Climate Denial about Sea Ice

When it comes to Arctic sea ice, climate deniers have a hard time explaining why it has declined so far so fast. It’s one of the most telling signs of global warming, a stark message from Earth to deniers: it’s getting hot in here.

Climate deniers hate that. Since honesty and accuracy aren’t relevant to them, and doubt is their product, lately they’ve concentrated on a new tactic: use the wrong data.

The data du jour for climate deniers is sea ice extent from MASIE, the Multisensor Analyzed Sea Ice Extent. It combines satellite data (from passive microwave sensors) with visual imagery and other sources to produce an “operational product.” Its focus is to locate the sea ice edge in real time and alert users to how it’s changing, which is very useful for organizations like the U.S. Navy.

Sounds great. But should it be used to study long-term changes, to compare one year to another, to find out how this year’s sea ice stacks up agains the past? The answer is a resounding no. Says who? Says the people who produce the MASIE data, that’s who. From the documentation (emphasis mine):

While operational analyses are usually the most accurate and timely representation of sea ice, they have errors and biases that change over time. If one is interested in long-term trends in sea ice or how it responds to changing climate forcing, generally, it is best not to use an operational product, but rather one that is consistently produced and retroactively quality controlled. The NSIDC Sea Ice Index monthly ice extent, and the satellite passive microwave data sets upon which it is based, is one example. The Sea Ice Index gives a daily image of extent as well as monthly products. However, these daily images are not meant to be used for climate studies or for inferring anything longer than seasonal trends.

In case that doesn’t make it clear enough, soon after they say this:

… in general, it would not be appropriate to compare a recent MASIE extent value to one more than a few weeks old …

There’s no ambiguity about any of this. It’s not unclear. If you want to study how sea ice has changed over the years — hell, if you just want to compare one year to another — don’t use this data. The folks who make it said so.

That won’t stop climate deniers from doing exactly what they were told not to do. Why? Because the “biases that change over time” mean that sometimes the MASIE data give an answer that’s wrong, but climate deniers like.

Case in point: the GWPF (“Global Warming Policy Forum”) tells us that “Arctic Sea Ice Grows Back to 2006 Levels” because, says Susan Crockford, “Sea ice charts for 18 January from NSIDC Masie show exactly as much sea ice in 2017 as there was back in 2006 — 13.4 million km^2.”

Didn’t the MASIE documentation say “it would not be appropriate to compare a recent MASIE extent value to one more than a few weeks old“? Yes, it did. Isn’t January 18th 2017 more than a few weeks later than January 18th 2006? Yes, it is. Did anybody associated with GWPF read the documentation about this data? Maybe yes, maybe no, but if they did, then it would seem they don’t care.

What if we use the data which the MASIE documentation recommends for that kind of comparison, the sea ice index from NSIDC? Here’s how Arctic sea ice extent during the early months has changed over the years:


The values for 2017 are highlighted as a read line. The value for January 18th 2017 is marked by a blue dot with a circle around it, and was quite a bit lower than that for January 18th 2006. In fact it was lower than all previous January 18ths.

That’s what climate deniers do: use the wrong data so they can promote the wrong answer.

Of course that’s not all climate deniers do. Even if this January 18th’s extent of Arctic sea ice did dip as low as in 2006, so what? Nobody ever claimed that sea ice would decline smoothly every year so that every daily value had to be lower than all previous years’ daily values. We’ve said all along that in addition to the trend of sea ice loss, there are also fluctuations. The fluctuations are about the weather — the trend is about climate change.

And what does the trend tell us? That’s easiest to see if we translate sea ice extent to extent anomaly, the difference between a given day’s value and the long-term average for that same day. Then we can separate the climate changes from the ups and downs that come with the seasons (winter being still colder than summer). What, you wonder, do those anomalies look like? This:


The trend is downward. Fast (at about 65000 km^2 per year). The fluctuations are sizeable, but they don’t alter the trend. Yet from climate deniers we don’t hear about the trend, instead they crow about how the value for a single day might be the same as it was in 2006. And they can’t even get that right.

