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Climate Hustle

Has Arctic sea ice returned to normal?

What the science says...

Select a level... Basic Intermediate

Thick arctic sea ice is in rapid retreat.

Climate Myth...

Arctic sea ice has recovered
"Those who have been following NSIDC and JAXA sea ice plots have noted that this has been an extraordinary year so far, with Arctic sea ice hitting the “normal” line on some datasets. ...

As of today,JAXA shows that we have more ice than any time on this date for the past 8 years of Aqua satellite measurement for this AMSRE dataset." (Anthony Watts, 22 April 2010)

Discussions about the amount of sea ice in the Arctic often confuse two very different measures of how much ice there is. One measure is sea-ice extent which, as the name implies, is a measure of coverage of the ocean where ice covers 15% or more of the surface. It is a two-dimensional measurement; extent does not tell us how thick the ice is. The other measure of Arctic ice, using all three dimensions, is volume, the measure of how much ice there really is.

Sea-ice consists of first-year ice, which is thin, and older ice which has accumulated volume, called multi-year ice. Multi-year ice is very important because it makes up most of the volume of ice at the North Pole. Volume is also the important measure when it comes to climate change, because it is the volume of the ice – the sheer amount of the stuff – that science is concerned about, rather than how much of the sea is covered in a thin layer of ice*.

Over time, sea ice reflects the fast-changing circumstances of weather. It is driven principally by changes in surface temperature, forming and melting according to the seasons, the winds, cloud cover and ocean currents. In 2010, for example, sea ice extent recovered dramatically in March, only to melt again by May.

Sea-ice is subject to powerful short-term effects so while we can't conclude anything about the health of the ice from just a few years' data, an obvious trend emerges over the space of a decade or more, showing a decrease of about 5% of average sea-ice cover per decade.

Click to enlarge
Source: Rayner et.al, 2004, updated

Where has the thick ice gone?

When we consider the multi-year ice and look at the various measurements of it, we see a steep decline in this thick ice. As you might imagine, thick ice takes a lot more heat to melt, so the fact that it is disappearing so fast is of great concern.

Click for larger version
Source: Polar Science Centre, University of Washington

It is clear from the various data sets, terrestrial and satellite, that both the sea ice extent and multi-year ice volume are reducing. Sea ice extent recovered slightly during the Arctic winters of 2008-09, but the full extent of annual ice reduction or gain is seen in September of each year, at the end of the Arctic summer. The volume of multi-year ice has not recovered at all, and is showing a steeply negative trend.

* Footnote: Although a thin layer of ice doesn’t tell us much about the overall state of ice loss at the Arctic, it does tell us a great deal about Albedo, the property of ice to reflect heat back into space. When the sea ice diminishes, more heat passes into the oceans. That heat melts the thick ice and speeds up the melting of thinner sea ice, which in turns allows more heat to accumulate in the oceans. This is an example of a positive feedback.

Basic rebuttal written by GPWayne


Update July 2015:

Here is a related lecture-video from Denial101x - Making Sense of Climate Science Denial

 

Last updated on 14 July 2015 by MichaelK. View Archives

Printable Version  |  Offline PDF Version  |  Link to this page

Comments

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Comments 51 to 100 out of 100:

  1. Just saw some great news about significantly increasing multi-year arctic ice! (2014 compared to 2013 and previous). Hopefully we will see a continued gain in "older" (2-4+ year old ice) ice extent.      nsidc.org/arcticseaicenews/files/2014/04/Figure5-350x618.png  

    Multi-year ice gain 2014

  2. Juan_H...  It's nice to be optimistic but this is unlikely to be anything more than a temporary change. We're still likely looking at seasonally ice-free conditions starting around 2030. 

    It's just that, on the way to the bottom the numbers are going to bounce around like this. 

