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  • O que Dispara as Eras Glaciais? « RealClimate
    for cloud droplets More clouds means higher albedo which in turn might mean a cooler climate Response Note also that more low clouds would unambiguously mean a cooling effect but more high clouds could lead to either a warming effect or a cooling effect depending on the altitude of the clouds and the typical particle size in the GCR induced clouds if any raypierre 18 Ray says 16 Feb 2007 at 11 20 AM Surprising there isn t a more obvious relationship between solar forcing and the growth and ebb of the ice I m glad you posted this article 19 tamino says 16 Feb 2007 at 11 25 AM Re 15 The FFT is a poor choice because is requires the data to be evenly spaced in time which often it is not and requires the number of data points to be a power of 2 which it almost never is I applied the DCDFT date compensated discrete Fourier transform to generate Fourier power spectra of all five signals shown in the original plot assuming that the last graph is the LR04 stack I ve posted them on my blog Re 9 When giving the range of 65N insolation I mistakenly looked at the data for insolation at the pole 90N The correct range for 65N insolation is aobut 390 to 490 watts per square meter 20 Barton Paul Levenson says 16 Feb 2007 at 11 31 AM What if a massive amount was removed from one side of the earth to the other could that cause the earth to wabble the removal of steel metal iron or maybe even OIL with the combination of all of these burnt into smoke Wobble Yes it does But the effect is far too tiny to detect Compare the mass of iron ore mined since the beginning of the industrial revolution to the mass of the Earth There s no comparison Don t worry about it Is the smoke from all of these that i mentioned part of the cause for the ozone layer to be thinning Probably not That seems to be from human use of chloroflurocarbons for spray cans and refrigerants The Montreal Protocol of 1979 banned use of these and industry now uses substitutes 21 SteveF says 16 Feb 2007 at 11 52 AM On the subject Robert Ehrlich has a recent paper on solar forcing of ice ages He claims to have solved all but one of the major problems of Milankovitch forcing Solar Resonant Diffusion Waves as a Driver of Terrestrial Climate Change ABSTRACT A theory is described based on resonant thermal diffusion waves in the sun that explains many details of the paleotemperature record for the last 5 3 million years These include the observed periodicities the relative strengths of each observed cycle and the sudden emergence in time for the 100 thousand year cycle Other prior work suggesting a link between terrestrial paleoclimate and solar luminosity variations has not provided any specific mechanism The particular mechanism described here has been demonstrated empirically although not previously invoked in the solar context The theory while not without its own unresolved issues also lacks most of the problems associated with Milankovitch cycle theory http arxiv org PS cache astro ph pdf 0701 0701117 pdf I think the paper has now been published earlier this month but can t remember where Still its an interesting read Another provocative paper well worth reading is by Carl Wunsch and attempts to uage the contribution of orbital variations to climate change http ocean mit edu cwunsch papersonline milankovitchqsr2004 pdf He argues that stochastic variation is responsible although wimps out of actually coming up with an explanation His alternative hypothesis regarding abrupt climate change was rubbish too but thats another story 22 Aziz Poonawalla says 16 Feb 2007 at 1 11 PM Thanks tamino those graphs deserve to be disseminated It s quite a bit more informative thanthe original 23 SecularAnimist says 16 Feb 2007 at 2 06 PM Sorry off topic but this is in the news today and seems rather alarming Scientists Sound Alarm Over Melting Antarctic Ice Sheets by Steve Connor Science Editor in San Francisco February 16 2007 The lndependent UK Excerpt The long term stability of the massive ice sheets of Antarctica which have the potential to raise sea levels by hundreds of meters has been called into question with the discovery of fast moving rivers of water sliding beneath their base Scientists analyzing satellite data were astonished to discover the size of the vast lakes and river systems flowing beneath the Antarctic ice sheets which may lubricate the movement of these glaciers as they flow into the surrounding sea The discovery raises fresh questions about the speed at which sea levels might rise in a warmer world due to the rate at which parts of the ice sheets slide from the land into the ocean scientists said at the American Association for the Advancement of Science in San Francisco We ve found that there are substantial subglacial lakes under ice that s moving a couple of meters per day It s really ripping along It s the fast moving ice that determines how the ice sheet responds to climate change on a short timescale said Robert Bindschadler a NASA scientist at the Goddard Space Flight Centre in Maryland one of the study s co authors While the water under the Antarctic ice is not itself related to global warming the suprisingly large amount of water the surprising speed with which it moves and its effect of lubricating the movement of the Antarctic ice may affect how the ice sheets respond to warming This new discovery is of course not accounted for in the IPCC AR4 and suggests we may be in for some unpleasant surprises from Antarctica 24 P Lewis says 16 Feb 2007 at 2 23 PM Re 21 and Ehrlich It s to be published in the Journal of Atmospheric and Solar Terrestrial Physics will be doi 10 1016 j jastp 2007 01 005 And SteveF you will know this is currently newolder s favourite anti AGW evidence which it isn t so far as I can see 25 Hank Roberts says 16 Feb 2007 at 2 59 PM 1 000 kyear no significant continental drift in that time span right Just checking 26 Barton Paul Levenson says 16 Feb 2007 at 3 17 PM 1 000 kyear no significant continental drift in that time span right Just checking Actually I think there might well be significant continental drift over that period I assume by 1 000 kyear you mean 10 6 years It wouldn t be as obvious as over 100 million years but it would be enough to distort maps noticeably 27 tamino says 16 Feb 2007 at 3 52 PM Re 25 26 There s not a lot of tectonic movement in a mere million years but it may not take a lot to have a climate impact For example closure of the Isthmus of Panama and restriction of the Indonesian seaway have been suggested as reasons for the onset of northern hemisphere glaciation 3 million years ago but that s 3 million not 1 million 28 Steve Bloom says 16 Feb 2007 at 3 58 PM Re 21 SteveF thanks for the link to the new paper Regarding Wunsch both he and Huybers who was Wunsch s grad student have done follow up papers one of which was linked by Tamino in 19 Re 23 SA and what a great handle that is BTW the moment I saw this I wondered if it could explain the other recent results showing a sudden slowdown in two of the Greenland outlet glaciers Despite being trumpeted in certain circles as meaning that there s really nothing to worry about regarding the Greenland ice sheet the authors made a point of noting although not in this press release that an additional source of mass loss needs to be identified in order to reconcile their results with the GRACE data which do not show a reduction in mass loss for the same period Similar subglacial water activity in Greenland would seem to fill the bill nicely in particular because it would also explain the sharp changes in outlet glacier speed See also the interesting tone taken by this IPY press release 29 David B Benson says 16 Feb 2007 at 4 34 PM Re 25 26 27 The Indio Australian plate moves generally north at a very high rate for a tectonic plate So in a mere one million years the Himalayan Mountains and in general the Tibetian Plateau would have been modified To the east the boundary between the Indian Ocean and the South China Sea would have been altered 30 Hank Roberts says 16 Feb 2007 at 4 52 PM Can anyone add something about how the biology is changing in that time span That would I d guess be interesting as a very fast feedback effect if say plankton s changing year by year as one or more of those other signals change Might be some proxy for total primary productivity or biomass or respiration or photosynthesis or chemistry of diatom shells or lack thereof in each slice of the sediment core Not sure how to tease that out just wondering if Gaia s in there swinging behind some of that variation 31 John D says 16 Feb 2007 at 5 04 PM 23 If there is running water and lakes beneath the ice in Antarctica could it be that the earth is warming substantially and causing the ice to melt from the bottom up Interesting 32 David B Benson says 16 Feb 2007 at 5 16 PM Re 30 Hank Roberts Not directly the answer to your latest question but at each major sea low stand East Asia expands to the east and Southeast Asia grows into Sundaland Both locations will continue to contribute to biological productivity in contrast to the expanded deserts in many other locations 33 Bob M says 16 Feb 2007 at 5 49 PM I ve always been impressed by the rapidity with which glacial periods end despite the expected high feedback of all that ice cover I don t follow climate science in detail with all the ins and outs of competing models but as an interested non specialist I hope to live long enough to see a consensus explanation emerge 34 SecularAnimist says 16 Feb 2007 at 7 14 PM Bob M wrote I ve always been impressed by the rapidity with which glacial periods end Speaking of which Great Andean Glacier Will Melt to Nothing by 2012 By Mark Henderson The Times UK 16 February 2007 The principal glacier of the world s biggest tropical ice cap could disappear within five years as a result of global warming one of the world s leading glaciologists predicted yesterday The imminent demise of the Qori Kalis glacier the main component of the Quelccaya ice cap in the Peruvian Andes offers the starkest evidence yet of the effects of climate change according to Lonnie Thompson of Ohio State University Although scientists have known for decades that Qori Kalis and the other Quelccaya glaciers are melting new observations indicate that the rate of retreat is increasing Professor Thompson said When he visits this summer he expects to find that the glacier has halved in size since last year and he believes that Qori Kalis will be gone within five years This widespread retreat of mountain glaciers may be our clearest evidence of global warming as they integrate many climate variables Professor Thompson told the American Association for the Advancement of Science conference in San Francisco Most importantly they have no political agenda The Quelccaya ice cap covering 17 square miles 44 sq km in the Cordillera Oriental region of the Peruvian Andes is the world s largest tropical ice mass Qori Kalis its biggest glacier has receded by at least 0 6 miles 1 1km since 1963 when the first formal measurements were made from aerial photographs The rate of retreat has increased between 1963 and 1978 it shrank by 6 5 yards 6m a year a rate that has now risen tenfold to 65 yards annually Professor Thompson predicted six years ago that the celebrated snows of Kilimanjaro would be gone from Africa s highest mountain by 2015 and he now thinks that that estimate may have been too conservative He said Tropical glaciers are the canaries in the coalmine for our global climate system as they integrate and respond to most of the key climatological variables temperature precipitation cloudiness humidity and radiation A critical piece of evidence from almost fifty scientific expeditions to seven shrinking tropical ice caps points to global warming as the reason for their decline In all but one case snowfall has increased as ice volume has fallen More snow should mean advancing glaciers unless rising temperatures are melting the extra precipitation and the ice tongues themselves 35 Dan Robinson says 16 Feb 2007 at 8 03 PM Is it reasonable to think this is the other side of this question What ends hot ages especially artificial ones WITH INSUFFICIENT ARTIFICIAL HELP I keep hearing about how much hotter it s going to be in 2100 but nothing about after that as though one way or another it s going to end there With all the forms of positive feedback we already see what s going to create negative feedback while life is still possible on Earth like before the oceans have finished evaporating and adding to greenhouse gasses It also seems many changes are occurring faster than scientists previously expected Does someone have some hope for our grandchildren and beyond Is it possible that even climate scientists believe only what their minds can tolerate and ignore the rest 36 Wang Dang says 16 Feb 2007 at 10 59 PM Re 23 What is alarming other than the word alarm in the title You say there is a surpisingly large amount of water what amount of water would you expect And the water is moving at a surprising speed what speed would not surprise you I find this new information interesting and important but not alarming 37 BarbieDoll Moment says 17 Feb 2007 at 4 15 AM re Scientists Sound Alarm Over Melting Antarctic Ice Sheets 13 Feb 2007 Antarctic Temperatures Disagree with Climate Model Predictions Ohio State University http www newswise com articles view 527313 A new report on climate over the world s southernmost continent shows that temperatures during the late 20th century did not climb as had been predicted by many global climate models Bromwich said that the increase in the ozone hole above the central Antarctic continent may also be affecting temperatures on the mainland If you have less ozone there s less absorption of the ultraviolet light and the stratosphere doesn t warm as much That would mean that winter like conditions would remain later in the spring than normal lowering temperatures In some sense we might have competing effects going on in Antarctica where there is low level CO2 warming but that may be swamped by the effects of ozone depletion he said The year 2006 was the all time maximum for ozone depletion over the Antarctic Bromwich said the disagreement between climate model predictions and the snowfall and temperature records doesn t necessarily mean that the models are wrong It isn t surprising that these models are not doing as well in these remote parts of the world These are global models and shouldn t be expected to be equally exact for all locations he said Sea Level Rise After the Ice Melted and Today Vivien Gornitz NASA GISS Science Briefs Jan 2007 http www giss nasa gov research briefs gornitz 09 Meltwater from glacial Lake Agassiz southwest of Hudson Bay draining catastrophically into the North Atlantic via Lake Superior and the St Laurence seaway was once thought to have initiated ocean circulation changes leading to the Younger Dryas cold period Regional removal of ice sheets however occurred nearly 1000 years later and hence draining of Lake Agassiz could not likely have caused the Younger Dryas cold reversal This cold spell may have instead been triggered by increased outflow into the Arctic Ocean the Fram Strait east of Greenland and ultimately the eastern North Atlantic between 12 900 and 12 800 years before present as suggested by the glacial model of Tarasov and Peltier On the other hand Leventer et al indicate that the timing of deglaciation in eastern Antarctica roughly coincides with the onset of meltwater pulse 1B 38 William Astley says 17 Feb 2007 at 9 59 AM Another hypothesis for why the glacial periods terminate and restart is GCR modulation by changes in the intensity of the earth s magnetic field GCR changes of course as we all know it is hypothesized affect global cloud cover I am not sure why the response to the hypothesis that changes in the intensity of the geomagnetic field triggers controls the timing of the ice ages in this forum was rubbish The rubbish comment noted that geomagnetic field intensity changes do not correlate with the ice age cycles Perhaps we are looking at different data The following is data from the review paper Time Variations in Geomagnetic Field Intensity http ssn dgf uchile cl home informe 2001RG000104b pdf See Page 4 22 Figure 9 Geomagnetic field intensity level derived from composite volcanic records not sea floor sediments for the past 45 kyr Obviously Figure 9 shows that 40 kyrs ago the earth s magnetic field intensity was 75 less 2 10 22Am 2 than the geomagnetic field s current intensity 8 10 22Am 2 and that the earth s magnetic field intensity peaked at around 12 10 22Am 2 and has dropped 30 in the last 1000 years and that the geomagnetic field intensity is now dropping

    Original URL path: http://www.realclimate.org/index.php/archives/2007/02/what-triggers-ice-ages/langswitch_lang/po/ (2016-02-13)
    Open archived version from archive


  • Buzul Çağlarını Tetikleyen Nedir? « RealClimate
