conservation of mass, regardless of whether horizontal forces are balanced or not.) **PS NOTE THIS PARAGRAPH FOR LATER (REMINDER: 2AGEO1). This diabatic circulation is the residual meridional circulation (Holton, p.323) (For here, RMC for short). The coriolis effect acts on the horizontal part of RMC to produce acceleration in a perpendicular direction (this is part of the geostrophic (or gradient-wind or whatever) adjustment just described, which conserves IPV while bringing horizontal variations in S into geostrophic (or gradient wind) balance with vertical variations in RV). For zonal averages, seen in the y,z* plane, the coriolis effect acts on northward RMC to cause zonal wind acceleration (westerly). This is in addition to zonal wind accelerations caused by EP flux divergence (which is proportional to an IPV flux - which only redistributes IPV that exists: it is an adiabatic process, as I understand it) AND viscous forces (which are strongest near the surface, and can create or destroy IPV - near the surface, this generally tends to bring it toward f*S*g (that is, tending to bring RV toward zero). (PS the RMC is weak enough that one can approximate IPV fluxes without actually including IPV advection from the RMC; but RMC, although diabatically driven, can adiabatically advect IPV as well as be related to the diabatic creating and destruction of IPV). And the Ferrel cell?: The total MMC (mean meridional circulation) is the superposition of the RMC, which is necessarily thermally direct everwhere, with the adiabatic component of the MMC (mean meridional circulation), and a part due to friction (I'll just refer to that as VMC for now). The adiabatic component of the MMC could be divided into two components: one driven by eddy heat fluxes (v'T') and one driven by eddy momentum fluxes (u'v'). The first is thermally direct relative to the horizontal convergence and divergence of eddy heat fluxes (the temperature CHANGES driven by eddies), although it can be thermally indirect relative to the actual temperature distribution (as it typically is in midlatitudes). The second is thermally direct where the vertical variation in the convergence in the momentum flux (WHICH is equal to the vertical variation in the RV flux (v'RV') - see Holton p.320) is in the opposite direction of the geostrophic wind shear; otherwise it is thermally indirect. My understanding is that Both of these, and the sum of the two together, can be seen as the ageostrophi secondary circulation that is necessary to maintain nearly geostrophic balances between pressure gradients, temperature gradients, and horizontal stability variations, AND wind , wind shear, and vertical vorticity variations. So the adiabatic eddy-flux driven portion of the MMC is the process by which the eddy-driven adiabatic rearrangements of zonally-averaged IPV are brought back toward geostrophic balance. **PS NOTE THESE TWO PARAGRAPHS FOR LATER (REMINDER: 2AGEO2). The vertical motion of adiabatic MMC moves WITH isentropes, not across them. (continual transport of isentropes cannot occur indefinitely, of course. If the MMC is taken as averaged motion in the y,z plane, averaged over x along constant y and z* (or z or p), then it is not averaged along isentropes. The vertical part of the adiabatic MMC is the average of all adiabatic vertical motions - **if, on average, downward vertical motions occur where the stability is greater than where upward vertical motion occurs, then the average change in q could be zero while the average adiabatic vertical motion is upward, etc**. Of course, over any given time period, there could be some change in q, and then, diabatic processes could act to cancel the change in some places and times. SO, I think this is essentially what's happenning.: Increasing Rossby wave amplitude at a given position** (not to be confused with amplitude changes following propagation to different places, although the two could happen at the same time and place sometimes) tends to involve an adiabatic flux of IPV that is down gradient. Other waves can also cause IPV fluxes although some will not depend on IPV gradients to exist so much (gravity waves, for example). (PS the analogy for gravity waves is that increasing amplitude at a given location** corresponds to a downgradient flux of q - a vertical maximum in increasing amplitude corresponds to an area-average decrease in S at that level.) ** - well, actually it is at a location that moves with the air...but not too important a distinction, I think, for the following: For zonal averages: Divergence of the EP flux corresponds to a northward IPV flux; the resulting adiabatic rearranging of IPV drives a secondary ageostrophic circulation - in this case, the adiabatic MMC. The coriolis effect acting on the horizontal part of that MMC produces the acceleration of the zonal wind that is 'caused' by the EP flux divergence. The vertical and horizontal parts of