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Kevin McKinney

Thanks, Tim! Er, I probably should have acknowledged upfront that it's actually my piece--"Doc Snow" being my nom de plume on Hubpages.

Werther

Professional confirmation…

Referring to my entries on 24, 27 June and 30 August on calving at the Jakobshavn Isbrae terminus.
Jason Box confirms the retreat I measured through CAD comparison:

www.meltfactor.org/blog/?p=762

My take on this is that the glacier is in no way stabilizing. While rapidly moving, the replenishing isn’t enough to compensate for large sinking/calving events like the one that took place during the third week of June.
The calving front is about 130 m high above sea level. I haven’t got information how high the front is together with its part under sea level. I heard someone mention 1000 m lately (on you tube footage) but I have no bookmark of that info.
Anyway, the calving front receded from the sill (about 400 m bSL) and is over the deep part of the fjord (up to 1600 m bSL).

On the speculative side: IF the fjord isn’t filled up to the bedrock with ice, THEN there actually is a fluid connection between Disko Bay and the deep fjord now.

I wouldn’t say that Atlantic water can now exchange with the bSL interior under the ice sheet. But the ‘weakness’ can facilitate subglacial runoff much easier than the probably very complicated plumbing under pressure elsewhere under the ablation zone.
In that case, the glacier would more and more take form of an ice river. Speeding up way above the acceleration during the last decade. Calving rapidly deeper into its fjord.
It is 60 km to the feeding zone at 1100 m aSL, where several pressure vectors from the central icesheet converge. The glacier retreated 16 km since 2002. Could it recede that 60 km let’s say within 25 years?

A retreat like that, under forcing and feedback as we saw this summer, matches supposed rapid mass loss on the southern tip of Greenland. Producing part of the sea level rise forecast by Rahmstorf during this century.

Brian

Werther: Thanks for the info/update on Jakobshavn Isbrae. I've been following it myself from http://ocean.dmi.dk/arctic/disko.uk.php
I find the activity this year to bee quite fascinating (never would have thought, even just ten years ago, that I would now be on the edge of my seat watching ice melt, and considering it to be of dire importance/urgency).

Werther

Hi Brian,
One of our blogfriends inspired me to get some more from the work of poet Longfellow (as you may have read the quote 'quos deus vult perdere prius dementat'.

Flooded by rain and snow
In their inexhaustible sources,
Swollen by affluent streams
Hurrying onward and hurled
Headlong over the crags,
The impetuous water-courses,
Rush and roar and plunge
Down to the nethermost world.

Now that is a fierce description of what may come out of Pandora's Box!

For me, my love for the natural world has been spoilt by worries ever since I was a boy. I thought for long pollution was the main plague. Since the near-river-flooding in the Netherlands 1995 I've seen Climate change as the most visible one. I'm amazed it is now becoming obvious.

dabize

http://ucl.academia....a_Slide_Tsunami

The above is a link to a reconstruction of the contribution of the Storegga Slide tsunami to the final flooding of the North Sea, inundating Mesolithic Doggerland around 8-9,000 years ago (~6000-7000 BCE). The interesting aspect of it to me is the relatively small scale of the tsunami, which was estimated to be 3-5 meters at most in this region (although much more than that closer to the site of the slide in Scotland, the Faeroes and Norway)
Another interesting aspect is that it mentioned that the rates of sea level rise (due to ice sheet melting after the last ice age) were around 1 meter per century, which is higher than now but likely lower than the rate will be in 50-100 years.

The final flooding of Doggerland is one of the most clearly defined SLR episodes in "recent prehistory", with evidence of the response of human settlement patterns to SLR rates that we will soon be seeing. It offers a scale for considering the ultimate fate of low lying places (probably not of the Netherlands, where they know how to deal with SLR) but more like Bangladesh, South Louisiana and Florida - over the next few hundred years, during which the earth will be facing similar (and probably rapidly increasing) rates of SLR. The final depopulation of a place like South Florida will likely occur with a major natural disaster (perhaps an uberKatrina) that makes it ridiculous for the survivors to keep up the pretense of habitability.

Artful Dodger

Hi Werther,

Have you seen "The Last Days on Earth"? It's an American Broadcasting Corporation (ABC) 20/20 science special which aired in August 2006 and has subsequently on "The History Channel" (USA). More about this Special here:

http://en.wikipedia.org/wiki/Last_Days_on_Earth

The 7th and last part describes the threat from Climate change. It's 10 minutes on Youtube:

http://www.youtube.com/watch?v=2VxvQGe7Bgc

It's remarkable how quickly the U.S. denial machine mobilized to defeat the real threat of climate change: to their bottom line.

"Move along. Nothing to see here. Resume shopping."

dabize

Lodger,

Gotta hand it to them - According to the Wiki link, they saw that AGW was the most likely of the threats and ranked nuclear war only 3rd. Ironic when one compares the amount spent in the past 50 years on national defense from threat #3 (ineffectively to boot) versus threat #1.

As for the bottom line - shouldn't it be: "Resume shopping! Don't invest the USA's (once) current leading position in the relevant new technology to address the problem, develop major new industries and make money - Let the Europeans and Chinese do that!"

We now lead the world in conspicuous stupidity - not a very salable technology, last time I checked.........

Protege Cuajimalpa

IJIS: The latest value : 3,595,781 km2 (September 8, 2012)

Brian

Hi Werther, thanks for the Longfelow; Indeed, have "the ice-helmed... scattered their arms abroad"- excellent allegory,and highly apropos.

Hi Lodger, thanks for sharing the link to Last Days on Earth; I watched the last three parts, and I found it quite interesting and relevant. Good to see that they mentioned ice melt specifically, including Greenland and WAIS.

Artful Dodger

de nada, Brian. Welcome to the ASI blog.

Cheers,
Lodger

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