    and the typical particle size in the GCR induced clouds if any raypierre 18 Ray says 16 Feb 2007 at 11 20 AM Surprising there isn t a more obvious relationship between solar forcing and the growth and ebb of the ice I m glad you posted this article 19 tamino says 16 Feb 2007 at 11 25 AM Re 15 The FFT is a poor choice because is requires the data to be evenly spaced in time which often it is not and requires the number of data points to be a power of 2 which it almost never is I applied the DCDFT date compensated discrete Fourier transform to generate Fourier power spectra of all five signals shown in the original plot assuming that the last graph is the LR04 stack I ve posted them on my blog Re 9 When giving the range of 65N insolation I mistakenly looked at the data for insolation at the pole 90N The correct range for 65N insolation is aobut 390 to 490 watts per square meter 20 Barton Paul Levenson says 16 Feb 2007 at 11 31 AM What if a massive amount was removed from one side of the earth to the other could that cause the earth to wabble the removal of steel metal iron or maybe even OIL with the combination of all of these burnt into smoke Wobble Yes it does But the effect is far too tiny to detect Compare the mass of iron ore mined since the beginning of the industrial revolution to the mass of the Earth There s no comparison Don t worry about it Is the smoke from all of these that i mentioned part of the cause for the ozone layer to be thinning Probably not That seems to be from human use of chloroflurocarbons for spray cans and refrigerants The Montreal Protocol of 1979 banned use of these and industry now uses substitutes 21 SteveF says 16 Feb 2007 at 11 52 AM On the subject Robert Ehrlich has a recent paper on solar forcing of ice ages He claims to have solved all but one of the major problems of Milankovitch forcing Solar Resonant Diffusion Waves as a Driver of Terrestrial Climate Change ABSTRACT A theory is described based on resonant thermal diffusion waves in the sun that explains many details of the paleotemperature record for the last 5 3 million years These include the observed periodicities the relative strengths of each observed cycle and the sudden emergence in time for the 100 thousand year cycle Other prior work suggesting a link between terrestrial paleoclimate and solar luminosity variations has not provided any specific mechanism The particular mechanism described here has been demonstrated empirically although not previously invoked in the solar context The theory while not without its own unresolved issues also lacks most of the problems associated with Milankovitch cycle theory http arxiv org PS cache astro ph pdf 0701 0701117 pdf I think the paper has now been published earlier this month but can t remember where Still its an interesting read Another provocative paper well worth reading is by Carl Wunsch and attempts to uage the contribution of orbital variations to climate change http ocean mit edu cwunsch papersonline milankovitchqsr2004 pdf He argues that stochastic variation is responsible although wimps out of actually coming up with an explanation His alternative hypothesis regarding abrupt climate change was rubbish too but thats another story 22 Aziz Poonawalla says 16 Feb 2007 at 1 11 PM Thanks tamino those graphs deserve to be disseminated It s quite a bit more informative thanthe original 23 SecularAnimist says 16 Feb 2007 at 2 06 PM Sorry off topic but this is in the news today and seems rather alarming Scientists Sound Alarm Over Melting Antarctic Ice Sheets by Steve Connor Science Editor in San Francisco February 16 2007 The lndependent UK Excerpt The long term stability of the massive ice sheets of Antarctica which have the potential to raise sea levels by hundreds of meters has been called into question with the discovery of fast moving rivers of water sliding beneath their base Scientists analyzing satellite data were astonished to discover the size of the vast lakes and river systems flowing beneath the Antarctic ice sheets which may lubricate the movement of these glaciers as they flow into the surrounding sea The discovery raises fresh questions about the speed at which sea levels might rise in a warmer world due to the rate at which parts of the ice sheets slide from the land into the ocean scientists said at the American Association for the Advancement of Science in San Francisco We ve found that there are substantial subglacial lakes under ice that s moving a couple of meters per day It s really ripping along It s the fast moving ice that determines how the ice sheet responds to climate change on a short timescale said Robert Bindschadler a NASA scientist at the Goddard Space Flight Centre in Maryland one of the study s co authors While the water under the Antarctic ice is not itself related to global warming the suprisingly large amount of water the surprising speed with which it moves and its effect of lubricating the movement of the Antarctic ice may affect how the ice sheets respond to warming This new discovery is of course not accounted for in the IPCC AR4 and suggests we may be in for some unpleasant surprises from Antarctica 24 P Lewis says 16 Feb 2007 at 2 23 PM Re 21 and Ehrlich It s to be published in the Journal of Atmospheric and Solar Terrestrial Physics will be doi 10 1016 j jastp 2007 01 005 And SteveF you will know this is currently newolder s favourite anti AGW evidence which it isn t so far as I can see 25 Hank Roberts says 16 Feb 2007 at 2 59 PM 1 000 kyear no significant continental drift in that time span right Just checking 26 Barton Paul Levenson says 16 Feb 2007 at 3 17 PM 1 000 kyear no significant continental drift in that time span right Just checking Actually I think there might well be significant continental drift over that period I assume by 1 000 kyear you mean 10 6 years It wouldn t be as obvious as over 100 million years but it would be enough to distort maps noticeably 27 tamino says 16 Feb 2007 at 3 52 PM Re 25 26 There s not a lot of tectonic movement in a mere million years but it may not take a lot to have a climate impact For example closure of the Isthmus of Panama and restriction of the Indonesian seaway have been suggested as reasons for the onset of northern hemisphere glaciation 3 million years ago but that s 3 million not 1 million 28 Steve Bloom says 16 Feb 2007 at 3 58 PM Re 21 SteveF thanks for the link to the new paper Regarding Wunsch both he and Huybers who was Wunsch s grad student have done follow up papers one of which was linked by Tamino in 19 Re 23 SA and what a great handle that is BTW the moment I saw this I wondered if it could explain the other recent results showing a sudden slowdown in two of the Greenland outlet glaciers Despite being trumpeted in certain circles as meaning that there s really nothing to worry about regarding the Greenland ice sheet the authors made a point of noting although not in this press release that an additional source of mass loss needs to be identified in order to reconcile their results with the GRACE data which do not show a reduction in mass loss for the same period Similar subglacial water activity in Greenland would seem to fill the bill nicely in particular because it would also explain the sharp changes in outlet glacier speed See also the interesting tone taken by this IPY press release 29 David B Benson says 16 Feb 2007 at 4 34 PM Re 25 26 27 The Indio Australian plate moves generally north at a very high rate for a tectonic plate So in a mere one million years the Himalayan Mountains and in general the Tibetian Plateau would have been modified To the east the boundary between the Indian Ocean and the South China Sea would have been altered 30 Hank Roberts says 16 Feb 2007 at 4 52 PM Can anyone add something about how the biology is changing in that time span That would I d guess be interesting as a very fast feedback effect if say plankton s changing year by year as one or more of those other signals change Might be some proxy for total primary productivity or biomass or respiration or photosynthesis or chemistry of diatom shells or lack thereof in each slice of the sediment core Not sure how to tease that out just wondering if Gaia s in there swinging behind some of that variation 31 John D says 16 Feb 2007 at 5 04 PM 23 If there is running water and lakes beneath the ice in Antarctica could it be that the earth is warming substantially and causing the ice to melt from the bottom up Interesting 32 David B Benson says 16 Feb 2007 at 5 16 PM Re 30 Hank Roberts Not directly the answer to your latest question but at each major sea low stand East Asia expands to the east and Southeast Asia grows into Sundaland Both locations will continue to contribute to biological productivity in contrast to the expanded deserts in many other locations 33 Bob M says 16 Feb 2007 at 5 49 PM I ve always been impressed by the rapidity with which glacial periods end despite the expected high feedback of all that ice cover I don t follow climate science in detail with all the ins and outs of competing models but as an interested non specialist I hope to live long enough to see a consensus explanation emerge 34 SecularAnimist says 16 Feb 2007 at 7 14 PM Bob M wrote I ve always been impressed by the rapidity with which glacial periods end Speaking of which Great Andean Glacier Will Melt to Nothing by 2012 By Mark Henderson The Times UK 16 February 2007 The principal glacier of the world s biggest tropical ice cap could disappear within five years as a result of global warming one of the world s leading glaciologists predicted yesterday The imminent demise of the Qori Kalis glacier the main component of the Quelccaya ice cap in the Peruvian Andes offers the starkest evidence yet of the effects of climate change according to Lonnie Thompson of Ohio State University Although scientists have known for decades that Qori Kalis and the other Quelccaya glaciers are melting new observations indicate that the rate of retreat is increasing Professor Thompson said When he visits this summer he expects to find that the glacier has halved in size since last year and he believes that Qori Kalis will be gone within five years This widespread retreat of mountain glaciers may be our clearest evidence of global warming as they integrate many climate variables Professor Thompson told the American Association for the Advancement of Science conference in San Francisco Most importantly they have no political agenda The Quelccaya ice cap covering 17 square miles 44 sq km in the Cordillera Oriental region of the Peruvian Andes is the world s largest tropical ice mass Qori Kalis its biggest glacier has receded by at least 0 6 miles 1 1km since 1963 when the first formal measurements were made from aerial photographs The rate of retreat has increased between 1963 and 1978 it shrank by 6 5 yards 6m a year a rate that has now risen tenfold to 65 yards annually Professor Thompson predicted six years ago that the celebrated snows of Kilimanjaro would be gone from Africa s highest mountain by 2015 and he now thinks that that estimate may have been too conservative He said Tropical glaciers are the canaries in the coalmine for our global climate system as they integrate and respond to most of the key climatological variables temperature precipitation cloudiness humidity and radiation A critical piece of evidence from almost fifty scientific expeditions to seven shrinking tropical ice caps points to global warming as the reason for their decline In all but one case snowfall has increased as ice volume has fallen More snow should mean advancing glaciers unless rising temperatures are melting the extra precipitation and the ice tongues themselves 35 Dan Robinson says 16 Feb 2007 at 8 03 PM Is it reasonable to think this is the other side of this question What ends hot ages especially artificial ones WITH INSUFFICIENT ARTIFICIAL HELP I keep hearing about how much hotter it s going to be in 2100 but nothing about after that as though one way or another it s going to end there With all the forms of positive feedback we already see what s going to create negative feedback while life is still possible on Earth like before the oceans have finished evaporating and adding to greenhouse gasses It also seems many changes are occurring faster than scientists previously expected Does someone have some hope for our grandchildren and beyond Is it possible that even climate scientists believe only what their minds can tolerate and ignore the rest 36 Wang Dang says 16 Feb 2007 at 10 59 PM Re 23 What is alarming other than the word alarm in the title You say there is a surpisingly large amount of water what amount of water would you expect And the water is moving at a surprising speed what speed would not surprise you I find this new information interesting and important but not alarming 37 BarbieDoll Moment says 17 Feb 2007 at 4 15 AM re Scientists Sound Alarm Over Melting Antarctic Ice Sheets 13 Feb 2007 Antarctic Temperatures Disagree with Climate Model Predictions Ohio State University http www newswise com articles view 527313 A new report on climate over the world s southernmost continent shows that temperatures during the late 20th century did not climb as had been predicted by many global climate models Bromwich said that the increase in the ozone hole above the central Antarctic continent may also be affecting temperatures on the mainland If you have less ozone there s less absorption of the ultraviolet light and the stratosphere doesn t warm as much That would mean that winter like conditions would remain later in the spring than normal lowering temperatures In some sense we might have competing effects going on in Antarctica where there is low level CO2 warming but that may be swamped by the effects of ozone depletion he said The year 2006 was the all time maximum for ozone depletion over the Antarctic Bromwich said the disagreement between climate model predictions and the snowfall and temperature records doesn t necessarily mean that the models are wrong It isn t surprising that these models are not doing as well in these remote parts of the world These are global models and shouldn t be expected to be equally exact for all locations he said Sea Level Rise After the Ice Melted and Today Vivien Gornitz NASA GISS Science Briefs Jan 2007 http www giss nasa gov research briefs gornitz 09 Meltwater from glacial Lake Agassiz southwest of Hudson Bay draining catastrophically into the North Atlantic via Lake Superior and the St Laurence seaway was once thought to have initiated ocean circulation changes leading to the Younger Dryas cold period Regional removal of ice sheets however occurred nearly 1000 years later and hence draining of Lake Agassiz could not likely have caused the Younger Dryas cold reversal This cold spell may have instead been triggered by increased outflow into the Arctic Ocean the Fram Strait east of Greenland and ultimately the eastern North Atlantic between 12 900 and 12 800 years before present as suggested by the glacial model of Tarasov and Peltier On the other hand Leventer et al indicate that the timing of deglaciation in eastern Antarctica roughly coincides with the onset of meltwater pulse 1B 38 William Astley says 17 Feb 2007 at 9 59 AM Another hypothesis for why the glacial periods terminate and restart is GCR modulation by changes in the intensity of the earth s magnetic field GCR changes of course as we all know it is hypothesized affect global cloud cover I am not sure why the response to the hypothesis that changes in the intensity of the geomagnetic field triggers controls the timing of the ice ages in this forum was rubbish The rubbish comment noted that geomagnetic field intensity changes do not correlate with the ice age cycles Perhaps we are looking at different data The following is data from the review paper Time Variations in Geomagnetic Field Intensity http ssn dgf uchile cl home informe 2001RG000104b pdf See Page 4 22 Figure 9 Geomagnetic field intensity level derived from composite volcanic records not sea floor sediments for the past 45 kyr Obviously Figure 9 shows that 40 kyrs ago the earth s magnetic field intensity was 75 less 2 10 22Am 2 than the geomagnetic field s current intensity 8 10 22Am 2 and that the earth s magnetic field intensity peaked at around 12 10 22Am 2 and has dropped 30 in the last 1000 years and that the geomagnetic field intensity is now dropping at the rate of 5 100yrs Comments 1 The geomagnetic field researchers do not even have a hypothesis as to why there are cyclic changes in the geomagnetic field intensity Something is fundamental incorrect with the most basic assumptions concerning what creates the geomagnetic field and what causes it to change

    Original URL path: http://www.realclimate.org/index.php/archives/2007/02/what-triggers-ice-ages/langswitch_lang/tk/ (2016-02-13)
    Open archived version from archive

  • Qu’est ce qui déclenche les glaciations? « RealClimate
    have a direct effect on Earth climate A weakening magnetic field might lead to more cloud formation because more air molecules would be ionized by incoming high energy radiation and ionized air molecules are nucleation sites for cloud droplets More clouds means higher albedo which in turn might mean a cooler climate Response Note also that more low clouds would unambiguously mean a cooling effect but more high clouds could lead to either a warming effect or a cooling effect depending on the altitude of the clouds and the typical particle size in the GCR induced clouds if any raypierre 18 Ray says 16 Feb 2007 at 11 20 AM Surprising there isn t a more obvious relationship between solar forcing and the growth and ebb of the ice I m glad you posted this article 19 tamino says 16 Feb 2007 at 11 25 AM Re 15 The FFT is a poor choice because is requires the data to be evenly spaced in time which often it is not and requires the number of data points to be a power of 2 which it almost never is I applied the DCDFT date compensated discrete Fourier transform to generate Fourier power spectra of all five signals shown in the original plot assuming that the last graph is the LR04 stack I ve posted them on my blog Re 9 When giving the range of 65N insolation I mistakenly looked at the data for insolation at the pole 90N The correct range for 65N insolation is aobut 390 to 490 watts per square meter 20 Barton Paul Levenson says 16 Feb 2007 at 11 31 AM What if a massive amount was removed from one side of the earth to the other could that cause the earth to wabble the removal of steel metal iron or maybe even OIL with the combination of all of these burnt into smoke Wobble Yes it does But the effect is far too tiny to detect Compare the mass of iron ore mined since the beginning of the industrial revolution to the mass of the Earth There s no comparison Don t worry about it Is the smoke from all of these that i mentioned part of the cause for the ozone layer to be thinning Probably not That seems to be from human use of chloroflurocarbons for spray cans and refrigerants The Montreal Protocol of 1979 banned use of these and industry now uses substitutes 21 SteveF says 16 Feb 2007 at 11 52 AM On the subject Robert Ehrlich has a recent paper on solar forcing of ice ages He claims to have solved all but one of the major problems of Milankovitch forcing Solar Resonant Diffusion Waves as a Driver of Terrestrial Climate Change ABSTRACT A theory is described based on resonant thermal diffusion waves in the sun that explains many details of the paleotemperature record for the last 5 3 million years These include the observed periodicities the relative strengths of each observed cycle and the sudden emergence in time for the 100 thousand year cycle Other prior work suggesting a link between terrestrial paleoclimate and solar luminosity variations has not provided any specific mechanism The particular mechanism described here has been demonstrated empirically although not previously invoked in the solar context The theory while not without its own unresolved issues also lacks most of the problems associated with Milankovitch