Climate Science Glossary

Term Lookup

Enter a term in the search box to find its definition.


Use the controls in the far right panel to increase or decrease the number of terms automatically displayed (or to completely turn that feature off).

Term Lookup


All IPCC definitions taken from Climate Change 2007: The Physical Science Basis. Working Group I Contribution to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, Annex I, Glossary, pp. 941-954. Cambridge University Press.

Home Arguments Software Resources Comments The Consensus Project Translations About Donate

Twitter Facebook YouTube Pinterest

RSS Posts RSS Comments Email Subscribe

Climate's changed before
It's the sun
It's not bad
There is no consensus
It's cooling
Models are unreliable
Temp record is unreliable
Animals and plants can adapt
It hasn't warmed since 1998
Antarctica is gaining ice
View All Arguments...

Keep me logged in
New? Register here
Forgot your password?

Latest Posts


Climate Hustle

Is Antarctica losing or gaining ice?

What the science says...

Select a level... Basic Intermediate

Satellites measure Antarctica is gaining sea ice but losing land ice at an accelerating rate which has implications for sea level rise.

Climate Myth...

Antarctica is gaining ice
"[Ice] is expanding in much of Antarctica, contrary to the widespread public belief that global warming is melting the continental ice cap." (Greg Roberts, The Australian)

Update Nov. 7 2015

A study published by Jay Zwally and his team on Oct. 30 (Zwally et al. 2015) has suggested that until 2008 there might have been a bigger increase in ice on East Antarctica than there is a decrease in the west, meaning that total Antarctic land ice is increasing. While their results for the Antarctic Peninsula and much of West Antarctica agree with other research, the study disagrees with many other techniques. We will update this discussion once more studies address this issue. Until then here are links to some recently published takes on the study:

A controversial NASA study says Antarctica is gaining ice. Here’s why you should be skeptical - Chris Mooney (Nov. 5)

NASA Scientist Warned Deniers Would Distort His Antarctic Ice Study — That's Exactly What They Did - Media Matters (Nov.4)

More on Antarctic Ice Melt - ClimateCrocks (Nov. 3)

Is Antarctica Gaining or Losing Ice? Hint: Losing. - Phil Plait (Nov. 3)

Q&A: Is Antarctica gaining or losing ice? - Carbon Brief (Nov. 3)

Just Because Antarctica Might Be Gaining Ice Doesn't Mean Climate Change Isn't Happening - Vice (Nov. 2)

Skeptic arguments that Antarctica is gaining ice frequently hinge on an error of omission, namely ignoring the difference between land ice and sea ice.

In glaciology and particularly with respect to Antarctic ice, not all things are created equal. Let us consider the following differences. Antarctic land ice is the ice which has accumulated over thousands of years on the Antarctica landmass itself through snowfall. This land ice therefore is actually stored ocean water that once fell as precipitation. Sea ice in Antarctica is quite different as it is ice which forms in salt water primarily during the winter months. When land ice melts and flows into the oceans global sea levels rise on average; when sea ice melts sea levels do not change measurably.

In Antarctica, sea ice grows quite extensively during winter but nearly completely melts away during the summer (Figure 1). That is where the important difference between Antarctic and Arctic sea ice exists as much of the Arctic's sea ice lasts all the year round. During the winter months it increases and before decreasing during the summer months, but an ice cover does in fact remain in the North which includes quite a bit of ice from previous years (Figure 1). Essentially Arctic sea ice is more important for the earth's energy balance because when it increasingly melts, more sunlight is absorbed by the oceans whereas Antarctic sea ice normally melts each summer leaving the earth's energy balance largely unchanged.

Figure 1: Coverage of sea ice in both the Arctic (Top) and Antarctica (Bottom) for both summer minimums and winter maximums
Source: National Snow and Ice Data Center

One must also be careful how you interpret trends in Antarctic sea ice. Currently this ice is increasing overall and has been for years but is this the smoking gun against climate change? Not quite. Antarctic sea ice is gaining because of many different reasons but the most accepted recent explanations are listed below:

i) Ozone levels over Antarctica have dropped causing stratospheric cooling and increasing winds which lead to more areas of open water that can be frozen (Gillet 2003, Thompson 2002, Turner 2009).


ii) The Southern Ocean is freshening because of increased rain and snowfall as well as an increase in meltwater coming from the edges of Antarctica's land ice (Zhang 2007, Bintanga et al. 2013). Together, these change the composition of the different layers in the ocean there causing less mixing between warm and cold layers and thus less melted sea and coastal land ice.

