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The most popular deceptive climate graph

The “World Climate Widget” from Tony Watts’ blog is probably the most popular deceptive image among climate “skeptics”.  We’ll take it under the microscope and show what it would look like when done properly.

So called “climate skeptics” deploy an arsenal of misleading graphics, with which the human influence on the climate can be down played (here are two other  examples deconstructed at Realclimate).  The image below is especially widespread.  It is displayed on many “climate skeptic” websites and is regularly updated.


The “World Climate Widget” of US “climate skeptic” Anthony Watts with our explanations added.  The original can be found on Watts’ blog

What would a more honest display of temperature, CO2 and sunspots look like?

  1.  It is better to plot the surface air temperature.  That is what is relevant for us humans: we do not live up in the troposphere, nor do natural ecosystems, nor do we grow our food up there. By the way, the satellite-based tropospheric temperatures shown by Watts show almost the same climatic warming trend as those measured by weather stations near ground level (in both cases 0.16 C per decade over the last 30 years).  However, variability in the tropospheric data is considerably larger, especially because of higher sensitivity to El Niño (as happened in 1998) and the solar cycle (we showed that in Foster and Rahmstorf ERL 2011 – when corrected for those factors the surface and troposphere data agree closely).  Because of increased noise, the trend is less obvious to the eye, especially if one shows monthly values which adds yet more noise.  Let us thus use the GISTEMP global annual temperature record from NASA’s Goddard Institute for Space Science (all surface data sets agree to better than 0.1 °C, see comparison graph).
  1.  One needs to scale the CO2 data correctly for an honest comparison with temperature, so that it can actually be used to evaluate climate scientists’ predictions of the CO2 effect.  You can calculate this with a complicated climate model, but one can also use a back-of-envelope estimate.  A CO2 increase from 280 to 400 ppm (equivalent to 2 Watts/meter2 radiative forcing) produces about 1 °C of global warming (at the time when 400 ppm is reached – some further warming will follow with delay). Thus, an increase of 100 ppm CO2 on the right hand side of the graph corresponds to a temperature increase of 0.8°C on the left hand side. That matches the IPCC’s estimate of the “transient climate response (TCR)” of ~2°C at the time of CO2 doubling (see Technical Summary of the IPCC WG1 report, p. 84). The TCR is smaller than the equilibrium climate sensitivity (about 3°C for doubled CO2) because it takes time to warm the oceans. The full equilibrium warming is thus only reached after a time delay. We are going to use the annual values from the famous CO2 measurements which began in 1958 on Mauna Loa in Hawaii.
  1.  And last but not least one should show honest sunspot data (annual time series), not just a snapshot of the number of spots on the sun today (which is completely uninformative for climate purposes – it’s apparently been added to the widget simply to insinuate an important role of the sun). Here also there is a question of the proper scaling (which is actually not that important because solar activity is cyclical and shows no significant trend over the period of the graph).  We will chose the scaling from the correlation analysis of Lean and Rind (2008) from which one can find a measurable effect on global temperature with an amplitude of 0.05°C.

When done this way the graph looks like this:


One of the readers of our German sister blog KlimaLounge, Bernd Herd, has programmed a widget for this graph so it can be added to any website at a size you like, automatically updated annually.

The trends in the CO2 and temperature anomaly curves agree very well with each other.  This is surprising at first because CO2 is of course not the only factor that influences global temperature. There are two reasons for this agreement:

(1)  Of the other anthropogenic factors, some have a warming effect (other greenhouse gases such as methane) while others have a cooling effect (air pollution). These roughly balance in global average. The IPCC AR4 report found a radiative forcing of 1.7 W/m2 from the CO2 increase alone, while the total from all anthropogenic factors amounted to 1.6 W/m2.

(2)  Natural factors (volcanoes, solar cycle) influencing the trend are very small in comparison to anthropogenic CO2 (as e.g. standard correlation analyses show, see for example Lean and Rind 2008Foster and Rahmstorf 2011). The IPCC AR5 found their contribution to global temperature change since 1951 to be in the range of −0.1°C to 0.1°C.

It requires quite some skill to produce a misleading graph like Watts’ global climate widget, which hides the actual connections between global temperature, CO2 and the sunspot cycle. Watts’ widget is quite a useful indicator though: whenever you see it on a website, you know they are trying to fool rather than inform you there.


A quick ‘n dirty guide to falsifying AGW

Dot Earth: Warming Trend and Variations on a Greenhouse-Heated Planet

217 Responses to “The most popular deceptive climate graph”

  1. 151
    Dave Walker says:

    Re Steve Harris @ 44 and responses at 49, 50, 53, 57, etc, etc

    Before you all go into apoplexy, please read what I write – rather
    than make assumptions about my “position” or whether I am a skeptic, denier, etc.

    The general public knows little about the facts of climate change. Mostly, they get their information from news items on TV and in the press. You will agree, I assume, that it is very rare that any story to do with climate change is published that does not carry a “scare” element, or “it’s worse than we thought” or that some extreme weather event is positively linked to climate change.

