Antarctic sea ice

i-641e3c9a49d4b9ad0b3b2b2c8de87551-arctic-ice-2007-sept-12.jpg A reader writes… why don’t I write about the Arctic sea ice? The answer is, what is there to say that others haven’t already? Cryosphere today seems to be a good source, from which my graph is taken. Actually there is something to say which others don’t seem to, which is “don’t get too carried away with one years anomaly”. 2007 is exceptional; so was 1995 which wasn’t exceeded until 2005.

[Update: oh dear, Ctoday have now corrected themselves: the Ant ice *wasn’t* quite a maximum after all: Correction: we had previously reported that there had been a new SH historic maximum ice area. Unfortunately, we found a small glitch in our software. The timeseries have now been corrected and are showing that we are very close to, but not yet, a new historic maximum sea ice area for the Southern Hemisphere. -W]

The other thing to say, now that RP Sr is orf, is that the Antarctic ice has hit a record (since 1979) max: The Southern Hemisphere sea ice area has broken the previous maximum of 16.03 million sq. km and is currently at 16.26 million sq. km. This represents an increase of about 1.4% above the previous SH ice area record high. The observed sea ice record in the Southern Hemisphere (1979-present) is not as long as the Northern Hemisphere. Prior to the satellite era, direct observations of the SH sea ice edge were sporadic. Seems fair enough. Sea ice is “supposed” to be declining in the SH according to the GCMs, but not by much, so this isn’t desperately anomalous. But it is a bit.

Comments

  1. #1 llewelly
    2007/09/15

    Despite the record high antarctic sea ice area, the world sea ice area recently reached a record low.

  2. #2 llewelly
    2007/09/15

    Oops. I intended:
    Despite the record high antarctic sea ice area, the world sea ice area anomaly recently nearly reached the late 2006 record low. See here .

  3. #3 Eli Rabett
    2007/09/15

    Seems to me you are comparing an open ocean to a closed one here. I might be wrong, but it seems a lot easier to cool or heat the Arctic than the Southern Ocean. Moreover, I suspect that it would be important to compare precip trends in both places. For example, if precip is constant in the Arctic but increasing in the Antarctic it would be one thing, and you can build your own scenario.

    [The southern ocean is a major heat sink which is much of the reason that the Antaractic doesn’t warm fast -W]

  4. #4 Hank Roberts
    2007/09/15

    Yeek! This just got updated. 1995 doesn’t look similar here.

    http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/seasonal.extent.1900-2007.jpg

    [Even on that pic 95 was not exceeded until 2005 -W]

  5. #5 KenH
    2007/09/15

    The National Post has a column by Lawrence Solomon in his series ‘The Deniers’ about Antarctic sea ice. http://www.canada.com/nationalpost/financialpost/comment/story.html?id=1edd8fbd-7084-4eb1-9f39-ecdee5378809

  6. #6 bigcitylib
    2007/09/15

    See if Bromwich doesn’t sue the National Post for using the term Denier in reference to his work, the way N. Weiss did.

  7. #7 Hank Roberts
    2007/09/15

    > 1995
    Yep, I was comparing the size of the year-to-year change in area, not the minimum size reached.

    Could you do one of your trend line images showing what changes are statistically significant, as you did with temp data a while back debunking 5-year trends? I know a change has to be very large to be significant over a short time span.

  8. #8 Alexander Ac
    2007/09/16

    Dear William,

    still, I think that the (arctic?) melting trend is *fastening*, look at this graph from Tamino:

    http://tamino.files.wordpress.com/2007/08/extent.jpg

    In 1995, the record low hit the border already in august?

    And obvious question, do you expect another record low year in 2017? ;-)

    [Yes, it does seem to reducing faster (you can’t say “fastening, BTW :-) -W]

  9. #9 Luke
    2007/09/17

    Perhaps Antarctica showing an interaction between tropospheric greenhouse warming and stratospheric ozone depletion?

    http://www.sciencemag.org/cgi/content/abstract/296/5569/895

    Some recent SAM research

    http://www.amos.org.au/conf2007/AMOS07_ABSTRACTS.pdf

  10. #10 Hank Roberts
    2007/09/22

    Another Antarctic piece just out, but the abstract is a bit garbled; I wonder if anyone can make sense of this?

    “We find that melting areas have been moving inland since 1987. A first-time extensive melting (1987-2006) is detected over the Transantarctic Mountains on January 2005, 875 Km inland and 2000 m above sea level. Melting extent and index have been decreasing over Antarctica, since 1987, although either positive and negative trends are observed from a sub-continental scale analysis.”

    http://www.agu.org/pubs/crossref/2007/2007GL031199.shtml

    First time — over a 19 year period, or in January 2005?
    Extent and index have been decreasing — so is this a change from that trend?

    Either positive and negative trends are observed –??

    (All NASA authors, if I find email for them I’ll ask directly)

  11. #11 llewelly
    2007/09/22

    Alexander Ac:

    I think that the (arctic?) melting trend is *fastening*, look at this graph from Tamino:

    William:

    … you can’t say “fastening, BTW …

    The Free Online Dictionary:

    fas-ten-ing
    n
    Something, such as a hook, used to attach one thing to another firmly.

    Graphs like Tamino’s are certainly keeping peoples’ attention firmly attached to this issue …

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