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  • Antarctic cooling, global warming? « RealClimate
    effect did not apply 2 Doug says 12 Dec 2004 at 9 21 PM The fact that the southern oceans are absorbing heat may set up another interesting lag effect Warming oceans will increase rates of evaporation which will pump more heat trapping large molecules i e gaseous H2O into the atmosphere So while the oceans are a heat sink in the short term warmer oceans are a source of climate gases in the long term More positive feedback See for instance http www gcrio org ipcc qa 09 html 3 David Risen says 27 Dec 2004 at 4 13 PM I agree that local events should not be used as evidence for or against global warming Do you apply the same degree of criticism to authors who use local warming to argue for global warming Discover Magazine s 1 story in science for 2004 is that Evidence of global warming became so overwhelming in 2004 that now the question is What can we do about it http www discover com issues jan 05 cover Read the article You will see that the overwhelming evidence listed is based on LOCAL conditions I look forward to your editorial comments debunking this dishonest use of science 4 Oscar says 29 Dec 2004 at 8 31 PM Wouldn t the real issue about Antarctic cooling be if the amount of water locked up in the ice cap increasing or decreasing and at what rate There is a lot of water down there now but given the fact that parts of the continent are getting cooler and parts are getting warmers plus the effects on air currents etc this seems like an interesting question to answer Any studies on the depth of the ice cap 5 Understanding Global Warming Understanding Global Warming says 30 Dec 2007 at 3 55 AM of extra water vapor and is not inconsistent with a warming world Despite this and a slight cooling in parts of Antarctica now abating most of the world s glaciers have been receding as part of an inter decadal 6 Understanding Global Warming says 6 Jan 2008 at 9 38 PM of extra water vapor and is not inconsistent with a warming world Despite this and a slight cooling in parts of Antarctica now abating most of the world s glaciers have been receding as part of an inter decadal 7 Right wing agenda in the public schools Page 4 Political Forum says 15 Apr 2008 at 3 07 AM the level of man s role in global climate change don t call it global warming since some areas of the earth get cooler as a result of the change But maintaining clean water and air to stay on the safe side seems like a good idea I don t 8 Cardinal Pell Australia s Climate Change Lyre Bird Under The Milky Way says 21 Jan 2009 at 8 26 PM short on Antarctica Pell was selective to the point of myopia Really he

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  • The Arctic Climate Impact Assessment II « RealClimate
    Baliunas explained The first point was addressed in a previous post and the second statement probably refers to the mid Holocene and so the previous comment on Michaels is relevant The degree of natural variability is of course key in attributing climate change to anthropogenic changes and all estimates of this based on proxy records in the past and modelling studies point to the recent warming as being outside the range of natural variability Change is indeed a constant but it is the magnitude and rate of change in the current situation that is unusual And finally a new definition of the word refute McCain s claims about a robin population explosion in the Arctic were refuted as well Marlo Lewis a senior fellow at the Competitive Enterprise Institute CEI said Even if it s true that robins are making their first appearance in Arctic areas what it means it that the robin s habitat is expanding I always thought environmentalists liked birds To me this is good news Lewis added Apparently refute now means to agree in every respect Comments pop up 1 One Response to The Arctic Climate Impact Assessment II 1 Ziel says 15 Dec 2004 at 1 57 AM Do you think that McCain s comment about robins in the Arctic being a sure sign of global warming is worthy of refutation on this site Site Google Custom Search Recent Comments What is the best description of the greenhouse effect Jim Eager What is the best description of the greenhouse effect Patrick Eriksson What is the best description of the greenhouse effect Kevin McKinney Anti scientists Carbomontanus What is the best description of the greenhouse effect Spencer Marvel et al 2015 Part III Response to Nic Lewis SteveS What is the best description of the greenhouse effect Chris Colose Blizzard Jonas and the slowdown of the Gulf Stream System doiknow What is the best description of the greenhouse effect James Powell Unforced Variations Feb 2016 Jim Galasyn With Inline Responses Marvel et al 2015 Part III Response to Nic Lewis SteveS Marvel et al 2015 Part III Response to Nic Lewis steve s Marvel et al 2015 Part III Response to Nic Lewis Andrew Kerber Blizzard Jonas and the slowdown of the Gulf Stream System Hank Roberts Blizzard Jonas and the slowdown of the Gulf Stream System doiknow Marvel et al 2015 Part III Response to Nic Lewis MartinM Anti scientists Don McKenzie Marvel et al 2015 Part III Response to Nic Lewis Matt Skaggs Anti scientists mikeworst New On line Classes and Models Marcus Pages Acronym index Data Sources Categories Climate Science Aerosols Arctic and Antarctic Carbon cycle Climate impacts Climate modelling El Nino Geoengineering Greenhouse gases Hurricanes Instrumental Record IPCC Oceans Paleoclimate Sun earth connections Communicating Climate Reporting on climate skeptics Extras Attic Comment Policy Contributor Bio s FAQ Glossary In the News Reviews Supplemental data Tutorials hydrological cycle Open thread RC Forum Scientific practice statistics The Bore Hole Books Contributors Highlights Dummies Guide

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  • Pourquoi la stratosphère refroidit alors que la troposphère se réchauffe ? « RealClimate