    As an example, rarely will a “scientist” be quoted in the MSM saying, for instance, that there is no evidence, whatsoever, of a particular Hurricane, a flood, a heatwave, a cold snap being anything other than just weather – and absolutely “normal” weather at that. There is, seemingly, always a backhanded reference to “proof” of climate change and that we can expect more of the same. Readers here know that is not true – but the reader/listener/viewer is left with the view that “scientists” all agree that it is. Similarly, I think most of the general public, if asked, would say that the ice caps are melting – because that is what they have been lead to believe as a result of various news items over the last 10 years. They probably think that Global Sea Ice levels are way down and inexorably melting.

    [Response: Melt from Greenland, Antarctica, mountain glaciers around the world and Arctic sea ice (which is less important for sea level) is in fact increasing fast. Antarctic *sea ice* has increased a little which is indeed interesting, but net ice changes are strongly and steadily increasing sea level. – gavin]

    I also think that most of the general public will have heard of, and will believe, that the “hockey stick” graph is accepted by the “scientific community” (without debate) as being the fairest representation of the globe’s historic temperatures – because of the publicity and news coverage the graph received. They will not be aware of the scientific debate that has occurred since – and continues to occur.

    [Response: The basic pattern – pre-industrial long term cooling with some ups and downs and a sharp uptick in the 20th and 21st Century is indeed what most paleoclimate people think is the most accurate assessment of the last centuries. ]

    So, I guess, Steve references to debate may be more about balance in the sense of what we know as fact rather than inferences that are drawn or, more probably, float without correction because it isn’t anybody’s job to “correct” a news story subsequently.

    [Response: We try to correct many false claims made in the media, whether they are giving credence to fringe forecasts or totally misrepresenting mainstream science. No one can do everything though! ]

    But those are the time’s we live in. Whether it’s climate change or politics, if a spokesperson makes a statement on a particular subject or policy then the statement has to be unequivocal with absolutely no room left for doubt/opinion/musing etc. – or debate.

  2. 152

    “As an example, rarely will a “scientist” be quoted in the MSM saying, for instance, that there is no evidence, whatsoever, of a particular Hurricane, a flood, a heatwave, a cold snap being anything other than just weather – and absolutely “normal” weather at that.”

    – See more at:

    I disagree. I’ve heard such comments and caveats quite often.

    “They probably think that Global Sea Ice levels are way down and inexorably melting.”

    If so, they aren’t far wrong:

    “…the “hockey stick” graph…”

    Well, technically, it can’t be a representation of global temps at all, because its scope was hemispheric–“Northern Hemisphere” is right in the title. And it would be rather strange if work from 1999 remained definitive 15 years later. I rather think the only reason that it’s in the public ear at all is because denialists persist in attacking it (apparently in the belief that, if it were to be ‘broken’, climate science would likewise be broken.)

    That’s not true, of course–as Dr. Mann himself has pointed out, the question of whether humans are driving current warming, and whether it has the potential to do harm, are completely independent, logically, of whether previous natural variations are smaller, larger, or about the same. And the physics and meteorology are likewise completely independent of paleoclimatology.

    However, MBH ’99 was an important study–it’s probably fair to call it ‘seminal’ in the use of proxies to reconstruct temperatures. That’s why Google Scholar finds it to have been cited 1741 times:,11&hl=en

  3. 153
    Jim Eager says:

    Sorry Dave, but both the Greenland and Antarctic ice caps are melting and loosing mass. And global sea ice level is down, even when you include the recent increase in Antarctic sea ice, which is much smaller than the concurrent decrease in Arctic sea ice, btw. There is no real scientific debate about either of those facts, only faux debate fostered by those in denial of the science.

    And the “hockey stick” graph of global temperature over time is accepted by the relevant scientific community because it has been replicated numerous times using different proxies, metrics and independent techniques. Again, there is no real scientific debate about the hockey stick like track of global temperature shown in the graph, just dogged sniping by those who refuse to accept reality and use deceptive arguments to sow doubt.

    Again, someone brings little more than concern trolling and false assertions to the discussion.

  4. 154
    Dave Walker says:

    Re Your Responses in #151

    Your first two responses sort of make my point. In the first response, quite understandably, you broadened the point to address the issues of sea level – which is the bit that ends up being the resultant area of concern. However, I believe that most of the general public have the impression (through what they have read and heard) that the ice caps at the north and south poles are melting – but global sea ice graphs, produced by scientists, tell us otherwise. When did anyone get reported in the MSM as saying that global sea ice is on the increase? The fact that this isn’t the whole story is not the issue. Do 97% of scientists agree that the ice “caps” are melting – I think not.