cycle theory http arxiv org PS cache astro ph pdf 0701 0701117 pdf I think the paper has now been published earlier this month but can t remember where Still its an interesting read Another provocative paper well worth reading is by Carl Wunsch and attempts to uage the contribution of orbital variations to climate change http ocean mit edu cwunsch papersonline milankovitchqsr2004 pdf He argues that stochastic variation is responsible although wimps out of actually coming up with an explanation His alternative hypothesis regarding abrupt climate change was rubbish too but thats another story 22 Aziz Poonawalla says 16 Feb 2007 at 1 11 PM Thanks tamino those graphs deserve to be disseminated It s quite a bit more informative thanthe original 23 SecularAnimist says 16 Feb 2007 at 2 06 PM Sorry off topic but this is in the news today and seems rather alarming Scientists Sound Alarm Over Melting Antarctic Ice Sheets by Steve Connor Science Editor in San Francisco February 16 2007 The lndependent UK Excerpt The long term stability of the massive ice sheets of Antarctica which have the potential to raise sea levels by hundreds of meters has been called into question with the discovery of fast moving rivers of water sliding beneath their base Scientists analyzing satellite data were astonished to discover the size of the vast lakes and river systems flowing beneath the Antarctic ice sheets which may lubricate the movement of these glaciers as they flow into the surrounding sea The discovery raises fresh questions about the speed at which sea levels might rise in a warmer world due to the rate at which parts of the ice sheets slide from the land into the ocean scientists said at the American Association for the Advancement of Science in San Francisco We ve found that there are substantial subglacial lakes under ice that s moving a couple of meters per day It s really ripping along It s the fast moving ice that determines how the ice sheet responds to climate change on a short timescale said Robert Bindschadler a NASA scientist at the Goddard Space Flight Centre in Maryland one of the study s co authors While the water under the Antarctic ice is not itself related to global warming the suprisingly large amount of water the surprising speed with which it moves and its effect of lubricating the movement of the Antarctic ice may affect how the ice sheets respond to warming This new discovery is of course not accounted for in the IPCC AR4 and suggests we may be in for some unpleasant surprises from Antarctica 24 P Lewis says 16 Feb 2007 at 2 23 PM Re 21 and Ehrlich It s to be published in the Journal of Atmospheric and Solar Terrestrial Physics will be doi 10 1016 j jastp 2007 01 005 And SteveF you will know this is currently newolder s favourite anti AGW evidence which it isn t so far as I can see 25 Hank Roberts says 16 Feb 2007 at 2 59 PM 1 000 kyear no significant continental drift in that time span right Just checking 26 Barton Paul Levenson says 16 Feb 2007 at 3 17 PM 1 000 kyear no significant continental drift in that time span right Just checking Actually I think there might well be significant continental drift over that period I assume by 1 000 kyear you mean 10 6 years It wouldn t be as obvious as over 100 million years but it would be enough to distort maps noticeably 27 tamino says 16 Feb 2007 at 3 52 PM Re 25 26 There s not a lot of tectonic movement in a mere million years but it may not take a lot to have a climate impact For example closure of the Isthmus of Panama and restriction of the Indonesian seaway have been suggested as reasons for the onset of northern hemisphere glaciation 3 million years ago but that s 3 million not 1 million 28 Steve Bloom says 16 Feb 2007 at 3 58 PM Re 21 SteveF thanks for the link to the new paper Regarding Wunsch both he and Huybers who was Wunsch s grad student have done follow up papers one of which was linked by Tamino in 19 Re 23 SA and what a great handle that is BTW the moment I saw this I wondered if it could explain the other recent results showing a sudden slowdown in two of the Greenland outlet glaciers Despite being trumpeted in certain circles as meaning that there s really nothing to worry about regarding the Greenland ice sheet the authors made a point of noting although not in this press release that an additional source of mass loss needs to be identified in order to reconcile their results with the GRACE data which do not show a reduction in mass loss for the same period Similar subglacial water activity in Greenland would seem to fill the bill nicely in particular because it would also explain the sharp changes in outlet glacier speed See also the interesting tone taken by this IPY press release 29 David B Benson says 16 Feb 2007 at 4 34 PM Re 25 26 27 The Indio Australian plate moves generally north at a very high rate for a tectonic plate So in a mere one million years the Himalayan Mountains and in general the Tibetian Plateau would have been modified To the east the boundary between the Indian Ocean and the South China Sea would have been altered 30 Hank Roberts says 16 Feb 2007 at 4 52 PM Can anyone add something about how the biology is changing in that time span That would I d guess be interesting as a very fast feedback effect if say plankton s changing year by year as one or more of those other signals change Might be some proxy for total primary productivity or biomass or respiration or photosynthesis or chemistry of diatom shells or lack thereof in each slice of the sediment core Not sure how to tease that out just wondering if Gaia s in there swinging behind some of that variation 31 John D says 16 Feb 2007 at 5 04 PM 23 If there is running water and lakes beneath the ice in Antarctica could it be that the earth is warming substantially and causing the ice to melt from the bottom up Interesting 32 David B Benson says 16 Feb 2007 at 5 16 PM Re 30 Hank Roberts Not directly the answer to your latest question but at each major sea low stand East Asia expands to the east and Southeast Asia grows into Sundaland Both locations will continue to contribute to biological productivity in contrast to the expanded deserts in many other locations 33 Bob M says 16 Feb 2007 at 5 49 PM I ve always been impressed by the rapidity with which glacial periods end despite the expected high feedback of all that ice cover I don t follow climate science in detail with all the ins and outs of competing models but as an interested non specialist I hope to live long enough to see a consensus explanation emerge 34 SecularAnimist says 16 Feb 2007 at 7 14 PM Bob M wrote I ve always been impressed by the rapidity with which glacial periods end Speaking of which Great Andean Glacier Will Melt to Nothing by 2012 By Mark Henderson The Times UK 16 February 2007 The principal glacier of the world s biggest tropical ice cap could disappear within five years as a result of global warming one of the world s leading glaciologists predicted yesterday The imminent demise of the Qori Kalis glacier the main component of the Quelccaya ice cap in the Peruvian Andes offers the starkest evidence yet of the effects of climate change according to Lonnie Thompson of Ohio State University Although scientists have known for decades that Qori Kalis and the other Quelccaya glaciers are melting new observations indicate that the rate of retreat is increasing Professor Thompson said When he visits this summer he expects to find that the glacier has halved in size since last year and he believes that Qori Kalis will be gone within five years This widespread retreat of mountain glaciers may be our clearest evidence of global warming as they integrate many climate variables Professor Thompson told the American Association for the Advancement of Science conference in San Francisco Most importantly they have no political agenda The Quelccaya ice cap covering 17 square miles 44 sq km in the Cordillera Oriental region of the Peruvian Andes is the world s largest tropical ice mass Qori Kalis its biggest glacier has receded by at least 0 6 miles 1 1km since 1963 when the first formal measurements were made from aerial photographs The rate of retreat has increased between 1963 and 1978 it shrank by 6 5 yards 6m a year a rate that has now risen tenfold to 65 yards annually Professor Thompson predicted six years ago that the celebrated snows of Kilimanjaro would be gone from Africa s highest mountain by 2015 and he now thinks that that estimate may have been too conservative He said Tropical glaciers are the canaries in the coalmine for our global climate system as they integrate and respond to most of the key climatological variables temperature precipitation cloudiness humidity and radiation A critical piece of evidence from almost fifty scientific expeditions to seven shrinking tropical ice caps points to global warming as the reason for their decline In all but one case snowfall has increased as ice volume has fallen More snow should mean advancing glaciers unless rising temperatures are melting the extra precipitation and the ice tongues themselves 35 Dan Robinson says 16 Feb 2007 at 8 03 PM Is it reasonable to think this is the other side of this question What ends hot ages especially artificial ones WITH INSUFFICIENT ARTIFICIAL HELP I keep hearing about how much hotter it s going to be in 2100 but nothing about after that as though one way or another it s going to end there With all the forms of positive feedback we already see what s going to create negative feedback while life is still possible on Earth like before the oceans have finished evaporating and adding to greenhouse gasses It also seems many changes are occurring faster than scientists previously expected Does someone have some hope for our grandchildren and beyond Is it possible that even climate scientists believe only what their minds can tolerate and ignore the rest 36 Wang Dang says 16 Feb 2007 at 10 59 PM Re 23 What is alarming other than the word alarm in the title You say there is a surpisingly large amount of water what amount of water would you expect And the water is moving at a surprising speed what speed would not surprise you I find this new information interesting and important but not alarming 37 BarbieDoll Moment says 17 Feb 2007 at 4 15 AM re Scientists Sound Alarm Over Melting Antarctic Ice Sheets 13 Feb 2007 Antarctic Temperatures Disagree with Climate Model Predictions Ohio State University http www newswise com articles view 527313 A new report on climate over the world s southernmost continent shows that temperatures during the late 20th century did not climb as had been predicted by many global climate models Bromwich said that the increase in the ozone hole above the central Antarctic continent may also be affecting temperatures on the mainland If you have less ozone there s less absorption of the ultraviolet light and the stratosphere doesn t warm as much That would mean that winter like conditions would remain later in the spring than normal lowering temperatures In some sense we might have competing effects going on in Antarctica where there is low level CO2 warming but that may be swamped by the effects of ozone depletion he said The year 2006 was the all time maximum for ozone depletion over the Antarctic Bromwich said the disagreement between climate model predictions and the snowfall and temperature records doesn t necessarily mean that the models are wrong It isn t surprising that these models are not doing as well in these remote parts of the world These are global models and shouldn t be expected to be equally exact for all locations he said Sea Level Rise After the Ice Melted and Today Vivien Gornitz NASA GISS Science Briefs Jan 2007 http www giss nasa gov research briefs gornitz 09 Meltwater from glacial Lake Agassiz southwest of Hudson Bay draining catastrophically into the North Atlantic via Lake Superior and the St Laurence seaway was once thought to have initiated ocean circulation changes leading to the Younger Dryas cold period Regional removal of ice sheets however occurred nearly 1000 years later and hence draining of Lake Agassiz could not likely have caused the Younger Dryas cold reversal This cold spell may have instead been triggered by increased outflow into the Arctic Ocean the Fram Strait east of Greenland and ultimately the eastern North Atlantic between 12 900 and 12 800 years before present as suggested by the glacial model of Tarasov and Peltier On the other hand Leventer et al indicate that the timing of deglaciation in eastern Antarctica roughly coincides with the onset of meltwater pulse 1B 38 William Astley says 17 Feb 2007 at 9 59 AM Another hypothesis for why the glacial periods terminate and restart is GCR modulation by changes in the intensity of the earth s magnetic field GCR changes of course as we all know it is hypothesized affect global cloud cover I am not sure why the response to the hypothesis that changes in the intensity of the geomagnetic field triggers controls the timing of the ice ages in this forum was rubbish The rubbish comment noted that geomagnetic field intensity changes do not correlate with the ice age cycles Perhaps we are looking at different data The following is data from the review paper Time Variations in Geomagnetic Field Intensity http ssn dgf uchile cl home informe 2001RG000104b pdf See Page 4 22 Figure 9 Geomagnetic field intensity level derived from composite volcanic records not sea floor sediments for the past 45 kyr Obviously Figure 9 shows that 40 kyrs ago the earth s magnetic field intensity was 75 less 2 10 22Am 2 than the geomagnetic field s current intensity 8

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    more high clouds could lead to either a warming effect or a cooling effect depending on the altitude of the clouds and the typical particle size in the GCR induced clouds if any raypierre 18 Ray says 16 Feb 2007 at 11 20 AM Surprising there isn t a more obvious relationship between solar forcing and the growth and ebb of the ice I m glad you posted this article 19 tamino says 16 Feb 2007 at 11 25 AM Re 15 The FFT is a poor choice because is requires the data to be evenly spaced in time which often it is not and requires the number of data points to be a power of 2 which it almost never is I applied the DCDFT date compensated discrete Fourier transform to generate Fourier power spectra of all five signals shown in the original plot assuming that the last graph is the LR04 stack I ve posted them on my blog Re 9 When giving the range of 65N insolation I mistakenly looked at the data for insolation at the pole 90N The correct range for 65N insolation is aobut 390 to 490 watts per square meter 20 Barton Paul Levenson says 16 Feb 2007 at 11 31 AM What if a massive amount was removed from one side of the earth to the other could that cause the earth to wabble the removal of steel metal iron or maybe even OIL with the combination of all of these burnt into smoke Wobble Yes it does But the effect is far too tiny to detect Compare the mass of iron ore mined since the beginning of the industrial revolution to the mass of the Earth There s no comparison Don t worry about it Is the smoke from all of these that i mentioned part of the cause for the ozone layer to be thinning Probably not That seems to be from human use of chloroflurocarbons for spray cans and refrigerants The Montreal Protocol of 1979 banned use of these and industry now uses substitutes 21 SteveF says 16 Feb 2007 at 11 52 AM On the subject Robert Ehrlich has a recent paper on solar forcing of ice ages He claims to have solved all but one of the major problems of Milankovitch forcing Solar Resonant Diffusion Waves as a Driver of Terrestrial Climate Change ABSTRACT A theory is described based on resonant thermal diffusion waves in the sun that explains many details of the paleotemperature record for the last 5 3 million years These include the observed periodicities the relative strengths of each observed cycle and the sudden emergence in time for the 100 thousand year cycle Other prior work suggesting a link between terrestrial paleoclimate and solar luminosity variations has not provided any specific mechanism The particular mechanism described here has been demonstrated empirically although not previously invoked in the solar context The theory while not without its own unresolved issues also lacks most of the problems associated with Milankovitch cycle theory http arxiv org PS cache astro ph pdf 0701 0701117 pdf I think the paper has now been published earlier this month but can t remember where Still its an interesting read Another provocative paper well worth reading is by Carl Wunsch and attempts to uage the contribution of orbital variations to climate change http ocean mit edu cwunsch papersonline milankovitchqsr2004 pdf He argues that stochastic variation is responsible although wimps out of actually coming up with an explanation His alternative hypothesis regarding abrupt climate change was rubbish too but thats another story 22 Aziz Poonawalla says 16 Feb 2007 at 1 11 PM Thanks tamino those graphs deserve to be disseminated It s quite a bit more informative thanthe original 23 SecularAnimist says 16 Feb 2007 at 2 06 PM Sorry off topic but this is in the news today and seems rather alarming Scientists Sound Alarm Over Melting Antarctic Ice Sheets by Steve Connor Science Editor in San Francisco February 16 2007 The lndependent UK Excerpt The long term stability of the massive ice sheets of Antarctica which have the potential to raise sea levels by hundreds of meters has been called into question with the discovery of fast moving rivers of water sliding beneath their base Scientists analyzing satellite data were astonished to discover the size of the vast lakes and river systems flowing beneath the Antarctic ice sheets which may lubricate the movement of these glaciers as they flow into the surrounding sea The discovery raises fresh questions about the speed at which sea levels might rise in a warmer world due to the rate at which parts of the ice sheets slide from the land into the ocean scientists said at the American Association for the Advancement of Science in San Francisco We ve found that there are substantial subglacial lakes under ice that s moving a couple of meters per day It s really ripping along It s the fast moving ice that determines how the ice sheet responds to climate change on a short timescale said Robert Bindschadler a NASA scientist at the Goddard Space Flight Centre in Maryland one of the study s co authors While the water under the Antarctic ice is not