All the sea ice talk aside, it is quite clear that really when it comes to Antarctic ice and sea levels, sea ice is not the most important thing to measure. In Antarctica, the largest and most important ice mass is the land ice of the West Antarctic and East Antarctic ice sheets.

Therefore, how is Antarctic land ice doing?

Shepherd et al. 2012
Figure 2: Estimates of total Antarctic land ice changes and approximate sea level contributions using a combination of different measurement techniques (Shepherd, 2012). Shaded areas represent the estimate uncertainty (1-sigma).

Estimates of recent changes in Antarctic land ice (Figure 2, bottom panel) show an increasing contribution to sea level with time, although not as fast a rate or acceleration as Greenland. Between 1992 and 2011, the Antarctic Ice Sheets overall lost 1350 giga-tonnes (Gt) or 1,350,000,000,000 tonnes into the oceans, at an average rate of 70 Gt per year (Gt/yr). Because a reduction in mass of 360 Gt/year represents an annual global-average sea level rise of 1 mm, these estimates equate to an increase in global-average sea levels by 0.19 mm/yr.

There is variation between regions within Antarctica (Figure 2, top panel), with the West Antarctic Ice Sheet and the Antarctic Peninsula Ice Sheet losing ice mass, and with an increasing rate. The East Antarctic Ice Sheet is growing slightly over this period but not enough to offset the other losses.  There are of course uncertainties in the estimation methods but independent data from multiple measurement techniques (explained here) all show the same thing, Antarctica is losing land ice as a whole, and these losses are accelerating quickly.

Basic rebuttal written by mattking

Update July 2015:

Here is the relevant lecture-video from Denial101x - Making Sense of Climate Science Denial


Last updated on 8 November 2015 by BaerbelW . View Archives

Printable Version  |  Offline PDF Version  |  Link to this page

Further reading

Tamino compares and analyses the long term trends in sea ice data from the Northern and Southern Hemisphere in Sea Ice, North and South, Then and Now.


On 20 Jan 2012, we revised this article upon learning it referenced an incorrect quote. We apologize to Dr. Michaels and to our readers for the error.


Prev  1  2  3  4  5  6  7  8  9  10  Next

Comments 351 to 400 out of 463:

  1. Karly wrote "An interesting example of how science is not done."

    well quite, science is done by publishing papers in peer reviewed scientific journals and it is not done by gratuitously insulting those who disagree with you ("If I had but the time and you had but the brain—").

    FWIW I have a first class degree and a PhD, and I have published a fair few journal papers, including a couple on climate.  However that is irrelevant as in science it is the validity of the argument that matters, not its source.  Perhaps you should pay a bit more attention to the scientific argument rather than engaging in inaccurate ad-hominems.

  2. Oh, for heaven's sake. Validity is not measured by peer review...many, many peer  reviewed papers have been shown to be erroneous as knowledge has progressed. Duncan Steel has calculated a change in spring insolation over time. Either his calculations, using accepted orbital mechanics and physics are correct or not. No-one has yet shown they are incorrect. What the effect of that change in insolation is may well be arguable,  but it's the change that's significant, and unless you can show the calculations (of the change in insolation) are incorrect you have little to  add to the discussion of his 'essay'

  3. kiwiradical Validity is indeed not measured by peer review and many peer-reviewed papers have indeed been shown to be wrong.  However, the proportion of peer-reviewed papers that are wrong is rather less than the proportion of ideas on non-peer reviewed websites where people publish their ideas without submitting them to external scrutiny first.  That is why scientists use peer-review.

    The key thing here is that Duncan Steel has responded to criticisms of his work with gratuitous insults.  That is not the way science ought to procede.

  4. kiwiradical @352, granting that Steel is entirely correct about all that he claims with regard to changes in insolation only, his theory that it is a significant effect does not follow.  The reason it does not follow is that absent data on albedo, the the changes in insolation average out to near zero over the globe and over the year.  They are inconsequential.  Steel knows that, so he makes some attempt to indicate potential albedo changes that might make the effect significant.  I have criticized those attempts @342 above, something you have ignored.  Specifically, my criticisms were that:

    1)  The change in albedo he assumes is not justified by the magnitude of the effect, in that he conjectures that a 4.33 day drift in perihelion relative to the vernal equinox results in a 30 day drift in ice and snow melt;

    2)  The change in albedo he proposes is contradicted by emperical evidence of recent changes in snow and ice; and

    3)  He incorrectly includes feedbacks from AGW, from other natural warming, and from the drift of the perihelion in calculating the forcing of the the effect.