    [Response: You think wrong. The ice ‘caps’ (quite clearly taking in the Antarctic ice sheet) are indeed shrinking in both hemispheres. If you’re only point is that you have eyeballed the global sea ice area curve and you think there isn’t a trend, then you should have said that straight away. Then we could have pointed you to the analysis of the trend in that graph and you’d see that the trend is indeed negative. What the exact percentage of scientists that would agree with an ill-defined statement is of course somewhat more uncertain, but why debate strawmen? – gavin]

    Do 97% of scientists think that the Hockey Stick graph is the fairest known representation of historic temperatures. Again, I think not. Those that study the subject in more detail know that there are probably too many issues with data and the impact of some critical data in creating the uptick for that to be the case. Does that mean that another graph, created by other scientists, that produces a similar outcome in a different way is wrong too? Of course not.

    [Response: What do you even mean by the Hockey Stick graph? The specific result from MBH98? That was 16 years ago, and many other studies (including many by the same authors) have updated that in terms of data and methodology. However, all the updates show pretty much the same basic picture – which still resembles a hockey stick. What evidence do you have that the public even distinguishes between any of these? Are people wrong if they think that the warming in the 20th Century is exceptional on a multi-century basis? No – they aren’t – and that’s about as good as it gets. – gavin]

    However, such is the way that the media works, the original Hockey Stick graph is understood, by the press and the public, to be the graph accepted by 97% of scientists – and anyone who tries to argue, for whatever reason, anything else – will probably be held up, or dismissed, as a loony, or sceptic or denier – because the debate is over!

    [Response: That’s just low-level rhetoric. Leave it at home. – gavin]

    With respect to your final point, clearly it is just not possible for the resources available to RealClimate to be employed to “police” and/or correct the output of the MSM around the world.

    In summary, and just to be clear, it is simply not fair, or accurate, to label someone as a skeptic or denier – when they try to correct someone that says the ice caps are melting. Also, one is not a skeptic or denier if one says that there is absolutely no evidence to suggest that, for instance, Hurricane Sandy or the floods in Somerset in the UK was due to global warming. But, typically any one that tries – is!

    I am sure you get my point.

    [Response: I didn’t label you as anything. But if you want to have substantive discussions, be specific, don’t generalise and don’t spend all your time debating strawmen. – gavin]

  5. 155
    Dave Walker says:

    Response to Jim at #153

    Jim, you prove my point in a way I couldn’t do myself.

    I’ve just looked at the graph showing sea ice globally, in the Arctic and the Antarctic from ’79 to date. I assume that the graph was produced by scientists. Although I am a layman, I think I can read a graph – and that graph produced by those scientists shows that current global sea ice levels are roughly where they were in 1979.

    Now, you may have other information, you may have another data source, you may even be right – but, is the statement “there is no real scientific debate about either of those facts, only faux debate fostered by those in denial of the science” relevant or accurate in the context of my comments? Again, I think not.

  6. 156
    Ray Ladbury says:

    Dave Walker: “Although I am a layman, I think I can read a graph…”

    Evidently not. The global trend is about -1.4% per decade according to the NCDC.

    “Again, I think not.” That’s your problem…you don’t think.

  7. 157
    Jim Eager says:

    Dave, since you haven’t provided a link to the graph you cite there is no way to tell if it says what you assert it does or not.

    So let’s look and share, shall we?

    Northern Hemisphere:

    No where near the 1979 level, for either minimum or maximum, by about 2 to 3 million km^2 over the last 10 years, and the long term trend is clearly down sharply.

    Southern Hemisphere:

    Maximum is above 1979 by about 1 million km^2 over the last 10 years, by almost 2 million in 2014. One year does not make a trend, but the trend is up, yet not with as steep a slope as northern hemisphere decline.

    Clearly the loss in the Arctic has been much larger than the gain in the Antarctic, meaning there has been a net loss globally.

    In any case, the two poles are not alike. Sea ice gain in the Antarctic takes place in the winter darkness, when it can not affect earth’s abido. In the Arctic, on the other hand, there is no land mass to limit sea ice melt, and it happens in summer when it can change earth’s albido. That’s why arctic sea ice is more important in terms of global warming/climate change and thus why it gets more attention.

    [Response: Averaging Antarctica and the Arctic together and try to say that sea ice isn’t changing is like saying Iraq + Denmark = “there’s no social problems in the world.” –eric]

  8. 158
    Steve Fish says:

    Re- Comment by Dave Walker — 15 Dec 2014 @ 1:25 PM, ~#155

    Dave, when writing about what you see in a graph that you don’t even know was “produced by scientists” and don’t provide a link or a source for the graph, you are being impolite.


  9. 159
    Hank Roberts says:

    > Dave Walker

    Sea ice: One of these?

    Hockey sticks: One of these? or these? or these?

  10. 160
    Jim Eager says:

    Exactly, Eric (in-line response), but the average of the two isn’t even as Dave portrayed it. Clearly he is basing his assertions on some pretty suspect sources.

  11. 161
    Matthew R Marler says:

    158 eric in response: [Response: Averaging Antarctica and the Arctic together and try to say that sea ice isn’t changing is like saying Iraq + Denmark = “there’s no social problems in the world.” –eric] – See more at:

    First of all, we are looking at the total of Antarctic and Arctic, and the total ice cover is what is relevant to “global” warming. So the analogy would be summing Denmark and Iraq, not averaging them.