itself related to global warming the suprisingly large amount of water the surprising speed with which it moves and its effect of lubricating the movement of the Antarctic ice may affect how the ice sheets respond to warming This new discovery is of course not accounted for in the IPCC AR4 and suggests we may be in for some unpleasant surprises from Antarctica 24 P Lewis says 16 Feb 2007 at 2 23 PM Re 21 and Ehrlich It s to be published in the Journal of Atmospheric and Solar Terrestrial Physics will be doi 10 1016 j jastp 2007 01 005 And SteveF you will know this is currently newolder s favourite anti AGW evidence which it isn t so far as I can see 25 Hank Roberts says 16 Feb 2007 at 2 59 PM 1 000 kyear no significant continental drift in that time span right Just checking 26 Barton Paul Levenson says 16 Feb 2007 at 3 17 PM 1 000 kyear no significant continental drift in that time span right Just checking Actually I think there might well be significant continental drift over that period I assume by 1 000 kyear you mean 10 6 years It wouldn t be as obvious as over 100 million years but it would be enough to distort maps noticeably 27 tamino says 16 Feb 2007 at 3 52 PM Re 25 26 There s not a lot of tectonic movement in a mere million years but it may not take a lot to have a climate impact For example closure of the Isthmus of Panama and restriction of the Indonesian seaway have been suggested as reasons for the onset of northern hemisphere glaciation 3 million years ago but that s 3 million not 1 million 28 Steve Bloom says 16 Feb 2007 at 3 58 PM Re 21 SteveF thanks for the link to the new paper Regarding Wunsch both he and Huybers who was Wunsch s grad student have done follow up papers one of which was linked by Tamino in 19 Re 23 SA and what a great handle that is BTW the moment I saw this I wondered if it could explain the other recent results showing a sudden slowdown in two of the Greenland outlet glaciers Despite being trumpeted in certain circles as meaning that there s really nothing to worry about regarding the Greenland ice sheet the authors made a point of noting although not in this press release that an additional source of mass loss needs to be identified in order to reconcile their results with the GRACE data which do not show a reduction in mass loss for the same period Similar subglacial water activity in Greenland would seem to fill the bill nicely in particular because it would also explain the sharp changes in outlet glacier speed See also the interesting tone taken by this IPY press release 29 David B Benson says 16 Feb 2007 at 4 34 PM Re 25 26 27 The Indio Australian plate moves generally north at a very high rate for a tectonic plate So in a mere one million years the Himalayan Mountains and in general the Tibetian Plateau would have been modified To the east the boundary between the Indian Ocean and the South China Sea would have been altered 30 Hank Roberts says 16 Feb 2007 at 4 52 PM Can anyone add something about how the biology is changing in that time span That would I d guess be interesting as a very fast feedback effect if say plankton s changing year by year as one or more of those other signals change Might be some proxy for total primary productivity or biomass or respiration or photosynthesis or chemistry of diatom shells or lack thereof in each slice of the sediment core Not sure how to tease that out just wondering if Gaia s in there swinging behind some of that variation 31 John D says 16 Feb 2007 at 5 04 PM 23 If there is running water and lakes beneath the ice in Antarctica could it be that the earth is warming substantially and causing the ice to melt from the bottom up Interesting 32 David B Benson says 16 Feb 2007 at 5 16 PM Re 30 Hank Roberts Not directly the answer to your latest question but at each major sea low stand East Asia expands to the east and Southeast Asia grows into Sundaland Both locations will continue to contribute to biological productivity in contrast to the expanded deserts in many other locations 33 Bob M says 16 Feb 2007 at 5 49 PM I ve always been impressed by the rapidity with which glacial periods end despite the expected high feedback of all that ice cover I don t follow climate science in detail with all the ins and outs of competing models but as an interested non specialist I hope to live long enough to see a consensus explanation emerge 34 SecularAnimist says 16 Feb 2007 at 7 14 PM Bob M wrote I ve always been impressed by the rapidity with which glacial periods end Speaking of which Great Andean Glacier Will Melt to Nothing by 2012 By Mark Henderson The Times UK 16 February 2007 The principal glacier of the world s biggest tropical ice cap could disappear within five years as a result of global warming one of the world s leading glaciologists predicted yesterday The imminent demise of the Qori Kalis glacier the main component of the Quelccaya ice cap in the Peruvian Andes offers the starkest evidence yet of the effects of climate change according to Lonnie Thompson of Ohio State University Although scientists have known for decades that Qori Kalis and the other Quelccaya glaciers are melting new observations indicate that the rate of retreat is increasing Professor Thompson said When he visits this summer he expects to find that the glacier has halved in size since last year and he believes that Qori Kalis will be gone within five years This widespread retreat of mountain glaciers may be our clearest evidence of global warming as they integrate many climate variables Professor Thompson told the American Association for the Advancement of Science conference in San Francisco Most importantly they have no political agenda The Quelccaya ice cap covering 17 square miles 44 sq km in the Cordillera Oriental region of the Peruvian Andes is the world s largest tropical ice mass Qori Kalis its biggest glacier has receded by at least 0 6 miles 1 1km since 1963 when the first formal measurements were made from aerial photographs The rate of retreat has increased between 1963 and 1978 it shrank by 6 5 yards 6m a year a rate that has now risen tenfold to 65 yards annually Professor Thompson predicted six years ago that the celebrated snows of Kilimanjaro would be gone from Africa s highest mountain by 2015 and he now thinks that that estimate may have been too conservative He said Tropical glaciers are the canaries in the coalmine for our global climate system as they integrate and respond to most of the key climatological variables temperature precipitation cloudiness humidity and radiation A critical piece of evidence from almost fifty scientific expeditions to seven shrinking tropical ice caps points to global warming as the reason for their decline In all but one case snowfall has increased as ice volume has fallen More snow should mean advancing glaciers unless rising temperatures are melting the extra precipitation and the ice tongues themselves 35 Dan Robinson says 16 Feb 2007 at 8 03 PM Is it reasonable to think this is the other side of this question What ends hot ages especially artificial ones WITH INSUFFICIENT ARTIFICIAL HELP I keep hearing about how much hotter it s going to be in 2100 but nothing about after that as though one way or another it s going to end there With all the forms of positive feedback we already see what s going to create negative feedback while life is still possible on Earth like before the oceans have finished evaporating and adding to greenhouse gasses It also seems many changes are occurring faster than scientists previously expected Does someone have some hope for our grandchildren and beyond Is it possible that even climate scientists believe only what their minds can tolerate and ignore the rest 36 Wang Dang says 16 Feb 2007 at 10 59 PM Re 23 What is alarming other than the word alarm in the title You say there is a surpisingly large amount of water what amount of water would you expect And the water is moving at a surprising speed what speed would not surprise you I find this new information interesting and important but not alarming 37 BarbieDoll Moment says 17 Feb 2007 at 4 15 AM re Scientists Sound Alarm Over Melting Antarctic Ice Sheets 13 Feb 2007 Antarctic Temperatures Disagree with Climate Model Predictions Ohio State University http www newswise com articles view 527313 A new report on climate over the world s southernmost continent shows that temperatures during the late 20th century did not climb as had been predicted by many global climate models Bromwich said that the increase in the ozone hole above the central Antarctic continent may also be affecting temperatures on the mainland If you have less ozone there s less absorption of the ultraviolet light and the stratosphere doesn t warm as much That would mean that winter like conditions would remain later in the spring than normal lowering temperatures In some sense we might have competing effects going on in Antarctica where there is low level CO2 warming but that may be swamped by the effects of ozone depletion he said The year 2006 was the all time maximum for ozone depletion over the Antarctic Bromwich said the disagreement between climate model predictions and the snowfall and temperature records doesn t necessarily mean that the models are wrong It isn t surprising that these models are not doing as well in these remote parts of the world These are global models and shouldn t be expected to be equally exact for all locations he said Sea Level Rise After the Ice Melted and Today Vivien Gornitz NASA GISS Science Briefs Jan 2007 http www giss nasa gov research briefs gornitz 09 Meltwater from glacial Lake Agassiz southwest of Hudson Bay draining catastrophically into the North Atlantic via Lake Superior and the St Laurence seaway was once thought to have initiated ocean circulation changes leading to the Younger Dryas cold period Regional removal of ice sheets however occurred nearly 1000 years later and hence draining of Lake Agassiz could not likely have caused the Younger Dryas cold reversal This cold spell may have instead been triggered by increased outflow into the Arctic Ocean the Fram Strait east of Greenland and ultimately the eastern North Atlantic between 12 900 and 12 800 years before present as suggested by the glacial model of Tarasov and Peltier On the other hand Leventer et al indicate that the timing of deglaciation in eastern Antarctica roughly coincides with the onset of meltwater pulse 1B 38 William Astley says 17 Feb 2007 at 9 59 AM Another hypothesis for why the glacial periods terminate and restart is GCR modulation by changes in the intensity of the earth s magnetic field GCR changes of course as we all know it is hypothesized affect global cloud cover I am not sure why the response to the hypothesis that changes in the intensity of the geomagnetic field triggers controls the timing of the ice ages in this forum was rubbish The rubbish comment noted that geomagnetic field intensity changes do not correlate with the ice age cycles Perhaps we are looking at different data The following is data from the review paper Time Variations in Geomagnetic Field Intensity http ssn dgf uchile cl home informe 2001RG000104b pdf See Page 4 22 Figure 9 Geomagnetic field intensity level derived from composite volcanic records not sea floor sediments for the past 45 kyr Obviously Figure 9 shows that 40 kyrs ago the earth s magnetic field intensity was 75 less 2 10 22Am 2 than the geomagnetic field s current intensity 8 10 22Am 2 and that the earth s magnetic field intensity peaked at around 12 10 22Am 2 and has dropped 30 in the last 1000 years and that the geomagnetic field intensity is now dropping at the rate of 5 100yrs Comments 1 The geomagnetic field researchers do not even have a hypothesis as to why there are cyclic changes in the geomagnetic field intensity

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    most past times except the 55 251 mya events 57 David B Benson says 18 Feb 2007 at 1 37 PM Re 55 Lynn Vindentnathan My understanding is that without AGW the climate should have been very slightly cooling and doing so for the next 50 000 years At that time it might be cool enough for an ice age to start The next opportunity is in another 50 000 years or so 58 Blair Dowden says 18 Feb 2007 at 2 12 PM Re 56 I have seen estimates from ten thousand to fifty thousand years before the next ice age begins So the idea that global warming saved us from the ice age does not hold water or ice Your second question is more interesting Three degrees of warming takes us back about three million years to an era known as the Pliocene This was a much more stable climate that lasted a long time The Earth seemed quite happy with this climate although happiness included sea levels 25 to 35 meters higher than today The real question is what caused the increasingly severe ice ages in the first place I have not seen a clear answer to that I suspect that after the greenhouse pulse stopped the climate would return to near normal ie Holocene interglacial in a few hundred years But not quite normal because carbon dioxide levels take a long time to decay to nothing So global warming might actually delay the next ice age but only ten thousand years from now Response We ve just come out of one of the big every 100KYr glaciations and the normal course of events is to build up to another biggy through a series of small short glaciations over the next 100KYr In the normal course of events the first try at an ice age would be due sometime in the next 20 000 years but I myself wouldn t try to pin it down more than that One of the most interesting attempts so far to say what global warming might do to the glacial cycle is in the paper pdf by Archer and Ganopolski that appeared in the AGU journal GGG I ll leave it to David to say whether that has been followed up by more detailed GCM work raypierre 59 dhogaza says 18 Feb 2007 at 2 35 PM Real Climate regulars will be glad to learn that in a few short minutes DaveScot has overturned decades of climate research Pretty incredible I take one look at the real satellite temperature data instead of the pencil whipped crap thatâ s foisted upon the public and in a few hours figure out the real cause of global warming and then find the studies that confirm my suspicions Gawd Iâ m good Weâ ve been lied to C02 greenhouse effect is a lame duck All politics and no science He did this after lunch Before lunch he was busy overturning 150 years of evolutionary biology 60 Zeke Hausfather says 18 Feb 2007 at 3 27 PM For the RC folks I was at a talk by Jim Hansen awhile back where he argued that anthropogenic warming has brought us to a point where future ice ages are effectively impossible provided that atmospheric levels of GHGs remain at or above their current levels His point as far as I recall it was that the radiative forcing of anthropogenic GHGs is already greater than that of the Milankovich cycles that are thought to trigger ice ages I m curious about your take on this Response In the annual average Milankovich only gives you a around 5 W m 2 Whereas athrogopogenic CO2 and other human enhanced GHGs are now about 2 5 W m 2 above their preindustrial values We will certaintly push over 5 before the start coming down again So Hansen is right basically On the other hand it is the seasonal forcing in summer that really determines whether glaciers can survive the summer and GHGs are not going to approach the magnitude of seasonal Milankovich forcing So I would not cavalierly state that future glaciations are impossible eric 61 David B Benson says 18 Feb 2007 at 4 13 PM Raypierre Thank you for your comments at 58 by Blair Dowden Unfortunately the link to the paper by Archer Ganopolski fails to function correctly for me Response Fixed raypierre 62 Hank Roberts says 18 Feb 2007 at 4 23 PM Chuckle On Gaia evolutionary biology overturns you Can t hardly do climate change research without considering the cold case from geological time I guess climate change research isn t possible without Darwinism eh And if we didn t look at the geological history if all we could look at is the current few centuries of more reliable records who could know anything useful from just that much Has anyone illustrated what s known about climate forcings for various points in geologic time the same way the IPCC does forcings nowadays snips and cites Biostratigraphy is the differentiation of rock units based upon the fossils which they contain Paleoenvironmental analysis is the interpretation of the depositional environment 200 000 years ago Calcareous nannofossils are made of calcium carbonate Nannofossils first appeared during the Mesozoic Era and have persisted and evolved through time One extant group that produces nannofossils is the Coccolithophorans planktonic golden brown algae that are very abundant in the world s oceans The calcareous plates accumulate on the ocean floor become buried beneath later layers and are preserved as nannofossils Some chalks such as those comprising the White Cliffs of Dover are composed almost entirely of nannofossils planktonic mode of life and the tremendous abundance of calcareous nannofossils makes them very useful tools for biostratigraphy Nice drawings there cited to unpublished training manuals worth a look http www ucmp berkeley edu fosrec ONeill html and a hat tip to British Petroleum for data anyone know if this kind of imagery is online paleoshorelines through the 240 million years of the Mesozoic and Cenozoic are presented within this atlas Thirty one maps generally corresponding to stratigraphic stages provide a snapshot of the continents and their shorelines at approximately 8 million year intervals http www3 cambridge org uk catalogue catalogue asp isbn 9780521602877 63 Glen Fergus says 18 Feb 2007 at 7 21 PM Re 34 OT Great Andean Glacier Will Melt to Nothing by 2012 Thompson s suggestion is that the main Quelccaya outlet glacier Qori Kalis will disappear by 2012 not that the whole ice cap will That has a way to go yet See http en wikipedia org wiki Quelccaya Ice Cap Qori Kalis is the little valley glacier left of centre in the sat pic I should find a more recent image to add to the animation 64 tamino says 18 Feb 2007 at 7 32 PM Re response to 60 In the annual average Milankovich only gives you a around 5 W m 2 Isn t that the figure for latitude 65 o Isn t the global annual average from Milankovitch generally no more than about 0 4 W m 2 insolation 65 Regina says 18 Feb 2007 at 8 47 PM What triggers obscuring of an issue that should concern every living soul on this planet Privileged rhetoric for academics only 