RealClimate logo


Antarctica is Cold? Yeah, We Knew That

Filed under: — group @ 12 February 2008 - (Español)

Guest commentary from Spencer Weart, science historian

Despite the recent announcement that the discharge from some Antarctic glaciers is accelerating, we often hear people remarking that parts of Antarctica are getting colder, and indeed the ice pack in the Southern Ocean around Antarctica has actually been getting bigger. Doesn’t this contradict the calculations that greenhouse gases are warming the globe? Not at all, because a cold Antarctica is just what calculations predict… and have predicted for the past quarter century.

It’s not just that Antarctica is covered with a gazillion tons of ice, although that certainly helps keep it cold. The ocean also plays a role, which is doubly important because of the way it has delayed the world’s recognition of global warming.


When the first rudimentary models of climate change were developed in the early 1970s, some modelers pointed out that as the increase of greenhouse gases added heat to the atmosphere, much of the energy would be absorbed into the upper layer of the oceans. While the water was warming up, the world’s perception of climate change would be delayed. Up to this point most calculations had started with a doubled CO2 level and figured out how the world’s temperature would look in equilibrium. But in the real world, when the rising level of gas reached that point the system would still be a long way from equilibrium. “We may not be given a warning until the CO2 loading is such that an appreciable climate change is inevitable,” a National Academy of Sciences panel warned in 1979.(1)

Modelers took a closer look and noticed some complications. As greenhouse gases increase, the heat seeps gradually deeper and deeper into the oceans. But when larger volumes of water are brought into play, they bring a larger heat capacity. Thus as the years passed, the atmospheric warming would increasingly lag behind what would happen if there were no oceans. In 1980 a New York University group reported that “the influence of deep sea thermal storage could delay the full value of temperature increment predicted by equilibrium models by 10 to 20 years” just between 1980 and 2000 A.D. (2)

The delay would not be the same everywhere. After all, the Southern Hemisphere is mostly ocean, whereas land occupies a good part of the Northern Hemisphere. A model constructed by Stephen Schneider and Thompson, highly simplified in modern terms but sophisticated for its time, suggested that the Southern Hemisphere would experience delays decades longer than the Northern. Schneider and Thompson warned that if people compared observations with what would be expected from a simple equilibrium model, “we may still be misled… in the decade A.D. 2000-2010.” (3)

The pioneer climate modelers Kirk Bryan and Syukuro Manabe took up the question with a more detailed model that revealed an additional effect. In the Southern Ocean around Antarctica the mixing of water went deeper than in Northern waters, so more volumes of water were brought into play earlier. In their model, around Antarctica “there is no warming at the sea surface, and even a slight cooling over the 50-year duration of the experiment.” (4) In the twenty years since, computer models have improved by orders of magnitude, but they continue to show that Antarctica cannot be expected to warm up very significantly until long after the rest of the world’s climate is radically changed.

Bottom line: A cold Antarctica and Southern Ocean do not contradict our models of global warming. For a long time the models have predicted just that.


(1) National Academy of Sciences, Climate Research Board (1979). Carbon Dioxide and Climate: A Scientific Assessment (Jule Charney, Chair). Washington, DC: National Academy of Sciences.

(2) Martin I. Hoffert, et al. (1980) J. Geophysical Research 85: 6667-6679.

(3) Stephen H. Schneider and S.L. Thompson (1981) J. Geophysical Research 86: 3135-3147.

(4) Kirk Bryan et al. (1988). J. Physical Oceanography 18: 851-67. For the story overall see Syukuro Manabe and Ronald J. Stouffer (2007) Journal of the Meteorological Society of Japan 85B: 385-403.


449 Responses to “Antarctica is Cold? Yeah, We Knew That”

  1. 151
    David B. Benson says:

    zualufg (144) — Nothing worth even thinking about. Consider how small the volcano is and how very large the Southrn Ocean…

  2. 152
    Craig Allen says:

    zualufug, did you read that abstract properly. The volcano in question erupted in 325BC. The researchers found evidence that the glacier under which it sits has speeded up recently and suggest that increased heat output from volcano may play a role by melting ice which then lubricates the glacier’s base. But they point out that this does not explain why all the other glaciers in the region are speeding up also. There is no mention of there being enough heat to affect the temperature of the southern ocean to any significant degree.

  3. 153

    #141 Gareth, Well written, the combo LaNina and thin polar ice has made identifiable patterns which were surprisingly steady, its a planetary wave phenom, not to be mistaken with a sudden cooling trend, to confirm one must wait a few months. A couple of other under the common radar simultaneous mysteries if you like, +200 knot stratospheric winds, along with a cold stratosphere with frequent bouts of explosive stratospheric warming, although far above, these events are tied with what is happening well below. Recent sun disk refraction readings in the Arctic were not abnormal compared with 2002-07, strongly suggesting that Jan 08 temperature anomaly will be short lived. Finally for those who think 1 degree C mean GT cooling (or warming) is insignificant, think China and snow balls…

  4. 154
    Tilo Reber says:

    I see an explanation for why the Antarctic oceans should warm more slowly in the Weart article. I see no explanation for why it should cool.

