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Fattail
01-05-2009, 01:52 PM
http://www.dailytech.com/Article.aspx?newsid=13834

Science
Sea Ice Ends Year at Same Level as 1979Michael Asher (Blog) - January 1, 2009 11:31 AM

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Thirty years of sea ice data. The record begins at 1979, the year satellite observations began (Source: Arctic Research Center, University of Illinois)Rapid growth spurt leaves amount of ice at levels seen 29 years ago.


Thanks to a rapid rebound in recent months, global sea ice levels now equal those seen 29 years ago, when the year 1979 also drew to a close.

Ice levels had been tracking lower throughout much of 2008, but rapidly recovered in the last quarter. In fact, the rate of increase from September onward is the fastest rate of change on record, either upwards or downwards.

The data is being reported by the University of Illinois's Arctic Climate Research Center, and is derived from satellite observations of the Northern and Southern hemisphere polar regions.

Each year, millions of square kilometers of sea ice melt and refreeze. However, the mean ice anomaly -- defined as the seasonally-adjusted difference between the current value and the average from 1979-2000, varies much more slowly. That anomaly now stands at just under zero, a value identical to one recorded at the end of 1979, the year satellite record-keeping began.

Sea ice is floating and, unlike the massive ice sheets anchored to bedrock in Greenland and Antarctica, doesn't affect ocean levels. However, due to its transient nature, sea ice responds much faster to changes in temperature or precipitation and is therefore a useful barometer of changing conditions.

Earlier this year, predictions were rife that the North Pole could melt entirely in 2008. Instead, the Arctic ice saw a substantial recovery. Bill Chapman, a researcher with the UIUC's Arctic Center, tells DailyTech this was due in part to colder temperatures in the region. Chapman says wind patterns have also been weaker this year. Strong winds can slow ice formation as well as forcing ice into warmer waters where it will melt.

Why were predictions so wrong? Researchers had expected the newer sea ice, which is thinner, to be less resilient and melt easier. Instead, the thinner ice had less snow cover to insulate it from the bitterly cold air, and therefore grew much faster than expected, according to the National Snow and Ice Data Center.

In May, concerns over disappearing sea ice led the U.S. to officially list the polar bear a threatened species, over objections from experts who claimed the animal's numbers were increasing.

Ought Six
01-06-2009, 12:02 AM
Burn the heretic! He has defiled the Gospel of St. Gore!

Kassy
01-06-2009, 06:28 PM
No it's more sloppiness.

Some of the predictions were posted in the Arctic Watch at CE.COM. All of them pertained to minimum summer ice extent which is much more interesting. The article mentions this and notices this shocking fact:
Instead, the Arctic ice saw a substantial recovery.


Which glosses over details like:
1) which scientists predicted the total disappearance of summer ice? Most relevant parties predicted between 2007 and 2005 which doesn't involve ice disappearing at all.

Some parties might have claimed total disappearance but i'd like to see their scientific merit. Politicians and bloggers don't count.

2) The recovery happens every winter. Which is taken for granted. There's no 'instead'.

The extent depends on the summer ice and some other factors. The trend in summer is not good:
http://arctic.atmos.uiuc.edu/cryosphere/sea.ice.minimum.2008.html

From march on we'll see how all the new ice holds up.

*

As for numbers.
http://answers.yahoo.com/question/index;_ylc=X3oDMTB1a2x0anY5BF9TAzIxMTU1MDA0NDMEc2V jA3BlZXBfZQRzbGsDcQ--?qid=20090105152615AA5kcZG

However, since 1979 northern hemisphere sea ice extent has changed by -1.08 to -1.66 million km^2, while southern hemisphere extent has changed from -0.466 to +1.2 million km^2.
http://nsidc.org/data/seaice_index/

This means that global sea ice has changed from +0.12 to -2.126 million km^2 with a most likely value of a 1 million km^2 loss of sea ice.

*

If they are right about the graph (their first link) the article is even worse.

Kassy
01-06-2009, 06:28 PM
No it's more sloppiness.

Some of the predictions were posted in the Arctic Watch at CE.COM. All of them pertained to minimum summer ice extent which is much more interesting. The article mentions this and notices this shocking fact:
Instead, the Arctic ice saw a substantial recovery.


Which glosses over details like:
1) which scientists predicted the total disappearance of summer ice? Most relevant parties predicted between 2007 and 2005 which doesn't involve ice disappearing at all.

Some parties might have claimed total disappearance but i'd like to see their scientific merit. Politicians and bloggers don't count.

2) The recovery happens every winter. Which is taken for granted. There's no 'instead'.

The extent depends on the summer ice and some other factors. The trend in summer is not good:
http://arctic.atmos.uiuc.edu/cryosphere/sea.ice.minimum.2008.html

From march on we'll see how all the new ice holds up.

*

As for numbers.
http://answers.yahoo.com/question/index;_ylc=X3oDMTB1a2x0anY5BF9TAzIxMTU1MDA0NDMEc2V jA3BlZXBfZQRzbGsDcQ--?qid=20090105152615AA5kcZG

However, since 1979 northern hemisphere sea ice extent has changed by -1.08 to -1.66 million km^2, while southern hemisphere extent has changed from -0.466 to +1.2 million km^2.
http://nsidc.org/data/seaice_index/

This means that global sea ice has changed from +0.12 to -2.126 million km^2 with a most likely value of a 1 million km^2 loss of sea ice.

*

If they are right about the graph (their first link) the article is even worse.

Auburn Boy
01-06-2009, 06:41 PM
Besides, one good year does not correct the negative trend.., It's just one more point in the graph and just may be statistically insignificant in the long run..,

cpeterka
01-07-2009, 12:23 PM
I suspect ( Just a suspicion ) that the Satellite view of the ice is the same, but what about the Thickness ?

They may only be thinking 2 dimensionally.
Same effect that saved Captain Kirk in the Wrath of Kahn movie.

Take a million square kilometers and then multiply by
a. 1 Meter thick
b. 2 Meters thick
c. 3 Meters thick

That's what they should be looking at, thinking about, IMHO.

southerncross
01-08-2009, 09:02 AM
Why oh Why is it so easy to accept when the Ice is on the decrease instead of on the increase? Do you even stop to think?

Auburn Boy
01-08-2009, 12:28 PM
Why oh Why is it so easy to accept when the Ice is on the decrease instead of on the increase? Do you even stop to think?


And what about the converse question? It's all in what you chose to believe. Until the evidence overwhelms you..,

Kassy
01-10-2009, 10:54 AM
Alternatively track the maximum northern ice extent from 1900 to 2008. :beer: