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Author Topic: GIS influence on sea level rise  (Read 4994 times)

werther

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GIS influence on sea level rise
« on: February 04, 2013, 11:36:30 AM »


I placed the above map made June 2012 again, as a test and because it corresponds with a recently released paper on meltwater lakes:

http://www.the-cryosphere.net/7/201/2013/tc-7-201-2013.html

Continuing, here's my take on the NEEM ice core results…
On the info I’ve taken in so far (definitely not very much), I’m not too impressed. The initial conclusion is that through the Eemian the GIS contribution to SLR was 2 m as maximum. From that, it is assumed that most of the present ice-covered area was covered through the Eemian too.
This fits the markings I’ve made in my thinking for this century. The GIS will loose mass in a continuous geometric progression up to 2050, when the stage is reached as the southern tip of the island has lost a considerable amount of vulnerable ice. SL should be about 50cm up then, imagine 15 cm in ten years soon enough, more than 4000 km3 yearly.
Later this century shedding from the large, northern part of the GIS will come in progressively. I have read remarks lately that the 79/Zachariae NE part could be in a lot sooner. Such developments could worsen the picture.

I have assumed the Antarctic to line up considerably later.

All in, the forecast made by Rahmstorf is what I expect, 1-1,5 m SLR up to 2100.
The part where Eemian comparisons get irrelevant (if it is relevant at all…) is beyond 2100.

To my amateur knowledge, an interglacial warm period about 30K years long won’t reproduce exactly the same physical response in the current, fossil fuel initiated forcing blip of time.
It can give clues on individual processes, yes. But we can’t afford to assume the result of 6K years during the last Interglacial in a restricted area of Greenland will be repeated under present conditions.
« Last Edit: February 17, 2013, 11:38:57 AM by Neven »

TerryM

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Re: GIS influence on sea level rise
« Reply #1 on: February 20, 2013, 09:02:48 PM »
Werther

I feel that our present situation, with most of the GHG forcing coming in the winter months will differ significantly from the Eemian when warm summers were the norm.

The daily melt charts at

http://nsidc.org/greenland-today/

should be an interesting addition once the melt season takes off  - and this year it looks as though we're coming out of the gate a little early.

Flade Isblink, because it melted out in the Holocene Thermal Maximum, is a feature worth watching even though it's separate from the GIS.

Terry

Neven

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Re: GIS influence on sea level rise
« Reply #2 on: February 20, 2013, 09:30:27 PM »
Welcome to the forum, Terry.

Yes, Greenland/Baffin Bay air temps have really been jumping out at me this winter, even now when most of the Arctic has been much colder than usual for the past two weeks or so. That doesn't bode well at all.

I will do a post on that NSIDC website, which is a great addition, but after the melting season has started.
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TenneyNaumer

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Re: GIS influence on sea level rise
« Reply #3 on: February 21, 2013, 04:01:44 AM »
More and more, I am doubtful that there was much about the Eemian that is similar to the situation now.

Wasn't there a paper lately that concluded that the Arctic Ocean was not all that warm during the last interglacial, that the warm ocean waters extended up around Norway but not much further north?

And, a few months ago, in an email, P. Wadhams told me that some of the land-fast ice shelves breaking off had been in place for 60,000 years, based on sediment cores taken by some Danish researchers (sorry, I don't have the reference for that).

If the Arctic Ocean was not as warm during the last interglacial, then it is also likely that there was far more snow cover at high latitudes in the NH.

This is like cooking vegetables on a wood stove or on one of those induction burners.  Both cook the food, but the induction burner cooked food sure doesn't taste as good.

Gray-Wolf

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Re: GIS influence on sea level rise
« Reply #4 on: February 22, 2013, 01:43:10 AM »
I think we all need take care in using paleo data as a guide?

For myself the novel forcings of our industrialisation is what brought me to the understanding that we had altered Natures balance. As such we need understand that our forcing has been far faster than Nature has been able to reproduce and it has been this scale of 'nudge' that brings us the speed of changes we see?

This year may well silence the myth that the 2012 melt was due to some majik cycle by repeating the feat.

If so then a 5 year 'doubling' of mass loss brings us a rapid escalation of sea level rises even without Antarctica coming out of her 'Ozone induced Splendid isolation'.
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gfwellman

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Re: GIS influence on sea level rise
« Reply #5 on: February 22, 2013, 07:14:49 PM »
(off topic)  Grey Wolf, did you used to post at "Solar Cycle 24"?

DungeonMaster

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Re: GIS influence on sea level rise
« Reply #6 on: February 26, 2013, 01:34:16 AM »
Werther, by "NEEM" do you mean this :
http://www.explorersweb.com/polar/news.php?id=21240 ?

The AWI team seems to draw quite non-pessimistic conclusions.
This forum helps me to feel less uncomfortable about "doing something" about the melting Arctic and the warming world.
Read again  Maslowski paper : why Arctic could melt in 2016 +/- 3Y !