  5. 155
    floodguy says:

    what affect will transpire in AGW assumptions, if we see a long-term trend develop denoting increases in global NH and SH sea ice with anomalies above the average recorded mean? For argument’s sake, lets say the trend began in Jan 08 and continues for 4 years, Jan ’12 and along with the trend, decreases in sea and global surface temperatures decrease as well. Thank you.

  6. 156
    Mike Donald says:

    #135
    Thanks Jim for the Oildrum reference. FYI what’s part of the office furniture where I’ve worked is the freebie magazine “Offshore Engineer”. (Which has a yellow border – just like National Geographic). I also get the other freebie “World Oil” which has more stats in it.

    But neither of those prepared me for an article I stumbled upon (no plug intended) via The Times on Friday I believe.

    http://www.lifeaftertheoilcrash.net/

    Gloomy but it argues its case so well (to a non-economist like me) I’m thinking of building an eco home. And it looks like I’ll be in good company. (See what it says about President Bush’s Crawford ranch).

  7. 157

    Rod, actually while I highly appreciate your digging into the science — a manificent hobby! I am an amateur astronomer myself — don’t expect it to answer for you the problem you are trying to solve. Just like your attempt at micro-classifying the authoritativeness of various types of critics/sceptics is IMO useless.

    You see, non-scientists shouldn’t ever be expected to dig into the science in that way, just like you should’t have to question what your GP tells you. Sure, you may want to get a second opinion; but you don’t want to follow your own medical judgment over that of a trained professional.

    The fact that organizations like AGU found it necessary to make ‘position statements’ on this, and also on evolution denial, just tells a sad tale about a failure of communication between ‘science’ and society. The amusing thing is that this appears to happen exclusively with science outcomes that people — or vested interests, or religious nuts, or…. — have an emotional problem with. Not with the vast, immensely successful and hugely useful majority of science (and medicine) that people gratefully accept in their daily lives :-)

    The primary source is always the original research; The primary source is always the original
    research; everything else is derived. Why the
    non-atmospheric scientists in AGU support the
    position statement is because of their
    commitment to the scientific method, the rules
    of evidence, best practices, and the culture
    and traditions of the scientific community —
    this is a community in a way that
    climate change denial will never be.

    I too have only a very superficial understanding of climatology and its methods. Sure, my science (geodesy) and climatology have some physics in common, and some more math; but the essential commonality is the scientific method. I support AGU because I know the climatology community works by the same rules as apply in my discipline (as in many others), and are the only known successful rules by which valid, working science is produced. These rules are learned the hard way by every young scientist as he/she is taken up into the community. Similar to med school (for those that watch hospital series on the box): you come out a permanently different person. There are some things a doctor would never do, and never accept from a colleague.

    This is the kind of ‘groupthink’ there could be more of.

  8. 158
    B Buckner says:

    Re: 156, well that is one gloomy article. For anyone looking for some optimism, read this:

    http://www.lanl.gov/news/index.php/fuseaction/home.story/story_id/12554

    It seems the folks at Los Alamos National Laboratory think they can take CO2 directly out of the atmosphere and make liquid fuels at a competitive cost. Who knows if this will work in the real world, but if so it would help to address two huge problems of global warming and our energy supply.

  9. 159
    Ellis says:

    Mr Weart states,

    Bottom line: A cold Antarctica and Southern Ocean do not contradict our models of global warming. For a long time the models have predicted just that.

    Dr. Schmidt states in response to 94,

    The models are always wrong

    Pardon my naiveity, but shouldn’t the modelers goal be to recreate the Earth in a box, without any concern as to which hypothesis that supports, until such time that the modeler has confidence that they can fairly represent the world, and then, and only then, can the models can be used to prove or disprove any theory? When I see someone write “our models of global warming”, it makes me wonder whether the models are made to accurately portray the world or to accurately portray a theory, with all of the biases and assumptions contained within. So to answer you Gavin, is a model useful? Only if in good faith the modeler has tried to recreate the world and not the theory. Perhaps, you meant is the ensemble of models useful? To which I can only reply from the bias of my upbringing, two wrongs don’t make a right.

    [Response: The models are developed with the maximum flexibility possible. Global warming is only a small part of what they are used for and does not determine how they are developed. You appear to be a little confused as to how models are used in any case. The models don’t prove anything one way or another. Instead, they quantify the implications of various assumptions about how the climate operates and allow us to quantify different hypotheses for how climate changes. If you get a match to the observations when given a plausible cause, that adds to the credibility of that cause causing the observed effects. Different hypotheses are tested and the ones that match the data best are taken as being most likely. There is never any absolute proof – only a series of increasing probabilities. Models are useful because they have, for over 30 years, been predicting things that were subsequently observed. In many cases where there was an apparent contradiction between models and observations, the models ended up vindicated due to a processing or other error in the observations. They have therefore earned a certain respect. – gavin]

  10. 160
    Hank Roberts says:

    Rod, your 147 is perhaps a teachable moment. You wrote:

    > would seem not to be involved …
    > would not increase …
    > would be constant …
    > insignificant changes …
    > no matter what …
    > might or might not …

    Then you ask

    > Am I correct here?

