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Comments 76 to 100 out of 237:

76. Patrick 027 at 12:59 PM on 13 October, 2008
    SO how/why would global warming alter storm tracks? I know a good amount about circulation patterns in the atmosphere and yet there is A LOT I don't know, but what I know, have been able to deduce, or otherwise have gotten the impression of, is: Remember hot air tends to rise and cold air tends to sink; this happens because of the pressure variations caused by the variations in air density. For a column of warmer air, the pressure is either lower than otherwise below it, higher than otherwise above it, or some combination of the two (at least for the hydrostatic approximation). The coriolis effect, on the large scale more than on smaller scales, tends to impede the simple 'thermally direct' circulation just described by causing wind to blow nearly parallel to isobars (or lines of constant geopotential on isobaric surfaces). The atmosphere is generally at least somewhat stable to dry vertical motion; this means that dry adiabatic cooling and warming are such that, the rising/sinking induced by a warm/cold anomaly tends to reduce the anomaly. Midlatitude storms do get some energy from latent heating (as with tropical storms), but unlike tropical cyclones, midlatitude storms get much of their energy from the available potential energy of a background horizontal thermal gradient. This thermal gradient supports a vertical wind shear (hence the jet streams). In the hydrostatic approximation (which is a good approximation in the asence of significant vertical acceleration, which is generally the case of larger scale motions), horizontal divergence/convergence must occur along with vertical compression/stretching (in pressure coordinates), respectively, which implies variations in vertical velocity with height (in pressure coordinates). In order to conserve angular momentum, which is the case in the absence of friction (and friction is generally weaker than the pressure gradient and coriolis forces in the midlatitudes), horizontal convergence/divergence must occur with an increase/decrease in the magnitude of vorticity - vorticity is a measure of the air's 'spin'. It's important to realize that this pertains to absolute vorticity, which is the sum of planetary vorticity (which is proportional the coriolis effect itself) and relative vorticity. Relative vorticity can be cyclonic or anticyclonic, such as in cyclones or anticyclones, respectively (although horizontal shear also contributes to vorticity). But the absolute vorticity is never anticyclonic except near the equator. Thus, vertical stretching, such as below rising motion or above sinking motion, tends to cause cyclonic motion, which requires a low pressure area to be balanced; and the opposite tends to cause anticyclonic motion, etc. *A1*.(Notice that if continued to extremes, relative anticyclonic vorticity can be at most equal and opposite to planetary vorticity, whereas there isn't such an upper bound to cyclonic vorticity, aside from the limits of the vertical stretching itself). Related to that, centrifugal forces allow for, for a given wind speed, greater pressure gradient around a low center than around a high center. (?? Another potential reason for assymetry is that divergence is ultimately limited by space but convergence is not ??, and also, a divergent air mass is growing larger in area whereas a converging air mass is shrinking ??, although air diverging from one point must ultimately also be converging toward another. ??) PS the measure of absolute angular momentum that is conserved during any inviscid (frictionless) adiabatic motion is isentropic potential vorticity. With constant static stability, potential vorticity (PV) is higher where absolute vorticity is higher; with constant absolute vorticity, PV is higher where static stability is greater. AND THEN: Disturbances in a region of vertical shear that are tilted into the shear - that is, if the vertical shear is westerly (eastward) with increasing height, the tilt of the pressure perturbations is westward with height - and moving at an intermediate speed between the extremes that occur higher and lower in the troposphere - can grow because the configuration allows for ...(Baroclinic instability) ... okay, well that's too complicated to go into right now, but to summarize: I think these disturbances can grow faster when the vertical static stability is lower - that is, when the laspe rate is higher. At the same time, higher lapse rates favor shorter-wavelength systems for maximum growth rates. Development is enhanced by greater horizontal temperature gradients and associated vertical wind shear. Although these disturbances could start out sufficiently small that linearized equations may describe them initially, they may eventually grow to the point that nonlinearities become important, and nonlinearities may be important to start with depending... so surface low pressure systems develop east of developing upper level troughs (assuming overall westerly average winds) and west of developing upper level ridges, and high pressure systems at the surface would develop east of upper level ridges and west of upper level troughs. There are also fronts. warm air heads poleward east of the low and rises, cold air west of the low heads equatorward and sinks. The configuration is such that (generally**) the low pressure system itself will tend to build poleward, eventually with the center attached to the warm air mass at the surface by an occluded front that underlies warmer air aloft. The high pressure will build equatorward. The pressure systems eventually lose some of their tilt, and thus their ability to strengthen vanishes. At this point, due to the sorting out of surface highs and lows, there is an overall westerly flow at lower levels in between them. If the north-south transport of heat by these systems was fast enough relative to the gradients in radiative and latent heating, vertical shear will have been reduced within the heart of the storm track, though it and the temperature gradient may actually have increased on the edges of the storm track as the warm fronts push into the cold air and the cold fronts push into the warm air. The overall effect of the disturbances may generally be to concentrate westerly momentum at upper levels into the storm track but also to transfer westerly momentum from upper levels to lower levels. Eddy potential energy and kinetic energy have both been produced from some of the available potential energy of the original horizontal thermal gradient, but also some has been produced from eddy-correlated latent heating and perhaps radiative heating (??) patterns, although radiative heating in the absence of cloud or humidity variations will tend to reduce eddy energy; some eddy