  3. Note that the NSIDC states along with the graphic Juan presented...

    "The percentage of the Arctic Ocean consisting of ice at least five years or older remains at only 7%, half of what it was in February 2007. Moreover, a large area of the multiyear ice has drifted to the southern Beaufort Sea and East Siberian Sea (north of Alaska and the Lena River delta), where warm conditions are likely to exist later in the year."

  4. There's an interesting post or two by Tamino noting that ice variability greatly increased around 2007 - smaller amounts of ice are simply going to be more affected by yearly weather. 

  5. The 'significant increase' seems to have gotten us back to ~ March 2008 multi-year ice levels... yet PIOMAS shows that after the 'high' ice volume at the end of last summer's melt, the final March 2014 volume was lower than every previous year except 2011.

    That seems contradictory... until we consider that the multi-year ice chart shows percentages. The percentage of the ice which is now multi-year is similar to what it was in March 2008. However, the total amount of ice has decreased and thus the 'same percentage' actually means less multi-year ice. This can also be seen on the PIOMAS average ice thickness graph. There, 2014 is higher than all years since 2008, but significantly below 2007. The average thickness has increased because the percentage of thick ice is higher while the total ice volume has declined.

    Volume will always be the determining factor because it quite simply is the amount of ice. The fact that the volume at the end of March 2014 was slightly lower than that of March 2012, which went on to have the lowest summer volume (and extent) ever, tells me that there has not been any 'recovery' in sea ice. We are at essentially the same place we were in 2012. Thus, if we again see weather conditions like that year we could again see new record lows this year. If we get better weather conditions maybe we'll start to see an actual recovery in a few years, but it clearly hasn't happened yet and doesn't seem likely to as the planet continues to warm.

  6. Interesting aside: When nearly all of the sea ice has melted out, the last remaining bits will be large 'ice islands' of very thick ice broken off from land. At that point, the 'multi-year ice' in summer will be near 100% while the ice extent and volume will be near zero.

    I suspect that in the upcoming years we'll see a trend of growing percentages of summer multi-year ice (and average ice thickness). Not because the ice is 'recovering', but simply because the thicker multi-year ice will be the last to go.

  7. CBD,

    Broken off glacier ends called ice islands and ice bergs are not sea ice, they are land ice.  If they are the only ice left than sea ice extent is zero.  The extent of these ice islands is very samll, even near Greenland.

  8. jetfuel, so what if anything is up from year to year?  In the 35 years of the satellite record for ASI area, area at minimum exceeded the previous year's minimum fifteen times, yet the overall trend is strongly negative.  If this year's minimum drops below last year's, what will it tell us?  Very little.  Just as 2013's increase at minimum over 2012 told us very little.  As for multiyear ice, there's so little left--like volume--that variance can be played up into quite a rhetorical pudding: "multi-year ice has doubled over last year!"

    Response:

    Please do not respond to any future comments by jetfuel until a Moderator has had a chance to ascertain whether or not it is in full compliance with the SkS Comments Policy. From here on out, jetfuel is on a very short leash. His/her shennanigans will be stopped one way or another.  

  9. per nsidc: "The multi-year ice in the Arctic Basin increased from 2.25 to 3.17 million square kilometers during the year.

    Multi-year sea ice made up a total of 30% of the Arctic icepack the previous compared to 43% this winter." (2014)

    Also from another nsidc article: "It was the sixth-lowest extent recorded since satellites began measuring sea ice in 1979. The number is above the 2012 record extent but is still below the long-term average. "

    3.17M out of the 5.02M min for 2014 is 63% of remaining ice being multiyear ice. 3.17M of the 2014 max of 14.9m is 21.3% multiyear ice. The 7% number is stale news as of today. Out of the last ten years, only one year, 2006, had more min sea ice worth mentioning than 2014. Any trend line drawn for the last 2-8 years shows upward trend in Arctic minimums, if it accounts for 2012 as being an anomolous year due to rare wind storms that caused unusually high melting by pusing huge sections of sea ice south. Throw out that datapoint or bump it up to 4.4M and the trendline is unquestionably upward since summer of 2007. It appears as though we are headed more towards another 5.0M+ min next year, making it a 9 year upward trend in Arctic SI mins. At what point can we call this a turnaround? At what point do we stop being so confident that the Arctic will be seasonally ice free by 2030? Not when 8, going on 9 years are pointing the other way? My guess is that 9 years won't be enough to quiet the 2030ers.