    Until a few centuries ago, this method was the best available way to do science — relying on founders, original documents, and the building of logical structures based on the one original basic work. Find a flaw in the first paper and everything after collapsed.

    There’s a different way to approach science. Below I quote you one of the earliest statements of the method, as a fable. I commend it as worth thinking about:

    http://web.sbu.edu/history/tschaeper/Hist101/101wwwfbacon.html
    ————–Quoted below in full———-

    Francis Bacon (1561-1626) was a prominent English politician and writer. He is most famous as a proponent of the new scientific ideas and methods that nowadays we call the Scientific Revolution. He himself was not a scientist, but he wrote several books defending the use of reason, experimentation, mathematics, and observation in science. These new tools replaced older methods of doing science: tradition, the acceptance of old authorities (like the Greeks and the Bible), and the basing of conclusions on “common sense” that was not backed up by experimentation.

    In one of his books published early in the 17th century he reprinted a passage that he had found in the records of a Franciscan friary.

    This passage from 1432 concerns how a group of friars tried to figure out how many teeth a horse had in its mouth. It is a good example of the “old” way of doing science.

    The passage goes as follows:

    In the year of our Lord 1432, there arose a grievous quarrel among the brethren over the number of teeth in the mouth of a horse. For 13 days the disputation raged without ceasing. All the ancient books and chronicles were fetched out, and wonderful and ponderous erudition, such as was never before heard of in this region, was made manifest. At the beginning of the 14th day, a youthful friar of goodly bearing asked his learned superiors for permission to add a word, and straightway, to the wonderment of the disputants, whose wisdom he sore vexed, he beseeched them to unbend in a manner coarse and unheard-of, and to look in the open mouth of a horse and find answer to their questionings. At this, their dignity being grievously hurt, they waxed exceedingly wroth; and, joining in a mighty uproar, they flew upon him and smote him hip and thigh, and cast him out forthwith. For, said they, surely Satan hath tempted this bold neophyte to declare unholy and unheard-of ways of finding the truth contrary to all the teachings of the fathers. After many days more of grievous strife the dove of peace sat on the assembly, and they as one man, declaring the problem to be an everlasting mystery because of a grievous dearth of historical and theological evidence thereof, so ordered the same writ down.

  11. 161
    Thomas says:

    If I were to break up a global temperature change into spherical dynamics, I would expect that most important mode would be the constant temperature change mode. Another mode of interest to this discussion would be the one where one pole warms, and the other cools, with delta T being proportional to the sine of latitude. It doesn’t sound unreasonable to me that with greater NH arctic sensitivity, as well as the assymetries of land ocean area, that this second mode might be “excited” with considerable amplitude. Could the amplitude be strong enough cool Antarctica? Is there any evidence that the relative distribution of heat between the northern, and southern hemispheres is/can be affected?

  12. 162
    Hank Roberts says:

    T. Reber writes:
    > I see no reason why …

    Did you see, read, and check the sources cited?
    That’s footnote 4. It’s easy to find. See? Look.

  13. 163

    Tilo Reber (#154) wrote:

    I see an explanation for why the Antarctic oceans should warm more slowly in the Weart article. I see no explanation for why it should cool.

    Maybe because the Antarctic oceans aren’t cooling?

    Please see:

    Antarctic Temperature Trend, 1982-2004
    http://rst.gsfc.nasa.gov/Sect16/antarctic_temp-AVH1982-2004.jpg

    from:

    Evidence for Global Warming:
    Degradation of Earth’s Atmosphere; Temperature Rise; Glacial Melting and Sealevel Rise; Ozone Holes; Vegetation Response
    http://rst.gsfc.nasa.gov/Sect16/Sect16_2.html

    What is cooling is the interior of Antarctica — although the the actual sign of the trend may change depending upon the starting and ending date over which you are measuring the trend. However, both ozone depletion and increased precipitation in the continental interior have been thought to play a role in the cooling of the interior of the continent. Ozone depletion seems more likely nowadays, though since there really hasn’t been any significant increase in precipitation. The falling temperature of the stratosphere and rising temperature of the majority of the troposphere increases the strength of the downward polar vortex, cooling the surface nearest the southern pole.

  14. 164

    Arctic sea ice winter break up: Does anyone know if this is typical or significant?

    http://ice-glaces.ec.gc.ca/app/WsvPageDsp.cfm?id=11892&Lang=eng
    Sea ice breakup …winter ice in the Arctic..