    two layers have different composition If we are talking about clear atmosphere then no because the radiation will be ONLY at exactly those frequencies where the greenhouse gases above and below absorb emit If you are talking about clouds and aerosols then maybe but maybe not if the layer above is also cloud aerosol Trapping of radiation in clouds can be significant 7 James B Shearer says 26 Dec 2004 at 10 05 PM Eli Rabett I don t understand your point If we consider a thin enough layer most radiation will pass right through the layer even at the most absorbant frequencies 8 Eli Rabett says 28 Dec 2004 at 12 19 AM You have to integrate my answer As you say in the limit everything is thin but irrelevant 9 James B Shearer says 28 Dec 2004 at 10 10 PM Let me present a model illustrating my point Consider a slab atmosphere modeled as a gray body at long wavelengths with emissivity e Suppose further that a fraction a of the incoming shortwave radiation is absorbed in the atmosphere with the remainder being absorbed by the ground Let T1 be the temperature of the atmosphere T2 be the temperature of the ground and TB be the black body temperature of the ground with no atmosphere Then I believe we have T1 4 TB 4 a e a e e 2 e T2 4 TB 4 2 a 2 e Then for certain values of a and e the atmosphere will be cooler than the ground but increasing e will cool the atmosphere further For example a 05 e 1 I think this shows gavin s argument that this cannot occur is incorrect 10 Nobuki Matsui says 30 Dec 2004 at 6 32 PM I found those web site below Are they really non sense If so how Could anybody explain to us http people freenet de klima indexe htm http www geocities com atmosco2 backrad htm http www geocities com atmosco2 Influence htm Response Yes These arguments are nonsense If I have time I ll try and see what the major error is and report back gavin 11 James B Shearer says 15 Jan 2005 at 6 46 PM Unfortunately I believe the updated post is still incorrect First as the temperature gradient in the atmosphere increases at a certain point the atmosphere becomes unstable because rising falling packets of air do not cool warm fast enough by expansion compression to stop rising falling When this point is reached convection starts and effectively prevents the temperature gradient from increasing further This point has already been reached in the lower atmosphere otherwise the surface would be much warmer than it actually is As far as I know there is no reason to expect greenhouse warming to increase the lapse rate near the surface Second even if we ignore convection and assume all warming of the atmosphere is from below ie no incoming solar radiation is absorbed in the atmosphere it is not the case that the atmosphere temperatures will pivot around some fixed level increasing below it and falling above it Instead it is reasonably easy to see that in this case the temperature of the top of the atmosphere will remain fixed at 84 TB where TB is the black body temperature of the earth and the rest of the atmosphere will warm with the greatest warming near the ground This means the effective radiating level will rise which makes sense as it is harder to see into the atmosphere Finally if I am not mistaken the temperature of the top layer of an atmosphere consisting of n blackbody shells should be Tg n 1 25 not Tg 2 n 4 as stated Response I concur with your correction of the n shell problem I should have worked it out for myself instead of trusting what someone told me and the post is amended accordingly While your other two points are valid they are not strictly corrections I specifically state that I m ignoring convection and other atmospheric mixing processes in order to simplify the discussion They are clearly important in the troposphere but it doesn t help understand the stratospheric part As part of the final response to a change in GHGs the effective radiating level will indeed move up but above that level the tendency will be to cool Possibly a more complete statement would have been that you can think of the temperature profile pivoting around the radiative level and having that pivot move up a bit There will still be cooling in the upper atmosphere gavin 12 John Davis says 18 Jan 2005 at 5 25 AM I see that Steve Milloy has posted some graphs on junkscience com which purport to show that the stratosphere has in fact NOT cooled over the past 10 years or so Can you debunk please Response There is too much junk on junkscience to take it seriously A better reference is http www ghcc msfc nasa gov MSU msusci html though the graph there is substantially the same as SM s Fitting a curve through 10 years of data isn t a very good idea if you use the full set you obviously get a very different answer Given that CFC concentrations in the atmos have largely stabalised I would suppose that ozone too should stabalise SM seems to reject that but for no very clear reason William Response This is bad even by Milloy s own standards While the basic physics is sometimes difficult to explain see above the basic issue is that stratospheric temperatures change in response to local effects they do not change because the troposphere does i e troposphere warming does NOT imply stratosphere cooling Thus the changes in the stratosphere are basically a function of the greenhouse gases ozone levels and volcanic aerosols there The changes seen in the MSU 4 data as even Roy Spencer has pointed out are mainly due to ozone depletion cooling and volcanic eruptions which warm the stratopshere because the extra aerosols absorb more heat locally As William points out ozone depletion is levelling out since the Montreal Protocol and so lower stratospheric cooling will start to attenuate but then Milloy doesn t appear to think that ozone depletion was a real phenomena either gavin 13 Eli Rabett says 26 Feb 2005 at 8 47 PM I don t know if this is still open but one point to keep in mind is that the temperature increases with altitude in the stratosphere James Shearer seems to be saying that it decreases with altitude 14 James B Shearer says 26 Feb 2005 at 9 12 PM I don t agree that temperatures will pivot around the effective radiating level Instead the entire atmosphere will get warmer assuming no atmospheric absorption of incoming solar radiation Consider the case of n black body shells Adding shells