    Second, the conclusion from little or no change in the total would not be “there’s no social problems in the world” but that the change observed in this part of the world is little to none. There is lots of regional variation in both cases, so no two places are trustworthy samples — that said, it is better to consider both the Antarctic and Arctic with respect to “global” warming, than to consider only one of them.

  12. 162
    Keith Woollard says:

    Why hasn’t anyone put up a graph of both.
    OK, there may be a very slight trend, but no-one can look at this and be worried about “the ice caps melting”

  13. 163
    Pehr says:

    May be Watts’ widget isn’t without some interesting points.

    The diagram shows 0.9 C temperature rise corresponding to a carbon dioxide rise from circa 340 to circa 385 during 1979 to 2009. However the equivalent carbon dioxide rise is greater due to the other GHGs, from 382 to 465 during this period according to table 2 on NOAAs page:

    So in order to estimate which climate sensitivity was assumed in the widget, not the real but the equivalent carbon dioxide mixing ratio should be used. From this we may calculate a climate sensitivity according to a standard equation of 0.9/ln(465/382)*ln 2 =3.2 C per doubling.

    This is av value of the climate sensitivity at the high end, however more usual 2009 than today and used in some projections, perhaps studies published by the World Bank may give examples of this.

  14. 164
    Jim Eager says:

    “First of all, we are looking at the total of Antarctic and Arctic, and the total ice cover is what is relevant to “global” warming.”

    No, Matthew, it is not, for the reason that I gave in my response to Dave: Sea ice gain in the Antarctic takes place in winter darkness, when it can not affect earth’s abido, while Arctic sea ice melt takes place in the summer, when it can lower surface albido and thereby amplify warming in the arctic. The one obviously does not simply offset the other. You are adding apples and oranges when it comes to global warming/climate change.

  15. 165
    Jim Eager says:

    Why hasn’t anyone put up a graph of both.

    Because the two components do not have the same impact on climate, and thus the total does not show what you think it does.

    Because it also presents the data on a much larger scale, which is exactly what one does when one wants to reduce the apparent magnitude of a change one does not like. There’s a word for that.

  16. 166
    Matthew R Marler says:

    164, Jim Eager: Sea ice gain in the Antarctic takes place in winter darkness, when it can not affect earth’s abido, while Arctic sea ice melt takes place in the summer, when it can lower surface albido and thereby amplify warming in the arctic. – See more at:

    If what is recorded now is the result of 20 years of Arctic “amplification”, that “amplification” must be considered slight. As an indication of current global state, Antarctic and Arctic considered together are better than one of them alone.

  17. 167
    Ragnaar says:

    Jim Eager says:
    Arctic sea ice melt takes place in the summer, when it can lower surface albedo and thereby amplify warming in the arctic.” With no sea ice, the SW watts go into the water. Lacking insulation from sea ice they don’t stay there long (I can’t find the study that said the near surface Arctic water heat gain lasted 2 or 3 months and then pretty much zeroed ) with the cold Arctic air above them. With less sea ice the Arctic ocean can vent more heat all year long. We see the atmospheric temperature rise way up North and see cooling of that ocean. This is a good thing. There is an albedo effect over sea ice. We might consider that the albedo protects the ice from melting because the earth thinks it needs the ice to insulate the Arctic waters. When you make sea ice, it’s good to put white snow on it, so it doesn’t melt during the Summer. Sea ice may be white with snow on it, not to cool the earth but to protect the sea ice so it can insulate the oceans to keep them warmer. The sea ice probably evolved to help regulate the earth’s ocean temperatures. CO2 does cause us to have less sea ice. But I think that sea ice loss cools the oceans more than it warms them.

  18. 168
    Keith Woollard says:

    Jim @ 165, no – this subject came up at #151 when Dave was talking about the general public’s perception of what they read in papers about the poles melting. I would suggest that the vast majority of the popolation would be very surprised by the graph I put up at #162.
    And really, your #164 comment?????? who’s winter are you talking about? The average is staying the same with an extremely low negative slope.

  19. 169
    Hank Roberts says:

    National Snow and Ice Data Center

    Why don’t you publish a global sea ice extent number?

    The combined number, while easy to derive from our online posted data, is not useful as an analysis tool or indicator of climate trends. Looking at each region’s ice extent trends and its processes separately provides more insight into how and why ice extent is changing. Sea ice in the Arctic is governed by somewhat different processes than the sea ice around Antarctica, and the very different geography of the two poles plays a large role. Sea ice in the Arctic exists in a small ocean surrounded by land masses, with greater input of dust, aerosols, and soot than in the Southern Hemisphere. Sea ice in the Southern Hemisphere fringes an ice-covered continent, Antarctica, surrounded by open oceans. While both regions are affected by air, wind, and ocean, the systems and their patterns are inherently very different. Moreover, at any point in time, the two poles are in opposite seasons, and so a combined number would conflate summer and winter trends, or spring and autumn trends, for the two regions.