66 William Astley says 18 Feb 2007 at 9 12 PM In reply to comment 41 What is the evidence for rapid geomagnetic field changes Attached are two links to papers http www geo edu ro paleomag PDF 00 180 225 pdf From Acton s paper that discusses the Africian Afar anomaly One lava flow has recorded both of the antipodal transitional components with the two components residing in magnetic minerals with unblocking temperature above and below approx 500C Hence the configuration of the geomagnetic field appears to have jumped nearly instantaneous from a north hemisphere transitional state to a south hemisphere one during this normal to reverse polarity transition From Coe et al s 2002 paper that discusses the Oregon anomaly Paleomagnetic results from lava flow recording a geomagnetic polarity reversal at Steens Mountain Oregon suggest the occurrence of brief episodes of astonishing rapid field changes of six degrees per day The evidence is large systematic variations in a single flow most simply explained by the hypothesis that the field has changed direction as the flow cooled http scholar google com url sa U q http www nature com nature journal v374 n6524 abs 374687a0 html 67 Hank Roberts says 18 Feb 2007 at 10 38 PM How about this one All researchers agree that the very very rapid field changes could not possibly be due to changes in the earth s core If the problematic data is correct the earth s magnetic field is not generated in the core 68 Blair Dowden says 18 Feb 2007 at 11 17 PM Re Ray s response to 58 When you refer me to a paper I read it and have questions First does this page correctly represent the carbon dioxide absorption rate Do the three scenarios in the Archer paper represent carbon dioxide emissions from the start of the industrial era ie 300 Gt is what we already have or from now I don t understand why the present interglacial is supposed to last so much longer than the others without human input Is there another cycle longer than the 400 Ky eccentricity cycle To answer the original question it appears that emissions of 1000 Gt which is not unreasonable could delay the next ice age by 50 000 years contrary to what I said 69 Lynn Vincentnathan says 19 Feb 2007 at 8 55 AM Looking at the stages of glaciation line at the bottom I m thinking that the cooling downswing is gradual hitting plateaus while the warming upswing is rather sharp strickly increasing It seems that the positive warming feedbacks are somewhat stronger than the positive cooling feedbacks struggling against them if you will It may be that both cooling warming may trigger methane clathrate release from the oceans which eventually breaks down into CO2 These are at various sea levels apparently some closer to sea level than previously thought according to a recent study I m imagining this scenario which may be wrong As it cools the sea level goes down with ice going into glaciers and this exposes the clathrates at various levels which melt during warm summer days and go into the atmosphere cause warming or counterbalance or slow the cooling Other geological cataclysms such as landslides are also releasing these Then during the warming even though the sea is rising it is also warming releasing these clathrates reinforcing the other warming mechanisms But it never quite warms deep enough to melt all of it though underwater landslides earthquakes or volcanoes could release these deeper colder deposits now and then Which brings us to now Here we are lickity split in geological time releasing carbon into the atmosphere causing warming to perhaps go above the usual thermal maximums and even though the sea is rising it is also warming rapidly so we could expect more methane to be released as we heat up Does the atmospheric carbon chart follow this slow nonstrictly cooling and quicker strictly warming patterns as least for some of the events of course other mechanisms would be at play since they re not staying constant 70 Lynn Vincentnathan says 19 Feb 2007 at 9 07 AM My thinking about GCR magnetic fields is this we can t really do much about them So if they do have an effect on warming then we need to focus even more strongly on what is under our control and that is our own GHG emissions What if all these warming factors were to converge solar GCR magnetic fields volcanos AND our high GHG emissions we d really be in hot water So we must do all we can to reduce our GHG as quickly as possible We human might just be the straw that triggers the greatest mass extinction ever 71 tamino says 19 Feb 2007 at 10 31 AM Re 69 I don t think it s the greater rapidity of warming feedbacks over cooling feedbacks that causes the skewness of glacial patterns It s more likely due to the fact that building an ice sheet is a slow process of steady accumulation a thermodynamic process while wasting an ice sheet can happen rapidly as a mechanical process Think of an iceberg calving off a glacier into the sea in a few seconds the glacier loses tons of ice But the creation of that ice happens one snowflake at a time 72 Leif G Liland says 19 Feb 2007 at 11 50 AM Could this fresh water inflow and change in salinity also be the force behind the 3500 years cycle shown here http virakkraft com greenland curves html and how much of the ongoing warming at high latitudes could be caused by this natural cycle 73 Ray Ladbury says 19 Feb 2007 at 12 21 PM My take on the GCR forcing mechanism is that it is an interesting hypothesis that should be investigated further However given that we already have even larger variations on an 11 year timescale and that the CR fluxes in the space era have not changed it s hard to credit the hypothesis The speculations about the geomagnetic field are in my opinion rather wild If you look at the way a field flip occurs initially you start seeing more of the energy going into the higher multipoles These configurations are not stable and oscillate rapidly Perhaps these flows took place during the few thousand years of a flip and the anomalies are due to rapid local variations To hypothesize the the geomagnetic field might originate somewhere other than the core is well beyond speculative I think what we see here is the tendency of humans to try to explain the unexplained in terms of the unexplained or at least the not well understood Humans seem to like even better to explain things in terms of SEP somebody else s problem or best of all NP Nobody s problem i e nobody can do anything so lets all sit in the deckchairs on the Titanic and pop a cold one rather than rearranging them 74 pete best says 19 Feb 2007 at 2 20 PM Off Topic but now the Arctic is at 390 ppm http environment newscientist com article dn11213 greenhouse gases hit new high html 2 ppm annual increase 75 Margo says 19 Feb 2007 at 5 05 PM Response This is just science fiction You can spin all the word tales you want but until you come up with a set of equations saying why the cloud cover changes should have been less in glacial times or why the climate should have been less sensitive to cloud cover at the time you might as well be talking about space aliens blocking the sunlight You talk a good tale Mr Astley but science is a high stakes game and you ve got to pony up some real equations if you want to play raypierre It s fair enough to ask for equations to back up speculative arguments and to suggest that without them one might as well be suggesting space aliens are involved I had the same reaction when I read the equationless article What does the lag of CO2 behind temperature in ice cores tell us about global warming published at realclimate in 2004 I clicked the link to http icebubbles ucsd edu CaillonTermIII pdf to find the equations but that link is dead I found this icebubbles ucsd edu Publications CaillonTermIII pdf which contains no equations showing how this positive feedback mechanism works in practice So is there a paper showing a model for the evolution of both Temperature and CO2 with time based on any known physical processes Does solution of these equations suggest an 800 year lag in CO2 Does the solution explain cycles in temperature etc I ve been wondering because as it stands the RC article is interesting but it would be nice to see it firmed up and quantified so the speculative idea could be tested 76 Steve Bloom says 19 Feb 2007 at 6 24 PM Re 62 That joke is great Hank It s the funniest thing Yakov Smirnov never said Re 75 But why risk sullying the purity of your denialist views Seriously Margo if you think there s anything to William Astley s stuff I believe you have a blog you can devote to exploring it in detail You might start with taking the obvious step of backing up to the main pub page at the link you noted and looking at all those other papers The try Google Scholar and make use of your fine university library If you have any remaining questions try emailing Jeff Severinghaus Good luck with that In the meantime if the RC authors think an idea amounts to flat earthism IMHO spending any time on it beyond a brief summary refutation is contrary ro the purposes of this blog 77 Margo says 19 Feb 2007 at 6 50 PM Re 76 Steve How is that any sort of answer to my question Why are you suggesting I am thinking of anything to do with William Astley I asked whether or not there is a complete theory describing the speculative feedback mechanism advanced here at Real Climate Presumably since the whole team at RC wrote the post proposing the existance of a positive feedback between T and CO2 and raypierre is holding a high standard against mere speculation about physical mechanisms someone here at Real Climate has seen such a mathematical model If they have should be able to point me to they paper As it happens if such a theory exists it would touch on the topic or what triggers the ice ages so I suspect others might like to see it It also happens that if the whole team doesn t know of such a paper describing such a model then that might suggest that raypierre doesn t really think these mathematical models really need to exist to before one can speculate about phenomenology It won t make the previous commenters speculation correct but it would suggest that little space alien comment was a bit harsh For the record Steve it may come as a surprise to you but I am not a denialist I think we ve increased the amount of CO2 in the atmosphere and I think it s likely resulted in some increase in global temperature Also for what it s worth I m under the impression that the authors of RC actually like to provide references and explanations for their theories when they have them However if you are correct and they don t like to do so I m sure they can tell me that themselves So in the hope of getting what I most want let me close by saying If the team or raypierre or their guest author is familiar with a paper that contains an actual full mathematical model describing the effect of a positive feedback mechanism between CO2 and T discussed in their previous article I d like to read it Honestly 78 Hank Roberts says 19 Feb 2007 at 7 38 PM Er You re asking for a complete theory and an actual full mathematical model can you say what papers you would say don t meet your standards of the major ones Have you read this one I ve seen only this press release for it http www agu org sci soc prrl prrl0617 html 26 May 2006 in Geophysical Research Letters Marten Scheffer of Wageningen University in the Netherlands and colleagues at the Potsdam Institute for Climate Impact Research in Germany and the Centre for Ecology and Hydrology in the United Kingdom use newly acquired ancient climate data to quantify the two way phenomenon by which greenhouse gases not only contribute to higher temperatures but are themselves increased by the higher temperatures This higher concentration leads to still higher temperatures in what scientists call a positive feedback loop I don t know if the commenters here have mentioned it not finding it with the search tool 79 Margo says 19 Feb 2007 at 9 12 PM Hank Roberts Er You re asking for a complete theory and an actual full mathematical model can you say what papers you would say don t meet your standards of the major ones I wasn t saying I knew of papers that don t meet standards I was saying that the paper cited in your real climate article What does the lag of CO2 behind temperature in ice cores tell us about global warming speculated about the existence of a positive feedback but cited zero articles containing anything that could remotely be called a mathematical model to describe any sort of positive feedback loop That s why I was asking for a citation Like Raypierrs I happen to like these models which is why I said it s reasonable to ask for them That s why I wished the earlier RC post had cited a model it would make the idea more concrete and testable So far no one had suggested a paper containing a model The only person who responded was Steve Bloom who seemed to think I should not be asking for any such paper Or something The link you gave was for the press release but I think I found the pre press version here http www pik potsdam de victor recent scheffer etal T CO2 GRL in press pdf Is this the correct paper This does contain an actual mathematical model Now I can print it out and read it to see what I think of it And as a bonus Steve Bloom can read it too Thanks Oh if there are other papers that would be of interest too 80 Steve Bloom says 20 Feb 2007 at 1 05 AM Re 77 Regarding the Astley reference it sounded on first reading as if you were defending him On a more careful reading I see that what you were really doing was snarkily equating Ray with him Whatever Regarding your particular brand of denialism it appears clear enough from your blog and posting record that you re only interested in learning enough about climate science to go on the attack against it Of course you re free to refer to yourself using any term you like On the substance I was curious enough about this issue to be willing to do some of your research for you I couldn t find public access copies of any of the papers but the short answer seems to be that the equations are built into specialized models not GCMs that are used to look at ice age behavior This student paper from 2005 has a nice narrative of the history of these modeling efforts and then discusses in some detail the plans for improving the McGill one although I m sure plenty has happened in the intervening two years It names many if not most of the models involved so it should be easy to go find current information on them and extract the relevant algorithms As you ve recently been spending time trying to pick apart the GISS GCM that shouldn t be too tall of an order for you BTW you use the phrase speculative feedback but the existence of the feedback itself is not a matter of speculation at all The exact mechanism for the feedback is not settled call that speculative if you want although many of its parameters have been determined Be sure to give my regards to John A 81 Steve Bloom says 20 Feb 2007 at 1 29 AM Re 78 9 The paper Hank linked is on the strength of the amplification effect of anthropogenic GHG emissions at the present time which is rather different issue from the past lagged relationship between glaciations and CO2 82 Margo says 20 Feb 2007 at 10 07 AM Re 81 Steve Bloom The paper Hank suggested does not contain a positive feed back model of the sort that would explain why the 800 years lag in CO2 in ice cores As it happens the student paper you cite contains no such model In fact it doesn t even contain a single equation which would be a rather minimal requirement for a paper describing a mathematical model But since you ask me what I am looking I shouldn t be surprised the paper you suggested doesn t provide a mathematical model Here s what I am looking for A specific model that would support the specific argument in What does the lag of CO2 behind temperature in ice cores tell us about global warming written by the RC team The argument they advanced in their article includes the claim that the 800 year lag in CO2 can be explained by a positive feedback mechanism That s a rather precise claim not only is there a positive feedback but it s consistent with the 800 year lag in CO2 and the whole ball of wax explains the magnitude of the changes in temperature associated with ice ages and interglacials A reference containing such a model should be rather easy for the team to supply if as raypierre s response to Astley suggests the RC team members really don t accept speculation until after they have read and accepted some sort of mathematical model to explain the speculation Of course if there is no such paper or even if it exists but the RC authors are unaware of the paper then with regard to this specific theory explaining the meaning of the ice cores maybe that would suggest the RC authors including raypierre don t actually believe these sorts of models are always required before one can accept a speculative argument For the record I happen to think speculative arguments do have a legitimate place in science Mathematical models are more concrete and so I like to see to see them If the RC team knows of a mathematical model to explain the argument advanced in What does the lag of CO2 behind temperature in ice cores tell us about global warming I really would like to see it Response I don t really know what you are looking for since I don t know that anyone has ever claimed to have a pure mathematical basis for the changes in oceanography and biology that control the CO2 level However there are lots of reasonable heuristic models that demonstrate the reasonableness of the idea Didier Pallaird for instance Paillard 1998 2001 and references therein It should be clearly stated that a full understanding of ice age carbon dioxide cycles is still elusive but conceptually there is absolutely nothing difficult about a lags in the system on the order of the ocean overturning timescale on the contrary it is to be expected gavin 83 Reid says 20 Feb 2007 at 10 14 AM Tamino said The FFT is a poor choice because is requires the data to be evenly spaced in time which often it is not and requires the number of data points to be a power of 2 which it almost never is The number of data points does not have to be a power of 2 Modern FFT algorithms automatically break up the time series into a subset of primes It goes faster as a power of two though and this can be effected simply by padding the series with zeros up to the power of two Zero padding can also be used to increase the resolution of the PSD See the classic text by Oppenheim and Schafer the