makes the ground hotter but the temperature of the top shell remains at TB the blackbody temperature of the earth More generally assume the top shell is a graybody shell with emissivity e Then its temperature will be 1 2 e 25 TB Note this is an increasing function of e so even for the top layer increasing e causes the layer to warm As we let this layer get thinner e will go to 0 and the temperature of the top layer will go to 84 TB So as I said in my previous comment the temperature at the top of the atmosphere is effectively fixed at 84 TB Still more generally consider n graybody shells emissivity e numbered from the top Then if I calculated correctly the temperature of the jth shell is TB 1 j 1 e 2 e 25 and the temperature of the ground is TB 2 n 1 e 2 e 25 All of these are increasing in e Also note the discontinuity at the ground If we let e 1 n and let n go to infinity the temperature of the bottom layer is TB but the temperature of the ground is 1 1 TB Response You can only understand the strat cooling by knowing the atmos is non grey In a grey atmos it all warms The stratosphere exists because it is non grey ozone abs of UV Adding CO2 increases its ability to cool but less its ability to warm since most comes from UV so it cools I think this means I m agreeing with JBS William Response Et tu William Take a step back here I am not saying the atmosphere is like the n blackbody shell atmosphere This example is given as an end member for the extreme GHG effect which is to be compared to the no GHG case It is the difference between them that tells you what increasing GHGs do not what happens when you increase the number of shells In the real world we are in between the two cases but increasing GHGs pushes us towards an n shell case Since that case has a much steeper temperature gradient the basic effect of increasing GHG is to increase that gradient Given that the effective blackbody emission must be constant and allowing for a small movement in the effective radiating level an increasing gradient must therefore lead to cooling far above this level UV absorbtion by O3 is irrelevant for this point as is convection in the troposphere although it is key in setting the actual temperature profile gavin 15 James B Shearer says 27 Feb 2005 at 6 51 PM Eli Gavin is arguing above that adding greenhouse gasses would cause the stratosphere to cool even if the stratosphere was not being warmed by the adsorption of UV and that this is the explanantion of stratosphere cooling I am arguing that this is incorrect if all warming was from below there would be no cooling Gavin the gradient increases but the fixed point is the top of the atmosphere not the effective radiating level As a result all layers warm with the amount of warming increasing as you move towards the surface This means the effective radiating level rises Consider the top of the atmosphere as an arbitrarily thin gray body Looking down from this layer we see the earth radiating at its black body temperature TB Looking up we see space at near absolute zero So this layer will have temperature TB 4 0 4 2 25 or 5 25 TB or 84 TB as claimed above If the top layer is not arbitrarily thin but instead has emissivity e then its temperature will be TB 2 e 25 In either case the temperature is independent of the details of the temperature structure below the key point is that the total outgoing radiation must balance the incoming solar radiation Response Obviously radiaitve balance must be maintained and I am not disputing that the effective radiative level will rise Possibly the solution to this is that in the real atmopshere the movement of this level is severely constrained mainly by adiabatic cooling and so cannot rise enough to produce your solution I ll think about this a little more gavin 16 James B Shearer says 28 Feb 2005 at 7 17 PM Suppose we add absorption of incoming solar radiation to our model of the top of the atmosphere Let the top layer be a gray body with emissivity e and suppose it also absorbs a fraction f of the incoming solar radiation Then if I have calculated correctly it will have temperature T e f ef e 2 e 25 TB where as before TB is the black body temperature of the earth Note for e f T TB so the temperature increases from the effective radiating level to the top of the atmosphere Now let f a e for some constant a and let e go to zero ie let the top layer become arbitrarily thin Then in the limit T 1 a 2 25 TB Now if adding greenhouse gasses increases e but not f then a will decrease as will the temperature at the top of the atmosphere We can check this by computing the dT de and comparing it to zero By my calculation the derivative will be negative for f e e 1 1 e 2 So if f a e for some fixed a 0 the derivative will become negative as e goes to zero as expected This is true even if a 1 and the temperature of the top of the atmosphere is less than the black body temperature of the earth So I agree with William the cooling effect at the top of the atmosphere requires that the atmosphere be absorbing some incoming radiation and that this absorption be mostly by non greenhouse gasses Response You have simply restated the problem as being the same as for a single atmospheric layer read Tg for your new TB This doesn t help ascertain why different layers react differently And it doesn t explain why the mesosphere with very few absorbers also cools gavin 17 Andy Lacis says 2 Mar 2005 at 12 56 PM The question of why the stratosphere cools when the troposphere warms addresses an important validation point for the CO2 greenhouse effect but the question as stated is ill posed in that the correct answer depends on the proverbial details Climate forcing perturbations such as increasing the solar constant increasing black carbon aerosols tropospheric and decreasing surface albedo low cloud cover sea salt aerosol will on global average warm the ground and troposphere and will also warm the stratosphere For these types of radiative climate forcings the atmospheric temperature profile will be shifted basically unchanged to its new equilibrium position On the other hand decreasing stratospheric ozone above 25 km increasing