    November 2014

  20. 170
    Dave Walker says:

    Re: 151, 152, 153, 154, 156,157, 158, 159, 160, 161, 162, 164, 165

    The graph that I was referring to is at:

    It shows global sea ice levels over the last 25 years. To me eye, global sea ice levels are roughly where they were in 1979 – hence my comment that, simply, it should be OK to point out that the ice caps are not melting (i.e. one is, one isnt) -but that doesn’t mean that there is a broader point to discuss about sea level as raised by Gavin.

    If you go back to my original comment at #151, I was trying to make the point that the general public assumes, as a result of things they hear and read in the MSM, that some things are agreed by 97% of scientists, when they are not – and i used melting ice caps purely as an example – that’s all.

    In summary, it it possible to say that the ice caps (plural) are not melting without being shouted down and

  21. 171
    Dave Walker says:

    sorry, two errors in my last comment

    1. ” …-but that doesn’t mean that there isn’t a broader point to discuss about sea level as raised by Gavin.

    2. I didn’t finish my final paragraph properly – ignore it.

  22. 172
    Hank Roberts says:

    > Dave Walker … two errors

    Three errors, at least.

    The third is a big one; you’ve fallen for a Joe Bast talking point you’re mistakenly repeating as though it were factual.

    The number you’re thinking of — 97 percent — is of actively publishing climate scientists.

    Not all scientists.
    Not all scientists and retired scientists.
    Not all scientists, retired scientists, medical doctors, and engineers.
    Not all people who, in polls, make an unconfirmed claim to be scientists.

    What kind of information would change your mind?

  23. 173
    Dave Walker says:

    Ref Jim at #164 and #165

    …. goodness me, this is hard work.

    Jim, are Antarctic sea ice area levels receding or growing? Do you think that the general public know the answer?

  24. 174
    Dave Walker says:

    To Hank at #172

    Please try to understand where I am coming from. I am not trying to argue science with anyone here. I don’t have the knowledge, education or reason to do so. I can however comment on things that I believe to be facts about the general public perceptions.

    Given that we seem to have focused matters around the ice caps, lets stay with it. I think, that the general public thinks. that both the ice caps are melting – when they are not. One is, one isn’t (source: the link referenced in #170 above).

    What do you think?

  25. 175

    #167–Yes, open water in the cold parts of the Arctic winter leads to increased heat flux to the atmosphere, and yes, that is known to be a negative feedback.

    No, it doesn’t seem to overpower the positive albedo feedback.

    WRT the latter, here’s one recent study (of many that have been done on the general question):

    This albedo evolution provides a simplified method of estimating the changing albedo of seasonal ice during melt and the amount of solar heat input to the ice. During the melt season the albedo of seasonal ice is consistently smaller than multiyear ice. Thus the ongoing shift from multiyear ice to seasonal ice will increase the total solar heat input to the ice cover, enhance summer melting, and increase the amount of sunlight transmitted through the ice into the upper ocean. This transmitted sunlight will be available for warming the ocean, melting the bottom of the ice cover, and increasing the photosynthetically available radiation for primary productivity.

  26. 176
    Jim Eager says:

    For Keith Woollard: I’m aware of who brought the subject up and in what comment since I responded to it in 153.

    As for who’s winter I’m talking about, seeing as I wrote “Sea ice gain in the Antarctic” I would think it obvious, or are you being deliberately obtuse for rhetorical effect?

    The bottom line is those insisting on averaging Arctic and Antarctic sea ice area as if one balances the other out are suffering from the self-imposed handicap of willful ignorance. There is no point engaging with such individuals.

  27. 177
    MARodger says:

    Dave Walker @173.
    There are folk who will see a graph of the global sea ice area anomaly (perhaps the NSIDC version you link to @170 or the Chryosphere Today version) and feel reassured believing such data demonstrates that AGW isn’t such a problem after all, the polar ice isn’t melting out. It isn’t even melting!! Such folk are poor deluded fools.

    One point to make is that normally the term “ice caps” refers to land ice not sea ice. You however are referring to sea ice and thus not “ice caps.” But for the record, in recent years the “ice caps” and mountain glaciers have been together losing in excess of 700 cu km a year. We can also be quite confident that the Arctic sea ice has lost 10,000 cu km since 1979. (See here – usually two clicks to download your attachment.) The value for Antarctic sea ice volumes is very poorly defined. However the Antarctic melts out each summer so the ice is all first year ice which is thinner ice. This allows the inference that any increase in Antarctic sea ice area will have less impact on global ice volumes because it is thinner than the lost ice in the Arctic.

    Another point is that the Antarctic sea ice area is increasing at some points around the continent and decreasing at others. Such a situation suggests the likelihood of greater variability as the net trend is the product of two far larger processes. And this potential greater variability in Antarctica raises the question of what levels of Antarctic sea ice area exisited before 1979. (This is more interesting than for the Arctic as there is enough data for Arctic from earlier decades to leave no room for any big surprises.) As there were satellite data from the 1960s it is possible to see that while Antarctic sea ice area has increased since 1979, it is a long way below the levels represented in these limited 1960s satellite data. (See Fig 4 in Meieer et al (2013). Ald also Fig 7 with the ‘no surprise’ Arctic equivalent.)
    All this is strongly suggestive that the growth of Antarctic sea ice area over the last 35 years is, unlike the Arctic equivalent, pretty small beer in the grand scheme of things.