latter one of my old profs Unfortunately though the FFT does require the data to be evenly spaced in order to take advantage of the symmetries of the Fourier series 84 Aziz Poonawalla says 20 Feb 2007 at 10 57 AM Reid thats true that you don t neccessarily need a factor of 2 Padding the series with zeres is essentially the same as interpolating the time series and if you re going to interpolate it anyway you might as well make it a power of 2 AND give it even spacing Tamino s use of the DCFT was appropriate though and makes the issue moot DCFT takes a lot more compute power but in this era of Core 2 Duo laptops and matlab licenses who cares I ve got an old pre Yonah Dothan Pentium M thinkpad which gets the job done just fine I still think that the frequency graphs are more intriguing than the original time series I work in MRI physics so I have a bias towards the frequency domain If you re trying to establish a case for the complexity of inputs to the warming cycles then overlaying the various peaks on each other on a single colored graph would be immensely useful for a layman 85 tamino says 20 Feb 2007 at 10 58 AM Re 83 Thanks for the correction 86 Hank Roberts says 20 Feb 2007 at 11 33 AM I m a reader not a contributor here Don t mistake me for a climate scientist I read try to learn try to ask questions to clarify Having looked at Margo s website I m done replying to your questions here it seems you re trying to be another auditor anonymous at that If you think you re doing science send it to a refereed journal for help The auditors might as well set up card tables and pull out e meters it s not science Yawn 87 Margo says 20 Feb 2007 at 12 59 PM Gavin I had two purposes in posting They are 1 I do think it s important to comment when inline replies are nothing but snark and double standards Contrary to raypierre s snark about space aliens the standard for a a more or less respectable idea is not that one must come up with a set of equations saying why to support your idea Heuristic explanations are widely used and perfectly respectable Based on your final reply RC is in fact relying on non mathematical heuristic explanations when discussing the ice core data That s what I thought you were doing when I first read the article 2 If someone had actually come up with a set of equations to explain why the ice core data looks the way it does I would have loved to have see that Evidently no one has come up with one and only heuristic explanations exist That s fine with me from a science point of view However the fact that this bang on explanatory mathematical model does not exist does illustrate that Raypierre was erecting a double standard in his snarky reply So thanks for the links to the papers I m reading them and I find them interesting For what it s worth I m entirely unfamiliar with what Astley is talking about It was the snarky reply that caught my eye But if Astley s heuristic argument has some deficiency other than not being described by a set of equations saying why could someone explain the deficiency If your position that the idea is just not even fleshed out enough to engage that s fine But if an inline reply is warranted surely it should provide a legitimate criticism Response I get your point but on the specifics of GCR climate links Ray is correct There has not been even one credible estimate of what the radiative forcing for a change in GCR would mean for climate This is something that clearly is amenable to equations and the like and is the standard by which all potential forcings CO2 CH4 volcanoes solar aerosols etc are measured Until that happens claims that GCR forcings are the dominant force in climate will continue to be dismissed as they are not based on anything quantitative We know to a pretty high accuracy what the man made greenhouse gases have done there is no comparable estimate for GCR effects That has nothing to do with heuristic arguments about the glacial interglacial cycle gavin 88 Steve Bloom says 20 Feb 2007 at 3 05 PM Re 82 Margo you need to read what I wrote The student paper was useful because it a contained a good AFAICT narrative of how the science had developed up through a little less than two years ago and b named at least some of the relevant models IMHO people who aren t in the field tend to have a hard time really understanding the state of the science without something like that as a guide so I was very happy to have found it In any event I didn t say the paper included the models or their underlying math but rather that it named them such that an interested party you e g could go look at them to find out about the math Just to restate a little what Gavin said I think your question betrayed a basic misunderstanding which is why I thought the student paper would be so useful for you The behavior of the CO2 around the glaciations can t be a forcing as such because that would conflict with our understanding of its physical behavior i e it can t start an increase or decrease by itself Something else is making it behave that way which means that it is a feedback to a forcing or forcings The way these terms are defined leaves no other option So to even refer to a speculative feedback betrays a fundamental misunderstanding Exactly how the behavior of that feedback is modeled is a very interesting question in climate science and as Gavin says not fully resolved as yet although it seems clear that the general answer is Milankovitch forcing leading to a combination of feedbacks e g ocean and vegetative that in turn result in the CO2 change The test of the models is how well they replicate ice sheet behavior in terms of timing size and location and based on that paper it doesn t seem like they re terribly far away from that Response In addition the main point of Severinghaus post referenced at the beginning of this thread was not to explain the possible mechanisms for the glacial interglacial CO2 fluctuations but only to explain that the lead lag relation cannot be used to infer that CO2 is caused by temperature rather than vice versa He was shooting down a fallacy in reasoning As such it s a point that is mathematical and independent of the specific mechanisms causing the CO2 feedback on temperature Jeff explained this in words to be more accessible but it s quite easy to cook up a pair of differential equations with an external periodic forcing think Milankovic which illustrates the point in quantitative terms By the way many scientists have proposed specific testable mechanisms for the CO2 glacial interglacial cycle They have all been falsified but that s just science The credit goes to the people who have formulated things like ice cover gas exchange feedback that can be quantified to the point of being tested This is very different from much of the commentary you see from the GCR crowd notably Mr Astley s waving a magic wand and inventing a lower glacial climate cloud sensitivity to make the problem with the Laschamp Magnetic Anomaly go away raypierre 89 Steve Sadlov says 20 Feb 2007 at 3 57 PM RE 48 The Dust Bowl years are extremely politically incorrect They make the 90s look too

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    in that article Or at least it should be easy if we understand the effect of temperature on CO2 uptake or release and if we also understand the effect of CO2 on factors that affect the energy balance One thing I was trying to find out was has anyone done it Have the solutions of these DE s differential equations been compared to the data and found to work Or not Do we have mathematical models for the effect of temperature on the CO2 uptake and release You seem to be saying maybe some mathematical models involving the CO2 Temperature linkage have been proposed but found failure I agree failure is part science And as it happens I d be interested in reading papers describing the failed models And not because I m trying to find holes I m curious about what someone tried to come up with in equation form rather than just words Do you have references Names Titles I can find them but it s a bit hard to google with random words Re 88 Steve I did read what you said I asked for something specific You decided to suggest a reference that did not discuss that specific thing Thanks anyway 111 Steve Bloom says 22 Feb 2007 at 7 56 PM Re 110 Margo it seemed to me that a list of various modeling efforts would be helpful in that you could go check them out Of course each of those modeling efforts would need to involve some sort of algorithm along the lines of what you say you want to see but I guess what you really wanted was a direct pointer to one or more of them Sorry I m interested in this subject but not interested enough to devote time to such a search By coincidence though I did just happen across this new paper not through peer review yet It uses an AR4 GCM recalling that as of two years ago GCMs weren t being used for this sort of thing but these authors have access to loads of time on an advanced supercomputer and seems to get pretty good results I haven t read through it carefully yet but it does include an equation or two 112 Margo says 22 Feb 2007 at 11 40 PM Re 111 Steve Bloom I don t know why it seems to you that student paper will help me find what I want I ve downloaded many of the papers discussed in section 2 4 in the paper you linked and let me assure you they don t describe the sort of thing I am looking for The paper you found today is even further from the mark Raypierre can very close to giving a qualitative description of what I want when he said eff explained this in words to be more accessible but it s quite easy to cook up a pair of differential equations with an external periodic forcing think Milankovic which illustrates the point in quantitative terms By the way many scientists have proposed specific testable mechanisms for the CO2 glacial interglacial cycle They have all been falsified but that s just science I agree that if the physical processes are sufficiently well understood then it would be quite easy to cook up these equations If I m understanding Raypierre correctly he is suggesting he is aware of some people who have attempted the quite easy task of cooking up equations of this sort but their models didn t pan out that is to say they were falsified If Raypierre knows the names of authors who documented their efforts to develop these models and compare them to data I d like to know those so I can search for the papers Falsified models are not generally widely cited So if Raypierre doesn t mention some names to give me a place to start I really don t think I m going to find them 113 Hank Roberts says 23 Feb 2007 at 8 51 AM http www agu org cgi bin SFgate SFgate listenv table multiple 1 range 1 directget 1 application os06 database 2Fdata 2Fepubs 2Fwais 2Findexes 2Fos06 2Fos06 maxhits 200 22OS26F 06 22 a close temporal coupling between events in the tropical and high latitude North Atlantic during the last deglaciation 1 We recently extended this record to approximately 120 000 years BP in order to track vegetation change over a full glacial cycle at millennial to orbital timescales High frequency oscillations in the Î 13C composition of long chain fatty acids during MIS 3 appear to coincide with Dansgaard Oeschger variability in high latitude ice cores with positive negative excursions occurring during stadial interstadial periods The largest enrichments up to 8 per mil are associated with Heinrich Events in the North Atlantic After a relatively stable MIS 2 period Termination 1 is marked by a rapid 13C depletion over the Glacial Bolling transition followed by a return to somewhat heavier values during the Younger Dryas similar to earlier observations 1 These high frequency fluctuations are superimposed upon a long term trend that tracks the variation in overhead insolation 114 Hank Roberts says 23 Feb 2007 at 12 21 PM There s always something interesting setting aside the fact that these astronomical variations are minuscule compared to the rate of the current human contribution to climate change there s plenty of interesting science Someone can now add this variable to all the others One pole of the sun is cooler than the other data from the ESA NASA Ulysses spacecraft One magnetic pole oooler temp difference flipped along with the field direction the one time so far that s been observed http science nasa gov headlines y2007 20feb coolmystery htm list15225 I don t know if that temperature difference detectable from the unique orbital perspective over the Sun s poles is also detectable in the plane of Earth s orbit now that we know to look for it that is I don t know if the whole Solar System is warmer on one side of the Sun s magnetic field it s a funny asymmetry eh And on the cosmic ray stuff And New Scientist last week had a good article on the upcoming chance to slingshot another deep space probe there s a configuration coming soon that would allow a spacecraft to pass Jupiter and be slung very fast out along the line the Sun will be traveling which could get among other things advance info on any change in dust levels one s certain to happen when we leave the local bubble there may be streams or clouds of dust And yes Svensmark is mentioned changes in dust will have local consequences changing cosmic ray rates though no one s quite sure yet how No online text that I am aware of library sub required 115 Reid says 23 Feb 2007 at 1 56 PM Aziz not to beat a dead horse but just be aware that interpolation is like low pass filtering and it will smudge and attenuate the higher frequencies Unless it s a high order interpolation which might amplify portions of the spectrum 116 Hank Roberts says 23 Feb 2007 at 3 28 PM There s a distorted echo This http climate weather com blog 9 11793 html and this http www realclimate org index php archives 2007 02 what triggers ice ages more 403 Both appear to be the exact same topic attributed to RC But the first link takes you into an independent and different thread of responses http climate weather com blog 9 11793 html readcomments This copy of this response is posted at RC 117 Lynn Vincentnathan says 23 Feb 2007 at 5 32 PM Re 102 thanks Mark And I too would like to know about There must be a curve which describes the amount of feedback that is created by each 1 degC of extra warming Is there any plotted historical data on this one I know Mark Lynas s book SIX DEGREES is coming out March 19th and I m hoping he s addressed this very question GW is a big complex issue we need some people to bring it all together in lay terms I just read that the Texas Water Dept Board projected that 85 of Texans will not have adequate water by 2060 during drought conditions and they didn t even take GW into consideration which would imply a still worse scenario So glad you are going into a field that could use a GW perspective 118 David B Benson says 23 Feb 2007 at 6 07 PM Re 102 117 Mark Schneeweiss Lynn Vincentnathan The paper Positive feedback between global warming and atmospheric CO2 concentration by Marten Scheffer Victor Brovkin and Peter Cox describes an important part of what you wish to know You can either web trawl for the preprint version of the paper or else find the comment here on RealClimate where the link was posted on the 19th or 20th of this month 119 Steve Bloom says 23 Feb 2007 at 6 10 PM Re 112 I imagine it s the case that not every piece of a model appears in a paper Margo if anything I would expect just the opposite until such time as one of the teams thinks they have it all nailed own at which time I would expect all of the details to be carefully described in papers Your next obvious step is to email the modelers since the one thing we can be confident about is that each of those models must contain a version of what you re after Also not to put words in Ray s mouth but when he said falsified I don t think that was the same thing as saying that there aren t valid algorithms that describe the relationships between the things we have paleo records of e g CO2 levels ice sheet mass and location and vegetative response per the paper Hank just linked or can calculate with exactness Milankovitch forcing The Japanese team does appear to be quite close with e g far better results than the McGill model was getting a couple of years ago What s still missing and the reason why their model too continues to be falsified is that there are literally dozens of important feedbacks and physical parameters that must be gotten right in order for the model not to be falsified They named a few that they know they need to continue to work on and I have to say it seemed like a pretty short list Comparing their overall results to what the McGill team was getting a couple of years ago it seems likely that they have the guts of it right That said I d love to know what other modelers think about this Anyway we ll see what happens over the next couple of years as they plug in those changes 120 Steve Bloom says 23 Feb 2007 at 6 34 PM Just to add to the above a little I m obviously no expert but it seems to me that it would be a comparatively trivial exercise to develop a set of equations that describe e g the relationship between CO2 levels insolation and ice sheet mass Could you use that set of equations in any direct way to describe the timing and location of the ice sheets I suspect not As I think about it it s not entirely clear to me that the modelers would need to go through a formal step of developing such a set of equations unless those steps were amenable to plugging into the model in a fairly direct way I did notice that the Japanese team had a fair number of equations they used to describe various relationships within their model but those may not be taken from the model in a strict sense IOW did they write those equations after they wrote the code simply as a convenient way to describe what they did Putting this whole thing another way would it be possible as to state an entire GCM as a set of formal equations as opposed to code Whether it is or not it seems clear that it would be pointless 121 David B Benson says 23 Feb 2007 at 8 01 PM Re 120 Steve Bloom B Saltzman Dynamical Paleoclimatolgy Academic Press 2002 is an attempt to develop equations to explain ice ages in a rigorous manner I am finding the book quite useful so at least I do not find Saltzman s effort to be pointless 122 William Astley says 23 Feb 2007 at 8 45 PM In Reply to Robert s Comment 67 to my comment 66 How about this one All researchers agree that the very very rapid field changes could not possibly be due to changes in the earth s core