kinetic energy is transferred back into the kinetic energy of an average across disturbances, and some of this kinetic energy is actually converted back into available potential energy by a thermally indirect circulation. I think this is because as the lows and highs 'sort out' and the warm air and cold air masses move past each other, the rising motion is shifted to the cold side of the storm track and the sinking motion is shifted to the warm side of the storm track. One way of quantifying this is with something called the EP flux, which is related to a potential vorticity flux. Factors, such as the horizontal shear of the average state, may affect the 'sorting' out process and the life cycles of the disturbances... Energy generated in the troposphere in these disturbances is spent in the lower stratosphere by lifting colder air and 'pulling' warmer air down. I'm not sure whether this energy is lost (radiatively ?) or is transferred back into the troposphere (to the extent the stratosphere acts like a trampoline). The thermal pattern produced in the lower stratosphere acts to reduce the strength of the disturbances at yet higher levels, thus they do not penetrate much above the lower stratosphere (though larger scale features do). Larger scale features (longer wavelength troughs and ridges) exist which do not grow in strength from baroclinic instability (although different waves can interact through nonlinearities), but rather propogate westward throw the air at all levels in the troposphere. These larger scale features may be excited by the wind's flow over topography and by some variations in temperature, and also by propogation around the globe of barotropic Rossby waves that are produced by convection over tropical sea-surface temperture anomalies, etc. These features affect the distribution/patterns of storm track activity. ------- So with global warming (in general, not generally specific to cause): The expected pattern in the Northern hemisphere (which would, I think, be expected in both hemispheres in the longest-term equilibrium states) is enhanced warming in the mid-to-upper troposphere in low-latitudes and, especially in the colder seasons, in the lower troposphere and surface at higher latitudes. This is because: At high latitudes, there is a strong albedo feedback, associated with reduced seasonal snow where there is some sunlight in winter, and summer sea-ice loss nearer the pole, which has a warming effect in winter by absorbing summer sun and taking longer to freeze while giving off more heat in the process during winter. The atmosphere is generally more stable at higher latitudes, especially in colder months, so the additional heat at lower levels may not be transfered to the rest of the troposphere by convection so much as it otherwise would. At low latitudes, there is a negative feedback over the ocean and moist surfaces (so long as they remain moist) as evaporation is faster at higher temperatures; the upper level heating is from the corresponding condensation of moisture. Some of that heat can be transported out of cloudy areas by circulation, of course. The changing lapse rate can be related to the temperature dependence of the moist adiabat. Thus the equator-to-pole temperature gradient, and thus the vertical wind shear at some point in between, is reduced at lower levels (except perhaps in summer or around that time of year) and increased at upper levels. These trends won't be distributed at both levels in the same way and won't be distributed evenly at all latitudes and longitudes, but starting with an even distribution assumption: 1. Due to the temperature gradient changes in the lower troposphere, one would expect reduced midlatitude storm track activity overall (except perhaps in or around summer, when it is not as great to start with, although mesoscale circulation (thunderstorms, squall lines, MCCs, etc.) do produce severe weather and intense precipitation events at that time, and severe thunderstorms are aided by vertical wind shear as well as moisture and moisture contrasts **). It might also perhaps allow for greater poleward-penetration of conditions that allow tropical cyclone development. HOWEVER: 2. Due to the temperature gradient trend at upper levels, one might expect greater midlatitude storm track activity (although this may be more sensitive to lower level thermal gradients and wind shear than upper level thermal gradients and wind shear), and also perhaps limit the regions that allow tropical cyclone development. 3. Interesting feedbacks: greater thermal gradients tend to enhance storm track activity which itself mixes the air on large scales which ultimately reduces the thermal gradient, so changes in storm track activity can be a negative feedback to changes in thermal gradients. If the reduced thermal gradient at lower levels reduces storm track activity, heat transport may be reduced at all levels, allowing the thermal gradient to increase at upper levels. If the increased thermal gradient at upper levels increases storm track activity, heat transport may be increased at all levels, reducing the thermal gradient at lower levels. Although of course the heat transport for a given circulation pattern will be greatest where the thermal gradient is greatest. (note that general circulation models, although not perfectly, will incorporate these effects, so the expected pattern of temperature change described before wouldn't necessarily be different because of storm track activity feedbacks). 4. Greater overall moisture in the atmosphere will also enhance storm track activity by adding to eddy available potential energy (and through that, to kinetic energy) by greater latent heating. *A2*. Since this affects essentially only precipitating systems, it's effect is asymmetrical between cyclones and anticyclones (as might also be the case with eddy-correlated cloud feedbacks). However, the more intense latent heating tends to be concentrated on smaller scales, so I'm not to what degrees it would enhance the synoptic-scale system, enhance mesoscale features, or change the character of the low pressure system, perhaps by making it more intense but more compact with more intense precipitation over a smaller area (?). Would there be more subtropical storms? PS more moisture overall in the air may also imply greater moisture transport across a given moisture gradient, and if temperature were rising equally everwhere, the moisture concentration gradients would increase - except of course, the temperature is not rising evenly everywhere. But temperature increases could increase the effect on regional and global circulation patterns of any given SST (Sea Surface Temperature) anomaly, such as that associated with ENSO (which itself may increase due to the delayed warming of upwelling cold water). Mesoscale humidity contrasts (drylines) are important in many severe thunderstorms, including tornadic storms. 