stratospheric water vapor and increasing atmospheric CO2 uniformly with height will produce global surface and tropospheric warming along with stratospheric cooling These results are described in considerable detail in Hansen Sato and Ruedy 1997 Radiative forcing and climate response in JGR 102 6831 6864 see their Plate 2 for 2xCO2 Plate 3 for 2 So Plate 5 for ozone The radiative effects of increased stratospheric water vapor act to cool the stratosphere and warm the troposphere and are described by Oinas et al 2001 Radiative cooling by stratospheric water vapor big differences in GCM results GRL 28 2791 2794 That holds for the global mean temperatures Oinas et al also show that stratospheric dynamics make their contribution in the polar vortex regions to produce local warming in the 1 mb region for the uniformly applied increase in stratospheric water vapor This just shows that while the stratosphere as a whole may be in radiative equilibrium i e energy transfer is primarily by radiative means there are some locations in the stratosphere where dynamic energy transport is also significant The oversimplified analytic expressions that have been used to make the case pro and con a given explanation for why the atmosphere responds as it does are of limited validity For example the formula given by JBS that T e f ef e 2 e 25 TB can t really be correct since setting the solar input fraction f to zero does not reproduce temperature of the earth TB unless the emissivity e is equal to unity The 2 layer equilibrium relationship Ta 0 84Tg which is valid for an isothermal gray absorbing layer above a Planck emitting ground when applied to multiple layers is valid only when the layers are either totally transparent or totally opaque Also the T 4 dependence refers only to spectrally integrated radiation Planck radiation is linear in T at microwave wavelengths and goes to an increasingly higher exponential dependence toward shorter wavelengths Simple formulas can be useful but they are a poor substitute for the physics involved Radiative transfer in the earth s atmosphere is not particularly amenable to simple formulas because the atmosphere is semi transparent to differing degree at different wavelengths which allows radiation emitted locally to interact with the entire atmosphere Even for a relatively simple example of a gray medium calculating the equilibrium temperature profile within a homogeneous slab involves a singular Fredholm integral equation of the second kind as described by M N Ozisik in Radiative Transfer 1973 The radiative transfer problem is best addressed numerically with a sufficient number of vertical layers to resolve the atmospheric temperature and absorber distributions and with a sufficient number of spectral intervals to resolve the spectral dependence of the contributing gases as is being done in most GCMs For radiative transfer the vertical geometric scale is not relevant only the optical depth distribution matters From a semi transparent atmosphere radiation to space can come from virtually all parts of the atmosphere But the bulk of it comes from the so called TAU 1 level looking down from space where the opacity is near unity This is because the fundamentals of thermal radiation from an isolated slab emissivity absorptivity transmissivity are related by emissivity absorptivity 1 transmissivity where transmissivity exp TAU neglecting directionality Thus radiation emitted from below the TAU 1 level gets mostly absorbed before it can get out to space And radiation emitted from the uppermost levels of the atmosphere is small because the opacity there hence the emissivity is small and little flux is emitted Spectrally the opacity of the atmospheric column ranges from a few tenths in the 10 micron window region to many thousands in the center of the 15 micron CO2 band As a result the thermal radiation that is emitted to space comes from a wide range of points in the atmosphere ranging all the way from the ground to the top of the stratosphere The spectrally averaged effective emission temperature of the earth is about 252 K which corresponds to the physical temperature near the 6 km level This is also then

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  • Le printemps 2005 comptera-t-il parmi les mauvais pour l’ozone arctique ? « RealClimate
    a background in environmental regulation so I took a few minutes to do some research The United Nations Environmental Program has some great information on this The Ozone Secretariat in the UNEP deals with the Montreal Protocol According to the Secretariat CFC production has dropped considerably This information is at http www unep org ozone index asp There is a ton of facts on this site You can look up which countries have ratified the Montreal Protocol http www unep org ozone Treaties and Ratification 2C ratification asp The Frequently Asked Questions has some great publications that address scientific questions environmental effects and the impact of the Montreal Protocol http www unep org ozone Public Information 4D PublicInfo FAQ asp 8 Pat Neuman Hydrologist says 15 Mar 2005 at 5 51 AM In Earth s past what was the ozone layer like during the globally high temperature episodes 55 mya 100 mya 220 mya Major extictions took place during these episodes The extinctions near the late Paleocene Eocene Thermal Maximum PETM 55 mya were mainly marine species It seems likely that depletion of the ozone layer near the PETM led to a loss of plankton and resulting collapse of marine ecosystems Evidence exists of ultra violet radiation in late Permian extictions 230 250 mya I haven t read anything on what may have contributed to the extinctions during the Cenomanian Turonian 94 100 mya It seems likely that ozone depletion contributed to the major extinctions that took place during these warm global periods Major extictions also occurred at the end of the Cretaceous 65 mya believed to be related to an asteroid crash into the sea off the Yucatan Peninsula Is it possible that the ozone layer was depleted from water vapor that entered the stratosphere from the big splash Response The problem with hypotheising ozone