    Since then I have done some analysis that may help give some idea of the impact of the third point.  Specifically, I have used Steel's image of latitudinal absorptivity by day of year to determine the absorptivity by day of year.  I have then plotted that against both the introduced drift in seasonal ice and snow cover that he appeals to, and the current insolation by day at that latitude:


    The units are standard deviation units.  To determine the change in the energy balance, you would actually need to take the integral of the produces of the absorptivity and the insolation, in original units.  It is far simpler, however, to compare them in StDev units so that you can compare the position of the peaks.

    Many people don't realize that the peak in insolation substantially precedes the peak in ice and snow melt, a fact that can be seen by comparing the blue and orange curves above.  The failure of the peaks to coincide significantly reduces the total energy input from the sun in high latitudes.

    That being the case, the effect of delaying the ice melt by another thirty days (Steel's model for the albedo 250 years ago) will by itself, without any change in insolation, greatly reduce the energy absorbed at high latitudes.  It does so by pushing the albedo and energy peaks further out of phase (blue and yellow curves).

    It is evident from this diagram, and without need of calculation that Steel's albedo model will introduce a large "forcing" all by itself, and without any change in insolation.  What is worse, however, is that the insolation change is a mere 4.33 day drift in insolation, just 14.4% of the albedo drift.  There is slightly more to it than that, but that is the most important effect.  That effect can be approximated by blue line four days the right, to represent the insolation change.  (Let me emphasize that that is not exact, but it is close enough for estimating the effect.)  

    The forcing from the insolation change can then be determined as the change in the integrated products of the orange line and the blue line relative to the orange line and the blue line shifted four days to the right.  The effects of the feedbacks from all forcings combined (assuming Steel's albedo model is correct) is then the difference between the integrated product of the blue and the orange lines, and the blue and the yellow lines.  Transparently, that will be of the order of 15% of the feedbacks. In other words, only about 13% of Steel's calculated "forcing" is an actual forcing effect of the change in insolation.

    That is a large error on Steel's behalf (far larger in effect than any he is attributing to the climate scientists).  It is somewhat mute because of the clear errors in his albedo model; but the flaw in method revealed would have exagerated the absolute value of the apparent impact of the effect no matter what albedo model was used.

    Put simply, he is counting feedbacks as part of the forcing - and not just feedbacks from the forcing under consideration, but feedbacks from any forcing, including some which are far stronger and hence far more dominant than those he has found.

    While on the topic of his albedo model, I noticed today a nuance that I had previously ignored.  Specifically, he describes the model, saying:

    "What I will do is to pick up the absorptivities in a region of interest (latitudes northwards of 30 degrees north, March through June), and replace them with the absorptivities from 30 days earlier (February through May), so as to simulate the effect of the putative delayed melting of the snow and ice back in 1750 compared to the present. "

    (My emphasis)

    Note that northern latitudes from March to June is when the change in insolation is strongly positive.  He has deliberately excluded changes in albedo for periods when the change in insolation has been negative, thereby exagerating the effect still further.  (Note that the time restriction on the adjustment means he assumes snow and ice will freeze at the same time 250 years ago as they do currently, not later as I have stated elsewhere.  That assumption is still falfified by the fact that they are freezing later.  It also means the graph above is not representative of his model in that it applies the adjustement to the entire year.  The adjustment applied as he states, however, would introduce discontinuities into the graph, which would consequently be underspecified.  Therefore, until he sees fit to fully specifiy the model, it stands as a reasonable approximation.)

  5. kiwiradical @352.

    You say "Either his calculations, using accepted orbital mechanics and physics are correct or not." You ignore the possibility that the subject of the calculations of duncansteel are already being accounted for. And also that the effect may or may not be significant.

    duncansteel is actually presenting two effects although he doesn't make this at all clear.

    In his published paper he calls one CIT. This is undisputedly already taken onboard by climatology (although to read his paper you wouldn't think so). And note that the effect of this orbital change is small in comparison with solar variation which is itself small in comparison with AGW. So in the grand scheme of things it is insignificant.