    Response:

    [JH] Future posts of this nature will be summarily deleted. 

    [PS] Jetfuel, you have had cherry-picking explained to you. You were invited to respond if you didnt understand. Your continued use of cherrypicking as an argument would imply either wilful ignorance or trolling. Moderator tolerance is at the end.

  10. jetfuel...  Them's bettin' words! I'd put $100 on seeing a new Arctic sea ice minimum within the next 3-5 years.

    Do you really not understand the difference between the two sides here, jetfuel? You're taking a small group of data points – isolated from any science – and are trying to extrapolate what you would prefer to see happen.

    The other side is looking at science. We're looking at what's been happening over the past 150 years. We're looking at the changing radiative forcing of the planet. We're looking at interconnected climate systems with ocean/atmosphere/land/ice, and hundreds of other factors. 

    When you look at all these things combined you get exactly one answer relative to Arctic sea ice: It's going away and, at this point, there is nothing we can do about it. Even the oil companies know this and, in a  very sad irony, are spending lots of money planning how to drill the Arctic ocean.

    You can play around with Excell and make plots for what you want to believe, but it's wrong. There is functionally zero chance that Arctic sea ice is going to see a recovery to anything like we saw 20-30 years ago.

    I would almost be willing to bet that we'll see initial ice free conditions (defined as <1M/km2) within the next ~5 years.

  11. jetfuel - Let's see, insufficient data to establish trend significance (2-8 years, check)? Cherry-picking established. 

    Tamino had an interesting post in 2012, Sea Ice Forecasts, noting that Arctic ice extent statistics demonstrated a change in 2007 - with an amplified annual cycle, more year-to-year variation than before. This change persists today with yearly swings in extent averaging larger than previously observed. A reasonable understanding of this change is that the much reduced ice volume and thickness has made Arctic ice extents more susceptible to wind/weather effects than earlier, thicker ice. 

    Meanwhile, ice volume continues to decrease.

    PIOMAS volume extreme trends

    [Source]

  12. jetfuel, you're cracking me up.  You toss out 2012 but don't toss out 2007 for similar reasons.  Why?  Because if you did, you'd have no "recovery" claim.  Instead, the long-term decline would be even more obvious, and 2013 would look like a normal year in that long-term trend.  Your logic is identical to the "no warming since 1998" logic, and it's just as goofy.

    I wonder: did you run the same analysis after 2007 and conclude that science had massively underestimated future sea ice loss and that the Arctic would be ice free at summer minimum within three years? 

  13. [Moderator's Comment] All: Three repsonses to jetfuel's nonsensical comment #59 is quite enough. Dog-piling is a prohibited by the SkS Comments Policy.

  14. Interested party,

    You would be better off studying climate science that chaos theory when you want to comment on a climate board.  The natural trend now is cooling.  Without human influence the temperature would be cooler.  Your general comment seems to suggest it is impossible to know anything.  Scientists feel we can learn and project what needs to be done.

    Perhaps you can sugggest a specific topic you want to discuss and we can help you figure out what you want to learn.

  15. interestedparty... "...to comment on the obvious."

    Therein lay the problem. You don't have to be an expert but you would need to have a little bit of humility regarding a complex field outside of your own when it comes to understanding what is, and what is not, "obvious."

    What, pray tell, would you think is so obvious that specialists in the field have failed to already consider and include in their overwhelmingly agreed upon positions regarding man-made causation of global warming?