  28. 178
    Ray Ladbury says:

    Dave Walker: “In summary, it it possible to say that the ice caps (plural) are not melting without being shouted down and,,,”

    No, Dave. We won’t shout you down. We’ll just laugh at you. When you construct a statistic, you have to ask yourself whether it is meaningful or not. Adding Arctic and Antarctic sea ice together is absurd on the face of it. When Arctic sea ice is melting, Antarctic sea ice is of course freezing. It’s Winter there ferchrissake. And likewise when Antarctic sea ice is melting. You have just constructed a metric that will only be minimally sensitive to global changes.

    What is more, you’ve completely ignored the physics–both of what is driving the trends and of their consequences for future warming.

    Gee, it’s almost as if you guys are devoting a lot of effort to not understanding this stuff.

  29. 179
    David Miller says:

    Dave Welker, what you’re doing is taking issue with “the ice caps are melting” but equating the southern “ice cap” with the sea ice surrounding antarctica.

    As you’ve acknowledged, the sea ice trend is down. What you ignore is that antarctica itself is losing cubic kilometers of ice every year, and that the rate at which it’s losing ice is increasing. This is a part of the reason that sea ice is increasing, but the greater factor is circumpolar winds driven by ozone loss.

    So I think it’s very safe to say that “the ice caps are melting”.

  30. 180
    Jim Eager says:

    Dave, I’ll try one more time. When you say “ice cap” you are describing three different components:

    One is floating sea ice, which expands and melts with the annual seasons. Arctic sea ice is declining in both minimum and maximum extent and volume, while Antarctic sea ice is growing in in both extents, although that growth is less than the Arctic decline. The net change is a decline in total global polar sea ice, although it has been pointed out to you repeatedly that is a poor metric.

    Two would be land-fixed ice shelves, which are hundreds of meters thick. These do not melt away annually. Centuries old Ice shelves in the Canadian Arctic, Greenland, Antarctic Peninsula, and parts of West Antarctica are melting in place from below, breaking up and disintegrating. Ice shelves grow slowly, so these will take centuries to replace. Fixed polar ice shelves are clearly declining at both poles.

    Three would grounded marine and land based ice sheets and glaciers. The Greenland ice sheet is definitely loosing ice mass, as is the Antarctic Peninsula and much of West Antarctica. Even small perimeter areas of East Antarctica are loosing mass, while some parts of EA interior are gaining mass due to increased snowfall, itself due to the climate warming sufficiently to allow snow fall to increase (the high East Antarctic ice cap is a desert). Still, the net change for Antarctica is a loss of mass, so grounded ice sheets are loosing mass at both poles.

    All three polar ice cap components are in decline, meaning public perception that both polar ice caps are melting is correct. Your assertion is not.

  31. 181
    Jim Eager says:

    “Jim, are Antarctic sea ice area levels receding or growing?”

    Dave, I clearly stated that annual Antarctic sea ice area is growing. What’s interesting is that no one bringing this up has been curious enough to ask why. That’s telling. Asking why tends to separate those who want to find out what’s going on from those who just want to score debating points.

    I just posted that parts of Antarctica are losing considerable ice mass from both ice shelf and ice sheet and glacier melt. The fresh water from that ice goes directly into the surrounding sea, lowering its salinity slightly. Think about what effect that has on the temperature at which that sea water will freeze. That’s right, the expanding extent of annual Antarctic sea ice is at least in part due to the melting of land-fast and land based ice in Antarctica.

    [Response: Please read my write-up on this over at ClimateChangeNationalForum. I’ll probably post a shorter and slightly updated version here at RealClimate, soon. I think the importance of buoyancy (meltwater from glaciers) is probably overstated, but it’s certainly part of the picture.–eric]

  32. 182
    Hank Roberts says:

    > For Dave Walker

    You have read a bit of the science? How much have you read so far?
    — You know that fresh water floats on top of salt water, right?
    — You know that fresh water freezes at zero degrees?
    — You know salt water freezes colder than zero, right?
    — You’ve thought ‘where is the water that freezes into sea ice coming from’?
    — You know there’s more melting, and so freshwater flowing from the land?
    — And you know there’s more winter sea ice forming in that area recently.

    So — you can figure out that there’s fresh water — more than in the past — available on the surface at the edges of the Antarctic ice in recent years, right? You know where it’s coming from and why it’s available?

    Now, what was your question? What’s happening here?
    There’s much more going on and more to learn about all that.

    You wouldn’t be tricked into thinking the total global amount of annual sea ice isn’t changing — because both poles are changing by larger and larger amounts in recent years — would you?

    You know the age of the Arctic sea ice, right? A layer forms each winter, then it breaks up and the wind pushes some of it into thicker stacks that refreeze into 2-year-old ice (while other pieces go south and melt). Next year wind produces some 3-year-old ice (while other ice melts).