    Then at the bottom of the page note a sequence of last JAN 4th images for the last 3 years of Arctic sea ice for that day. Noticeably diminishing winter pack.

    http://ice-glaces.ec.gc.ca/content_contenu/SIE/Beaufort/ANIM-BE2007.gif
    (my Firefox browser does not like this.. but IE works fine )
    Notes from the web page:
    “Other interesting features are shown in the quikscat animation from Sept 7th, 2007 to January 29th, 2008 below.
    The progression of the old ice edge towards the pole from the eastern Siberian side of the arctic.
    An open water area from the Bering Strait to the Chukchi Sea persisted longer than surrounding areas. This open water area can be identified from the beginning of November (around day 305) and persisted until about mid-December (day 350)
    The amount of ice through Fram Strait with the southern edge near the southern tip of Greenland during the first week of January.
    The fracture of the ice pack off the western shore of Banks Island.
    The unusual extent of sea ice in the Eastern Labrador Sea. “

  15. 165
    pete best says:

    Slightly off topic but is there an answer ?

    In all of the paleoclimatic data does the rate of change matter? I mean we are told that th rate of warming is some 30x faster than anything the earth has experienced before it. Does this rapid climate change change the rules at all or are we just going to get the same warming as has happenned before only faster?

    Can animals and plants adapt to the fast warming climate? Glaciers and the Arctic react unpredictably?

  16. 166
    David B. Benson says:

    pete best (154) — The biology cannot evolve/adapt fast enough. There is plenty of evidence for this.

    Very, very bad.

  17. 167
    Walt Bennett says:

    Re: #140 and #145,

    Does anybody have information for me?

    Also, Gavin I have a request for you. “The Global Warming Debate” is no longer active on the GISS site. (has it been updated/replaced?) There was a part which read as follows:

    [
    4. CO2 contribution to the ~33°C natural greenhouse effect

    Lindzen: “Even if all other greenhouse gases (such as carbon dioxide and methane) were to disappear, we would still be left with over 98 percent of the current greenhouse effect.” Cato Review, Spring issue, 87-98, 1992; “If all CO2 were removed from the atmosphere, water vapor and clouds would still provide almost all of the present greenhouse effect.” Res. Explor. 9, 191-200, 1993.

    Lacis and Hansen: removing CO2, with water vapor kept fixed, would cool the Earth 5-10°C; removing CO2 and trace gases with water vapor allowed to respond would remove most of the natural greenhouse effect.
    ]

    There does not seem to be any attribution in the article for the case made by Lacis/Hansen. Could you provide a relevant reference?

    Thanks.

  18. 168
    Jim Eager says:

    Re Pete Best @ 164: “Can animals and plants adapt to the fast warming climate?”

    Some will be able to adapt, many won’t. Some will be able to migrate to find habitats similar to those they are already adapted to, many will simply not be able to migrate fast enough or at all.

  19. 169
    Tilo Reber says:

    Re #161 Hank
    “Did you see, read, and check the sources cited?”

    No, when someone sets out to write an article to answer a question I assume that they will do so in the text of their article, not that they will give me a research project.

  20. 170
    Tilo Reber says:

    Re #162 Timothy
    “Maybe because the Antarctic oceans aren’t cooling?”

    Okay, let’s say that the southern oceans are not cooling, even though we had record sea ice extent this past year. And let’s say that the explanation that you just gave for Antarctic cooling is correct. Then what does Mr. Weart’s article about slow ocean warming have to do with Antartic cooling, since his implication was obviously that the two are connected. Your explanation, on the other hand, is completely different from the approach that he took. He doesn’t go to ozone depletion or increased percipitation at all.

    I’m having a little bit of a problem with the increased percipitation angle as well. In order to get cooling from increased percipitation wouldn’t that percipitation need to be evaporating as it fell. And how much evaporation will we get from snow that is far below the freezing point? I suppose that snow could cause cooling through an albedo effect, but since it is already falling on a white continent, I don’t follow that either.

    Now, going back to the original question for a moment, Mr Weart says:

    “In their model, around Antarctica “there is no warming at the sea surface, and even a slight cooling over the 50-year duration of the experiment.” ”

    But I didn’t see any explanation of why such a model would produce “a slight cooling”.

  21. 171
    Rod B says:

    Martin (157), I appreciate your thought But I disagree with the premise and conclusion. First, as an aside, if I challenge some of the AGW theory it behooves me to reach a certain level of scientific understanding. More to the point, as said before, I most certainly do have a right, maybe even duty, to challenge aspects of AGW that I think might be faulty. Their using the scientific method raises their credulity, but they absolutely are not infallible. Neither are GPs or medical practioners. In fact the percentage of misdiagnosis and/or mistreatment, while small, is astounding. And I personally once rejected a GP’s diagnosis and treatment — and was correct.

  22. 172
    Rod B says:

    Hank (159), I enjoyed your post, but I missed how it applies to my 147….

  23. 173
    Rod B says:

    Timothy (162), I don’t think you answered Tilo’s question. Also, frankly, you’re description of the process of cooling the interior of Antarctica sounds contrived, on the surface of it. This thread’s lead-in post said nothing of the sort….

  24. 174
    Hank Roberts says:

    Rod writes
    > … using the scientific method raises their credulity

    What’s the difference between credulity and credibility?