  16. Interestedparty... I would highly suggest you read the SkS commenting policy before posting any further.

    Response:

    [PS] It would seem that Interestedparty does not have the slightest interest in abiding the comments policy.

  17. There's a BBC story today about a paper by Rachel Tilling to be presented at the AGU.  She mentions "a decline that looks a bit like a sawtooth, where we can lose volume but then recover some of it if there happens to be a shorter melt season one year".  Unfortunately the news story doesn't make it clear what the period of this sawtooth would be.  The minimum this year seems to have recovered nearly to 2009 levels, but the longer-term trend is still towards an ice-free Arctic summer by the 2020s, as shown in ArctischePinguin's graphs here.

  18. alan2112drums:

    Further to your comment on the Antarctic thread, please see the original post and review the findings on sea ice.

    You may also wish to review the behaviour of the sea ice relative to the IPCC AR4 projections (here) - note that this information is only from 2009, so it doesn't show the record low set in 2012 - or the behaviour of the sea ice over the last (not quite) 1,500 years (here).

    Basically, Arctic sea ice has fallen off the proverbial cliff. Al Gore got that right, at any rate.

    Arctic sea ice minimum in 2014 (September) was 5.02 million km², which NSIDC reports is the 6th lowest on record. Arctic sea ice maximum in 2014 (March) was 14.8 million km², which NSIDC reports is the 5th lowest on record.

    Arctic sea ice behaviour year-over-year is not monotonic, and as far as I can see the Daily Mail is taking advantage of this fact to form a narrative that casts doubt on the science, when in fact what is seen is merely the result of stochastic fluctuation.

    Just to be clear, what I perceive the Mail as doing is:

    • Provide quote from Al Gore (despite Gore emphatically not being a climate scientist, "spokesperson" for climate science, or otherwise generally a source of information used by scientists), possibly omitting contextual remarks (and definitely ignoring Gore's own inclusion of uncertainty - note the words "could" and "in as little as seven years", which allow that an ice-free summer could be more than 7 years away, too) to maximise dramatic effect.
    • Contradict Gore with very careful framing (notice how much the Mail emphasises the degree to which Arctic sea ice has increased relative to 2012, despite the general irrelevancy of that information).
    • This allows a reader who wishes to dismiss the actual science to do so - "Well, if Gore got it so wrong in 2007, why should we take climate scientists so seriously now?" - without the Mail taking responsibility for making false claims.
  19. In reality, Gore echoed Wieslaw Maslowski's prediction.

    Maslowski's prediction, originally made in 2006, was that Arctic sea ice would decline to <1,000,000 square kilometers extent (with no ice at the North Pole) by the end of the September melt by 2016, +/- 3 years. So 2013-2019. [Source, slide 6]

    But that truth is always inconvenient to deniers, who revert to their preferred idiom of mendacity, prevarication and lies indiscriminately, without pretext needed.

  20. Responding to off-topic comment here (as is #68 & #69 above).

    The David Rose item in the Rail on Sunday of 30/8/14 basically does the usual Rose trick of "hiding his bogus decline" in AGW predictions by making such predictions as extreme as possible and then proving them to be in error. Sadly, and Rose is a real saddo, he is unable to do this without misrepresenting those extreme positions and his proofs.

    To debunk his 30/8/14 piece would take a while to write out. But it would likely start something like this.

    ☻ Rose misrepresents what Gore said in 2007. Firstly Gore was reporting what others had said and secondly he mentioned two predictions for an ice-free summer - 7 years and 22 years. Rose usually plays an extremly strong game misrepresenting AGW comment.
    ☻ The 25th August date is a bit of a cherry-pick. A couple of days earlier and it would have been "since 2009" not since "since 2006" because 2009, 2013 and 2015 SIE were very similar through the height of the melt season.
    ☻Rose mischaracterises the period 2012-14. Most of the SIE increase (90%) occurred 2012-13. His comment about 'consentrations' is likewise a mischaracterisation. Most of the SIA increase (95%) occurred 2012-13. So his news story is a year out-of-date. SIV is however more even between the two years.
    ☻ Judy Curry is more a denialist blog-mom these days and no longer a pukka climatologist. Her assertion that the "death spiral" is (or will be) entering a reversal which will last decades is air-headed lunacy of her own creation.
    And on and on and on.