changes in the past is that ozone leaves no unique geochemical trace and thus you have to rely on models completely to fill in the gaps However ozone reponses to climate changes are quite sensitive to the initial base state how much stratospheric water vapour was there how much methane volcanic aerosols etc since it forms as a delicate balance between UV related production and chemical loss which is highly non linear I would be very hesitant in attributing mass extinctions to ozone losses In the PETM case we did some calculations showing around 20 max depletion for various CH4 release scenarios I m sure someone will do a better calculation at some point but this first cut doesn t seem high enough to justify your claim Global warming of around 4 to 5 degrees is a more likely cause gavin 9 Pat Neuman Hydrologist says 15 Mar 2005 at 10 36 PM I wrote It seems likely that depletion of the ozone layer near the PETM led to a loss of plankton and resulting collapse of marine ecosystems gavin replied I would be very hesitant in attributing mass extinctions to ozone losses My comment It seems unlikely to me that a 4 to 5 degree warming of the atmosphere would have caused the PETM marine extinctions I think the food supply plankton for marine ecosystems was cut off near the PETM What happened to the PETM marine vegetation and why How important is the ozone layer in protecting vegetation on water and land Vegetation is at the bottom of the food chain If vegetation dies 10 William says 18 Mar 2005 at 4 23 PM This may be of interest Ozone values over the UK are currently quite low This afternoon I measured 230 DU over BAS in agreement with the forecast Values are normally around 350 DU at this time of year Values are probably at their lowest today but will remain significantly below average over the weekend Which i got from Jonathon Shanklin in Cambridge 11 Francis MASSEN says 22 Mar 2005 at 6 08 PM Answer to 10 Ozone values are VERY variable even if there is a mean sinusoidal pattern over Europes latitudes see http www meteo be english pages OzonEN html or http meteo lcd lu dobson05 html the variations from that mean trend are exceptional great as such a local measurement of low values is never a hint to a lowering trend and the opposite is true also Btw I am still waiting for Gavins Arctic ozone loss happening read my comment 5 and again watch http www temis nl protocols o3field data forecast today np gif for a very healthy O3 layer 12 Ferdinand Engelbeen says 22 Mar 2005 at 6 18 PM Data from the Swedish Odin satellite indicate that no arctic ozone hole will appear this winter despite fears to that effect See for the full article http www spacedaily com news ozone 05d html 13 Markus Rex says 24 Mar 2005 at 6 48 AM Comment on 5 and 11 The Arctic ozone layer is very variable mainly for dynamical reasons This makes it difficult to separate chemical ozone loss from natural changes induced by transport Sophisticated approaches are needed to reliably quantify anthropogenic chemical loss of ozone from observations A number of approaches have been developed over the past couple of decades and these are well documented in the literature But it is also well known that just looking at fields of total ozone does not tell us much about chemical loss total ozone is a measure of the thickness of the ozone layer The link given in the comment of Francis Massen points to a total ozone map The comment suggests that by looking at this map everyone can convince himself that no chemical ozone loss took place so far But total ozone maps are not able to support any statement about chemical ozone loss in the Arctic Due to transport processes total ozone over the Arctic and northern mid latitudes increases each winter Depending on the meteorological conditions during the winter chemical loss chews away part of this increase The

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  • Will spring 2005 be a bad one for Arctic ozone? « RealClimate
    has some great publications that address scientific questions environmental effects and the impact of the Montreal Protocol http www unep org ozone Public Information 4D PublicInfo FAQ asp 8 Pat Neuman Hydrologist says 15 Mar 2005 at 5 51 AM In Earth s past what was the ozone layer like during the globally high temperature episodes 55 mya 100 mya 220 mya Major extictions took place during these episodes The extinctions near the late Paleocene Eocene Thermal Maximum PETM 55 mya were mainly marine species It seems likely that depletion of the ozone layer near the PETM led to a loss of plankton and resulting collapse of marine ecosystems Evidence exists of ultra violet radiation in late Permian extictions 230 250 mya I haven t read anything on what may have contributed to the extinctions during the Cenomanian Turonian 94 100 mya It seems likely that ozone depletion contributed to the major extinctions that took place during these warm global periods Major extictions also occurred at the end of the Cretaceous 65 mya believed to be related to an asteroid crash into the sea off the Yucatan Peninsula Is it possible that the ozone layer was depleted from water vapor that entered the stratosphere from the big splash Response The problem with hypotheising ozone changes in the past is that ozone leaves no unique geochemical trace and thus you have to rely on models completely to fill in the gaps However ozone reponses to climate changes are quite sensitive to the initial base state how much stratospheric water vapour was there how much methane volcanic aerosols etc since it forms as a delicate balance between UV related production and chemical loss which is highly non linear I would be very hesitant in attributing mass extinctions to ozone losses In the PETM case we did some calculations showing around 20 max depletion for various CH4 release scenarios I m sure someone will do a better calculation at some point but this first cut doesn t seem high enough to justify your claim Global warming of around 4 to 5 degrees is a more likely cause gavin 9 Pat Neuman Hydrologist says 15 Mar 2005 at 10 36 PM I wrote It seems likely that depletion of the ozone layer near the