5. IF the lapse rate were to remain constant, the greater latent heating would reduce the static stability effect on cyclones, which might then develop more rapidly, especially those with smaller horizontal sizes, but not on anticyclones. The greater latent heating itself may reduce the lapse rate, perhaps reducing but not eliminating the changes in cyclone development, while also slowing the development of anticyclones, especially smaller anticyclones. (If larger anticyclones are preferred ??, would that lead to larger airmasses, with reduced thermal gradients across some regions but enhanced thermal gradients around the edges of anticyclones, perhaps if wind is delivering air from longer distances without getting side-tracked, and hence over shorter times ??). 6. Note also that the overall expected temperature change pattern is such that vertical static stability is increasing at lower latitudes, but is decreasing at higher latitudes. This could concievably account in part for a tendency to shift the storm track activity poleward Notice this may mean a poleward expansion of subtropical dry regions into the midlatitudes as well as an increase in precipitation at higher latitudes on top of what might be expected from higher humidity alone. 7. Interesting feedbacks. When the overall thermal gradient is increased from a low value, the circulation due to synoptic scale eddies (includes storm track extratropical cyclones) increases. This includes vertical motion. Hence, there is greater vertical heat transport, which tends to increase vertical static stability, which slows the development of these baroclinic disturbances (baroclinic eddies; a.k.a. midlatitude storms and anticyclones), especially those of shorter wavelengths. In actual 'dishpan' experiments (a spinning pan filled with fluid and differentially heated and cooled), when the thermal gradient is very low, there is a Hadley cell; when it is increased, baroclinic disturbances form, when it is increased further, the wavelengths of the disturbances increase (as I recall), up to a point, until the wavelength of unstable disturbances is too large to fit into the pan, and so the Hadley cell resumes. However, there isn't an actual short wave cutoff in the atmosphere, although some simplified mathematical descriptions produce one - but it is true that the most unstable wavelength increases with increasing vertical stability. In the actual atmosphere one can also have small scale overturning as in cumulus clouds and thunderstorms. If the large scale overturning of either the Hadley cells or the extratropical circulations or both were reduced, one might expect that the vertical stability would decrease until and causing the smaller scale overturning to pick up the slack. 8. The coriolis effect is of course also very important. The coriolis effect varies with latitude, increasing away from zero at the equator. The variation of the coriolis effect over a north-south distance is called beta, and beta effects tend to cause disturbances, especially larger horizontal wavelength disturbances, to propogate westward relatively to the air flow; this produces a long-wave cutoff where some wavelengths are too large to develope by baroclinic instability. If the wavelengh, beta, and windspeed are right, a wave may remain nearly stationary - such quasistationary planetary waves can be excited by topography and variations in temperature, as mentioned before. I think beta also reduces the mechanism by which baroclinic disturbances grow through baroclinic instability, by contributing to convergence where there is divergence and vice-versa - at upper levels, anyway (maybe the opposite at lower levels, however - do the effects cancel?). Perhaps not as much if the overall flow is somewhat northward or southward over a whole wavelength of ridges and troughs...? - actually, this might turn out to be mathematically equivalent to some fraction of the other beta effect in the prior paragraph. Beta decreases away from the equator, to zero at the poles. So if the storm tracks move, the coriolis and beta effects will vary as applied to the storm track activity. Also, the tropopause is expected to rise. But the tropopause slopes downward toward higher latitudes. So it is unclear what happens to tropopause height at a moving storm track. A higher tropopause could affect storm track activity - for example, for a given wind shear, the total variation in wind would be greater across the troposphere. Perhaps the effect of topography would be slightly reduced at the upper levels ???? - And a given level of divergence in the air through the troposphere could increase the surface pressure fall if occuring through a greater thickness of air ????. And the relationship to the stratospheric circulations... the energy generated in the troposphere relative to that expendended in the stratosphere, that relationship would change.... More generally, deeper convection = more intense precipitation, and higher cloud tops increase the cloud's contribution to the greenhouse effect. 9. So the storm track activity changes. This changes the average wind patterns. That affects the way quasistationary planetary waves develope from topography and temperature variations, which again affects the wind and thus the storm tracks. Changes in SST affects how the SST anomalies (which themselves could change in frequency/intensity/location/etc.)affect all of the above (including but not limited to ENSO, PNA?). Etc. One way storm track activity can change is by changing the motion of storms - if storms move more slowly or are farther apart, for example, one could have greater risks of floods or droughts, and the opposite for the reverse; a greater portion of precipitation coming in intense events may lead to greater runoff; the frequency and locations of blocking events could change; blocking anticyclones are associated with dry spells and heat waves; I suppose they might lead to the opposite somewhere else since cyclones may be rerouted around such anticyclones...Etc. Changing winds, wind shear, and static stability, affect the distribution of gravity waves and whether and how they propogate vertically, which would affect transfer of momentum from the troposphere to the mesosphere; the vertical propogation of planetary waves into the stratosphere could also be affected and that is associated within 'Sudden Stratospheric Warmings', and stratospheric circulation can then affect the troposphere. Related: would NAM, SAM, NAO, and QBO be affectd? Etc. I might be wrong about some things - especially towards the end, some of that was speculation (where I was unsure I tried to indicate as much). But at least I hope to have given you a sense of how global warming can alter weather patterns.