  21. Just caught this on Yahoo earlier:

    Link to Mashable article

    Response:

    [DB] Link truncated.

  22. Quantummist,

    Your quote from NSIDC is interesting.  I wonder why you picked a quote from Feburary 2014 istead of a more recent quote.  

    This years NSIDC report did not mention the CRYOSAT data.  Nevin has a good article on the January 2015 PIOMAS data here.  PIOMAS and CRYOSAT usually agree.  The data does not really have anything unusual to report.  Perhaps next week when the new PIOMAS data comes out it will be more interesting since, as the moderator pointed out, Arctic sea ice is currently at it's all time low for the date.

  23. michael sweet @72, perhaps more interesting is the Cryosat data, which for the most recent update (Dec 15) showed reduced ice volume relative to 2013:

    "Measurements made during October and November show that the volume of Arctic sea ice now stands at about 10 200 cubic km – a small drop compared to last year’s 10 900 cubic km."

    At that time, Piomass was showing the ice volume to have been the largest since 2008, whereas Cryosat ranked it fourth in its five years of observation.  The drop in volume relative to last year is more consistent with the sea ice extent figures, as linked by moderator PS:

  24. As of today, NSIDC's Charctic graph is showing 2015 as the lowest SIE on record having just dipped below 2006. JAXA, who show a less icy 2006, put 2015 well below 2006 & 2011.

    Mind, the timing of the maximum freeze is a little delayed nowadays compared with the climatology in the graph @73 so there is still a couple of weeks for things to change around.

  25. Re @73 & @74 - A whole range of Arctic sea ice metrics, now including Cryosphere Today area and DMI extent, are currently at their lowest ever levels for the date in their respective historical records:

    Arctic Sea Ice Area Lowest Ever (For the Date!)

  26. MA Rodger @ 74, How strong is the trend toward a later maximum freeze? 

  27. bozzza @76.

    I think the 'trend' is probably very small, far less than those weilding mention of it appear to imply, as I was myself doing @74. It is probably used more a cautionary note that there can be a very late daily maximum.

    The daily data from JAXA fails to give a statistically significat trend (and I use 9-day averages to reduce the noise), yielding a rather large +7days per decade +/-15 days. The average for the JAXA data (2003-14) is day 72.4. The climatology from NSIDC (1981-2010) gives the maximum 9-day period as day 70. These two suggest a trend of 1.8 days per decade.

    That said, I have elsewhere now bravely called this years maximum as having happened in February (coz I hate faffing about) which would put the 2015 maximum as a very early day 55.

  28. Further to #77, it occurred to me that the Feb & Mar SIE data would allow this "late maximum trend" to be examined all the way back to 1979. Plotting SIE(Feb)-SIE(Mar) shows a trend for a freezier March beginning about 20 years ago (1995-2014). That period does yield a statistically significant trend, but not as a date of maximum SIE. Over that period March is getting icier compared with February by 24,000 sq km per year +/-10,000(2sd).

  29. Continuing an (off topic!) conversation from elsewhere, Cryosphere Today is finally back to normal after its long "hiatus". The "homebrew" calculation from the Arctic Sea Ice Forum was in error by 0.3k.

    The official CT Arctic sea ice area is currently 11,796,725 km2 for day 124 of 2015.

  30. jetfuel:

    You forgot to mention that the NSID also qualified their multi-year ice reporting comment with the following very relevant facts:

    • During the summer of 2013, a larger fraction of first-year ice survived compared to recent years. This ice has now become second-year ice. (i.e. your multi-year ice thus keeping the 7% you tried to dismiss, very relevant.)