the adiabatic MMC together move the temperature and wind fields toward geostrophic balance in response to the changed distribution of IPV. Although there is a way for the vertical part of the adiabatic MMC not to always result in an average change in isentrope positions, the change in IPV distribution may require (I think) some average change in q as well as changing atmospheric winds. The diabatic RMC is air rising across isentropes where there is heating and air sinking across isentropes where there is cooling, and the resulting adiabatic ageostrophic secondary circulation (although actually I'm not sure if the vertical part of that adiabatic circulation is included in the RMC ... it isn't included in the adiabatic MMC, though). The coriolis effect acts on the horizontal part of the RMC to cause a zonal (westerly) acceleration of the wind; this combined with adiabatic vertical motions act to bring the wind and temperature back toward geostrophic balance with the IPV changes caused by diabatic processes. The VMC could be described similarly. For long-term stable atmospheric circulation, for the averages over time, the coriolis accelerations acting on the RMC and VMC must cancel the accelerations 'caused' by the EP flux divergence (the coriolis acceleration of the adiabatic MMC), and the q changes and IPV changes must cancel. The VMC is of course driven by friction ((vertical) mixing of momentum and exchange of momentum with the surface). (I think the VMC is weak compared to the rest of the MMC.) The RMC is driven by radiational heating and cooling and latent heating and cooling (much or most (?) of the later occuring at the surface, and not cooling the air directly). Some of the RMC is determined by variations in atmospheric and surface properties (albedo, opacity, temperature) and the stimulation of latent heating in the presence of moisture (fronts, cyclones, ITCZ, ...). BUT some of the RMC can be driven by the EP flux if/when the EP flux is not balanced by an RMC (or VMC) to begin with... (? I was about to describe sudden stratospheric warmings (SSWs here) but the description doesn't quite make sense given what I just wrote. An SSW can occur when an planetary waves (kind of Rossby wave) propagate up into the stratosphere but slow and stop and some point. EP flux convergence continues to occur there; IPV is moved southward. The westerly wind decelerates. AS I had just described it, the deceleration of the wind is due to the maintenance of near geostrophy by the coriolis effect acting on the adiabatic MMC which is in response to the IPV rearrangement - that MMC would involve rising air below poleward and above equatorward and sinking air below equatorward and above poleward. If that were the case, the following wouldn't happen: The coriolis effect acts on the deceleration, causing poleward drift, and a meridional circulation with sinking below poleward and above equatorward, and rising below equatorward and above poleward. The adiabatic changes in temperature CAUSE diabatic heating and cooling that act to reduce the temperature change - the rising air diabatically heats and the sinking air diabatically cools - the RMC in response to EP-flux (but the diabatic temperature changes, at least in the case of a SSW, do not completely offset the adiabatic temperature changes; the air that sank still has higher T). But that is what happens. So I must have goofed-up something before...(?)*** What happens after that: The changes in the state of the atmosphere around the level of the initial EP flux convergence change the way planetary waves can propagate; they block their upward propagation at a lower level. This causes EP flux convergence at a lower level. And so on - the EP flux convergence, deceleration of westerlies, adiabatic warming of the air on the poleward side only partially reduced by diabatic cooling, etc. - all propagates downward leaving changes in it's wake. There is some connection between this kind of phenomenon and AO/NAM and SAM.)
130393. chris at 10:15 AM on 13 January 2009
        Water vapor is the most powerful greenhouse gas
        All that grade school "numerology" isn't going to get you very far Mizimi. re #48 and "water vapour emitted by air breathers". Remember that every molecule of water vapour returned to the atmosphere by metabolic respiration was a water molecule pulled out of the atmosphere by photosynthesis: nCO2 + nH2O ------> (CHOH)n + nO2 photosynthesis where (CHOH)n is generic carbohydrate (CHOH)n + nO2 ------> nCO2 + nH2O respiration re #49 and atmospheric relative humidity. Remember that the bulk of the atmosphere is much colder than 15 oC and so the water content at 50% relative humidity is far lower rather quickly as one ascends re #47/#49 Which paper are you talking about (mizimi: "just re-read that paper....")? You should really give your sources when you start expounding numbers. You make so many mistakes that it would be helpful if you could simply state where you obtained your numbers/ideas from so that we could assess them ourselves. Otherwise it's hardly worth addressing many of your points since they are based on series of unattributed numbers which very often turn out to be incorrect...