    So — how old is the oldest Arctic sea ice now?
    You know that the age of the Arctic sea ice has changed a lot recently?
    Not always the same direction — nobody expects smooth steady changes, remember.

    Look, you just can’t sum this up in talking points and little sound bites.
    Anyone who does that is a fool, or a TV news talker, or a headline writer, or a PR person doing a press release, or a politician. I may repeat myself.

  33. 183
    Hank Roberts says:

    PS for Dave Walker, re my post above. You see, above that, an inline response from Eric (in square brackets) that I hadn’t seen yet.

    Between an answer from a real scientist here, and anything from me — go with the real scientist’s answer.
    Just to be clear about that.

  34. 184
    Jim Eager says:

    Thank you Eric, for your in-line pointer to your article Making sense of Antarctic sea ice changes at Climate Change National Forum. I’d urge everyoen to read it, you, too Hank, as it turns out changes in wind patterns play the larger role in expansion of sea ice surrounding Antarctica, while regions with the greatest freshwater melt counter intuitively show decreases in ice cover.

  35. 185
    Ragnaar says:

    “…and increase the amount of sunlight transmitted through the ice into the upper ocean.” A greenhouse effect of sea ice.
    “No, it (heat flux to the atmosphere) doesn’t seem to overpower the positive albedo feedback.” Maybe more of a balance. During the last glacial period, say 25,000 years ago I’d say we had lots of sea ice and a higher albedo in the higher latitudes. I think the oceans were trying to retain heat and a high albedo was not detrimental to that. The SW lost by reflection was possibly less than the LW retention in the oceans beneath sea ice.

  36. 186
    Ragnaar says:

    Total sea ice. There is a wish that we could look at something and have it give us a useful number. Sea level rise is a proxy for energy in the system. This or that glacier is a proxy for energy in the system. On long time scales of 100,000s of years, sea ice extent can tell us whether or not we are in a glacial or interglacial? With the current situation, I have a hard enough time trying to understand one polar region. It’s possible the Antarctic is off doing its own thing due to a different geography and different circulations.

    [Response: Sea ice has very little to do with the terms “glacial” or “interglacial”. What defines those terms is the amount of land ice. Again, see here for my take on Antarctic sea ice trends. –eric]

  37. 187
  38. 188
    Hank Roberts says:

    > Most deceptive climate graph

    Are nominations still open?

    the United States Energy Association, an industry trade group: Close Link Between CO2 & GDP

    “Over the past two centuries, global life expectancy has more than doubled, population has increased eightfold, incomes have increased 11-fold. At the same time, CO2 concentrations increased from 320 ppm to about 400 ppm,” Bezdek said, using the abbreviation for parts per million. The benefits of CO2, he said, exceed its costs by ratios of between 100-1 and 900-1. A chart helpfully illustrated this “Close Link Between CO2 & GDP.”

    Of course there are lots of ways to play this, e.g.

  39. 189
    Ragnaar says:

    Dr. Eric Steig:
    Is ANTARCTIC SEA ICE HISTORY, LATE QUATERNARY by Xavier Crosta worth looking at? I think he suggests the sea ice impacts heat transfer at the ocean-atmosphere interface. You write, “…it’s a combination of thermodynamics and dynamics: the rate of cooling to the atmosphere (c) vs. the delivery of heat from the ocean below (h), and the movement of sea ice by the winds and by surface ocean currents.” So sea ice depends on (c) and (h) and winds. At the same time it effects (c) and (h). Do you think I am setting my knowledge back by suggesting it has some regulatory effect?

  40. 190
    Dave Walker says:

    Re Ray #178

    … Ray, with greatest respect, you are completely missing my point, and you also misinterpreting what the graph referenced by me, shows.

    The graph shows three lines indicating Global, Arctic and Antarctic sea ice area levels over the last 25 years. It shows, over time that Arctic ice levels have receded and are below the average for the period. It shows Antarctic on a trend such that it is growing and above the average for the period. I assume the “global” line is the sum of the two and, as it so happens, that resultant sum is, marginally also above the average for the period.

    I am not drawing any inferences from this. I am not saying therefore everything is Ok. I am not saying (as “Gavin” pointed out very early on) that therefore sea levels are unaffected. I am not saying it “proves” anything. I am saying that Antarctic sea ice area levels are growing – but, almost certainly, the majority of the general public don’t know that.

    I cannot vouch for the accuracy of the information shown in the graph. But other readers have referenced similar graphs showing similar results – so I am working on the basis that the graph is a fair representation of what it is intending to show.

    To understand why that points raised by the graph was relevant at all you will need to reread why and how I got involved in the conversation.

    [Response: Generally speaking, conversations ns don’t solely consist of someone making the same point over and over again. I think we get that you think more people should know about Antarctic sea ice and of course we agree – and they should also know about Arctic sea ice loss, mass loss on Greenland and in the West Antarctic ice sheet, and loss of mountain glacier mass around the world. So either move on to discussing your plan for greater scientific literacy, or just move on. -gavin]

  41. 191
    Dave Walker says:

    To the moderators

    I note that a couple of reply comments I sent yesterday were not published – I assume because of the tone I used (in response to a particular comment from “Ray” that was very “robust” in its tone).