That’s what climate deniers do: focus on the short term, focus on “weather,” to draw attention away from the climate trend.

Of course that’s not all deniers do. They have an arsenal of weapons to spread doubt — that’s their product. They will question every study, dissect every method, and dispute every conclusion. It doesn’t matter how clear and beyond question it might be, they’ll throw doubt at it and hope something sticks. They don’t have to advance science, they just have to cloud public understanding.

They’ll even do it about something as undeniable as the loss of Arctic sea ice. If you wonder who is trying to pull the wool over your eyes, use this as a bellwether: Anybody who casts doubt on the loss of Arctic sea ice isn’t a skeptic, but a denier.

Because when it comes to Arctic sea ice, there’s no ambiguity about the trend. It’s not unclear. It’s going down faster than an Aerosmith groupie on an elevator.

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28 responses to “Climate Denial about Sea Ice

  1. “The current value for a few days this year tied for record-low and even got up to second-lowest, with the previous record set a whole 11 years ago” is the best they have anymore.

    Well they have that, and the president of the US.

  2. Good post, with one little glitch:

    Isn’t January 18th 2017 more than a few weeks older than January 18th 2006?

    Aren’t those dates reversed?

    [Response: I should have said, a few weeks *later*. I’ll fix it.]

  3. Also looks like the variance of the anomaly is increasing. A sign of critical slowing down as we approach a tipping point?

    • David, see kinimod’s comment below. The annual cycle has itself changed, so there’s a residual annual cycle after removing the average annual cycle. That’s (mostly) what you’re seeing.

  4. I believe both ocean and air temps in the Arctic are much higher than normal. That raises two concerns/tipping points: change in the albedo of the Arctic which would increase heat accumulation and thawing of methane clathrates. A good portion of the serial and serious deniers are professional liars. As you note, their job is to produce doubt. It is unfortunate that folks who let their economic interests sweep aside any semblance personal ethics can be so successful, but I think it’s best to ignore them, to talk past them to folks who are not paid to sow doubt. It’s hard to reach these folks and the professional liars make it harder, but every year the impact of AGW is greater and more folks may be willing to reconsider as the impact increases. Stick to the truth. Hit the important facts. Over and over. Kiss it (keep it simple stupid) when talking to citizens who don’t believe it’s happening. Move fast, don’t get bogged down. Time is on our side with overcoming the belief systems, but not with the impact and advance of AGW. We have to be relentless, smart and move fast to move the needle in the right direction.

    Daily CO2

    January 29, 2017: 405.76 ppm
    January 29, 2016: 402.24 ppm

    3.52 ppm increase over last year. Very bad (noisy) number. Dr. Mann said in 2014 that we should stay under 405 ppm. Uh-oh.

    Warm regards,


  5. Interestingly, in the anomaly plot, we see beginning with 2008 an annual fluctuation, which should not be there, except the annual cycle changes in itself. Would be interesting to analyze that. Hypothesis: melting starts earlier and is deeper than before.
    A similar pattern of an annual structure in an anomaly plot can be seen in the PIOMAS curve.
    This pattern change is IMO an additional signal that something is going the wrong way.

  6. I interviewed NASA’s Walt Meier on this self same topic this time last year:

    DMI, MASIE and the Sea Ice Index – An Interview With Walt Meier

    In brief:

    If you’re on the bridge of a vessel sailing in Arctic waters then MASIE is the right tool for the job. If on the other hand you’re sat in front of a computer trying to get the best estimate of trends in Arctic sea ice extent then the Sea Ice Index is what you’ll grab from your toolkit.

    • and if you are clutching at straws – anything will do!!

      you do have to wonder when they will give up (rhetorical question sadly) as they won’t, the hard-core deniers never will

    • I would assume that even though it’s the wrong tool for the job, the changes in the Arctic are so great that an anomaly curve fit (like Tamino does above) to the MASIE data couldn’t help but show basically the same result – possibly noisier and possibly with some systematic biases, but there’s no way to erase a decline of 1.5 million square km. I guess no one will bother, given that it is the wrong tool.