77. Patrick 027 at 16:00 PM on 13 October, 2008
    *A3*. If anticyclones are larger horizontally they will then tend to propogate westward relative to the wind faster than cyclones (beta effect), so cyclones will tend to move eastward with the overall wind faster than anticyclones, or in order to move at the same speed, anticyclones would have to be closer to a westerly jet ... etc... AND as anticyclones sort out equatorward of stormtracks, they would experience higher beta and so their eastward movement would be slower for that reason as well - unless there is another effect that counteracts this. PS to be clear, My understanding is that: In baroclinic instability, eddies grow by taking available potential energy (APE) from the average state (averaged along a storm track across a full eddy wavelength, for example, or a full zonal average across all longitudes for the overall midlatitude storm track activity) and thus creating eddy APE, essentially by moving the cold air and warm air into each other (creating a wave pattern in the isotherms or isentropes along a horizontal or near horizontal surface) - at the same time, this disrupts geostrophy so that a thermally direct circulation occurs, with winds moving from high to low pressure horizontally, with warmer air rising and colder air sinking. This converts some of that eddy APE to eddy kinetic energy (KE), which enables the eddy to distort the isotherms even more, and thus continue to grow - for small disturbances, growth can initially be exponential. Two things: when warm air is pushed as a protrusion into colder air, the resulting pressure perturbation is initially unbalanced by the coriolis effect and so the warmer air rises - warmer air that was initially surrounded (horizontally) by air of a more similar temperature is now surrounded by colder air, and so rises, just as actually adding heat to a region of air tends to make it rise. However, depending on the geometry, some of the surrounding colder air may also sink as it is now next to warmer air. The effect may not be as strong as in the warmer air since the colder air is not surrounded by the warmer air, however (mathematically, it depends on the laplacian of the temperature advection). But if new warm air continues to flow from the main warm air mass into the cold air, the cold air will eventually adjust and stop sinking while the warmer air is still coming into a new situation and will still rise. IF the temperature gradient is initially constant from warmer to colder, than, for the sake of clarity, assuming an initially north-south temperature gradient (east-west isotherms), a wave pattern of flow that is limited from north to south will pull isotherms apart in the warmer side while pushing them together in the colder side, or vice versa, and where isotherms are pulled apart, a thermally indirect circulation will develop, converting KE to APE. However, where isotherms are pushed together, the thermal gradient can get higher and higher (until some ageostrophic effects associated with frontal zones get strong), whereas the pulling apart of isotherms can at most reduce the gradient to zero (PS I haven't actually calculated this but I would assume this means the thermally direct circulation eventually dominates while the themally indirect circulation dies out). Also, if the initial thermal gradient is concentrated near or along the storm track, there might not be so much pulling apart of isotherms even initially to cause a balancing thermally indirect circulation. Anyway, an east west cross section of an idealized series of such growing eddies may show alternating high and low pressure centers tilting westward with height, regions of rising and sinking motion, strongest in midlevels (air won't rise into space or go down into the surface) which also tilt westward with height but not as much, and regions of warmer and colder air that tilt eastward with height. The air flows through these features from west to east higher up and from east to west closer to the surface. Because the temperature and vertical motion patterns don't tilt the same way with height, there can be some pockets of thermally indirect circulation, but overall it is mostly thermally direct. What is really interesting about these kinds of systems - you might well wonder, how can they grow - how can the pressure systems get stronger - when the thermally-direct motions that create the kinetic energy associated with the wind requires that air is on average flowing into low pressures and out of high pressures? The answer: by temperature advection (transport of air)(not actually by heating, although that will occur but is not part of this explanation), the air in between the highs and lows is warmed or cooled because of the north-south flows. But the east-west flows through the system act on this pattern, so that the resulting temperature field doesn't tilt as much as the pressure field and actually tilts the other way. The vertical motion reduces the growth of the temperature pattern by adiabatic cooling and warming of the warmer and colder air, respectively, and this effect is greatest at midlevels (or tends to be, but will also be greater at levels with higher static stability). Near the surface, warmer air is closer to lower pressure; at higher levels it is closer to the higher pressure (opposite for colder air). Pressure drops faster with height through colder denser air than through warmer air, so the low pressure tilts with height over the colder air to its west, and the high pressure tilts with height over the warmer air to its west. The temperature field explains the way pressure changes with height, but what explains the actual pressure field at any one level, such as the surface? There has to be some total divergence through the whole column of air above the surface low pressure to result in lowering the pressure (assuming flat topography - pressure systems can also be produced by motion over slopes). There has to be convergence into the low pressure on average in order to increase kinetic energy. But with height, the high pressure tilts part of the way over to above the surface low, so divergence from that high pressure can lower the pressure at the surface, while convergence at the surface increases the high pressure aloft. What about angular momentum? Air is vertically stretched beneath warm rising air at midlevels, while also being transported by relative westward motion (relative to this whole pattern) into the low pressure at low levels levels; so cyclonic relative vorticity is created that can nearly balance the pressure - but not quite, or else their could not be net convergence into the low (actually, there could also be some effect of centrifugal force, which affects high and low pressures asymmetrically - although centrifugal force depends on the trajectories, whereas vorticity is determined from streamlines**), and at upper levels, air is vertically stretched above sinking motion while being transported westward into the low pressure at that level. And so on for the growth of anticyclonic vorticity in the high pressure areas. The whole pattern can grow exponentially, up to a point. When the flow pattern of the disturbances is stronger, the warmer air is not just moved east west toward low and high pressure centers, but continues to move north and south more significantly due to the wind of the disturbances. Thus warm air flows northward from south of the low (did I mention I'm describing a Northern Hemisphere version) east of the low and westward relative to the low, into the low as the low moves east, but also continues northward and goes north of the low. Rising motion and the surface low itself will follow. Another way of looking at it is that the flow of air above the low is not just westward but northwestward, between a trough and a ridge at mid-to-upper levels... and generally, features at one level in the atmosphere tend to propogate with the wind at another level because the wind at that level must adjust to the feature, and the feature must adjust to that adjustment... So in the 'sorting out' process where the highs and lows at the surface tend to end up on different sides of the jet stream and temperature contrast associated with the storm track, when the motions are averaged along the length of the storm track, it may appear that colder air is rising and warmer air is sinking, but this may largely be (?) the result of warmer air rising while surrounded by colder air, and colder air sinking that is surrounded by warmer air. Mathematically this can be worked out as a thermally direct eddy circulation which is producing more kinetic energy than is being taken back by the weaker thermally indirect averge motion. At some point, though, I could imagine that even while the warmer air and colder air are still warmer and colder than their immediate surroundings, they may have cooled and warmed enough, respectively, that they are no longer warmer and colder than each other, respectively; at that point the average thermally indirect motion would be stronger than the eddy thermally direct motion, I think, so that in total kinetic energy is being converted to APE. Of course, the eddy motion itself might start converting some KE to APE at some point during the decay stage (?)- perhaps frictional dissipation may force cold air up in the lower levels of the low pressure system, for example - which would strengthen the low pressure aloft but reduce it at the surface (although the convergence at the surface would reduce it at all levels, but at higher levels the disruption of geostrophy would induce flow to counteract whatever pressure tendency there is - not entirely unlike the way electric currents respond to a changing magnetic field). I did see your most recent comments and I'll get back to you about that.