    A second orbital effect duncansteel calls CSI in his 'essay'. This is smaller again than CIT and duncansteel has identified its absence from a set of NOAA insolation tables. (These tables provide insolation data for the last 10 million years in 1,000 year steps.) It is probably no great loss from such tables as the impact of CSI is much smaller than even CIT. There is remaining doubt as to whether or not this CSI is accounted for already or whether it is something so far overlooked. Sadly it is duncansteel who should be the arbitor of his rather poorly described theorising, a role he appears poorly matched to, while the poor description makes it inconvenient for other to take on that role for him. Add in his crazy climatological inferences (as per @354) and all sympathy for duncansteel quickly discipates.

    The tenor of duncansteel in this matter can perhaps be judged by where he has come from on this matter. He talls us he was inspired to the research that led to his 'CSI/CIT trumps AGW' hypothesis by Thomson (1995) 'The Seasons, Global Temperature and prescession'. Thomson may be beating the drum for orbital effects to be accounted for better in AGW calculations but Thomson's two concluding paragraphs show clearly that duncansteel is way off on his own concerning the implications of such effects w.r.t AGW.

  6. @351

    Good on you.  I have an Honours BSc, a PhD, an MSc, and a DSc. I have also published over 150 peer reviewed journal articles.  Did you think you were going to intimidate me?

  7. Given Dikran opened his remarks on qualifications with 'FWIW' and then described his own qualifications as irrelevant to the science, I don't see an attempt at intimidation. I consider it a response to your statement:

    "Since none of the posters admit to any scientific training whatsoever (Mr Curtis is apparently a ‘philosopher’), or have stated their qualifications..."

    To me it looks like you have invited posters to lay out their expertise, only to accuse them of intimidation when they do.

  8. Can we actually have the qualifications of the commentators?

    Dr Steel is a world expert on astrophysics.  It seems only fair that tthose criticising him should acknowledge  their own expertise.

    If they are reluctant, then I think it is reasonable to discard their opinions as complete rubbish.


    [Rob P] - Presumably you'd be happy with a proctologist performing open heart surgery on you?

    Actual experts on any given subject are those that have their ideas published  in the scientific literature and their research subjected to scrutiny by their peers. Convincing ones peers of the validity of your research in a given scientific discipline is a good measure of expertise. Does Dr Steel have any publications relevant to the subject under discussion? Is there any indication of support for his ideas in the relevant scientific community?

  9. Karly,

    Dr Steel has the option of returning to defend his ideas in this forum, submitting his ideas to peer review, or leaving us with the impression that he is not to be taken seriously. So far, your efforts on his behalf have not really changed those options or improved that impression, but it is not to late to offer something useful. If you have specific comments to make on the content of his theories, rather than impressionistic views of the various personalities involved in this discussion, please share them.

  10. Karly, everyone possesses a set of naive algorithms for establishing the veracity of arguments that are beyond their comprehension.

    If you acknowledge that the contention between Steel and Curtis/Rodger is in fact, beyond your comprehension you will need to resort to your truthiness algorithm.

    The thing is, people don't necessarily want to engage in the requisite PhDenis measuring competition that you propose. Opinions have been provided, which the informed reader can use, along with the behaviour of the parties involved, to come to a conclusion.

  11. karly @358:

    "If they are reluctant, then I think it is reasonable to discard their opinions as complete rubbish."

    I take this to be an admission by karly that neither they, nor Dr Steel, are able to defend his numerous blunders on climate science, nor his completely falsified model of albedo changes; and that therefore they need to shift the grounds of debate to argument from illegitimate authority.  (Illegitimate because Dr Steel has no qualifications on climate science; and illegitimate because karly is "... not a physicist, astronomer or climate scientist".)

    Of course, having previously declared their incompetence to assess the empirical evidence and the cogency of arguments offered, it is a bit difficult now for karly to claim to be able to assess the arguments on their merits.

  12. "I have read [karly's contribution down] this thread with sheer astonishment." For someone to proclaim "I have an Honours BSc, a PhD, an MSc, and a DSc." Full stop. That is strange enough to raise questions as to why it would be said truthfully.

    And for that same person to also state that which is now erased by the moderators, that raises little doubt as to the answer to that question.

    Karly, even though I don't hold a DSc., trust me when I tell you that holders of multiple degrees almost always act with a certain humility (although that doesn't stop them behaving with extreme 'robustness' when the occasion calls for it, and may times when it isn't). It is not at all necessary for clever people to tell the world that they are clever. Their abilities speaks for themselves.