130394. tommybar at 06:50 AM on 13 January 2009
        It's the sun
        I've wasted a lot of my free time over the past year trying to make myself come to a conclusion of all the AGW debate. This argument, that the TSI correlation ended in 1975 doesn't prove CO2 is the driver, or disprove it either. If you look at the ENSO variations since 1975--totally dominated by warmer El Ninio events--there could definitely be a correlation there. So trying to limit the "it's the sun" argument to only TSI is misleading, because that is only one aspect of the sun's relationship with climate. Furthermore, it may be but one forcing--the oceans another, and greenhouse gasses another, and perhaps others as well. Fact is, it doesn't seem that past climate changes are very well understood, so it's fair to be skeptical that trace gasses are the primary reason for this climate change.
130395. Patrick 027 at 06:47 AM on 13 January 2009
        Arctic sea ice melt - natural or man-made?
        MORE EP FLUX: "(at least where RV variations are not significant relative to beta - I think)" Strike that - I think it includes RV variations. I took another look at the math (Holton p.326-327 in particular) and I understood much better the derivation of the relationship: (zonal (x) average of IPV'v')/g*S0) ~= zonal average of (quasigeostrophicPV)'*v' = divergence of EP flux / density. Where the quasigeostrophic potential vorticity = IPV/(g*S0), where S0 is a basic state S that is constant over x; the division is to give IPV in terms of vorticity AV while still accounting for variations in S. (Holton doesn't actually give the relationship as such but I conclude that this must be the case - ). One key thing to remember is that some of the variations over x can be dropped from the equations because the average over x, of the variation over x, taken along a closed loop (lines of latitude) must be zero. And for such a zonal average, net fluxes of IPV in the zonal direction obviously can't be accounted for; one would have to divise some regional EP flux averaged along the direction of one's choosing, etc. for that... BUT ANYWAY, at least in the quasigeostrophic beta-plane approximation in log-p coordinates, the zonal average of the northward eddy flux of IPV is proportional to (the divergence of the EP flux) / density (or the southward eddy flux is proportional to the convergence, etc.). So when the IPV gradient is to the north (which is the general tendency), EP flux convegence corresponds to increasing Rossby wave amplitudes, etc. PS other waves and eddies can contribute to a IPV fluxes and EP fluxes The meridional (y direction) variation in the EP flux divergence thus corresponds to a net depletion or accumulation of positive IPV (or the reverse for negative IPV), for increasing or decreasing divergence northward, respectively. The same variation in wind can be due to vorticity variation over a short distance with large vorticity maxima and minima magnitudes, or over a large distance with small vorticity maxima and minima magnitudes; wind is proportional to vorticity times length. In an analogous way, for a given magnitude of EP flux divergence (at a given y, z* location), whether it is spread out over y or concentrated, the same total amount of IPV*mass must be passing through that point; the same IPV * length scale of IPV must apply for the areas of IPV flux convergences and divergences; so the effect on the zonal wind is about the same. EP flux divergence accelerates the zonal wind to the east (more westerly), as can be understood from the changing PS since EP flux divergence and converge result in horizontal fluxes of IPV, and since there is only a finite distance from south pole to north pole, the IPV distribution (and the average zonal winds) has to change as a result, unless diabatic and viscous processes destroy and create IPV and transport it vertically across isentropes (which, without diabatic effects, otherwise act as material surfaces that air can't cross) in such a pattern as to balance the EP flux's effects.
130396. Ian Forrester at 05:02 AM on 13 January 2009
        Latest satellite data on Greenland mass change
        Mizimi could you please tell me where you got your information that Iceland has an estimated 250 x 10E6 km3 of ice? That seems rather unusual since Greenland only has 2.85 million km³ of ice. Also can you explain where the missing 17 Gtonnes of H2O disappears to when 179 Gtonnes of ice melts? I would have thought that a ton of ice would melt to give a ton of water.
130397. chris at 04:32 AM on 13 January 2009
        What does CO2 lagging temperature mean?
        Re #38