78. chris at 20:36 PM on 13 October, 2008
    Re #66, 67, 71, 73 etc. The notion of significant volcanic/tectonic contribution to polar ice melting simply isn't supported by the evidence, Quietman, and most of the articles that you link to don't support that notion either. Much of the analysis of enhanced melt/glacial runoff that is contributing to nett mass loss in Greenland is from regions far from the Gakkel ridge in the far NE region N of Greenland where some tectonic activity has been found. It's already been pointed out by Patrick that the surface melt highlighted by Tedesco et al in their EOS article is incompatible with the effects of undersea tectonic activity. This is highlighted by Tedesco himself who indicates that the snow melt is associated with surface/air maximum temperatures 3 oC above average. Clearly that cannot be the result of undersea volcanos. The situation is similar to the article you linked to on the Greenland thread (your link in post #66 above). It's easy to see that this article (citation below) discusses surface melt on the Western region of the Greenland ice sheet, and specifically concerns surface melt in the ablation zone 1500-2000 metres high up in the ice sheet. This enhanced surface melt cannot be the result of undersea volcanic activity 1000 miles away. and so on. The papers you link to are inconsistent with the effects of undersea tectonic activity. An additional problem relates to the question whether this activity (undersea tectonics) has increased in a manner that is consistent with the timescale of enhanced warming. You linked to a paper in your post #13 above which you consider to be some sort of support for a contribution from tectonic activity to the very marked enhanced warming of the last century and especially the last 30-0dd years. However this paper (Loyd et al, 2007; citation below) simply doesn't support that notion. The specific point of the Loyd paper that you link to is that the release of thermal heat from the earth's tectonic activity has steadily decreased over the last many million years. Now it may be that there is some evidence for enhanced tectonic activity, but the paper you linked to certainly doesn't provie any. If anything it provides completely contrary evidence to your hypothesis. R. S. W. van de Wal (2008) “Large and Rapid Melt-Induced Velocity Changes in the Ablation Zone of the Greenland Ice Sheet” Science 321, 111 – 113. S. J. Loyd et al (2007) "Time variability in Cenozoic reconstructions of mantle heat flow: Plate tectonic cycles and implications for Earth's thermal evolution" Proc. Natl. Acad. Sci. USA 104, 14266-14271.
79. chris at 22:33 PM on 13 October, 2008
    Re #74: The suggestion that scientists "skirt the issue" because of worries about funding/grant money or political correctness is ludicrous and isn't a scientific argument. It's a conspiracy theory. The essential element of science and one that allows us to address difficult and complex issues relating to real world phenomena is that it is evidence-based. All discoveries/interpretations that are supported by the evidence have a place in science and are likely to appear in the peer-reviewed scientific literature. If interpretations are not supported by real world evidence they are very unlikely to appear in the literature or to be taken very seriously, especially be scientists who are pretty skeptical people. And of course we should all be skeptical of assertions/arguments without an evidence-base. Of course we're free to discuss unsupported hypotheses to our hearts content, but unless evidence accrues to support these, one should remain skeptical. Castigating individuals as "environmental fanatics who look upon AGW as a bible thumper looks to the word of God", seems more like an insult that a scientific argument! I haven't posted here that long and haven't come across any people that seem to have unreasonable concern for the environment. However surely one should address their argument/evidence rather than insult them. In science it's all about the evidence Quietman.
80. Quietman at 08:32 AM on 14 October, 2008
    In science it's all about the evidence Quietman. Yes but first you have to examine it instead of dismissing anything you don't like off hand or because you don't like the author or what he/she says. You can't skip through and ignore key words and phrases the way you like to and you can't assume that a paper is fact, peer reviewed or not. It is an argument, ie. a hypothesis.
81. Quietman at 08:36 AM on 14 October, 2008
    Patrick That was directed at chris. You put forward a good argument regardless of what points I disagree with and do so using logic rather than a peer review bible. Keep it up, you do a good analysis.
82. Quietman at 08:40 AM on 14 October, 2008
    PS Re: "SO how/why would global warming alter storm tracks?" I thought that you made a good explanation or at least a good argument for that in the Bertha thread.
83. Quietman at 09:13 AM on 14 October, 2008
    Patrick "Sandwiched between Earth's crust and molten outer core, the vast mantle accounts for 83 percent of the planet's volume. It is filled with solid rock but, heated by the core and by its own radioactive decay, it circulates like a pot of impenetrable soup. That circulation is the driving force behind the surface motion of tectonic plates, which builds mountains and causes earthquakes." Ref: Geophysicists Propose A New Model Of Earth's Mantle ScienceDaily (Mar. 19, 1999) - Earth's mantle, a region as scientifically remote as outer space and the object of the most heated debate in geophysics, gets a remodeling this Friday by researchers at UC Davis and MIT PS I would remind you that the capacity for "sudden" changes was covered in my post 36. But I found a good link for the article at ScienceDaily (June 20, 2008) — Surprisingly Rapid Changes In Earth’s Core Discovered " The movements in the liquid part of the Earth’s core are changing surprisingly quickly, and this affects the Earth’s magnetic field, according to new research from DTU Space." ... “What is so surprising is that rapid, almost sudden, changes take place in the Earth’s magnetic field. This suggests that similar sudden changes take place in the movement of the liquid metal deep inside the Earth which is the reason for the Earth’s magnetic field,” Nils Olsen explains. Ref: The Abstract in Nature. Viewed with the article of Tectonics acting as the Earths thermostat it can be seen how the thermostat can become suddenly reset for periods of time.