PETM led to a loss of plankton and resulting collapse of marine ecosystems gavin replied I would be very hesitant in attributing mass extinctions to ozone losses My comment It seems unlikely to me that a 4 to 5 degree warming of the atmosphere would have caused the PETM marine extinctions I think the food supply plankton for marine ecosystems was cut off near the PETM What happened to the PETM marine vegetation and why How important is the ozone layer in protecting vegetation on water and land Vegetation is at the bottom of the food chain If vegetation dies 10 William says 18 Mar 2005 at 4 23 PM This may be of interest Ozone values over the UK are currently quite low This afternoon I measured 230 DU over BAS in agreement with the forecast Values are normally around 350 DU at this time of year Values are probably at their lowest today but will remain significantly below average over the weekend Which i got from Jonathon Shanklin in Cambridge 11 Francis MASSEN says 22 Mar 2005 at 6 08 PM Answer to 10 Ozone values are VERY variable even if there is a mean sinusoidal pattern over Europes latitudes see http www meteo be english pages OzonEN html or http meteo lcd lu dobson05 html the variations from that mean trend are exceptional great as such a local measurement of low values is never a hint to a lowering trend and the opposite is true also Btw I am still waiting for Gavins Arctic ozone loss happening read my comment 5 and again watch http www temis nl protocols o3field data forecast today np gif for a very healthy O3 layer 12 Ferdinand Engelbeen says 22 Mar 2005 at 6 18 PM Data from the Swedish Odin satellite indicate that no arctic ozone hole will appear this winter despite fears to that effect See for the full article http www spacedaily com news ozone 05d html 13 Markus Rex says 24 Mar 2005 at 6 48 AM Comment on 5 and 11 The Arctic ozone layer is very variable mainly for dynamical reasons This makes it difficult to separate chemical ozone loss from natural changes induced by transport Sophisticated approaches are needed to reliably quantify anthropogenic chemical loss of ozone from observations A number of approaches have been developed over the past couple of decades and these are well documented in the literature But it is also well known that just looking at fields of total ozone does not tell us much about chemical loss total ozone is a measure of the thickness of the ozone layer The link given in the comment of Francis Massen points to a total ozone map The comment suggests that by looking at this map everyone can convince himself that no chemical ozone loss took place so far But total ozone maps are not able to support any statement about chemical ozone loss in the Arctic Due to transport processes total ozone over the Arctic and northern mid latitudes increases each winter Depending on the meteorological conditions during the winter chemical loss chews away part of this increase The transport processes are also very variable from winter to winter and the amount of ozone pumped into the Arctic is also correlated with temperature this is not a causal relationship the correlation exists because variability in temperatures and in ozone transport are both driven by the same atmospheric processes From just looking at total ozone how can we seperate natural variability in transport from anthropogenic chemical loss Just one example how problematic the interpretation of total ozone maps is Look at ftp toms gsfc nasa gov pub eptoms images npole Y2005 IM

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  • 2005 Record Arctic Ozone Loss « RealClimate
    Roberts says 9 May 2005 at 8 37 PM Disclaimer I have no competence at all in this area professionally I search and sometimes ask questions to elicit answers that haven t been typed yet On this one I can t even guess which datasets were used I do find a few that are old but interesting http strat www met fu berlin de products cdrom html section4 html section4 2 QUOTE 4 2 SPARC Stratospheric Temperature Trend Assessment STTA Ramaswamy et al 2001 Under the auspices of the World Climate Research Program WCRP the sub program SPARC Stratospheric Processes and Their Role in Climate initiated the STTA Group The charter was 1 to bring together all available data sets of stratospheric temperatures and 2 to analyse the trends in a consistent manner The results of this work are published in Ramaswamy et al 2001 The report deals carefully with all the problems arising from the various very diverse data sets and their trends END QUOTE And this one does graph trend lines for polar stratospheric temperature that on average over recent years would correlate to the trend line for area for PSCs in the article being discussed http strat www met fu berlin de products cdrom html section2 3 html section2 3 1 QUOTE 2 3 1 Temperature Trends at the North Pole since 1956 The time series of the 30 hPa annual mean temperatures  C at the North Pole is shown in Fig 19 It is based on the data given in Table 4 If a linear trend is calculated for the whole series the trend is 0 50 K decade with a probability of 99 But again as discussed above the interannual variability is large even in the annual mean and it is difficult to decide if this calculation is the correct answer to the question about temperature trend in the stratosphere END QUOTE Again disclaimer I definitely don t know what I m talking about I m just pointing and grunting 6 Hank Roberts says 9 May 2005 at 8 47 PM Skip that last one this seems more on point well keep the disclaimers I still don t know anything From http strat www met fu berlin de products cdrom html section2 1 html fig13 Figure http strat www met fu berlin de products cdrom fig fig13 gif Caption Figure 13 Number of days with temperatures lower than Tnat white or Tice red at a 50 hPa and b 30 hPa Integral for each season of the area in of the Northern Hemisphere which had temperatures low enough for the formation of PSCs c at 50 hPa and d at 30 hPa Fig 2 in Pawson and Naujokat 1999 updated 7 Hank Roberts says 10 May 2005 at 6 06 PM Markus s thumbnail isn t yet linked to a full size image looks to me like the bottom two I found at http strat www met fu berlin de products cdrom fig fig13