    • The percentage of the Arctic Ocean consisting of ice at least five years or older remains at only 7%, half of what it was in February 2007. Moreover, a large area of the multiyear ice has drifted to the southern Beaufort Sea and East Siberian Sea (north of Alaska and the Lena River delta), where warm conditions are likely to exist later in the year.

    The Arctic sea ice extent as of December 2014 does not show any significant recovery. It appears to be 2% above the long term downward trend line.

    Extent coverage in January 2015 is showing a downward trend.

    Maximum extant coverage in February 2015 not only occurred early; it is also the lowest maximum in the satellite record.

    Maximum extant coverage in march 2015 is the lowest March ice extant in the satellite record.

    Extent coverage in April 2015 is the second lowest April ice extant in the satellite record: http://nsidc.org/arcticseaicenews/

    I remember when a science denier used to use 2007 as the year he demanded that people compare every year after 2007 to for the lowest Arctic sea ice extant coverage trying to claim that because 2007 was the new low point that the Arctic was recovering. That alleged recovery also ended up, in 2012 I think, according to NASA’s measurements, on the trash heap of history.

  31. With NOAA releasing a 2014 Artic report card that some people have used to claim that AGW is real: I can see NOAA being called to the carpet by Republicans in Congress like NASA was over its climate research.

    The only upside will be the entertainment value of look on the NOAA’s officials faces when they are instructed by Republicans to stop wasting their budget on AGW and use the money to find their Ark, which they, because they are laze unionized government employees, misplaced on mount Ararat in order to prove to the world that sea levels will not rise.

  32. Arctic sea-ice for July 19, 2015 seems to be taking a big dive again. Having recovered to near normal conditions I would be very interested to see if it once again goes below the 2 standard deviation level it was just over a month ago.

    I am thinking of the multi-year ice/thickness of it's current state... has anyone got any ideas about the latest multi-year ice/thickness data of the arctic with links?

    Response:

    [JH] Check out:

    Arctic Sea Ice Volume Rebounds, But Not Recovering by Andrea Thompson, Climate Central, July 20, 2015

  33. Si Senor, am doing that now!

    Keenly watching the Arctic sea extent graphs dipping down toward 2 standard deviations again, however... I don't like the angle on that graphology...

     

    Tieing the two sources together(...without having finished reading the article yet because I'm a betting man..) I am glad to be empowered by the knowledge that whilst 3 metre plus ice recovered in a big way in 2013 it fell back again in 2014.

     

    This is exactly what I needed, thanx!!! Are we witnessing disintegration? I won't be sleeping for approximately 7 days I'm telling you now!! 

  34. Interesting. Looking at this figure:

    arctic.atmos.uiuc.edu/cryosphere/IMAGES/seaice.area.arctic.png

    Northern sea ice is down about 2 million square kilometers since 1979....

    Okay, this post just went completely off of the rails. I read in Forbes that total polar ice extent has decreased by less than 10% since 1979. Of course, we are talking about Arctic ice here, and the Antarctic is completely different. 

    I guess it is correct to say that sea ice area and extent are far less sensitive to changes in temperature than is sea ice volume. That sets up an insidious tipping point, doesn't it?  We've lost maybe half of the Arctic's ice volume, but that change in albedo has hardly begun to take effect. 

    Then again, Antarctica is gaining ice which will make it more reflective. How does that affect the overall balance?

    If we have a much less reflective Arctic, but a more reflective antarctic, what are the implications of the uneven heating of the planet?

  35. Hi folks. I'm trying to get my head around the climate change science. I tend towards being sceptical, I am open to updating and correcting mu opinions. There's been a lot of sensationalism about this topic, and the reporting has flip-flopped all over the place for years. So I ran across this video on youtube that seems worthy of consideration. If any of you have some time to have a look and share your thooughts, I'd be grateful. Thanks.

    mobile.wnd.com/2015/08/mankind-threatened-by-global-cooling-not-warming/#ooid=MzYmo2dzpIBBM5k69b8gzRMIrdpIrtFQ

  36. ringingrocks... This is probably not the appropriate thread to be asking general questions about climate change. This thread is specific to Arctic sea ice. I will post a response on the "Empirical evidence" thread.

