And me too!
(see last paragraph)
john gorman
----- Original Message -----
From: John Nissen
To: [email protected] ; Geoengineering ; John Shepherd
Sent: Monday, July 06, 2009 11:09 PM
Subject: [geo] Re: Terrestrial Ice In West Greenland Under Attack from Weather
Hi Andrew,
I'm not saying "now or never", but I am saying "the sooner the better",
because (1) it is a question of risk reduction and (2) countering positive
feedback is best before the feedback has grown too much.
Scientists have spent a tremendous effort in persuading the politicians and
media that emissions reductions, of the kind "80% by 2050", can keep the global
warming below 2 degrees. But even if we could achieve such a target in every
country in the world, it wouldn't save the Arctic sea ice - and hence it would
not prevent outgassing of methane and disintegration of the Greenland ice
sheet. So how much cooling can geoengineering provide?
Albert writes: "I am increasingly concerned that temperatures at around
+24C, can't be tamed by sulphur dioxide or other means, it just could be a
magnitude or several times more than the negative feedback induced by the
geoengineering methods. I fear the not enough scenario." (see reproduced email
below)
The Arctic is warming twice as fast as the rest of the globe, in a process
known as "polar amplification". This process appears to be driven by "albedo
flip". As sea ice is replaced by water, the reflectivity, or "albedo", changes
by up to 70%, giving greater absorption of solar energy, April through
September. Suppose the use of enough stratospheric sulphur-based aerosols can
cause a reflection of 20% solar energy. It would have to be deployed over 3
times the area that the Arctic sea ice is melting in summer to counter the
albedo flip. That's my very rough calculation.
Once the sea ice is all melted, it may be impossible to rescue the situation
through any amount of geoengineering with stratospheric aerosols. And then we
are left helplessly with methane outgassing and Greenland ice sheet
disintegration - beyond the point of no return.
This is what is worrying me, and I think Albert too.
Cheers,
John
---
Andrew Lockley wrote:
I think it would be great if someone could bring forward a paper on the
'limits of geoengineering'. John Nissen has made much play of the 'now or
never' argument. I have no opinion as to whether he's right or not, and I
would love to see scientists with appropriate expertise bring forward a
relevant paper.
A
2009/7/6 Veli Albert Kallio <[email protected]>
Dear Alan,
It is not only melting of sea ice and permafrost that needs to be
highlighted.
Today's Temperature Legend Map from Foreca shows that Ilulissat Ice Fjord
that drains 7% of Greenland ice sheet bathin on top temperatures today between
+20-25C. This is substantial heat on the glacier, the morning temperatures
shown are littel more moderate.
Last time I saw these kind of temperatures +24C in Ellesmere Island, the
Aylers Ice Shelf collapsed on that particular week. The heat and warm water
does damage ice considerably and I expect that Greenland's temperatures are
much like the Baffin Island's once Arctic Ocean's sea ice is gone. I think
today's weather is a good indicator what shall become.
I am increasingly concerned that tempeartures at around +24C, can't be
tamed by sulphur dioxide or other means, it just could be a magnitude or
several times more than the negative feedback induced by the geoengineering
methods. I fear the not enough scenario.
I don't want to be devil's advocate, but weather's could rise too high
and out of control. Let's hope this peak heat stays short, but I would not be
surprised if glaciers speed up once again.
Kind regards,
Albert
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