      • Well, I have the MASIE data but I can’t see the point, unless it’s solely for the purpose of debunking deniers, of which I have done a bit! Here’s the one graph I have bothered to produce:

        A ten year trend anyone? More from Meier:

        The whole of the Arctic isn’t covered every day for example. In addition, and unlike the SII, data from different satellite sensors is incorporated which means there are inevitably inconsistencies from day to day and from year to year. There is also an element of “human subjectivity” because different analysts are working with different sources of data from one day to the next. Since the quantity and quality of data varies the time series will not be consistent over time.

      • Cool Jim! That graph is exactly the sort of thing I was thinking of (and yeah, for the motivation you suggest).

      • What else did you have in mind then Greg? As I said, the data is on my hard drive, and I’m in a debunking mood at the moment.

        However if “Don’t use this data. The folks who make it said so.” doesn’t do the trick what will?

  7. Susan Crockford? A self-employed biologist and ‘polar bear expert’ who didn’t do her PhD on polar bears, carries out no field, genetic, behavioural, geographic or ecological research on polar bears, publicly disparages the competence and ethics of actual polar bear experts, and runs a denier blog and collects a retainer from a denier think tank/lobby group.

    I can see why her opinion on remote sensing analysis of sea ice would carry great weight.

  8. I think you probably meant “red line” rather than “read line.”

  9. Excellent article. Good sources. However it sent me looking for the studies on elevator-constrained Aerowsmith groupies.

  10. Great responce and addressing of the contrarians tactics. Of value I think it is important to stress climate is a statistical representation of weather and as you have our concerns lay with the trends. When a weather event occurs it is rarely directly attributable to the climate trends but is immediately included in the climate records and will influence the trend. Trends allow us to predict the climate ( a statistical record of weather) not the weather itself. Those who cherry pick weather events to try and throw doubt on climate trends are simply ignorant at best or Machiavellian at worst.

  11. Watched a doco about the second world war, about 1943 in almost the middle of winter,Russian freighters were sailing in ice free waters, with German war ships chasing them, way up north. Those areas and seas are now blocked with ice for most of the year. To me it seems that it is not an uncommon occurrence for a lot or most of the Arctic to be ice free.

    • Which documentary? Without that you haven’t said anything worth discussing.

    • Wayne,
      Define “way up north”. And pray, why would you believe a random documentary over hard data?

    • I watched a doc, therefore climate science must be wrong. News at 11.

    • A bit vague, Wayne. During WW2, the two most used ports were Murmansk and Arkhangelsk. Murmansk is essentially ice-free all-year round. Arkhangelsk can be a bit trickier, as you have to go through the White Sea, which is the one (small) part of the journey where you can expect problematic ice. The Barents sea right above Norway, Finland and Russia is largely ice-free all-year round until you get to the White Sea.

      But normal ships can go there right here, now, today, all year round.
      See for example and check some of the ships that are expected or just arrived. We’re not talking huge ships with specially reinforced hulls, but plenty of general cargo ships. Yes, they do get help from ice-breakers.

      So, to correct you: “those areas and seas are now NOT blocked with ice for most of the year”.

    • Wayne Job.
      You may be right about 1943 but I’d be very surprised if your “doco” was describing events “almost the middle of winter” and if it was “way up north,” likely it wasn’t “Russian freighters” being chased. There were Russian freighters passing through the Bering Straights from the US during the war. There was even the German merchant raider Komet that Stalin allowed to sail from Europe through to the Pacific. But Russian freighters did not fight Gemans in the far North.) What is known of the ice during the 1940s allows folk to state eg here with some confidence that the seas are far less icy today than they were back then.

    • Commenting on the sate of Arctic sea ice on the basis of a Discovery channel documentary is like carrying a snowball into Congress. The WW2 arctic convoys were generally sailing to Murmansk – and Murmansk is affected by the Gulf stream bringing slightly warmer waters to the Barents sea. Part of the reason these convoys were so risky was that there was only a narrow passage between the coast and the ice, so that convoy routes were predictable. If you want data, not anecdote, it’s there to be found, in Tamino’s Climate Data links from this very page.