    And why is it necessary to know the qualifications of a commenter? Why would you say "If they are reluctant, then I think it is reasonable to discard their opinions as complete rubbish"? Somebody capable of post-graduate qualification should be able to judge the veracity of a commenter here by what they say alone. Or if not, the comment can be checked by a little research on this wonderful interweb the world is now blessed with. I thus would suggest to you that this thought @358, as you relate it to us, it is actually very "unreasonable."

  13. karly wrote "Good on you. I have an Honours BSc, a PhD, an MSc, and a DSc. I have also published over 150 peer reviewed journal articles. Did you think you were going to intimidate me?"

    No, it was you that questioned the qualifications of those posting criticisms of Dr Steel's work here, I was merey indulging your curiosity.   I also made it clear that qualifications mean nothing in scientific discussions, what matters is whether the argument is correct.  That would be an odd thing to write if I was trying to intimidate somebody.  My reason for mentioning this was to point out that questioning qualifications is an ad-hominem attack.

    ". It seems only fair that tthose criticising him should acknowledge their own expertise."

    why should anybody do that, given that your response to me indulging your curiosity on this point was a personal attack?

    I note that karly is trying very hard to avoid discussing the actual content of Dr Steel's argument, which seems pretty odd for an academic such high apparent calibre.

  14. "If they are reluctant, then I think it is reasonable to discard their opinions as complete rubbish."

    That is the most stupid thing I have read in a while. (-snip-) It amounts to  a blanket argument from authority. Not to mention we're not talking about opinions but specific criticisms that can be adressed in methodical fashion. It is hard to understand how someone with as much alphabet soup as Karly claims can have such a lapse in rational thinking. The argument can obviously be turned on its head to say that, if Dr Steel has no training in atmospheric sciences whatsoever, his opinion on climate should be dismissed as complete rubbish.

    Now, how about discussing that albedo problem?


    [RH] Let's check the tone here.

  15. "Dr Steel is a world expert on astrophysics."

    But that doesn't make him an expert on climate. Changes in insolation and their radiative effects on climate are understood by climate scientists. It's well understood as a very slow and minor forcing, whereas we are witnessing a large and rapid change in climate today that is consistent with the large radiative forcing of man-made greenhouse gases.

  16. Expert or not, Dr. Steele's credentials _do not automatically make him correct _. That is the basis of the fallacy of arguing from authority.

    As has been pointed out on this thread, Steele has made some rather elementary and invalidating errors. Science stands or falls based on content, on whether or not it fits the evidence. Steele's hypothesis fails that test.

  17. I know someone in the comments section must've already brought it up, but I don't really want to fish through eight pages.  Can anybody tell me what's the deal with the papers from Frezzotti et al and Zwally saying that in fact the Antarctic is actually gaining ice overall over the last 800 years?

    Antarctica gaining Ice Mass (balance*) — and is not extraordinary compared to 800 years of data


    [JH] For future reference, the SkS search engine is a useful tool. 

  18. @dvaytw 367:

    For a detailed discussion of Zwally et al (2005) and similar papers, see Robert Way's article, New and Improved Ice Loss Estimates for Polar Ice Sheets posted on Oct 1. 2014.

  19. dvaytw - Long story short, that title is based on a misunderstanding. Frezzotti et al 2013 is discussing the surface mass balance, which is the amount of incoming mass in Antarctica, comparing ice cores to models for that quantity. This is an input quantity only. 

    They are not looking at the total mass balance, the total change of ice mass due to the balance of input (snow) and output (melt, glacier calving), which show Antarctic mass loss. 

    I suspect the emphasis of that 'skeptic' title is due to a misunderstanding of that point. 

  20. Just thought that I would note that there is very nice review article on Antarctic sea ice increase and theories about why this happening by Eric Steig here. In short, it is the winds, but it is also rather complicated. Also, the transient response (what we see here) is likely different from the equilibrium response. It also points an interesting paper by here where a model driven by all the observed changes in winds pretty much reproduces the pattern in sea ice seen. h/t to Realclimate but thought this was an interesting addition to this thread.