84. chris at 09:56 AM on 14 October, 2008
    Re #80/#81 That makes no sense at all. The reason I questioned your choice of links is that I downloaded and read each paper thoroughly (rather than just the press releases). So I certainly "examined it"! In fact I thought the papers were excellent (papers have to be pretty good to be accepted in Proc Natl Acad Sci or Science and so on...). I thought the authors were fine and I was perfectly happy with what they said (male and female alike!). So your odd accusations don't apply and one wonders why you don't address the critique of your interpretations, rather than reply with inappropriate insults. There's clearly valid questions of whether (a) undersea volcanic/tectonic activity has increased in a manner that could have a causal relationship with the rather large global-scale warming of the last 100 years, especially the last 30; (b) whether tectonic activity has made a significant contribution to widescale polar ice melt. A skeptic should like to see some real world evidence. The point is that the papers that you cited don't support your notion. In other words you can't use as evidence of undersea tectonic contributions to Greenland melt, a paper that describes high level ice sheet surface melt at the ablation zone 1500-2000 metres in altitude in Western Greenland. That's not the result of undersea tectonic activity. It's a consequence of enhanced atmospheric warmth. Likewise one cannot use as evidence of enhanced tectonic contributions to global warming a paper whose essential analysis is to describe the continual steady decrease in thermal heat from plate boundaries due to their consolidation from previously smaller fragments over millions of years. And it's obvious that every paper about tectonics does not willy-nilly constitute an "argument" about tectonic contributions to global warming! We all know that plate tectonics is a fundamental element of the earth system. The question with respect to largescale global warming is whether this activity has increased recently. So there's nothing wrong with the papers - you've just chosen to cite papers that provide data and evidence that contradicts the notion that you are pursuing. And one should be careful in relying on press releases for scientific information.
85. Patrick 027 at 12:42 PM on 14 October, 2008
    "But in fact the thinned crust is the northern end of Greenland (in the articles linked in this thread) and surrounding Arctic ocean and that is exactly where the largest glacial melt is AND IT IS FROM THE BOTTOM. " I only read the abstract. It sounds like chris may have read more. Is he incorrect about the article? "But top down melting would not produce the same results" It depends on what exactly the results are. Meltwater could come from the surface, flowing down into the glacier through moulins - this source would explain the seasonality of any meltwater-induced lubrication of the glacier. (Of course, however the ice is melted or induced to flow, the resulting thinning would lower the ice surface and cause warming of the ice surface that way.) -- "Ice albedo will remain until all the ice is gone. Soot in the top layers lower the albedo so fresh ice will have a higher albedo if we control the output of soot." Dark aerosols are/have contributed to arctic warming and melting in that way; that is true. tropospheric ozone has also contributed to Arctic warming and melting. So has CO2, CH4, etc. However, the highest albedo is from fresh snow. Old snow and ice tends to have a lower albedo. When snow melts and refrezes or otherwise changes to form larger particles, the reflectivity is reduced - light may penetrate deeper before being reflected, giving it greater chance to be absorbed. Aerosols (and rocks), natural or anthropogenic, will be concentrated as the ice volume is reduced. Sea ice will become more transparent and thus darker when it gets thin enough to see the water beneath. The loss of sea ice will likely have a warming effect (in the winter, at least) on the region, not just where the ice was lost. -- "suggest that vulcanism is a "contributer" in an earlier article" Potentially so but only in a few locations, whereas the ice mass loss and general warming are far far far more widespread and general. "They do not say if it is AGW either." I think at least some of the articles you referenced did say that, not about some of the specific locations but about much of the other warming. ____________________________________ Entering danger zone? "Keep in mind that while you and I can speak openly for or against the AGW concept. there are others who need to be politically correct or they will lose their jobs or grant money and therefore skirt the issue." Scientists and politicians and everyone else are only human. However, if a scientist does work that has errors, and especially if it is a matter of interest to people, I expect some other scientist would want to capitalize on the opportunity to point out those errors. Can scientists be friends with each other? Yes, but that doesn't prevent them from pointing out each other's errors - especially if they don't take it personally. There may be actual examples to back up that point but I'll leave that to others. What about money and prestige? If there were no 'climate crisis', then there would be less money available to study AGW and climate in general, right? Well, I hardly think there's a Higg's particle crisis (that we know of :) ), and yet we've got a Large Hadron Collider now. Still, though, the argument is plausable. Then again, if there were more controversy than there would need to be more work done to resolve it, so... Still, though, whereever the bulk of the money and attention are going, there could be some scientists out there who would like to make a big name for themselves by successfully overturning the conventional wisdom of the day. If they are not able to do so, then there might be a reason why. And unless scientists are actually making up the data, the data is what it is, the potential error in that data and all, the theory (logic) is what it is, and any scientist, or student, with sufficient education can ask, does this make sense? There are people with an interest in overturning the current accepted science of global warming. Some of them have lots and lots and lots of money. Yet, rather than having funded real science on the matter (at least any that would successfully accomplish their goals), they instead lobby the government while launching silly propaganda campaigns about how CO2 'is life' (or that any effort to reduce CO2 emissions will harm the poor (often arguments ironically made by people who would rather not have the government do the poor any special favors, I think), or that free market capitalism will solve everything and any government involvement works against innovation - when in fact a carbon tax or some equivalent, etc, could help spur innovation and may be justified by (market) economic principles) ... Meanwhile, my impression is that, if anything, the IPCC summary for policymakers is watered down in favor of anti-alarmism, rather than hyped in the other direction. "Then there are those, like one poster at this site, that are environmental fanatics who look upon AGW as a bible thumper looks to the word of God." I can't help but wonder if this is the result of misunderstanding (not that I would pretend to know how your conversations with others have gone - I don't know). Not that it can't happen - many people don't understand science, regardless of what they have come to believe or accept as true (although the people who do understand science are more likely to accept or lean towards the accepted science or at least one or more promising contenders). But sometimes people who do know stuff just get