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Sea Ice And Albedo Effects

October 25, 2013

By Paul Homewood

 

image

http://nsidc.org/news/press/2013_minimum_final.html

 

NSIDC have grudgingly admitted that Arctic minimum sea ice extent has recovered from last year’s low.

(I think the headline says everything you need to know about the politicisation of NSIDC – “Avoids last year’s record low” – an unaware reader would assume that this year had just scraped above it, rather than exceed it by 50%).

 

But back to the point! We often hear that the loss of ice in the Arctic is of more significance than the gains in the Antarctic. As NSIDC lead scientist, Ted Scambos, says:

 

“The tiny gain in Antarctica’s ice is an interesting puzzle for scientists. The rapid loss of ice in the Arctic should be ringing alarm bells for everyone”

 

But why is this so? NSIDC explain:

 

Summer sea ice extent is important because, among other things, it reflects sunlight, keeping the Arctic region cool and moderating global climate.

  

But, of course, there is a slight problem here – the Arctic minimum occurs in September, around the autumn equinox, at the same time that the Antarctic maximum is occurring  at the southern hemisphere’s spring equinox. In other words, the albedo effect is the same at both poles at this time of year.

And as we already know, global sea ice extent was pretty much in balance in September, as the chart below shows. The global ice deficit is less than 1%.

 

Sea Ice Extent  – million sq km

  Arctic Antarctic Global
21st Sep 2013 5.212 19.513 24.725
1981-2010 Average
for 21st Sep
6.393 18.572 24.965
Excess/Deficit 1.181 0.941 0.240

http://nsidc.org/data/seaice_index/archives.html

 

If we are concerned with albedo, we really need to look at the mid summer numbers, i.e June and December for the Arctic and Antarctic respectively.

 

Sea Ice Extent – million sq km

  Arctic Antarctic Global
21st Jun 2013/21st Dec 2012 11.202 9.309 20.511
1981-2010 Average for above days 11.309 9.232 20.541
Excess/Deficit 0.107 0.077 0.030

http://nsidc.org/data/seaice_index/archives.html

 

 So, at the time of year when albedo is at its most significant, the global ice deficit is a tiny 0.1%.

 

There is another factor that needs to be taken into account as well. Antarctic sea ice tends to spread into lower latitudes than Arctic ice does.

The maps below show sea ice in the Arctic during June, and Antarctic during December, in 2010. (They are from the AMSR-E satellite, which stopped operations in 2011).

asi-n6250-20100621-v5_visual

asi-s6250-20101221-v5_visual

http://www.iup.uni-bremen.de:8084/amsr/

 

Even as late in the season as December, Antarctic ice extends well past the Antarctic Circle in places, and close to 60S.

In contrast, with the exception of Hudson Bay, most Arctic ice is above 70N. (At the South Pole, most of the area above 70S is land, and is obviously snow covered anyway).

All this means that changes in Antarctic sea ice at midsummer have much more effect on albedo, than changes in Arctic ice.

 

One other point. Ted Scambos talks of “The tiny gain in Antarctica’s ice” and “The rapid loss of ice in the Arctic “. But this statement simply is not true, and is highly misleading.

Below are the ice extents at the respective minimums, and compared with the 1981-2010 climatological average.

 

Minimum Sea Ice Extents – million sq km

  Arctic Antarctic
Minimum 2013 5.079 3.650
Climatological Minimum 6.262 2.876
% Increase/Decline 19% 27%

 

So we find that the percentage growth in Antarctic ice is greater than the “rapid loss” in the Arctic. Comparing changes in Arctic minimums, with changes in Antarctic maximums, is extremely deceptive, because the larger amounts at maximum, by necessity, make for lower percentage figures. An example:

 

1 sq km = 20% of 5 sq km.

But

1 sq km = 5% of 20 sq km.

 

Conclusion

It may be that Scambos, Serreze and the rest at NSIDC are simply incompetent, and unaware of these points I have raised.

But if they are not, then why are they not telling us the real story?

It is the duty of scientists, particularly public funded ones, to put all of the facts on the table, not just the ones that suit their agenda. And it is certainly not their job to issue misleading press releases.

8 Comments
  1. John F. Hultquist permalink
    October 25, 2013 5:22 pm

    A well done and informative post. Thanks.
    ~~~~

    About another albedo event: The west coast of North America has been and remains covered by a massive high pressure ridge. The no-wind and thick fog part of this has been noted by a Seattle meteorologist:
    http://www.komonews.com/weather/blogs/scott/Northwest-to-be-hit-by-virtual-anti-wind-storm-228533431.html

    Under ‘recent posts’ (right side of his blog), Scott links to several related stories.
    The widespread fog can be seen on the GOES-WEST visible satellite imagery. As I look, the latest image is 25 October 2013 Fri 1640 UTC. Either the 1 km or 8 km resolutions will show this fog layer.
    With this ridge along the west coast there is a jet stream moving from the north into the central part of the continent. It has been flowing along the border of Saskatchewan and Manitoba, then into North Dakota. This morning it appears to be changing and moving east. Helps explain the cold air in the USA’s north central parts.

    Follow the waves to Europe and we get your “Storm of the Century.”

    Anyway, my point started out to be that albedo is something one ought to look at as a global thing. As you mention, what happens to ice extent isn’t terribly important to albedo when there is very little sun.

  2. October 25, 2013 5:28 pm

    Reblogged this on CraigM350 and commented:
    Like all politicians they spin the message – but hey so can we and despite the fiddling the data most people are seeing the change to cooling first hand. It will be interesting how these press releases go in the future when their statements will look increasingly facile and more detatched from reality than they already are!

  3. mkelly permalink
    October 25, 2013 6:20 pm

    But in the dead of winter the snow cover of Canada, Siberia, US, etc cover more area than what can be covered in the Antarctic region.

    • DirkH permalink
      November 6, 2013 10:46 pm

      Then why do they talk about sea ice in the first place?

  4. October 25, 2013 7:51 pm

    I’ll wager Auntie’s resident pessimist (Jonathan Amos) won’t report this ‘good’ news.

  5. Green Sand permalink
    October 25, 2013 9:28 pm

    Snow blindness makes sums hard?

  6. Sparks permalink
    October 26, 2013 11:58 am

    When they issue misleading press releases do you think it’s because they are supporting the alarmist man made global warming opinion of the past 30 years that the poles will warm up and melt all the sea-ice due to human carbon dioxide emissions (which are a fraction of the entire planets atmospheric composition of carbon-dioxide anyway) and that the people who have their scientific-reputations and work on the line are covering up the fact that they have been completely scientifically incorrect?

    If a scientist claims that they have evidence that all sea-ice will melt due to a theoretical mechanism (i.e man made carbon dioxide emissions) and after 30 years of gathering and studying the data of sea ice variability in support of this theoretical mechanism their findings turn out to be meaningless and well within natural variability which inconveniently disagree with their claims, should a scientist;

    (a) Present reasonable grounds for the falsification of the theoretical mechanism and retract all claims based on 30 years of observation and study.

    or

    (b) Present a misleading account of the data and continue to declare, maintain, argue, state, advocate, affirm, swear, insist, avow and claim that their original claim is correct.

  7. DirkH permalink
    November 6, 2013 10:45 pm

    “It is the duty of scientists, particularly public funded ones, to put all of the facts on the table, not just the ones that suit their agenda.”

    That would be a novelty under the Obama doctrin.

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