

I had recalled that the Arctic Ice Cap had averaged about 10-20 feet, during the last century. This was measured to average around 5-6 feet, in the last decade. And more recently 2-3 feet thick Arctic Ice was becoming the norm.

Or so I explained.

While pulling Ice Thickness stats "out of the air" to back up my arguments -- I suddenly realized I didn't know the "science" as well as I thought I did ...

SO I have now done a little digging on the Topic, trying to establish some Cold, Hard Facts, for the next time this topic comes around.





North Pole poised to be largely ice-free by 2020: "It’s like the Arctic is covered with an egg shell and the egg shell is now just cracking completely"

climateprogress.org -- May 13, 2009

It’s the ice thickness, stupid. The Arctic ice cover, which has endured for at least 100,000 years, will be all but gone within a decade according to a volume-based projection by a leading British scientist, the BBC reports. At the same time, "a gruelling 73-day" survey of sea-ice thickness found "the average thickness of the sea ice was 1.774 m" [5.8 feet]. One surveyor said the data "seems to suggest it was almost all first-year ice."

[...] The view of the Arctic from above tells you only ice area, not volume. So even as the climate science deniers (temporarily) crow about the latest two-dimensional data, those who think three-dimensionally know that the Arctic is a cracking eggshell.

Sometimes Satellite Photos DON'T give you the full story.



NSIDC: Arctic is on thin ice -- literally -- and that means the "perma" frost is too

climateprogress.org -- April 7, 2009

The National Snow and Ice Data Center reported Monday: [Arctic] ice older than two years accounted for less than 10% of the ice cover at the end of February. So it is "thinner and more vulnerable than at anytime in the past three decades," as the AP reports.

[...] Why is that a concern? "That thick ice really traps ocean heat; it keeps the planet in its current state of balance," said Waleed Abdalati, director of the Center for the Study of Earth from Space at the University of Colorado and NASA’s former chief ice scientist. "When we start to diminish that, the state of balance is likely to change, tip one way or another." [...] Why should we care about Arctic ice disappearing ? Because, as a major 2008 study found, Permafrost loss linked to Arctic sea ice loss [...] In other words, the recent trend in sea ice loss is poised to triple Arctic warming, causing large emissions in carbon dioxide and methane from the tundra this century.

[...] So it will soon be time to retire the word "permafrost" from our vocabulary, along with "polar" bear and "glacial" change.

"Balance" is one of those new Anti-Science "catch words" now too -- with the caveat that "Humans shouldn't mess around with Nature's Checks and Balances"

My reply: So Why have we? CO2 is a Greenhouse Gas, isn't it.



Back to the boring Sciency stuff ...



Study: "It is clear ... that the precipitous decline in September sea ice extent in recent years is mainly due to the cumulative loss of multiyear ice."

Physicist: "If temperatures change just a few tenths of a degree then this oh-so-thin ice cap is doomed."

climateprogress.org-- March 22, 2010

Memo to media: Ignore the misreporting on the Arctic that focuses on sea-ice extent or area. The big Arctic news is the staggering decline in multiyear ice -- Ice Volume. No study has yet been published undermining our understanding that human emissions are the primary cause of that long-term decline -- a decline that shows no sign of reversal.

[...] The real news from the Arctic is the staggering decline in thicker, multi-year ice [red line] -- as seen in the [next] figure from leading cryoscientists who authored the 2009 study, "Thinning and volume loss of the Arctic Ocean sea ice cover: 2003–2008"

I annotated the Chart for Arctic Ice Thinning and Volume loss in recent years:



larger

even larger



The Key thing to notice is how Multi-Year Ice (thick stable ice) is being replaced by First-Year Ice (thin less stable ice). That Color bar gives the ratio of the 2 types of Ice, found in the survey.

Red [MY] is the strong Multi-Year Ice. And it is rapidly GOING AWAY.

Blue [FY] is the fragile First-Year Ice. And it is becoming the norm.

The Black line is the Total of both Ice Types -- in total, the Overall Volume is Declining too. Uh oh!



[Continuing ... with the geeky stuff ...]

Finally, the latest study is based on correlating Sea Ice Extent (SIE) with other factors, like Arctic winds. But another recent study -- "Perennial pack ice in the southern Beaufort Sea was not as it appeared in the summer of 2009" (subs. req’d) by Barber et al. -- suggests that standard measures of SIE extent may be unreliable. [...] It found: In September 2009 we observed a much different sea icescape in the Southern Beaufort Sea than anticipated, based on remotely sensed products. Radarsat derived ice charts predicted 7 to 9 tenths Multi-Year (MY) or thick First-Year (FY) sea ice throughout most of the Southern Beaufort Sea in the deep water of the Canada Basin. In situ observations found heavily decayed, very small remnant MY and FY floes interspersed with new ice between floes, in melt ponds, thaw holes and growing over negative freeboard older ice. This icescape contained approximately 25% open water, predominantly distributed in between floes or in thaw holes connected to the ocean below. Although this rotten ice regime was quite different that the expected MY regime in terms of ice volume and strength, their near-surface physical properties were found to be sufficiently alike that their radiometric and scattering characteristics were almost identical.

ie. it's hard to tell these types of ice apart with standard SIE techniques, like Satellite photography, I presume.



Popular Science spells out what all that means, using a bit more "plain English" ...



Arctic Ice Cap Coverage Isn't Only Shrinking, It's Getting Thinner, Too

The thorough satellite analysis yet paints a grim picture of Arctic ice's overall melt rate by looking beyond reduced surface area

By Stuart Fox, PopSci -- 07/09/2009

What they [NASA researchers] found is not good. It seems that the thick, permanent ice that used to constitute the majority of Arctic ice has been replaced by thinner, seasonal ice that melts away during the summer months. So not only is the ice covering less area than ever before, but the ice that does form is thinner than ever before. In total, the scientists calculated that the ice pack shrank by 57 percent between 2004 and 2008, thinning by 2.2 feet . The dramatic image above shows the difference in ice thickness between 2004 and 2008, and a progression of the ice thickness can be seen here. In just those four years, the ratio of permanent ice to seasonal ice completely flipped, with permanent ice forming 62 percent of the ice cap in 2004, but only 32 percent by 2008.



I thought you might find these "chilling" trends interesting, and topical too.

Who knows, they could be a good "Ice-breaker" at the next social gathering you find yourself in -- with the holidays coming up and all. (yuk, yuk)



And Please, if you have any other definitive links on the Science behind the incredibly Thinning Arctic Ice Cap -- DO Post em, if you Got em!

The Ice ain't getting any thicker, is it?

It's All Downhill from here ... Inertia.