tired and impatient from explaining and explaining and explaining and explaining and explaining and explaining and explaining and explaining and explaining again, especially when so many turn a deaf ear towards it or come back with accusations of communism, or just keep making the same arguments over and over and over and over and over and over and over and over and over and over and over and over and over and over and over and over and over, no matter how well it's been refuted to them (and maybe in some cases, being caught telling other people something totally false about what you told them - this has happened to me). Then what may happen is that people misread each other, assuming that the other guy is a member of the group of ignorant jerks s/he's become accustomed to dealing with. It may happen in particular when a new face advances an argument that the other person has seen before, perhaps from an actual 'denier/contrarian'. Or to save time, a person might refer to the 'scientific consensus', from which the other person may unfairly conclude that the other is just arguing 'from authority', rather than understanding the significance of such a consensus (ie sure, we can't be 100% sure about much, but there comes a time when we've got to make a decision - what do we put in our science textbooks? What do base public policy on? While there are loose ends still being worked out, relativity and quantum mechanics are scientific consensus. Many details have not been found, but the general picture of biological evolution by natural selection and some other things is scientific consensus. That the Earth is ~ 4.5 billion years old ... etc. PS Relativity didn't overturn Newtonian mechanics entirely (we still use the later for many things), and aside from that, if the argument is made that Einstein successfully overturned a consensus, 1. does that mean we could expect that Einstein will also be shown to be wrong someday, and 2. for every Einstein, how many had an idea that didn't pan out?) Although it is unfair, it is sometimes understandable why a person may make an assumption about someone's attitude to reality. There is also the time constraint - if a person smells 'silly' in an argument, they may decide (rationally) to not bother with it, hence, dismissing it. Certainly if I didn't have the time I couldn't have been discussing/arguing with you about the merits of various possibilities. I myself am quite satisfied that 'it' (you know what I mean) is mainly AGW. There are many arguments I won't look into further, because I judge them ahead of time to be wild-goose chases that will lead nowhere - I can do that with some confidence because of the arguments I have looked into that turned out to be just that, empty fluff. Occasionally I will look into such an argument though, just to debunk it - but of course, if I can't debunk it, that will tell me something, won't it? (Either that it may be possible, or that it is beyond my knowledge). Another aspect to this - perhaps an application of Occam's razor - there are so many things that are known, that lead to an expectation of significant CO2 causing significant warming - that Arrhenius (sp?) predicted as much long before CO2 emissions ever rose to such a level - the understanding of how radiation transfer actually opperates has been refined since then, as have the radiative properties of gases, etc, - but not in a way to discredit the basic idea, rather just to refine the theory. Then there is paleoclimatology, the computer models, the observations so far, etc. - they all inform each other, of course, but even taken independently they point in the same general direction. Given all that, some of these alternative explanations - it seems like throwing in extra Rube Goldberg devices and lasers to explain how the toaster works, after you've already seen the nichrome wires glowing red... Now, I may still want to learn about some things for other reasons - I don't think the tidal-driven ocean mixing will account for much of recent changes but I find it interesting as a phenomenon all by itself, for example. "Hopefully we will get to the truth behind all this regardless of their attempts to "enlighten" us "deniers" (that is their demonization of skeptics vocabulary, not mine)." This is messy. Take out the 'offensive words', and what is left behind essentially describes, in my mind, what I hoped to accomplish - enlighten you. Why wouldn't I call you a denier or contrarian? Well, because you've been polite and seem willing to listen, you haven't accused me of being a communist, a dumb parrot, or having malice or indifference towards innocent people, and you aren't trying to cast yourself as a climatologist or a scientist in some related field. I was actually afraid I've 'led you on' when you implied someone else might consider me a denier, so now - in jest - I will say that some of those I have argued with would call you a communist. As for those words - denier, contrarian - there are people out there to whom I think they would justifiably apply. For example, dare I say Fred Singer and Richard Lindzen. I don't say this just because they say things I disagree with - I say it because they say things that can't be backed up, they make arguments that are shot full of holes, and especially in Fred Singer's case, I am tempted to doubt whether he himself could possibly buy into his own arguments - or else, I think he must be horribly confused and sloppy - yet, perhaps some of his sleight-of-hand reasoning is too clever for that explanation? Other people - whether they knowlingly lie or just want to believe in those things that help them politically - Rush Limbaugh, Michael Crichton, Ann Coulter, James Inhoffe, James Dobson, CEI, etc... and even Jon Stossel and Glenn Beck, - well, ... they don't identify themselves as scientists, but in some cases they are quite biased in their work, and in some cases there furosity ... Some would say 'denier' is offensive because it may have been inspired by the use of the word next to 'Holocaust'. I can see that, however, I can also see that it is a word, like red, and certainly no one thinks cherries are communist. Does a person 'deny' in an irrational or dishonest way? Your response to chris: "Yes but first you have to examine it instead of dismissing anything you don't like off hand or because you don't like the author or what he/she says. You can't skip through and ignore key words and phrases the way you like to and you can't assume that a paper is fact, peer reviewed or not. It is an argument, ie. a hypothesis." Actually, I think chris may have been saying somewhat the same thing to you. Aside from that, of course one shouldn't assume a paper, even having passed peer review, reaches the correct conclusions. But there are so many many papers ... the balance of evidence tilts clearly toward significant AGW. That there are uncertainties in feedbacks - this applies to any climate forcing, so AGW still 'has a leg up on' various alternatives (in the sense of contenders to being the major forcing of relevant changes), and the 'burden of proof' doesn't fall all the way back to showing CO2, et. al., as big players, just because of feedback uncertainties. In particular with 'dismissing offhand' - see somewhere above...
86. Patrick 027 at 14:38 PM on 14 October, 2008
    "To save time and server space, I ask you to read the comments in "Arctic sea ice melt - natural or man-made?"" ... will do, eventually... -------- a few loose ends: quasistationary planetary waves - they don't tilt much with height - at least not relative to their wavelengh. Systems can/could also grow through barotropic instability, which is an instability caused by larger horizontal wind shear (such as on the sides of a jet stream). I don't know as much about that.