  37. Rovinpiper - Look at this figure from http://nsidc.org/arcticseaicenews/charctic-interactive-sea-ice-graph/




    Arctic sea ice extent is currently over two standard deviations below "normal".  Now click the "Antarctic" tab and take a look at this one:

     

    Antarctic sea ice extent is currently below "normal". Now consider the respective locations of all that sea ice when the sun is shining on it. The ice at the South Pole is more than a meter thick on midsummer's day!

  38. Can anyone comment on this:

    http://www.climatedepot.com/?mc_cid=b0364d923e&mc_eid=1bbdb183a9

    Based on MASIE data, they claim not much decline recently.

    Multisensor Analyzed Sea Ice

  39. See here for discussion of this. In particular, check the MASIE documentation page and what it has to say about the applicability of the data sets for analyzing trends. Then look at some datasets that are fit for purpose and draw the obvious conclusions about reliability of climatedepot.

  40.       So, many people think that the ice has recovered because of the extent of the ice without considering about the volume. The point is that we need to look at the volume to measure how much there really is. According to the thick ice graph, it is great concern that thick ice takes a lot more heat to melt and it is disappearing so fast.
          “Although a thin layer of ice doesn’t tell us much about the overall state of ice loss at the Arctic, it does tell us a great deal about Albedo, the property of ice to reflect heat back into space. When the sea ice diminishes, more heat passes into the oceans. That heat melts the thick ice and speeds up the melting of thinner sea ice, which in turns allows more heat to accumulate in the oceans.” My question is that, does the thickness of the ice really matter to how well it can reflect the heat? If it is thicker will it be better to reflect the heat or not so much difference?

  41. Bearling, the sea ice extent has not recovered at all. Although your remark about volume does have some validity, anyone attempting to argue that see ice extent has "recovered" is taking you for a ride. See NSIDC for the latest news.

  42. bearling, that's right. No, the thickness of sea ice doesn't affect its ability to reflect heat very much, it affects its ability to melt.

  43. I've seen a few mentions elsewhere that arctic ice volume is at near record highs for last 15 years.  

    Does anyone know what has triggered the change from being well below 2004-2013 average in May to now being well above average?

    I'm a complete amateur so I was making guesses of cloud cover (I beleive there was an unusual weather system in may) or volcanic activity (Kilauea, vanuatu or fuego eruptions) but it would be nice to have a clearer idea of what is happening.

  44. BeesKnees - I dont where you are getting your "elsewhere" information on arctic ice volume, but I would suggest that it is either extremely unreliable or you have misinterpreted.

    Here is the arctic ice volume from PIOMAS.

    Source: Polar Science Center

    It is higher than 2016, 2017, 2012, but weather causes year to year variability. The trend in ice volume is pretty clear in picture:

    Well below 2003 level.

  45. Note that BeesKnees said "arctic ice volume", not sea ice volume. Scaddenp has illustrated how BeesKnees statement about the past 15 years is not true with respect to sea ice.

    Someone may be tempted to say "what about Greenland?" You can use the search tool (top left) to find SkS articles on "Greenland Ice". BeesKnees statement is also not true for Greenland ice.

    The next stop on the denial train would be to shift the goalposts to snow cover. You can search for northern hemisphere snow, too. Turns out that it also is decreasing.

  46. For more up to date figure on Greenland Ice volume, try this

    Source NSIDC.

    We could have greater clarity if BeesKnees would give more detail on his/her source.

  47. Sorry I wasnt clear, I meant sea Ice.  

    this is the source I have been using

    http://polarportal.dk/en/sea-ice-and-icebergs/sea-ice-thickness-and-volume/

    My concern is that this information is being misused to deny climate change and wondered if the reason for the difference this year was easily explained.