  21. I am not a scientist, merely a layman that discusses politics and current events with my 20 year old son studying engineering, physics and math at the University of Waterloo in Canada. He supports the claim that climate is changing and the polar ice cap is shrinking. I am a right wing skeptic so I am searching for more info on this claim. Our only right wing media (Sun News) regularly scrutinizes these and other topics with in depth reports and documetaries. I find them extremely interesting and much more balanced than what I see on main stream media, (hence my skepticism). I found this article from "mail online", also called "Daily Mail" and was hoping this forum could do a "peer review" of sorts on it. (I'm sorry to have copied & pasted the entire document but I knew no other way to share it here).

    Read more:


    [Rob P] Please don't copy/paste screeds of text. I have removed it but, in the future, a simple link will suffice.  Also, note the correct threads for this are the Arctic sea ice and polar bear myths - as Composer99 points out. 

  22. alan2112drums:

    I believe you can simply share the link (which you did at the bottom of your post - unless that's for a related post) and either paste/quote relevant highlights or paraphrase what you think are the key points, rather than copy/pasting the entire article - especially since the Daily Mail still has copyright on its own content.

    Please note that this original post & thread are meant to discuss the behaviour of Antarctic ice, and as such remarks about either the Arctic sea ice or polar bear populations - which appear to be the main poitns of contention raised by the Daily Mail article - are off-topic.

    Threads for further follow-up (including responses):

  23. alan2112drums:

    I have responded here to the point raised by the Daily Mail about sea ice. Perhaps others will offer additional perspectives.

    I must leave it to others to address the polar bear matter - although the on-topic post I have shared does, too.

    (I have to get to cleaning a bathroom. Fun times.)

  24. I have placed some updated information on Polar Bears here.

  25. I have replied to that nonsense about Al Gore and Arctic Sea Ice demise by such-and-such date, here.

  26. alan2112drums @371.

    I think the writings of David Rose of the Daily Mail on the subject of AGW are usually requiring "rebuttal" rather than "peer review". Even the IPCC have found it necessary to carry out such corrections, as SkS posted here.

    I will add comment on this particular serving of gobshite from Rose on the same thread linked @373 & 375.

  27. Sometimes a newcomer to a discussion or even to a science may see something the experienced conversationalists overlook. Seventy four years of age, I was trained as a theologian and then switched to Bible studies more narrowly understood. After reading all the comments, I realized to my horror, that three things noticed by comment but not put together by anybody, might abundantly confirm our worst fears about the ice and snow of Antarctica and global warming generally. It would go this way. The land ice is sliding into the ocean faster and faster. Thus there is more sea ice! AND THUS and thus please kindly excuse the capital letters THE SURFACE OF THE WORLD'S OCEANS IS COOLING SLIGHTLY the surface of the world's oceans is cooling slightly. It naturally would if fresh water from the melt of land ice were spreading widely! So that a cooler ocean, if only on the surface, would be wrongly reassuring to those of us who would like to continue to live on a planet wearing a cap of ice and ice boots, on which we have desported ourselves for forty milllion years.


    [JH] The use of "all caps" constitutes shouting and is prohibited by the SkS Comments Policy.

    [Rob P] - Global sea surface temperatures exhibit a long-term warming trend:



  28. vincentfladk @377, the rate of sea level rise is approx 3 mm per year.  I will assume that all of it comes from melting ice (in fact a significant amount comes from thermal expansion).  The specific heat of water is 4.2 KJ/(Kg K).  That is, it takes 4,200 Joules to raise one Kilogram of water by one degree K.  The latent heat of fusion of water is 334 KJ/Kg.  That is, it takes 334,000 Joules to melt one Kg of ice.  Ergo, melting a Kg of ice takes approximately the same amount of energy as raising the temperature of that water by 80 degrees K.

    Assume for the sake of argument, that the average temperature of the Ice was - 15 C prior to being melted, and that it is raised to the global average temperature of 15 C.  The total energy involved in melting the ice and raising sea level on this assumption, therefore, is approximately equivalent to the energy required to raise 3 mm of sea water across the worlds ocean by 80 C.  However, because of strong mixing due to surface winds, the top 50 meters (very conservatively) of sea water has essentially the same temperature.  To cool the ocean surface, therefore, we need to cool that top 50 meters.  That 3 mm of sea level rise, therefore must cool 16,667 times as much water as it holds.  Averaging the heat over that depth, it means we have 80/16667 degrees C temperature decrease, or approximately 0.005 C decrease to small to be noticed.

