Eurekalert has a bit more interpretation from the authors (pasted below).
James, given that the study discusses sharply different conditions in the
Eemian as contrasted with prior post-MPT interglacials and implies a much
greater contribution from the WAIS, "relatively stable" isn't quite the
phrase that comes to my mind. That second sentence seems frankly
misleading.
-- Steve Bloom
Greenland's ancient forests shed light on stability of ice sheet
Ice cores drilled from southern Greenland have revealed the first evidence
of a surprisingly lush forest that existed in the region within the past
million years. The findings from an international study published today in
the journal Science suggest that the southern Greenland ice sheet may be
much more stable against rising temperatures than previously thought.
Researchers analysed ice cores from a number of locations in Greenland,
including Dye 3 in the south of the country. From the base of the 2km deep
Dye 3 core, they were able to extract what they believe is likely to be the
oldest authenticated DNA obtained to date.
By analysing these DNA samples, the researchers identified a surprising
variety of plant and insect life, including species of trees such as alder,
spruce, pine and members of the yew family, as well as invertebrates related
to beetles, flies, spiders, butterflies and moths. The researchers believe
that the samples date back to between 450,000 and 800,000 years ago.
"We have shown for the first time that southern Greenland, which is
currently hidden under more than 2km of ice, was once very different to the
Greenland we see today," explains Professor Eske Willerslev, a Wellcome
Trust Bioarchaeology Fellow from the University of Copenhagen, who led the
study."Back then, it was inhabited by a diverse array of conifer trees and
insects."
The research implies that ancient forests covered southern Greenland during
a period of increased global temperatures, known as an interglacial period.
When temperatures fell again, the area became covered in ice. This ice sheet
appears to have remained during the last interglacial period
(116,000-130,000 years ago) when the temperature was 5°C warmer than today,
contrary to the view currently held by scientists. Professor Dorthe
Dahl-Jensen, also at the University of Copenhagen, has shown that in fact,
even during this interglacial period, the ice thickness at Dye 3 would have
been reduced to between 1 km to 1.5km.
"If our data is correct, then this means that the southern Greenland ice cap
is more stable than previously thought," says Professor Willerslev. "This
may have implications for how the ice sheets respond to global warming."
However, Professor Willerslev was keen to dismiss the idea that this meant
sea levels would not rise to the levels predicted by scientific models.
"We know that during the last interglacial, sea levels rose by 5-6m, but
this must have come from other sources additional to the Greenland ice cap,
such as Antarctic ice. I would anticipate that as the Earth warms from
man-made climate change, these sources would still contribute to a rise in
sea levels."
The results also show conclusively that ancient biomolecules from the base
of ice cores can be used by scientists to reconstruct the environments
hidden underneath ice-covered areas and can yield insights into the climate
and the ecology of communities from the distant past.
"Analysing ancient biomolecules from beneath glaciers and ice sheets is
challenging due to the very low concentrations, but the information is worth
the effort," says Dr Enrico Cappellini, a member of the University of York's
new PALAEO Group and another of the paper's co-authors, whose work is
supported by the European Commission. "Our study suggests a solution to this
problem. Given that ten per cent of the Earth's terrestrial surface is
covered by thick ice sheets, it could open up a world of new discoveries."
----- Original Message -----
From: "James Annan" <[EMAIL PROTECTED]>
To: <[email protected]>
Sent: Friday, July 06, 2007 8:42 PM
Subject: [Global Change: 1870] Re: Latest Hansen
>
> Hank Roberts wrote:
>> William M Connolley <[EMAIL PROTECTED]> wrote:
>> Anyone believe it?
>>
>> I asked a while back in the 'Why Do Science in Antarctica' about some
>> of the reports --- remember 'Rapid Drumlin Formation'? at the time you
>> said you didn't know about it. I wondered who else at your shop might
>> know, since it seemed a rather dramatic bit of news that these
>> structures we've thought were longterm things could happen under the
>> ice and very fast.
>>
>> So I guess my question back to you is, who at BAS is familiar with the
>> new reports about water and mud flow under the ice, outburst floods,
>> and such that underlies the new concerns? And where are they
>> publishing or blogging?
>
> I wouldn't read too much into one piece of research (and still less into
> one journalist's report of same) but this does paint a picture of
> relatively stable ice sheets (at least, Greenland):
>
> http://news.bbc.co.uk/1/low/sci/tech/6276576.stm
>
> James
>
> >
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