87. Quietman at 04:00 AM on 15 October, 2008
    Patrick (and chris) The papers (all papers, peer reviewed or otherwise) present an argument. That state their observations, methods used (so you can duplicate the test) and references to avoid restating prior arguments. The argument is presented largely in the "conclusions". The papers are all worth reading but it must be remembered that the paper IS AN ARGUMENT, attempting to persuade others to see the authors viewpoint. Accepting the authors conslusions is not mandatory. Peer review indicates that at least one other person in the same field of research agrees, it does not make it fact. If you read the papers carefully, in particular the methods and results you can often come to a totally different conclusion using a wider bas of information. All of the articles cited are related but the authors have not connected the dots. Ignore their conclusions, connect the dots and draw your own conclusions. THAT is what science is all about.
88. Quietman at 04:05 AM on 15 October, 2008
    Patrick Re: My response to chris. It is exactly what he/she? has accused me of on several occasions because I often do not accept an authors conclusions, especially Hansens.
89. Quietman at 04:08 AM on 15 October, 2008
    Re: "Dark aerosols are/have contributed to arctic warming and melting in that way; that is true. tropospheric ozone has also contributed to Arctic warming and melting. So has CO2, CH4, etc. However, the highest albedo is from fresh snow. Old snow and ice tends to have a lower albedo." Agreed.
90. Quietman at 04:09 AM on 15 October, 2008
    Re: "Meltwater could come from the surface, flowing down into the glacier through moulins - this source would explain the seasonality of any meltwater-induced lubrication of the glacier. (Of course, however the ice is melted or induced to flow, the resulting thinning would lower the ice surface and cause warming of the ice surface that way.)" Agreed.
91. Quietman at 04:16 AM on 15 October, 2008
    Re: "Potentially so but only in a few locations, whereas the ice mass loss and general warming are far far far more widespread and general." Of those known or recognized at this point in time. All of these articles are findings after the IPCC had decided the cause was AGW. Re: "I think at least some of the articles you referenced did say that, not about some of the specific locations but about much of the other warming." Yes some cite AGW but without making it an argument (ie. it is assumed from the start). They did not look at the issue without the background assumption that it could only be AGW. Look at the facts, not the assumptions.
92. Quietman at 04:44 AM on 15 October, 2008
    Re: Your comments on plausibility. Yes the senate has even looked into the matter. If the scientist has a position like Spencer he can speak out, it's only reputation at stake. If the scientist is junior he can be fired or asked to resign. It has in fact happened. Polotical correctness is a disease of society that has been with us since the commie hunt back in the 1950s. That is why I said to read carefully. When a scientist skirts the issue it means that he/she does not agree but will not say so.
93. Quietman at 04:45 AM on 15 October, 2008
    Excuse the spelling, my attention is somewhat divided today with a sick grandson.
94. Quietman at 07:20 AM on 16 October, 2008
    PS I suggest that you read this BBC November 2007 article as it does explain the skeptic attitude on this issue.
95. Quietman at 07:29 AM on 16 October, 2008
    The link in 94 did not work. I think I put a slash after stm so heres a copy and paste version: http://news.bbc.co.uk/2/hi/science/nature/7081331.stm
96. Patrick 027 at 12:23 PM on 18 October, 2008
    - started reading comments in "Arctic sea ice melt - natural or man-made?" - up to 119 so far... will return later...
97. Patrick 027 at 15:46 PM on 18 October, 2008
    - now up to 158. Interesting. Not necessarily in a good way... :)? (PS there has not been an overall warming trend in the last five million years - if anything an overall cooling trend (PS NOT claiming it is a constant linear trend) - superimposed on which are glacial-interglacial fluctuations.)
98. Patrick 027 at 04:21 AM on 19 October, 2008
    - now up to 170... will comment more later but a brief note... Do the math. Do the math. Do the math. Do the math. Do the math. Do the math.
99. Patrick 027 at 04:29 AM on 19 October, 2008
    Re Quietman 186 (Arctic sea ice melt...): Many different people at different times may use any given word. People change. It's not even the same people around today as back then. In today's world, the worst treatment of returning soldiers and their families of which I am aware is by a far-right-wing reverend from - Kansas? - who goes around protesting at funerals, and by the government itself, but of course none of this is pertinent to the subject at hand. I was once told in high school by an aquaintance not to say 'pasta' because it's a 'yuppie word'. I was a bit puzzled by her concern on the matter - sure it's from a foreign language and may sound 'fancy' (if you're not used to it), but ... (doesn't my using it make it not so much of a yuppie word anymore?)
100. Patrick 027 at 04:48 AM on 19 October, 2008
     Echoing Philippe 190: Your complaints about abuse of peer review - this really doesn't prove anything regarding AGW but it may be worthwhile to note that one line of attack by creationists/ID proponents is to complaign about how their side is 'shut out' by the scientific establishment. ---- I can see why you would have gotten upset by the tone of your opponents; however, I can see why your opponents overall could have gotten very frustrated with you and why they would have labelled you a contrarian/denier. Also, your references to bibles and fundamentalists and evolution, and suggesting that a person should think for him/herself, were offensive because they imply things about your opponents which I don't think were generally true (certainly not anymore than they would apply to yourself - no offense.). More on that later... -- I can see why you (Quietman) and chris were having a hard time discussing the conclusions/interpretations of the paper(s) which used observed responses to solar forcing to figure out a climate sensitivity, which would then apply to CO2 forcing. What would have been helpful would have been for you to explicitly state one or more of the following (whichever applies to your thoughts): 1. the efficacy of the forcings could be different (** more on that later) 2. the solar forcing may extend beyond TSI (**although I would point out the authors apparently went on to find evidence for TSI being most/all of the solar (or solar-cycle-correlated??) forcing - I am only infering this from a quoted portion in the comments). 3. solar forcing may be correlated with some other forcing. 4. CO2 forcing is significantly overestimated (which is highly unlikely, I think - refer back to our earlier discussions). Any of these might have yielded some interesting conversation?

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