  25. 175

    re 170 “I most certainly do have a right, maybe even duty, to challenge aspects of AGW that I think might be faulty. ”

    Sorry, You do NOT have a right to keep crucial warnings away. You have no right to silence the warnings.

  26. 176
    Justin says:

    If you guys have the time to do it, could you, at some point in the near future, comment on this paper?:

    http://www.nature.com/nature/journal/v410/n6826/abs/410355a0.html

    “Increases in greenhouse forcing inferred from the outgoing longwave radiation spectra of the Earth in 1970 and 1997″

    by Harries, et al., 2001.

    I have not been able to read the paper directly from Nature, although I have been able to read another paper by Harries and colleagues which, I think, touches on the same issue.

    I feel that it would help to settle some latent skepticism that can still be seen in some of the readers and commenters to this blog. It would also help settle some questions I have: how conclusive is this paper on its own? Would I be too reckless to quote it as clear and sufficient ( and maybe even simple) proof of anthropogenic global warming?

  27. 177
    Jerry Toman says:

    Re # 158.

    The removal of CO2 from the atmosphere to produce “high energy” fuels cannot succeed for the same reason harvesting uranium from sea water cannot succeed. It has to do with a concept called “chemical potential” or “activity” (dU = dln (a)). For the CO2 case, using CO2 at one atmosphere as the reference state, the activity is 0.0004 for CO2 in the atmosphere. Stated in lay terms, “there is a lot of entropy to overcome”. If they had a reaction that actually worked, why wouldn’t they start by using some of the thousands of tons of quite pure CO2 that is emitted currently by hydrogen plants at about 2 atmospheres that has 80000 times the “reaction potential” as atmospheric co2.

    Similarly, the if the concentration of U235 in seawater were say 10^-9 moles per liter and the diffusivity were 10^-8cm2/S (they multiply, you know) the diffusive “flux” of U235 to a collecting surface would be horrendously tiny, and the pumping cost to cause the huge volumes of seawater to flow past the surface (not to mention the area that would be required) would be far greater than the energy that could be obtained from the U235.

    In the case of trees, which do use low P co2, in a process that evolved over hundreds of millions of years, all we have to do is chop the trees down and burn them to recover the fuel energy.

    In effect, that’s what we’re doing when we burn fossil fuels–burning up “fossil trees” that grew hundreds of millions of years ago.

  28. 178

    Tilo Reber (#169) wrote:

    Okay, let’s say that the southern oceans are not cooling, …

    It is probably best to say what is indeed the case.

    As I pointed out in what you are responding to (#162), the Southern Ocean has been warming, from 1982-2004, virtually throughout the entire ocean, but particularly along the Antarctic coast…

    Please see:

    Antarctic Temperature Trend, 1982-2004
    http://rst.gsfc.nasa.gov/Sect16/antarctic_temp-AVH1982-2004.jpg

    from:

    Evidence for Global Warming:
    Degradation of Earth’s Atmosphere; Temperature Rise; Glacial Melting and Sealevel Rise; Ozone Holes; Vegetation Response
    http://rst.gsfc.nasa.gov/Sect16/Sect16_2.html

    *

    Tilo Reber (#169) wrote:

    … even though we had record sea ice extent this past year.

    I suppose it depends upon what you mean by “record.”

    Has sea ice actually increased in the southern hemisphere?

    Over the past couple decades, yes, but only slightly. And this is after dropping precipitiously in the earlier part of the Twentieth century. We still aren’t back to where we were during the early 1970s — and the decline prior to the 1970s appears to have been rather dramatic.

    Please see:

    Sea Ice, North and South, Then and Now
    October 8, 2007
    http://tamino.wordpress.com/2007/10/08/sea-ice-north-and-south-then-and-now/

    *

    Of course, if sea ice has increased slightly over the past few years, it may in part be the result of increased fresh water due to all of the melting glaciers along the West Antarctic Peninsula and along the rest of the continental coasts. Fresh water freezes at a higher temperature than salt water, and Antarctic ice loss has increased by 75% over the past decade. Then again, a season may have a somewhat different trend (cooling, perhaps, during the fall — at least in some places) from the annual trend that I was citing.

    Please see:

    Antarctic Trend Map: March-April-May Trend 1958-2002
    http://igloo.atmos.uiuc.edu/ANTARCTIC/TRENDS/IMAGES/mam.trend.1958-2002.gif

    … from:

    Antarctic temperature trends
    http://igloo.atmos.uiuc.edu/ANTARCTIC/TRENDS/

    The sea ice is seasonal, I believe.

    *

    Tilo Reber (#169) wrote:

    And let’s say that the explanation that you just gave for Antarctic cooling is correct. Then what does Mr. Weart’s article about slow ocean warming have to do with Antartic cooling, since his implication was obviously that the two are connected.