    I resubmitted a couple the comments this morning (UK time) using a more moderate tone and responded to the comments accurately and politely. They do not appear to have been published either – which is a little frustrating given how it was left.

    I have entered my full email above (i dont normally give out my full email) so that you can email me let me know my status with the site. There is no point in me sending further comments if i am persona non grata.



    [Response: There is a comment policy – but basically, don’t attack other commenters and don’t be tedious (and this goes for everyone). Nothing to do with you persona, grata or non. – gavin]

  42. 192
    bobbyv says:

    This thread is too funny. You guys twist into knots to explain away increasing sea ice.

  43. 193
    Jim Eager says:

    Not explain away, bobby, just explain. It’s what separates those who want to understand what’s going on from those who don’t. Have you read Eric’s article or not?

  44. 194
    MARodger says:

    bobbyv @192.
    Perhaps then, you are more the sort to worry that there is 100,000 sq km less sea in the world today than there was yesterday, in fact 100,190 sq km less, and at that rate all the sea ice in the whole wide world will be melted away before the end of June next year. Not a word of a lie.

  45. 195
    Ray Ladbury says:

    Dave Walker: ” I am saying that Antarctic sea ice area levels are growing – but, almost certainly, the majority of the general public don’t know that.”

    The majority of the general public also do not know the density of squirrel turds in Central Park! The reason for this is that it doesn’t affect their lives much. Loss of Arctic sea ice does affect their lives. It feeds back on polar amplification. It may have weakened the Jet Stream, leading to influx of more polar air into the CONUS. It makes vulnerable methane deposits in polar seas that heretofore had been stable.

    And if your point is that Antarctic sea ice is growing, then fricking show Antarctic sea ice. Don’t show global sea ice, which isa next to meaningless metric due to the phase difference between Arctic and Antarctic melt cycles. What is more, you’d want to note that climate scientists have a pretty good handle on why Antarctic sea ice is growing.

    Look, Dave. I have been pretty hard on you, I admit. I am sorry for that. I am just tired of people mindlessly quoting meaningless statistics and pretending that they’ve come up with some smoking gun that climate scientists are ignoring. Sometimes, the reason why a meaningless statistic is ignored is because it is meaningless. If you are going to start quoting statistics, I would recommend becoming sufficiently familiar with the science that you can decide whether the statistic you see is meaningful. That really isn’t a lot to ask, is it?

    Start by reading Spencer Weart’s “Discovery of Global Warming” (linked on this page). Then read everything Tamino writes. We’re always happy to welcome new members to Team Reality.

  46. 196
    Hank Roberts says:

    > I am saying that Antarctic sea ice area levels are growing

    There’s your problem.
    Some people are saying Arctic sea ice area levels are shrinking.

    For some areas, at some seasons during the year, both statements are partly true. Neither is correct, as stated.

    Now, how old is the sea ice?


    Which sea ice? where? and when?

    It takes more to get you to “why?”

  47. 197
    SecularAnimist says:

    bobbyv wrote: “You guys twist into knots to explain away increasing sea ice.”

    If you are unable to follow the discussion, it’s nothing to be ashamed of. Ask for help. There are plenty of generous, patient people here who will explain whatever you don’t understand.

  48. 198

    “You guys twist into knots to explain away increasing sea ice.”

    – See more at:

    No, we don’t, because even the (pretty meaningless) global total is decreasing. Meanwhile the Arctic is in a trend for which “death spiral” remains pertinent.

  49. 199
    Jeffronicus says:

    re: bobbyv @ 192
    “This thread is too funny. You guys twist into knots to explain away increasing sea ice.”

    I don’t see anyone trying to explain it away. I see a lot of people trying to explain it. The leading theory seems to be that the circumpolar winds we know have increased in recent years are pushing sea ice (in some areas) farther afield.

    You fail to specify how they might be wrong.

  50. 200
    Hank Roberts says:

    So, are nominations still open for most deceptive?

    Google Image Search is a very useful view into what’s being prompted, and any climate-related search, when you click “Images”, will get you far more PR than science links.

    This particular graph of total global sea ice that’s now circulating (climate4u, watts, and so forth) that’s being hammered on by Dave is getting a lot of promotion lately online. It really hides the decline, so to speak.

    It’s been debunked, long since — but mostly in text:

    Fact Checker contacted Ted Scambos via email with help from the Climate Science Rapid Response Team. He has visited both polar regions several times, especially Antarctica. He is also lead scientist at the National Snow and Ice Data Center at the University of Colorado, where he works on Antarctic ice dynamics and polar climate change effects.

    Scambos said the trend for winter ice in Antarctica is to add about 5,000 miles each year whereas the Arctic summer loss is about 30,000 miles a year: “They certainly don’t offset each other.”