If the problematic data is correct the earth s magnetic field is not generated in the core Attached is a link to a summary that provides papers and a discussion of the salient scientific issues Physical issues with explaining rapid field changes http www amsta leeds ac uk livermor publications thesis chapter1 pdf 1 Did the very very rapid geomagnetic field changes occur Yes three papers two different authors confirm the event happened 2 How rapid is the observed geomagnetic field change of 6 degree day Current field change is 0 5 degree per year 3 Physically why is it difficult to explain this rapid change If the geomagnetic field change was caused by changes in core the outer core fluid velocity would have needed to increase a 1000 times what is the physical reason for a 1000 times increase or there would need to be a more complex field configuration in the core than is currently used in computer models i e A theoretical configuration of core currents which is believed to be physically not be possible No mechanism to move the core fluid to create the observed pattern 4 Regardless and most important the mantle is slightly conductive rapid changes in the core magnetic field would create currents in the mantle that would resist the changes Based on the theoretical geomagnetic field computer models Which are all incorrect as the geomagnetic field is not generated in the core Other theoretical problems with core as source such as what is driving the core fluid motion Heat flux problem it is believed and it is stated in paper s that reversals take a couple of 1000 years to complete 5 As the sea floor sediment proxy data filter s the geomagmetic field changes everyone assumed field changes took 1000 s of years to complete 123 Hank Roberts says 23 Feb 2007 at 10 40 PM Well http www agu org cgi bin wais bb MR43A 0876 124 Hank Roberts says 23 Feb 2007 at 10 43 PM and http www blackwell synergy com links doi 10 1111 j 1365 246X 2004 02510 x abs 125 Hank Roberts says 23 Feb 2007 at 10 47 PM Gah I thought I made this up as fiction a few weeks ago But no Can t get the page to open just Google Scholar hit External forcing of the geomagnetic field Implications for the cosmic ray uxâ climate variability J Wendler Journal of Atmospheric and Solar Terrestrial Physics 2004 alf zfn uni bremen de Thus the reversal rate of our planet is correlated This could mean that the geomagnetic field is not The polarity change between the Kiaman Reversed and the 126 Steve Bloom says 24 Feb 2007 at 5 11 PM Re 121 Interesting Was he then using those equations in a model and if so could you expand on that a bit 127 David B Benson says 24 Feb 2007 at 6 04 PM Re 126 Steve Bloom With pleasure The late Professor Satzman with colleagues develop a system of three first order nonlinear differential equations to represent ice mass carbon dioxide and ocean temperature all globally Using reasonable values for the parameters the model is tuned to naturally resonate at a 100 ky period Then orbital forcings are added The result gives a qualitatively good match to the most recent four ice age cycles according to the 1990s data that they used They then go on to somewhat more sophisticated models which assume a secular downwards trend in carbon dioxide over the last 5000 ky Running this model gives quite a decent but qualitative fit for the entire Late Cenezioc ice age The fits for the latest 700 ky are quite respectable The conclusion is that the ice age cycles occur because the climate system has a natural period of about 100 ky The orbital forcings just set the phase I interpret his view as implying that eccentricity has essentially nothing to do with the cycle length I am such an amateur at this that I am not in a position yet to suggest revising his constitutive equation for the rate of change of ice mass But either I am missing something or his equation is overly simple Either way he has done a most impressive piece of work in reducing the climate system into a form which can be expressed with only 4 free parameters 9 for the longer term model It is interesting to note that in this work even the carbon dioxide feedback does not suffice alone to quickly end the major glaciations There is a calving effect included once there is sufficent bedrock depression With this the modeled ice masses quickly and appropriately decay 128 Sashka says 26 Feb 2007 at 11 54 AM Satzman did interesting work but ultimately it was a blind alley because the equations that he and his colleagues were solving could not have been rigorously derived Their counter argument would be the same point that I keep trying to make here

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    for being too conservative and not including the possibility of limited runaway warming hysteresis in which our AGW triggers nature to emit more GHGs causing more warming causing more GHGs and so on all the way to oblivion for a large chunk of life on earth I ve learned to get in and out fast at various social gatherings moving on to a more benign conversation before the contrarians can sicken me ad nauseum with their usual criticisms I leave the contrarians with Just check out RealClimate org they re top climate scientists and they have all the refutations to your issues 16 raypierre says 14 Feb 2007 at 12 51 PM To carry further Gavin s fine analogy let s extend it to the fact that the most viable theory for Cretaceous warming and for a large part of glacial interglacial warming is also CO2 change though not CO2 change caused by humans I have some ideas how the storyline would go for that but instead of writing down my own analogy I thought I d toss it out to the crowd to play around with Just as a way to remind us that CO2 has indeed been implicated in past climate changes and that the role of CO2 in past climate changes tells us something about the present even though this time around it s humans that are causing the CO2 increase 17 Benny says 14 Feb 2007 at 1 18 PM Gavin I thought all you New Yorkers were too busy going to museums and attending art openings to waste time on commercial television Good grief You probably watch Stephen Colbert Response Actually I never watch TV I m just trying to get with the zeitgeist The good Colbert clips can be found on http onegoodmove org 1gm though gavin 18 Ray says 14 Feb 2007 at 1 24 PM My class and I reviewed paleoclimate over the last two weeks and the lightbulb moment was when we took the derivative of the Vostok ice core record in the Holocene to the last glacial 1 95 degC every 1000 years That is 0 2 deg century When you are talking about 1 5 deg C per century it s dimes and dollars 19 Philippe Chantreau says 14 Feb 2007 at 1 49 PM A Seattle PI blogger mentioned a study apparently published yesterday about glaciers whose title suggest the melting trend is not as clear cut as was accepted Do you know anyting about it These were the references provided Title Glaciers Not on Simple Upward Trend of Melting Author University of Washington Published on Feb 13 2007 06 42 Published Online February 8 2007 Science DOI 10 1126 science 1138478 20 tamino says 14 Feb 2007 at 2 10 PM Re 18 Don t forget that the Vostok ice core measurements indicate temperature in the Antarctic region that s why the net change glacial to interglacial is so high about 10 deg C The global change is less than that about 5 deg C So the indicated Antarctic rate 0 2 deg C century translates to a global rate of only about 0 1 deg C century The modern rate using the latest version of HADCRUT3 from 1975 to the present is nearly 1 9 deg C century So it s not dimes and dollars it s nickels and dollars 21 Lynn Vincentnathan says 14 Feb 2007 at 2 21 PM 16 here s one People walking through the woods sometimes eat poisonous mushrooms and die past GW mass extinctions However Mrs Smith wanted to bump off her husband so she fed him poisonous mushrooms our GHG emissions GW now The defense tried to claim it was his accidental eating of these natural fungi growing in the wild But the detectives found the stems in her Mrs Smith s garbage can and forensics detected trace amounts of poisonous mushroom on the dirty dishes and on Mrs Smith s knife and hands Furthermore Mr Smith had not been near that woods for the past week according to witnesses but Mrs had been The problem with this legal analogy is that policy makers and we as mini policy makers do not have to establish beyond reasonable doubt or even preponderance of evidence civil standard to take AGW seriously and address it the amount of evidence certainty Bush had for WMDs in Iraq would be more than enough to dig in and mitigate GW Wouldn t it have been great if instead of spending all that money on the Iraqi war we would have plowed even a tenth of that into GW mitigation measures most of which pay for themselves go on to save like investments And we could have used those savings to give even greater help to the poor of the world Then the whole world would have become our ally Even terrorists may possibly have started thinking we can t attack such good people bad PR for our cause 22 Sashka says 14 Feb 2007 at 2 50 PM Re 18 It would be another lightbulb moment if somebody took trouble answering questions about diffusion of gases within ice cores 23 Steve Bloom says 14 Feb 2007 at 2 57 PM Re 11 As a sort of consumer warning be aware that the bulk of the comments made on RC are not from climate scientists There are some climate scientists who comment a rather larger number of non climate scientists and a yet larger number of laypeople who have made a serious albeit amateur study of climate science I m one of those but all of these taken together are probably no more than half of the total comments As well bear in mind that you can t rely on there being a refuting comment to every single contrarian claim that gets made here So while you can rely on the main posts and the highlighted responses everything else should be taken with a grain of salt Note to RC authors When you post individual comments please highlight them as Mike did in 7 above Regulars know who you are most of the time but was that possibly Ray Bradley in 18 but nobody else does Thanks 24 Bill says 14 Feb 2007 at 3 27 PM Well argued sir I had the pleasure of listening to Dr Pachrui head guy at IPCC speak not long ago Thankfully this group s model is so comprehensive and conservative it isolates the climate change denies into a tiny indefensible pocket For those who want to carry the banner forward get involved I work for the American Council On Renewable Energy ACORE and we have a package deal for young professionals who are already working in the field The largest all renewables trade show is 3 weeks off and we have a special offer for RE professionals in their 30 s and early 40 s It s great opportunity to network and see the latest technology The show is Power GEN Renewable Energy Fuels and it s in Las Vegas Hereâ s the link http www acore org pgreypre php 25 coby says 14 Feb 2007 at 3 43 PM if you can t explain all of the past changes how can you explain anything now This illogic is the subject of one of my How To Talk To a Sceptic articles http illconsidered blogspot com 2006 04 no past no present html A very common attack 26 Hank Roberts says 14 Feb 2007 at 4 15 PM 19 P Chantreau This is sad A new NYT blogger not a science writer got this ball rolling recently Best response so far I think was this one there http tierneylab blogs nytimes com 2007 02 12 greenland redux comment 796 27 SecularAnimist says 14 Feb 2007 at 4 22 PM Lynn Vincentnathan wrote Wouldn t it have been great if instead of spending all that money on the Iraqi war we would have plowed even a tenth of that into GW mitigation measures most of which pay for themselves go on to save like investments And we could have used those savings to give even greater help to the poor of the world The governments of the world spend around ONE TRILLION DOLLARS per year on the military on weapons and other means for human beings to kill each other and more than half of that is the US military budget Imagine what those many many billions of dollars might accomplish what they might long ago have accomplished towards developing and deploying appropriate technologies for a sustainable human civilization living respectfully of all life and within the carrying capacity of the Earth s biosphere providing the means for health happiness peace and prosperity for all human beings everywhere It is almost painful to think about it Many critics of taking action to reduce fossil fuel related GHG emissions to mitigate anthropogenic global warming and climate change complain about the supposed high cost of doing so A trillion dollars a year would go a long way towards addressing the problem But we humans or at least a number of humans who are in the positions of power to direct such vast resources prefer to spend that amount on building weapons and killing each other Perhaps the reason the SETI project has been unable to detect signals from any technogically advanced civilizations on planets in other star systems is that all technologically advanced civilizations inevitably follow the same course that we are on and thus they only have very short periods of time decades when they are sufficiently advanced to generate such signals before they destroy the capacity of their planets to support life and themselves with it Response The NYT had an interesting series in the business section a few weeks ago called basically What could you do with a trillion dollars They had lots of good examples but unfortunately they left out climate stabilization In a recent talk at Chicago Steve Pacala estimated that a gross cost of about US 100 per ton of carbon would be enough to stabilize US emissions at a climatically acceptable rate using present technologies only Net cost would be lower since if you used a carbon tax some of that spending would get plowed back and even without a carbon tax there s the contribution to GDP from people working in carbon sequestration photovoltaic factories etc I think the same numbers can be gotten from Pacala and Sokolow s paper here but it was stated a bit more transparently in the talk That would mean a gross cost of 168 billion per year to stabilize the US carbon emissions given our current emission rate about 550 annually per person gross cost less if you rebated some carbon tax as income tax rebate Not something to break the bank You can compare that 168 billion with your favorite government spending number raypierre 28 Dave D says 14 Feb 2007 at 5 03 PM Someone was making a point about time resolution of ice cores in another thread on this site the other day I think his question is relevant here and I didn t see an answer so I will give my dumbed down understanding of it and ask for an expert to help The time constant for a perturbation of CO2 concentration to decay is about 100 to 150 years currently Is this about correct How long does it take a snow layer to be compressed to hermetically trap air bubbles One website I found said snow is compressed to ice at about 80 meters down How far back in time is that say for Vostok Ice cores come from up to 3000 m down Beyond that the bubble collapse under pressure How long ago is that 600 000 yr It seems like the trap rate is much slower that the CO2 sink rate Doesn t this low pass filter the CO2 time signal For instance hypothetically in 1 year a volcano could quadruple CO2 This excess CO2 would drain out over 100 to 200 years If it takes 1000 years to trap you would almost totally miss this excursion in concetration and temperature from isoptope analysis These numbers are just examples What is the time resolution of ice cores Should nt we be careful saying CO2 concentration is higher now than in any time in past 600 000 Our instantaneous Co2 concentration is higher now than the highest time averaged CO2 over XXXX years seen in the past 600 000 years Also does CO2 follow ocean temperature outgassing or lead it Thanks This is a great site 29 Daniel Goodwin says 14 Feb 2007 at 5 15 PM One problem with this paleoclimatic crime scene for purposes of figuring out where we re headed seems to be that the most recent precedents for current or impending CO2 levels may only be viewed as pre icecore fuzzy daguerreotypes Perhaps scientists have a technical definition of planetary disequilibrium but today seems close to such a state and that s a significant problem disequilibrium is grossly chaotic thus nearly impossible to reliably predict The current lag of the models behind what the splendid GRACE data is saying about the ice sheets is an example of a reality fatigue which will persist in studies of an Earth in a continuing state of disequilibrium 30 Steve Bloom says 14 Feb 2007 at 5 24 PM Re 22 Couldn t stay away eh Sashka Actually the issue you raise has been discussed here before so a search should locate the information It happens that Eric Steig one of the RC co authors is an expert on such matters 31 Ray Ladbury says 14 Feb 2007 at 5 56 PM Excellent post and the analog between the denialist camp yes I ll continue to us this word and the defense is appropriate as all defense views it s sole duty to sew doubt not to reach the truth However for someone who truly takes a scientific view it is not sufficient to say It s all natural variation We are witnessing changes and changes do not occur without an underlying driver Thus far they have advanced no credible candidate mechanism for the changes we are seeing while the anthropogenic greenhouse mechanism explains what we are seeing very well and is physically reasonable To demand that we drop the best candidate mechanism without advancing a credible scientific alternative is anti science every bit as much as demanding Darwin not be taught in biology class is anti science Re 22 Given that diffusion is controlled by molecular size and pressure it would be expected to occur differentially for different molecules Moreover the deuterium hydrogen ratio does not even depend on the gas but rather on the water ice The expectation if diffusion were a significant issue would be chaos indeed that is what is seen for very old ice not a self consistent body of evidence that favored climate change That is indeed a lightbulb moment if you understand it 32 Alexander Ac says 14 Feb 2007 at 5 58 PM Good post as always Though the comment is slightly off topic but I miss one point We are talking about inevitable reduction of CO2 emissions Let s consider the Japan which is country with very high energy use efficiency on the other hand they can t afford the Kyoto Why Because they are so developed that they use so much energy and the ONLY way how to significantly reduce the emissions is simply to use it LESS But is it even possible in practise to start use LESS energy without any APPARENT reason On the other hand everybody wants to be like Japan Highly efficient and highly developed P S For those who don t know Chzech president Vaclav Klaus is the new defender of climate and environmental truth http www klaus cz klaus2 asp clanek asp id 3laYoBP3mqrd of course backed up by Sen Inhofe and Vaclav Klaus chzech fan Lubos Motl 33 Eli Rabett says 14 Feb 2007 at 5 59 PM Perhaps this is a good thread for a question I have had for a long time Multiproxy reconstructions appear to underestimate climate sensistivity Was this an artifact from early reconstructions or a sign that preinstrumental forcings have been overestimated Response Don t know why you would think that Hegerl et al Nature 2006 did a reasonable job on the implications for climate sensitivity in the paleo reconstructions and find a range that is similar to that inferred elsewhere given the uncertainties in both the forcings and the response Did you have some other study in mind gavin 34 Marco Parigi says 14 Feb 2007 at 7 14 PM Ok great so you ve proven Humans guilty beyond reasonable doubt Stunning Now for the punishment I vote we just let the Global warming take its course as a suitable punishment for our collective sins The Easter Islanders were greedy and cut down all their trees and as a punishment they lost their Island paradise That s fair However bad things get or what actions we take the punishment will be proportional to our collective stupidity 35 Blair Dowden says 14 Feb 2007 at 7 33 PM I am wondering how Cretaceous sea level could be 100 meters higher than today when there is only about 70 m worth of water in the remaining ice caps Is there 30 m of thermal expansion And how can you compare sea level when the paleogeography arrangement and size of the continents was completely different 36 Marco Parigi says 14 Feb 2007 at 7 57 PM Instead of beating the drum on AGW why not get a little perspective on the range of GHG s After all there is plenty of damning evidence against CH4 CFC s etc This is a serious question by the way Is it plausible that ALL 90