    Well, if you look at the article, Spencer Weart actually does provide an explanation for a possible cooling of the ocean surface in the form of water being brought up from the deep due to increased mixing:

    The pioneer climate modelers Kirk Bryan and Syukuro Manabe took up the question with a more detailed model that revealed an additional effect. In the Southern Ocean around Antarctica the mixing of water went deeper than in Northern waters, so more volumes of water were brought into play earlier. In their model, around Antarctica “there is no warming at the sea surface, and even a slight cooling over the 50-year duration of the experiment.”

    Deeper water is likely cooler water — so that could cool the surface, in places at least, at least in theory. But as I have said, we aren’t seeing that, at least in terms of the annual average temperature, from 1982-2004 — except in a couple of highly localized places (i.e., “tiny spots”).

    *

    Tilo Reber (#169) wrote:

    Your explanation, on the other hand, is completely different from the approach that he took.

    The world is a messy place.

    For example, a seven-year trend in the global average annual temperature is mostly noise. You should probably use at least fifteen years to get a good signal — and given the existence of climate oscillations (the NAO, ENSO, etc.), one would be demonstrating incredible naivety (at best) if one tried to identify the trend in global temperature using only a five year stretch….

    *

    Tilo Reber (#169) wrote:

    I’m having a little bit of a problem with the increased percipitation angle as well. In order to get cooling from increased percipitation wouldn’t that percipitation need to be evaporating as it fell. And how much evaporation will we get from snow that is far below the freezing point? I suppose that snow could cause cooling through an albedo effect, but since it is already falling on a white continent, I don’t follow that either.

    I don’t rightly know, but I suppose it might have something to do with the albedo effect — and the fact that old snow is typically dirtier than new snow, or the fact that new snow is likely to be brighter than snow which has melted, then refrozen, or perhaps even due to the difference in infrared absorption properties of the above. But as I have said, snow doesn’t seem to be a factor — so hope you’ll forgive me for not having followed up that question. The hole in the ozone layer, however, does.

  29. 179

    Re #170 Rod,

    First, as an aside, if I challenge some of the AGW theory it behooves me to reach a certain level of scientific understanding.

    Correct. But that would be just you… it doesn’t scale. Only exceptional individuals can do this — and thus become climate scientists themselves — by the side of their daytime jobs. And you would still have to prove your newly acquired skills (no problem… start publishing!)

    … and I was once misdiagnosed too, and gave the correct diagnosis myself, later confirmed by surgery. Not unusual. You could have asked a second opinion. Not all doctors are good — and even the good ones make mistakes –, but the medical profession as a whole (the proper metaphor here) is a different story. And you don’t want to claim that self-diagnostication (Google diagnostication?) has an overall better record, do you?

  30. 180

    Re #169

    But I didn’t see any explanation of why such a model would produce “a slight cooling”.

    Neither did I (I can only access the abstract), but that doesn’t mean it isn’t true. As the climate changes, also ocean circulation patterns will change, and some places may actually get cooler. In the models as well as in reality.

  31. 181
    Cobblyworlds says:

    #163 Richard Pauli,

    Personally (as a non-professional) I don’t like the look of it one bit. I’ve posted my reasons here: http://www.sciencefile.org/cgi-bin/yabb2/YaBB.pl?num=1188389838/141#141

  32. 182

    Walt Bennett —

    Lindzen’s 98% figure was pulled directly out of his posterior. Studies with radiative-convective models of the Earth’s atmosphere say carbon dioxide accounts for 9-26% of the clear-sky greenhouse effect, not less than 2%. Here’s a reference:

    http://www.atmo.arizona.edu/students/courselinks/spring04/atmo451b/pdf/RadiationBudget.pdf

  33. 183
    tom says:

    #167.
    “Some will be able to adapt, many won’t. Some will be able to migrate to find habitats similar to those they are already adapted to, many will simply not be able to migrate fast enough or at all.”

    Please cite proof of the statement. List the species that you believe will not be able to adapt fast enough and the proof that backs this assertion.

    Also, please quantify the ‘many’ in your statement.

  34. 184

    Rod B wrote in 172:

    Timothy (162), I don’t think you answered Tilo’s question. Also, frankly, you’re description of the process of cooling the interior of Antarctica sounds contrived, on the surface of it. This thread’s lead-in post said nothing of the sort…

    You might try this for ozone — and a more positive phase Southern Annualar Mode:

    Thompson and Solomon (2002) showed that the Southern Annular Mode (a pattern of variability that affects the westerly winds around Antarctica) had been in a more positive phase (stronger winds) in recent years, and that this acts as a barrier, preventing warmer air from reaching the continent. There are also some indications from models that this may have been caused by a combination of stratospheric ozone depletion and stratospheric cooling due to CO2 (Gillett and Thompson, 2002 ; Shindell and Schmidt, 2004). It is important to note, though, that there is evidence from tree-ring based climate reconstructions that the phase of the Southern Annular Mode has changed similarly in the past (Jones and Widman, 2004). We cannot, therefore, ascribe observed recent temperature changes to any one particular cause.