    Response:

    [DB] In addition to Scaddenp's comment earlierArctic sea ice volume continues its long-term decline in both minima and maxima:

    Arctic sea ice volume minima and maxima

     

    While year-to-year variations exist, the long-term trend in volume and extent nevertheless continues to decline, despite the focus by some on those short-term periods:

    Arctic sea ice escalator

  48. BeesKnees,

    I looked at your reference.  They provide this graph:

    ice volume graph

    The Danish Polar Portal is a legitimate science data source.  It seems to me that  there are several issues with using their graph.

    Ice volume is very difficult to measure. The PIOMAS model is generally considered the best. It agrees fairly well with satalite measurements of sea ice volume. While the Danish site is OK, it seems to me that the people you are talking with selected it thinking that it supported their point.  That is cherry picking.

    Reading the tags I see that the baseline volume is the average from 2004 to 2013.  I see from the PIOMAS graph that the sea ice volume started decreasing before 1980.  If you go to the Arctic Sea Ice Graphs page, they have this graph:

    sea ice extent

    Close examination of this graph shows that sea ice extent  started to decrease in about 1950 when it was 8 million km2 and in 2000 was about 6 million km2.  The thickness and volume would also have decreased over that time period but I could not find any data.  Current forecasts suggest a minimum of about 4.6 million km2 this year.

    The baseline your graph uses of 2004-2013 includes the record setting low years.  It is really not much of a claim that the sea ice has returned to the level it was at 8 years ago when it has been in a long term decline for 70 years.

    Even accepting that the current volume is similar to the average from 2004-2013, the PIOMAS data shows that from 1980 to 2017 volume at the minimum decreased from 17 million km3 to 4.5 million km3.  This year is similar to last year so it is about 1/3 of the volume from 1980 which was lower than 1950.

    I would like to say that I am in the best physical shape of my life because my average weight for the past 10 years is 8 pounds more than I weigh today.  Unfortunately, 35 years ago, when I was in good shape,  I weighed 40 pounds less than I do now.

    In summary, your source data is OK but PIOMAS is usually used.  The baseline is not the "long term average", it is a recent average.  Sea ice volume has been decreasing for 70 years, a little noise does not mean a recovery.

  49. Bees Knees:

    Neven at the Arctic Sea Ice  Blog discusses PIOMAS sea ice volume every month when the data comes out (link is to a discussion of the May data).  Neven is not a scientist but is very well informed.  His posts are easy to read and generally even handed.  See if his post answers your questions about why the ice melt has been below average this year.

    At the Sea Ice Forum there is a free wheeling discussion of sea ice data.

  50. Bees Knees @97,

    The lack of rogour encompassed by the DMI modelling is perhaps best seen in that they wind-the-handle once a day to update their results while PIOMAS (who are ever conscious that their modelling could be deficient and thus checking for corroberating data from the likes of CryoSAT) run a monthly update. And in that regard, this means we cannot yet compare the DMI 2018 results that hae "crossed the line" with their PIOMAS equivalent as this "crossing the line" has only occurred through June.

    However we can compare the June to August 2014 DMI graphed results with the equivalent PIOMAS results, this  relative to a 2004-13 mean. The DMI graph shows June 2014 somewhat icier than the 2004-13 average and July & August both some 2,000 cu km icier. PIOMAS shows a meltier 2014 relative to the 2004-13 average with only August 2014 marginally icier than that 2004-13 average. Jun -1,500 cu km, Jul -600 cu km, Aug +100 cu km.

    So the upshot is we have a situation handed the denialists by DMI's light-weight modelling (who won't be the least bothered) providing a less-embarassing-than-normal excuse for them to troll their nonsense through the media. Yet denialists are not shaken by the embarassment of being continually wrong so it isn't something to be too exercised about.

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