        Yes chris, CO2 can cause a small temperature rise because it's a GHG.

        CO2 can cause a large temperature rise. It depends on the atmospheric concentrations of course.

        We also know that it can not prevent an Ice Age as shown by the historical record...

        The evidence indicates that it can indeed prevent an Ice Age. The evidence from paleoproxies for temperature and atmospheric greenhouse gases indicates that Ice Ages in the deep past were associated with the reduction of atmospheric greenhouse gas levels below thresholds required to maintain the Earth in a non-ice age state. In other words atmospheric CO2 has prevented Ice Ages for long, long periods of the Earth's deep past. (see for example: D.L. Royer (2006) "CO2-forced climate thresholds during the Phanerozoic" Geochim. Cosmochim. Acta 70, 5665-5675.)

        ...and it can't cause catastrophic global warming because life still exists on this planet even though CO2 reached levels in the Mesozoic over three times the proposed "tipping point" and never tipped.

        It certainly can cause catastrophic global warming. Global warming can obviously be catastrophic even if it doesn't eliminate life in its entirety. If, for example, global warming was to occur to an extent that resulted in widespread breakdown of the structures of our societies, we'd consider that catastrophic. Or if mankind were to succumb while a denuded life on Earth went on without out us, that would be catastrophic, wouldn't it? The latter scenario is rather more consistent with those resulting from the extinctions associated with the Early Jurassic, the end Permian, the end Cretaceous, the Paleo-Eocene Thermal Maximum and so on. P.S. what do you mean by "proposed tipping point"? No one has mentioned "tipping point" on this thread have they?
130398. Mizimi at 22:55 PM on 12 January 2009
        Latest satellite data on Greenland mass change
        Sorry..that .62m should have been 6.2 including differences in water/ice volumes. To melt that amount of ice would require an enormous amount of energy..around 950 x 10E21joules and I don't see where that excess energy is going to come from in a time frame of a few hundred years.
130399. Philippe Chantreau at 19:58 PM on 12 January 2009
        Arctic sea ice melt - natural or man-made?
        I don't care whether you agree with my definition or not, quite frankly. However, I care a little that you don't misunderstand what I say. I said that expertise usually implies an advanced degree. Not always, and it is not a requirement. However, that's the most common situation. Recognition as an expert is not nearly as important as genuine expertise, which stems from sincere pursuit of understanding through the scientific process. However, chances are that, if you are a genuine expert, you will get recognition. The scientific process involves peer-reviewed publications. I dont' care what you or anybody else says, peer-review publishing guarantees a minimum level of quality without which science would not be the successful enterprise that it is now. Everybody has anecdotes relating flaws in any system. So what? And please be more specific: "some fields" or "well known experts" does not tell me much. What exactly are you talking about? Why don't you cite these terrible dissertations, so we can see for ourselves? Furthermore, having references and cites listed actually enables anyone to verify things, so it is a good thing from that point of view also. I've read countless lines of BS about how the peer-review process is all wrong. Still not convinced and not about to be. This site is about peer-reviewed science, if you don't trust it, you shouldn't waste your time commenting about it. In the business and financial world, they operate differently. Their "standards" are about to cost us 800 billions, bar a complete collapse. Science does not do so bad in comparison. Lastly, I don't understand your circular thingy. I'm writing a paper and doing my research. I cite an article. How can that article reference another that will then reference the one that I haven't even finished writing?
130400. Wondering Aloud at 13:37 PM on 12 January 2009
        Arctic sea ice melt - natural or man-made?
        I just came here because there were so many posts but Phillipe I could not disagree more with you on your definition of what a scientist is. A scientist is someone who uses scientific method. Compared to this one requirement, advanced degrees and "expert" recognition are just trivia. Also how often a paper is cited is not an indication of accuracy though it may be an indication of popularity. At best it may tell you who had an idea first. If you want an ugly experience spend a few days tracing references in papers and find out how many are fake, misquoted, unrelated or describe other "experiments" so badly done they were meaningless. See how long it takes you to find a circular citation. (A cites B who sites C who was citing A in the first place) In some fields 50% bs is fairly common, I've seen PhD disertations from well known "experts" that when you eliminate the fake references and the unrelated ones didn't have anything left.

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