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  • Cold Case vs. CSI « RealClimate
    are not conversant with every acronym and appreciate it when the professionals remember they re also in a teaching mode on RC Response Last Glacial Maximum around 20 000 years ago Sorry about that we will try harder in future gavin Response This is defined in past RC posts But in most cases as here just stick LGM in our search window and you ll get an answer instantly Unfortunately our glossary is still a bit sparse This should have been in there mike 12 SecularAnimist says 14 Feb 2007 at 12 37 PM gavin wrote there are many periods in Earth history that are unequivocablely accepted to be warmer than the present The word you want there is unequivocally from unequivocal meaning unambiguous clear having only one possible meaning or interpretation absolute unqualified not subject to conditions or exceptions Response whoops thanks gavin gavin wrote If you are a follower of TV crime shows it is likely that you ve come across one of the CSI offshoots CSI stands for Crime Scene Investigation and a slightly less well known show called Cold Case In both these shows difficult crimes usually murders are solved using the most up to date forensic methods and incredible detective work it illustrates nicely how paleo climate research fits in to our understanding of current changes Hmmm Consider the insights into climate research and the global warming policy debates that might be revealed by extending this metaphor to include Law And Order Without A Trace and The Closer 13 Mike says 14 Feb 2007 at 12 38 PM I m pleased to see that your articles seem to be more frequent A daily fix would be most appreciated Ps that s not how you spell comparatively or unequivocally Keep up the good work Mike Response You are unequivocally correct gavin 14 teacher ocean says 14 Feb 2007 at 12 44 PM They made a big deal about AGW on Boston Legal last night and the lead character s argument before the jury was that AGW is not only real but a big problem and we should all on an individual basis do something to minimize our impact The story line and evidence were meant to be humorous and has no scientific relevance because Boston Legal is mostly a comedy but it was good 15 Lynn Vincentnathan says 14 Feb 2007 at 12 46 PM RE how the contrarians trot out past warming as evidence AGW is not happening even if GW may be happening I ve learned to jump the gun on them at social gatherings I trot out past warmings first as evidence that it s happened in the past with 90 of life dying 251 mya and it could happen again only this time we re triggering it faster esp if we get to the 6C increase upper projection for 2100 but who knows for 2200 or 2300 Then before they can even criticize Gore s AIT I criticize it for being too conservative and not including the possibility of limited runaway warming hysteresis in which our AGW triggers nature to emit more GHGs causing more warming causing more GHGs and so on all the way to oblivion for a large chunk of life on earth I ve learned to get in and out fast at various social gatherings moving on to a more benign conversation before the contrarians can sicken me ad nauseum with their usual criticisms I leave the contrarians with Just check out RealClimate org they re top climate scientists and they have all the refutations to your issues 16 raypierre says 14 Feb 2007 at 12 51 PM To carry further Gavin s fine analogy let s extend it to the fact that the most viable theory for Cretaceous warming and for a large part of glacial interglacial warming is also CO2 change though not CO2 change caused by humans I have some ideas how the storyline would go for that but instead of writing down my own analogy I thought I d toss it out to the crowd to play around with Just as a way to remind us that CO2 has indeed been implicated in past climate changes and that the role of CO2 in past climate changes tells us something about the present even though this time around it s humans that are causing the CO2 increase 17 Benny says 14 Feb 2007 at 1 18 PM Gavin I thought all you New Yorkers were too busy going to museums and attending art openings to waste time on commercial television Good grief You probably watch Stephen Colbert Response Actually I never watch TV I m just trying to get with the zeitgeist The good Colbert clips can be found on http onegoodmove org 1gm though gavin 18 Ray says 14 Feb 2007 at 1 24 PM My class and I reviewed paleoclimate over the last two weeks and the lightbulb moment was when we took the derivative of the Vostok ice core record in the Holocene to the last glacial 1 95 degC every 1000 years That is 0 2 deg century When you are talking about 1 5 deg C per century it s dimes and dollars 19 Philippe Chantreau says 14 Feb 2007 at 1 49 PM A Seattle PI blogger mentioned a study apparently published yesterday about glaciers whose title suggest the melting trend is not as clear cut as was accepted Do you know anyting about it These were the references provided Title Glaciers Not on Simple Upward Trend of Melting Author University of Washington Published on Feb 13 2007 06 42 Published Online February 8 2007 Science DOI 10 1126 science 1138478 20 tamino says 14 Feb 2007 at 2 10 PM Re 18 Don t forget that the Vostok ice core measurements indicate temperature in the Antarctic region that s why the net change glacial to interglacial is so high about 10 deg C The global change is less than that about 5 deg C So the indicated Antarctic rate 0 2 deg C century translates to a global rate of only about 0 1 deg C century The modern rate using the latest version of HADCRUT3 from 1975 to the present is nearly 1 9 deg C century So it s not dimes and dollars it s nickels and dollars 21 Lynn Vincentnathan says 14 Feb 2007 at 2 21 PM 16 here s one People walking through the woods sometimes eat poisonous mushrooms and die past GW mass extinctions However Mrs Smith wanted to bump off her husband so she fed him poisonous mushrooms our GHG emissions GW now The defense tried to claim it was his accidental eating of these natural fungi growing in the wild But the detectives found the stems in her Mrs Smith s garbage can and forensics detected trace amounts of poisonous mushroom on the dirty dishes and on Mrs Smith s knife and hands Furthermore Mr Smith had not been near that woods for the past week according to witnesses but Mrs had been The problem with this legal analogy is that policy makers and we as mini policy makers do not have to establish beyond reasonable doubt or even preponderance of evidence civil standard to take AGW seriously and address it the amount of evidence certainty Bush had for WMDs in Iraq would be more than enough to dig in and mitigate GW Wouldn t it have been great if instead of spending all that money on the Iraqi war we would have plowed even a tenth of that into GW mitigation measures most of which pay for themselves go on to save like investments And we could have used those savings to give even greater help to the poor of the world Then the whole world would have become our ally Even terrorists may possibly have started thinking we can t attack such good people bad PR for our cause 22 Sashka says 14 Feb 2007 at 2 50 PM Re 18 It would be another lightbulb moment if somebody took trouble answering questions about diffusion of gases within ice cores 23 Steve Bloom says 14 Feb 2007 at 2 57 PM Re 11 As a sort of consumer warning be aware that the bulk of the comments made on RC are not from climate scientists There are some climate scientists who comment a rather larger number of non climate scientists and a yet larger number of laypeople who have made a serious albeit amateur study of climate science I m one of those but all of these taken together are probably no more than half of the total comments As well bear in mind that you can t rely on there being a refuting comment to every single contrarian claim that gets made here So while you can rely on the main posts and the highlighted responses everything else should be taken with a grain of salt Note to RC authors When you post individual comments please highlight them as Mike did in 7 above Regulars know who you are most of the time but was that possibly Ray Bradley in 18 but nobody else does Thanks 24 Bill says 14 Feb 2007 at 3 27 PM Well argued sir I had the pleasure of listening to Dr Pachrui head guy at IPCC speak not long ago Thankfully this group s model is so comprehensive and conservative it isolates the climate change denies into a tiny indefensible pocket For those who want to carry the banner forward get involved I work for the American Council On Renewable Energy ACORE and we have a package deal for young professionals who are already working in the field The largest all renewables trade show is 3 weeks off and we have a special offer for RE professionals in their 30 s and early 40 s It s great opportunity to network and see the latest technology The show is Power GEN Renewable Energy Fuels and it s in Las Vegas Hereâ s the link http www acore org pgreypre php 25 coby says 14 Feb 2007 at 3 43 PM if you can t explain all of the past changes how can you explain anything now This illogic is the subject of one of my How To Talk To a Sceptic articles http illconsidered blogspot com 2006 04 no past no present html A very common attack 26 Hank Roberts says 14 Feb 2007 at 4 15 PM 19 P Chantreau This is sad A new NYT blogger not a science writer got this ball rolling recently Best response so far I think was this one there http tierneylab blogs nytimes com 2007 02 12 greenland redux comment 796 27 SecularAnimist says 14 Feb 2007 at 4 22 PM Lynn Vincentnathan wrote Wouldn t it have been great if instead of spending all that money on the Iraqi war we would have plowed even a tenth of that into GW mitigation measures most of which pay for themselves go on to save like investments And we could have used those savings to give even greater help to the poor of the world The governments of the world spend around ONE TRILLION DOLLARS per year on the military on weapons and other means for human beings to kill each other and more than half of that is the US military budget Imagine what those many many billions of dollars might accomplish what they might long ago have accomplished towards developing and deploying appropriate technologies for a sustainable human civilization living respectfully of all life and within the carrying capacity of the Earth s biosphere providing the means for health happiness peace and prosperity for all human beings everywhere It is almost painful to think about it Many critics of taking action to reduce fossil fuel related GHG emissions to mitigate anthropogenic global warming and climate change complain about the supposed high cost of doing so A trillion dollars a year would go a long way towards addressing the problem But we humans or at least a number of humans who are in the positions of power to direct such vast resources prefer to spend that amount on building weapons and killing each other Perhaps the reason the SETI project has been unable to detect signals from any technogically advanced civilizations on planets in other star systems is that all technologically advanced civilizations inevitably follow the same course that we are on and thus they only have very short periods of time decades when they are sufficiently advanced to generate such signals before they destroy the capacity of their planets to support life and themselves with it Response The NYT had an interesting series in the business section a few weeks ago called basically What could you do with a trillion dollars They had lots of good examples but unfortunately they left out climate stabilization In a recent talk at Chicago Steve Pacala estimated that a gross cost of about US 100 per ton of carbon would be enough to stabilize US emissions at a climatically acceptable rate using present technologies only Net cost would be lower since if you used a carbon tax some of that spending would get plowed back and even without a carbon tax there s the contribution to GDP from people working in carbon sequestration photovoltaic factories etc I think the same numbers can be gotten from Pacala and Sokolow s paper here but it was stated a bit more transparently in the talk That would mean a gross cost of 168 billion per year to stabilize the US carbon emissions given our current emission rate about 550 annually per person gross cost less if you rebated some carbon tax as income tax rebate Not something to break the bank You can compare that 168 billion with your favorite government spending number raypierre 28 Dave D says 14 Feb 2007 at 5 03 PM Someone was making a point about time resolution of ice cores in another thread on this site the other day I think his question is relevant here and I didn t see an answer so I will give my dumbed down understanding of it and ask for an expert to help The time constant for a perturbation of CO2 concentration to decay is about 100 to 150 years currently Is this about correct How long does it take a snow layer to be compressed to hermetically trap air bubbles One website I found said snow is compressed to ice at about 80 meters down How far back in time is that say for Vostok Ice cores come from up to 3000 m down Beyond that the bubble collapse under pressure How long ago is that 600 000 yr It seems like the trap rate is much slower that the CO2 sink rate Doesn t this low pass filter the CO2 time signal For instance hypothetically in 1 year a volcano could quadruple CO2 This excess CO2 would drain out over 100 to 200 years If it takes 1000 years to trap you would almost totally miss this excursion in concetration and temperature from isoptope analysis These numbers are just examples What is the time resolution of ice cores Should nt we be careful saying CO2 concentration is higher now than in any time in past 600 000 Our instantaneous Co2 concentration is higher now than the highest time averaged CO2 over XXXX years seen in the past 600 000 years Also does CO2 follow ocean temperature outgassing or lead it Thanks This is a great site 29 Daniel Goodwin says 14 Feb 2007 at 5 15 PM One problem with this paleoclimatic crime scene for purposes of figuring out where we re headed seems to be that the most recent precedents for current or impending CO2 levels may only be viewed as pre icecore fuzzy daguerreotypes Perhaps scientists have a technical definition of planetary disequilibrium but today seems close to such a state and that s a significant problem disequilibrium is grossly chaotic thus nearly impossible to reliably predict The current lag of the models behind what the splendid GRACE data is saying about the ice sheets is an example of a reality fatigue which will persist in studies of an Earth in a continuing state of disequilibrium 30 Steve Bloom says 14 Feb 2007 at 5 24 PM Re 22 Couldn t stay away eh Sashka Actually the issue you raise has been discussed here before so a search should locate the information It happens that Eric Steig one of the RC co authors is an expert on such matters 31 Ray Ladbury says 14 Feb 2007 at 5 56 PM Excellent post and the analog between the denialist camp yes I ll continue to us this word and the defense is appropriate as all defense views it s sole duty to sew doubt not to reach the truth However for someone who truly takes a scientific view it is not sufficient to say It s all natural variation We are witnessing changes and changes do not occur without an underlying driver Thus far they have advanced no credible candidate mechanism for the changes we are seeing while the anthropogenic greenhouse mechanism explains what we are seeing very well and is physically reasonable To demand that we drop the best candidate mechanism without advancing a credible scientific alternative is anti science every bit as much as demanding Darwin not be taught in biology class is anti science Re 22 Given that diffusion is controlled by molecular size and pressure it would be expected to occur differentially for different molecules Moreover the deuterium hydrogen ratio does not even depend on the gas but rather on the water ice The expectation if diffusion were a significant issue would be chaos indeed that is what is seen for very old ice not a self consistent body of

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