Wednesday, December 17, 2008

The Rabett was wrong and you were right, Stoat?

More later, perhaps, but by way of Climate Progess from Reuters and the World Meteorological Organization, for 2008

"Overall [Arctic] ice volume was less than that in any other year”

mostly because a lot of the ice that was left in 2007 was new ice.
Arctic sea ice extent during the 2008 melt season dropped to its second-lowest level since satellite measurements began in 1979, reaching the lowest point in its annual cycle of melt and growth on 14 September 2008. Average sea ice extent over the month of September, a standard measure in the scientific study of Arctic sea ice, was 4.67 million km2. The record monthly low, set in 2007, was 4.3 million km2.

Because ice was thinner in 2008, overall ice volume was less than that in any other year.

A remarkable occurrence in 2008 was the dramatic disappearance of nearly one-quarter of the massive ancient ice shelves on Ellesmere Island. Ice 70 metres thick, which a century ago covered 9 000 km2, has been chiselled down to just 1 000 km2 today, underscoring the rapidity of changes taking place in the Arctic. The season strongly reinforces the 30-year downward trend in Artic sea ice extent.
Wm owes Eli a beer, Eli owes William a beer or something.


William M. Connolley said...

Senility claims me: remind me why I owe you a beer?

EliRabett said...

Ah, if you don't remember, you owe me two beers.

Anonymous said...

New metric, new metric!!!

There we were, placing bets on area and extent and CT and NSIDC and so forth, when all the time we should have said 'volume'.

Since I don't recall this measure referred to in any of the bets, this news does not effect the original.

Neither area nor extent was a record in '08. Think Eli owes William a pint of Theakston's Old Pernickety, or similar.

melly Xmas.

EliRabett said...

It's Eli's blog and he can move the goalposts

Fergus, good to hear from you. And a wonderful Christmas to you too and to all the constant readers and the occasional ones.

Dano said...

The degradation of perennial ice - along with the increasing CH4 from melting permafrost - are worrisome indicators.

Would that we had some more folks out there who could explain these indicators in such a way to spur action...



Anonymous said...

People will debate (and make bets) about changes in sea ice area and/or extent from year to year, but the critical sentence is this:

"The season strongly reinforces the 30-year downward trend in Arctic sea ice extent."

It really matters not even whether ice volume this year was less than that last year.

What matters is the (downward) trend over the past few decades.

Anonymous said...

Alas, William has become very grouchy and uninspired over the last year, scolding Hansen and taking potshots at the Guardian's sensationalized climate coverage. He did scoff at Climate Progress for writing about the very subject of Eli's post here. Why I even saw him use the argument "sea ice increased in 2008" to question the characterization of an increasing downward trend! tsk tsk.

I think a winter spent shoveling coal in the Sea Shepard's engine room might be in order!

Anonymous said...

Speculation about next summer's ice by some scientists with blogs really serves no useful scientific purpose.

I realize it is all in good fun, but the plays into the hands of AGW "skeptics".

it is hard to criticize a "skeptic" for arguments based on short time periods when some scientists are playing the same game.

The motivation gets lost on an unscientific public, who can not distinguish between the two cases.

Anonymous said...

I like the opening sentence to Smedsrud et al. 2008;

"The interest in the Arctic sea ice seems inversely proportional to the area covered, and has exploded after the record minimum September 2007."

Anonymous said...

Meantime RP Sr. is on about changes in melt-season length, flashing a table of figures as if it means something absent any trend analysis, using the unusual definition of dates of ice maxima and minima (compared to the norm of SAT above and below melting point), and ignoring at least three papers that use either surface or satellite measurments to show, yes Pollyana, that the melt-season trend is up!

Magnus said...

what was the bet again? ;)

Magnus said...

Anonymous said...

Meanwhile, ice extent seems to have totally stalled in a way that some of 2008 will actually see lower extent than the previous year (the record breaking 07). Interesting. Fits well the idea of an accelerating trend.