    3 December 2004
    Antarctic cooling, global warming?
    http://www.realclimate.org/index.php/archives/2004/12/antarctic-cooling-global-warming/

    The possibility that increased precipitation might lower temperatures in Antarctica has been discussed elsewhere — but as I have said, doesn’t seem to be happening.

  35. 185
    Tom Mckissic says:

    Re 137 & 149 – I plot the data, I run the running slope backwards from today, I see the long term trend. I’m not arguing these points. I’m not cherry picking a date – only observing the most recent short term trend in SST.

    My questions about this recent trend as compared to past trends relate the following.

    1) Cooling SST during an El Nino characterized period earlier this decade. It seems previous SST trends were heavily affected by ENSO.

    2) The downward trend in SST during an upward trend in land temps during the same period. Over the past century the two trends seem to march mainly in step.

    I would greatly appreciate any comments clarifying (or even refuting accurately) these points.

  36. 186
    recon says:

    So we can conclude that there is little or no global warming because:

    a) Antarctica as a whole is still not melting, nearly three decades after NH ice started its decline.

    b) Southern ocean has seen no significant or widespread increase in SST, more than three decades after the northern counterpart seas started to warm.

    c) Snowfall has not increased anywhere but the Antarctic penninsula for the past 50 years, according to a new study by BAS

    Aside from this, climate models do indeed show polar amplification for the South pole. Here’s a GISS model screen dump from this very web site. The amplification is not as prononounced as for the North pole, partly because of the 1000-850 hPa pressure altitudes being masked out for whatever reasons (terrain?) but unmistakeably there. What models fail to show is a cooling, and a cooling is exactly what is observed.

    [Response: You are wrong on at least three counts. First off, global warming is defined as an increase in the global average, not that everywhere on the globe is warming. Three decade trends in the Southern Hemisphere are all positive – just not as positive as in the North. Finally, your use of a result for an equilibrium 2xCO2 model run is not the correct comparison to recent decades at all. All the quotes above are related to transient runs. To see that there is a difference, go to http://data.giss.nasa.gov/modelE/transient/Rc_ij.1.11.html and plot the trend/ESD (the ensemble standard deviation) for the annual SAT for recent decades. You will note that the southern hemisphere high latitude trends are mostly blank – implying that any trend in the ensemble mean is smaller than the inter-member standard deviation – making it pretty insignificant. You might also be interested in reading Shindell and Schmidt (2004). – gavin]

  37. 187
    Hank Roberts says:

    > Please cite proof…
    Tom, 182, 167
    > List the species …
    > and the proof that backs this assertion.

    Someone’s got a homework assignment due tomorrow?

    We can help. You need to ask smarter questions. Here:
    http://catb.org/~esr/faqs/smart-questions.html

    Let me get you started though, since you’re obviously just quoting from an assignment and in a hurry, and since this is such an active area of research that the list I gave you last month is not the same list you’ll be able to put together tonight and hand in tomorrow (science is like that, you have to do your own looking).

    http://www.google.com/search?q=+spring+timing+species+climate+change

    You will, in fact, find scientists doing this work online, and once you’ve understood the first link I suggest above, you’ll find people eager to help you understand. Just do the first basic work as suggested in the first link to show you want to learn how to learn.

  38. 188
    Hank Roberts says:

    Tom wrote
    > Re 137 & 149 – I plot the data, I run the running
    > slope backwards from today …

    I think you need to use the whole data set, not consider “today” as anything special. Remember error bars apply to each individual point, so you can’t decide that “today” is really a point to work from. It’s a range.

    Starting from today and working backward is the same as starting from any individual point years ago and working forward, innit?

  39. 189
    Walt Bennett says:

    Re: #181

    Barton,

    Thanks for attempting to answer my question in #166, but the part that interests me is the Lacis/Hansen assertion that removing all CO2 would cause most water vapor to leave (I suspect through a downward temperature/condensation spiral).

    There are some vigorous opponents of that assertion, and I cannot find independent attribution for it.

    Gavin, I asked you because, well, you work for the man who said it :-)

    So I figured you could just ask him. Was it based on models? I would suppose there must be some math or a paper somewhere which spells out the process?

    Thanks!

    [Response: The 5 to 10 deg C number comes from an assessment of radiative-convective modelling – what temperature drop is required to rebalance the TOA fluxes (Hansen et al, 1984 I think), while the eventual cooling takes into account the feedbacks. Actually doing the experiment is problematic because it gets so cold that many of the model assumptions are violated. On this count, it is indisputable that Lindzen is wrong. – gavin]

  40. 190
    Walt Bennett says:

    Gavin,

    Thanks for your lightning fast response. Unfortunately for this layman, you gave short shrift to some points which elude me. I beg that you perhaps assist me with some clarification of something which I am sure is simple to you, and perhaps not so simple to explain to non-scientists.

    While I agree that it makes common sense to deduce what Lacis/Hansen asserted, you know as well as I do that there is a heavy burden to “prove” assertions such as this in the context of the modern day debate.