    In this calculation, I have made a number of assumptions that were generous (to say the least) to your theory.  Even so, it does not hold water (pun intended).  This is one of the things that distinguishes science from theology (or most of philosophy, ie, my own native discipline) is the use of mathematics to filter out those theories that seem plausible when not expressed with enough precission.  It is also why newcomers very rarely see things that have not been considered and rejected as implausible by the actual scientific experts.

  29. vincentfladk, the idea that Antarctic land ice falling into the ocean could be causing increased Antarctic sea ice has actually been floated and examined before. However, as Tom Curtis explains, in this case the situation is quite a bit more complicated.

    That said, I have seen some suggestion that the decreased salinity of ocean water caused by melting land ice leads to a higher freezing point and thus some increase in sea ice formation. However, the prevailing theory seems to be that most of the Antarctic sea ice increase is caused by changes in wind patterns and/or the ozone hole.

  30. CBDunkerson

    I have heart similar and in the Arctic it seems true. However one of the team at RealClimate commented on that reccently that because most of the melt in the Antarctic, particularly West Antarctica flows under the ice sheet it emerges at the sea floor not the surface. So it is too far down to impact salinity in a way that influences freezing at the surface.But it can freeze in situ when it hits the slightly colder, saline water at depth.

  31. In a statement issued on 5 February, the NSIDC said: “Preliminary measurements from the CryoSat show that the volume of Arctic sea ice in autumn 2013 was about 50% higher than in the autumn of 2012. In October 2013, CryoSat measured approximately 9,000 cubic kilometers (approximately 2,200 cubic miles) of sea ice compared to 6,000 cubic kilometers (approximately 1,400 cubic miles) in October 2012.”


    [PS] Please note that this topic is for discussion of Antarctic sea ice so arctic conditions are off topic. Also note that it is better to look at trends rather than short term variation though today's ice numbers are "interesting".

  32. Quantummist,

    I posted a reply here where it is on topic.

  33. The year 2010-2011 for the Arctic, (from here) , shows a late peak... not to mention a very flat projection towards said late peak. The following year, 2011-2012, didn't seem to suffer in terms of ice extent!!

    From this may I be permitted to guess that we perhaps haven't seen the maximum ice extent for 2014-2015 yet??

  34. bozzza

    That might have been a fair possibility a week ago. Now a late rise in extent would look less likely. That said, a record low maximum extent doesn't tell us what the minimum in September will look like. 2012 was the record minimum, but it certainly wasn't an unusually low maximum. It all depends on the weather up there over the next 6 months.

    Regions to watch:

    • The Kara and Laptev Seas. They seem to have been stubbonly refusing to thicken over this winter so might melt out quickly.

    • The central Arctic Basin above the Barentz and Kara. Much of the ice there seems to be quite broken up - more easily moved around, splashed with water etc.

    • The Beaufort Sea. Currently a lot of the older, thicker ice is there (and the Canadian Archepelago). If the weather applies a blow torch to that, while it may not contribute much to what happens to Extent and Area, it could have a big impact on what happens to Volume.

    If you haven't discovered it already, Neven's Arctic Sea Ice Blog is a treasure house:

    • The Arctic Sea Ice Graphics page give you links to loads of different resources, webcams, long term data sets etc. If a Polar Bear is going to get it's picture taken by a drifting ice buoy, somone at Neven's blog will probably spot it.

    • His Forum has a lot of true Arctic Nerds (in the very best sense of the word) who can dissect data you may not have even heard of. One regular (Wipneus) produces his own area/extent calculations by combining the best of the raw data feeds from multiple satellites. A regular here at SkS, Jim Hunt, can wax lyrical about what the thermocouple tree below a buoy can tell us about the mixing of waters below the ice - when he isn't tearing David Rose at the Mail in England a 'new one'.

  35. Arctic sea ice is 1.2 million square kilometers below average. Antarctic Sea ice is 1.7 million above average.

    How does a climate change advocate deny the reality of this?

  36. bozzza@385 - As the self same "Arctic Nerd" mentioned by Glenn above I'm afraid that I don't understand your question in this context. Is there any chance that you can rephrase it? What precisely is "a climate change advocate" in your terminology?

  37. "climate change advocate" = a non-denier of climate change 

  38. In which case doesn't this very article answer your question in great detail?

    If not you will need to elucidate in much greater detail!

  39. I'm not denying the article is helpful in explaining that ozone depletion is causing wind increases and melting of land ice plus rain increases are freshening the Southern ocean changing the layers so that warm and cold waters don't mix like they once did... I'm simply saying the numbers look curious.