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  • Recul du Front des Glaciers de la Péninsule Antarctique au cours des 50 dernières années « RealClimate
    seen the warming that this penninsula has He also complains that the authors Science made no mention of the studies concerning the rest of Antarctica and I see his point Personally I would ve included or required wording as such in the background info and possibly the conclusions to put the results of the study in the proper context 7 Stephen Berg says 26 Apr 2005 at 9 51 PM Authors Cook and Dr Vaughan were on the CBC s Quirks and Quarks radio show this past Saturday Here is an excerpt of their segment http www cbc ca quirks media 2004 2005 mp3 qq 2005 04 23c mp3 A description of the show can be found here http www cbc ca quirks archives 04 05 apr23 html 8 Steve Bloom says 27 Apr 2005 at 4 18 AM Re 5 To understand this issue you need to read the prior RC article the second linked reference at the end of this article and all of its linked references There is no substitute for a little homework and in any case it s unfair to the RC authors to ask them to simply repeat or restate information that s already been provided Re 6 I don t believe Michaels is taken seriously in the scientific community His favorable reference to State of Fear is a dead giveaway as is his broad brush scathing dismissal of the scientific consensus on human caused climate disruption In any case why should the Science article s references be limited to just the purported cooling in the main part of Antarctica What about all the melting ice everywhere else on the planet 9 John Booth says 27 Apr 2005 at 3 14 PM Very interesting piece I look forward to reading it in Science A couple of questions immediately came to mind that perhaps someone can answer Is the determination of glacier recession based solely on interpolation of aerial and satelite images If so does the report detail how scaling viewing angle and sea level were accounted for 10 alex kahl says 28 Apr 2005 at 8 15 PM Has anyone else been following Elizabeth Kolbert s series in the New Yorker Although she is a political correspondent her work usually includes the interaction of science and politics She was the New Yorker reviewer of Crichton s book back in December Anyways I have found the first two parts of her series to be enjoyable even though I was highly skeptical at the outset as I am with any mainstream presentation of the climate change science The first two parts of her series seem to be the type of writing that we really need to bring the mounting evidence of anthropogenically induced climate change into the public arena without contention I am curious what other folks think about the series thus far The first part is available here at the New Yorker magazine s website As a grduate student studying the export flux of biogenic particles from the ocean s surface I have been pleasantly surprised with the breadth of scientific evidence she has brought together Plus she seems to have given the appropriate credit where it is due by citing Manabe among others for early climate modelling and Broecker for his conceptualization of the conveyor belt as two of many examples 11 Brad Westervelt says 30 Apr 2005 at 7 17 PM In particular there was a period in the late 1980s and early 1990s when retreat slowed down along most of the coast and we don t see any cause for this in the temperature records so there may be some other factors at work perhaps ocean temperature Perhaps the elsewhere discussed global dimming phenomena airborne particulate from volcanoes unusual storms or other factors during said period reducing the cumulative light energy worldwide Response Global dimming is mostly associated with anthropogenic aerosols and in the southern hemisphere these are in pretty short supply gavin 12 stephan harrison says 2 May 2005 at 4 33 AM Response to Number 11 Could this slowing of glacier recession be related to changes in precipitation In Patagonia we noticed a short readvance within a general recession phase of the outlet glaciers around the early 1990s The glaciers were probably responding to a marked increase in precipitation in the region in the 1970s and 1980s and I think a similar situation has occurred in parts of New Zealand 13 Joseph O Sullivan says 2 May 2005 at 8 50 AM RE 5 Michaels on the TCS website is referring to an AP article The article is at http www enn com today html id 7581 RealClimate has mentioned Patrick Michaels on the Jan 20 post Peer Review A Necessary but not Sufficient Condition and TCS on the Feb 8 post Strange Bedfellows Bringing up Michaels employment with Cato is important Cato and TCS are political advocacy groups as are many of these think tanks They advance conservative and corporate political agendas That is why conservative foundations and industry fund them For examples see http www environmentaldefense org article cfm contentid 3804 CFID 21084385 CFTOKEN 29888831 and http www motherjones com news feature 2005 05 some like it hot html Being politically active for conservatives industry environmentalists or any other group is not a bad thing Any political advocacy group has an agenda and when evaluating their messages about climate change science it is important to examine how they advance this agenda Every political group uses spin to try to persuade the public but Cato and TCS are some of the groups that use what can be called extreme tactics in the climate change science debate Cato and TCS are hostile to environmental regulation Current environmental regulations were passed after environmental groups ran political campaigns that reflected the public s call for action addressing environmental problems Conservatives and industry were stung by these political defeats Noting the success of environmentalists conservatives and industry founded their own political advocacy groups

    Original URL path: http://www.realclimate.org/index.php/archives/2005/04/retreating-glacier-fronts-on-the-antarctic-peninsula-over-the-past-half-century/langswitch_lang/fr/ (2016-02-13)