    Again, the 5-10*C number is not so controversial; it’s the second part that raises hackles. Lacis/Hansen state “emoving CO2 and trace gases with water vapor allowed to respond would remove most of the natural greenhouse effect.”

    You say that actually doing the experiment is problematic because the models are basically not built for such an analysis (perhaps that’s why EdGCM didn’t seem to care that I zeroed out CO2). I would be grateful for a link to either a mathematical or theoretical explanation of the process.

    When I try to imagine it, I keep running into this: daytime temps would excite the ocean surface to produce vapor, and the oceans would also heat, giving back some of that at night. Would the planet maintain a baseline H2O-greenhouse effect in this scenario?

    Thanks for taking the time.

    [Response: If you take EdGCM with 0 CO2 and allow the ocean temperatures to change, the planet will freeze over and the model will crash as it uses up available ocean depth to make ice. Since there is no observational data to validate against, you are only talking about a hypothetical situation, in which case only models can be used for insight. And in all such cases, ocena temperatures cool dramatically, water vapour plummets and baseline greenhouse effects do so as well. – gavin]

  41. 191
    tom says:

    187.

    As I supected, it’s more speculative hyperbole than historical fact. Some species thrive when habitat changes and some don’t.

  42. 192
    Tom Mckissic says:

    Re 186 and 187 – First, doesn’t the CURRENT trend REQUIRE the use of TODAY as an end point for the RANGE?

    Researching AGW as a hobby I do have some questions which come to mind every once in a while. Often I can research these questions on my own or find article or reference which relate. At other times the information is not readily available or is too recent to have published information.

    I will try to find a way to post the graphed data I have so the areas in question can be highlighted. All I need is a nudge in the right direction, I can take over from there.

  43. 193
    Walt Bennett says:

    Re: #140, #145,

    Anybody? Am I really the only one who cares?

    :-)

  44. 194
    Walt Bennett says:

    Re: #190

    Gavin,

    Gracias. I wish I had a link :-) but I do accept the baseline logic. My confusion was with regard to whether or not the oceans freeze, or if they net retain heat.

    Your answer is that they freeze, and then of course the feedbacks kick in.

    Thanks again.

  45. 195
    Rod B says:

    Hank, credulity is more pedantic??

  46. 196
    Rod B says:

    Richard (175) I never said or implied anything about “silencing”.

  47. 197
    Hank Roberts says:

    Tom, re detecting trends, nope, you can do the math yourself and see how much any individual year, for example the past year, changes the trend. Do the calculation with it and without it. Or use Stoat’s (link below) and do it with last year’s added in.

    We don’t have “today’s” number; we have one number each year, from each of several different data sets.

    You understand I hope that you need either a long time, or many observations, to detect a trend statistically.

    That’s not a choice, it falls out of the math. To be able to detect a trend as expected from CO2 increase takes a couple of decades.

    Eyeballs detect trends that don’t exist, reliably. Better to imagine a tiger in the bushes than miss a real one, we’re wired to see patterns in randomness. Those in the past who did not imagine tigers didn’t have descendants.

    see 56 above, the link to Tamino there,
    and http://scienceblogs.com/stoat/2007/05/the_significance_of_5_year_tre.php#more
    and http://atmoz.org/blog/2008/01/29/on-the-insignificance-of-a-5-year-temperature-trend/

    Statistics is a math tool — if you have Excel you can follow Stoat’s link to a public data set, add the past year or two to it, and see what difference a couple of years make.

    Statistics changes how you think. It really does. It’s a very new science, it’s not something amateur readers like me are going to be experts at. A college or graduate course in statistics is an experience that changes your faith in your own ability to know what’s going on in the world. I recommend it.

  48. 198
    Cobblyworlds says:

    #192 Walt,

    When the first Lyman results were doing the rounds various contrary(ish) types were claiming it was a problem for the AGW theory. I pointed out that in Levitus’ study they mention greater cooling episodes. That point was ignored.

    It’s interesting. But I am too busy with Arctic issues and am in no way qualified to start guessing what is going on – I leave such detail to the experts.

    PS I noted your complaint about papers being being pay-to-view barriers. Let me know what you need I’ll see if I have links (or try for yourself locating the names of the researchers and seeing if they have free pre-prints on their publications pages). I’ve only ever paid for one paper, but have hundreds from various sources. Not ideal but as I’m broke it has to do.

  49. 199

    Re #196: Rod, an excess of noise silences the soft-spoken. Everybody has a right to speak, but only the few deserve to be listened to. Don’t aspire to making the problem worse.

  50. 200

    Re #190 Gavin’s comment: “Since there is no observational data to validate against…”

    There’s Snowball Earth. Okay, not quite zero CO2, different continental geometry, weaker Sun (?) …

    [Response: That’s a very different kettle of fish, but in a broader sense you are correct. If Snowball Earth (or something close) ever happened it makes it very hard to argue for a very small climate sensitivity. But on the other hand, all the differences in conditions (and very limited data) make the modelling tricky. – gavin]


Switch to our mobile site