  40. I not entirely sure I understand your concern. As far as I can see, the article is comparing Winter Antarctica seaice (no climaticalogical effect because it happens when the sun isnt shining), versus Summer Arctic sea ice (where the loss is significant due to reduce albedo). The skeptic narrative is that northern hemisphere warming is more than matched by southern hemisphere cooling (sea ice as evidence). However the narrative fails because sea ice increase isnt due to SH cooling - the Antarctic is warming too. Its just that real situation is more complicated.

    A better comparison is to compare the climatological effect from sea ice albedo between hemispheres. Tamino did that here - compare that with the rather deceptive approach at Nova.

  41. Ok, I was just saying the numbers look weird and I think that is worthy of considered comment as to why.. I haven't understood the meaning of statistical significance but as far as sea-ice area graphs of Antarctica are concerned the last few results seems to be worth talking about.


    I get the mechanisms discussed but the real-politik of statistics and publicly inspired meaningful thresholds cannot go unanswered.

  42. bozzza@391 - So you're seeking a punchy "elevator pitch" that addresses the misleading headlines of Nova et al.?

    And/or suggesting that this article needs updating to include the 2014/15 numbers?

  43. I am saying it makes the fight to have climate science recognised by the trolls more difficult, yes!

  44. bozzza,  Re the data you reference regarding 2D ice extent increases in Antarctica, the 3D ice mass budget studies indicate large accelarations in the rate of 3D ice loss (mass not 2D measurment).

    See the article SOTC: Ice Sheets, which refernces these studies (Rignot et al. 2008).

    The 2D ice extent in the Arctic (north pole) indicates a downward trend.

  45. UW - Perhaps I'm being naive. but it seems bozzza understands all that. I ultimately understood his question to be "how might one wrap all that up neatly in a catchy headline", or at most a sentence or two.

    "Real-politik" rather than "Rignot et al."?

  46. UW/bozzza - Perhaps this is a canonical example?

  47. Bozzza - Antarctic sea ice is not relevant because unlike the Arctic, which is 100% sea ice, the Antarctic ice pack is overwhelmingly non-sea ice.

    The Antarctic ice pack should only be tracked in its entirety unless one’s intention is to mislead people as to the extent of the disaster.

  48. Is there a way to edit ones’ posts here?

    I forgot to add that the hole in the ozone layer is also man made so even if one wanted to use that as an excuse for the Antarctic ice pack declining, it is still man made ice pack destruction/global warming.

  49. Ok, so we're saying sea ice is a worthy indicator of something amiss in the N.H. but as an indicator of something amiss in the S.H. it is not as relevant. I will just have to accept for now that I was getting hooked up with a red herring or atleast feeling the need to explain it...(such is life!)

    What's been bugging me forever(I was going to say lately but that wouldn't quite express it correctly) is this: ocean-pump-keeps-northern-hemisphere-hot

    As a failed engineering student I know it's all about heat pumps and this article says the phenomenon of the N.H. being hotter was discovered in the 1600s because it was observed that icebergs survived at lower latitudes in the S.H. than would be allowed in the N.H. 

    The question is why is the above- the fact that the NH is warmer than the SH- not common knowledge?

    Am I wrong, perhaps?

    If not then I really question why it hasn't been made common knowledge as most people who are fans of science will understand this completely as the process that needs to be witnessed very very closely.... and at the moment it looks as if the problem can't be made intelligible to the public because of this basic information scarity.

    (Simply my opinion of course but that's my 2 cents...)

  50. Bozzza

    2010-2011 2011-2012 are by themselves not relevant. The only thing that is relevant is the trend. If there are some outliners, not relevant to the trend, that is still the way that trends work.

    One could even argue that trend lines were created so that people would not be fooled by the outliners to make foolish decisions based on something that has no real relevance to reality.

    P.S. The maximum extent for the Arctic in 2015 not only occurred early, it was the lowest maxium in the satelite record.

Prev  1  2  3  4  5  6  7  8  9  10  Next

Post a Comment

Political, off-topic or ad hominem comments will be deleted. Comments Policy...

You need to be logged in to post a comment. Login via the left margin or if you're new, register here.

Link to this page

Get It Here or via iBooks.

The Consensus Project Website



(free to republish)



The Scientific Guide to
Global Warming Skepticism

Smartphone Apps


© Copyright 2017 John Cook
Home | Links | Translations | About Us | Contact Us