    Open archived version from archive

  • Retreating Glacier Fronts on the Antarctic Peninsula over the Past Half-Century « RealClimate
    the studies concerning the rest of Antarctica and I see his point Personally I would ve included or required wording as such in the background info and possibly the conclusions to put the results of the study in the proper context 7 Stephen Berg says 26 Apr 2005 at 9 51 PM Authors Cook and Dr Vaughan were on the CBC s Quirks and Quarks radio show this past Saturday Here is an excerpt of their segment http www cbc ca quirks media 2004 2005 mp3 qq 2005 04 23c mp3 A description of the show can be found here http www cbc ca quirks archives 04 05 apr23 html 8 Steve Bloom says 27 Apr 2005 at 4 18 AM Re 5 To understand this issue you need to read the prior RC article the second linked reference at the end of this article and all of its linked references There is no substitute for a little homework and in any case it s unfair to the RC authors to ask them to simply repeat or restate information that s already been provided Re 6 I don t believe Michaels is taken seriously in the scientific community His favorable reference to State of Fear is a dead giveaway as is his broad brush scathing dismissal of the scientific consensus on human caused climate disruption In any case why should the Science article s references be limited to just the purported cooling in the main part of Antarctica What about all the melting ice everywhere else on the planet 9 John Booth says 27 Apr 2005 at 3 14 PM Very interesting piece I look forward to reading it in Science A couple of questions immediately came to mind that perhaps someone can answer Is the determination of glacier recession based solely on interpolation of aerial and satelite images If so does the report detail how scaling viewing angle and sea level were accounted for 10 alex kahl says 28 Apr 2005 at 8 15 PM Has anyone else been following Elizabeth Kolbert s series in the New Yorker Although she is a political correspondent her work usually includes the interaction of science and politics She was the New Yorker reviewer of Crichton s book back in December Anyways I have found the first two parts of her series to be enjoyable even though I was highly skeptical at the outset as I am with any mainstream presentation of the climate change science The first two parts of her series seem to be the type of writing that we really need to bring the mounting evidence of anthropogenically induced climate change into the public arena without contention I am curious what other folks think about the series thus far The first part is available here at the New Yorker magazine s website As a grduate student studying the export flux of biogenic particles from the ocean s surface I have been pleasantly surprised with the breadth of scientific evidence she has brought together Plus she seems to have given the appropriate credit where it is due by citing Manabe among others for early climate modelling and Broecker for his conceptualization of the conveyor belt as two of many examples 11 Brad Westervelt says 30 Apr 2005 at 7 17 PM In particular there was a period in the late 1980s and early 1990s when retreat slowed down along most of the coast and we don t see any cause for this in the temperature records so there may be some other factors at work perhaps ocean temperature Perhaps the elsewhere discussed global dimming phenomena airborne particulate from volcanoes unusual storms or other factors during said period reducing the cumulative light energy worldwide Response Global dimming is mostly associated with anthropogenic aerosols and in the southern hemisphere these are in pretty short supply gavin 12 stephan harrison says 2 May 2005 at 4 33 AM Response to Number 11 Could this slowing of glacier recession be related to changes in precipitation In Patagonia we noticed a short readvance within a general recession phase of the outlet glaciers around the early 1990s The glaciers were probably responding to a marked increase in precipitation in the region in the 1970s and 1980s and I think a similar situation has occurred in parts of New Zealand 13 Joseph O Sullivan says 2 May 2005 at 8 50 AM RE 5 Michaels on the TCS website is referring to an AP article The article is at http www enn com today html id 7581 RealClimate has mentioned Patrick Michaels on the Jan 20 post Peer Review A Necessary but not Sufficient Condition and TCS on the Feb 8 post Strange Bedfellows Bringing up Michaels employment with Cato is important Cato and TCS are political advocacy groups as are many of these think tanks They advance conservative and corporate political agendas That is why conservative foundations and industry fund them For examples see http www environmentaldefense org article cfm contentid 3804 CFID 21084385 CFTOKEN 29888831 and http www motherjones com news feature 2005 05 some like it hot html Being politically active for conservatives industry environmentalists or any other group is not a bad thing Any political advocacy group has an agenda and when evaluating their messages about climate change science it is important to examine how they advance this agenda Every political group uses spin to try to persuade the public but Cato and TCS are some of the groups that use what can be called extreme tactics in the climate change science debate Cato and TCS are hostile to environmental regulation Current environmental regulations were passed after environmental groups ran political campaigns that reflected the public s call for action addressing environmental problems Conservatives and industry were stung by these political defeats Noting the success of environmentalists conservatives and industry founded their own political advocacy groups like Cato and TCS to oppose environmental regulation Cato TCS and other groups are waging a public relations

    Original URL path: http://www.realclimate.org/index.php/archives/2005/04/retreating-glacier-fronts-on-the-antarctic-peninsula-over-the-past-half-century/langswitch_lang/en/ (2016-02-13)
    Open archived version from archive



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