Hi Oliver,
Yes, it would be a very good plan to use marine cloud brightening to
cool the Gulf Stream (North Atlantic Drift), in combination with
stratospheric sulphate aerosol at high latitudes to cool the Arctic and
Antarctic (to maintain N-S balance). BTW, there's enough sunshine at
high latitudes for the aerosol to work.
BUT, and that's a big but, CAN WE SAVE THE ARCTIC IN TIME? Albert's
alarming analysis of the situation suggests that we may be too late
already. Nobody will want to stuff loads of aerosol into the
stratosphere in spring, which is what is needed to have a reasonable
chance of success. And the marine cloud brightening cannot be ready.
Yet we cannot afford to risk failure on this one.
We are in a heck of a mess.
Cheers,
John
--
Oliver Tickell wrote:
I just saw some of John
Latham's graphics (shown by John Shepherd in lecture in Oxford today)
on effects of increasing marine cloud reflectance by saline droplets
and the biggest insolation differentials are in the tropical oceans
where you are getting 50W/m2. One idea might be to deploy the boats in
the tropical / subtropical Atlantic and so reduce the temperature of
the North Atlantic Drift, as it is this warm water flux that is surely
doing much of the sea ice melting. This may be a necessary adjunct to
directly cooling the Arctic as otherwise you are not doing any cooling
in the winter when the Arctic ocean is all frozen up (still) - and in
any case there is no sunshine to reflect away. Or indeed this may just
a more effective approach in all seasons. Anyone up for some modelling?
One
further thought of Shepherd's is that you have to balance any Arctic
cooling with Antarctic cooling, or run risk of N-S shift of jet stream,
monsoon etc.
Best, Oliver.
Hi Oliver,
I think we should all be extremely alarmed by what Albert has said!!
So a plan of action is urgently needed.
I've been talking about this with Albert, on and off, for nearly two
years now. Somehow we have to stabilise the Greenland ice sheet. But
if we do not save the Arctic sea ice, it is highly unlikely that we can
save the Greenland ice sheet. Albert estimates that the Greenland ice
sheet could become unstable within 5 years of end-summer disappearance
of the Arctic sea ice. Moreover, once this end-summer disappearance
has happened, it is highly unlikely that the sea ice can be restored
and eventually it will be gone throughout the year.
The approaches to trying to stabilise the Greenland ice sheet (either
directly or indirectly through saving the sea ice) mainly fall into two
categories: mechanical/hydrological techniques, and solar radiation
management (SRM) techniques. I also mention a third, concerning
Siberia and Canada, which hasn't been discussed much, to my knowledge.
1. Mechanical/hydrological techniques
At first Albert and I discussed techniques, such as ice barriers, river
diversion and blocking up moulins. Such techniques have generally been
dismissed by other experts, such as Peter Wadhams, and they are
unlikely to succeed in stabilising the Greenland ice sheet on their
own. However they could be a step in the right direction, and perhaps
buy a little time for SRM to get going.
Ice barriers would be used to stop the flow of ice to the south between
islands, or to prevent icebergs leaving fiords. We are not sure that
they would work - or rather could be designedto work effectively.
Albert has considered diversions of Russian rivers flowing into the
Arctic ocean, as they transfer considerable heat in the process. These
would be massive projects, probably taking years to complete. However
they might not work as intended, since the fresh water decreases
salinity of the ocean, making it easier to freeze.
Also there is the possibility of spraying, or otherwise distributing,
the fresh river water over existing sea ice to thicken it in winter. I
don't know how much thought anybody has given to this - e.g. whether it
would work.
The blocking of moulins is an interesting possibility - Albert has
suggested using plugs of ultra-cold material - I have wondered about
using pykrete. This might be done at end summer, when the moulins are
of maximum size.
The costs of barriers and river diversions would be typical of very
large construction projects, perhaps a few billion dollars - but
essentially one off. The cost of blocking up moulins would be
ongoing. Operating in Greenland is extremely expensive, but we would
be talking of perhaps millions of dollars per year rather than billions.
2. SRM geoengineering techniques
I had hoped we could have got SRM geoengineering off the ground by now,
but it looks as if it could be too late, unless we are lucky and Albert
is wrong on the timescale. Unfortunately almost all other experts on
the Arctic have proved optimistic. (Mark Serreze might have some
comment here.) The main thought is to try and save the Arctic sea ice,
rather than deal with the Greenland ice sheet directly. There are
three approaches that I know of: stratospheric aerosols, marine cloud
brightening, and (recently proposed again) white covering materials.
Stratospheric aerosols could be applied most quickly - and would be
applied at high latitudes. Costs might be in the hundreds of millions
of dollars per annum (not billions).
The marine cloud brightening would be applied over the north-east
Atlantic, cooling the surface of the Gulf Stream entering the Arctic
ocean, and allowing it freeze more readily. Modelling by John Latham
et al suggests that this would be effective. However there are
probably several years development and ship-building to do, before
deployment could be started in earnest. Again costs might be in the
hundreds of millions of dollars per annum (not billions).
I don't know any details about using white covering materials. There
are two possibilities. They could be used to cover areas of Greenland
where the surface melts in summer, to try and prevent lakes and moulins
forming. They could be used to float on the sea, reflecting sunlight
but also insulating the water beneath and allowing snow to accumulate
above. I don't know what the latest thinking is, and have no idea of
costs.
3. Siberia and Canada
There is a contribution to polar warming from Siberia and Canada, with
an increase of shrubs and lowered albedo. Something might be done on
this - but I don't know what latest thinking is. Certainly it is
important to try and keep the permafrost frozen, because of potential
massive methane discharge.
Best wishes,
John
P.S. I am copying this to the whole geoengineering group, as there
could be some useful feedback to help answer your question.
---
Oliver Tickell wrote:
Thanks very much for this alarming and
timely account of what is actually going on, and the instabilities
inherent in the physics of ice sheets.
Could you maybe set out a plan of action,
with cost estimates, to deal with this problem on the appropriate time
scale?
Regards, Oliver.
Dear Mike,
When I was in Greenland with Jane Lubachenko as press-spokesmen for the
symposium "Arctic - Mirror of Life" convened by H.E. Kofi Annan and
H.E. Jose Manuel Barroso, the Greenlanders came to tell us, their ice
age is ending. But there are many ways it to end.
There is no more important issue than the ice in Greenland as there is
the impending switch-over to post-sea ice conditions taking place in
the Arctic Ocean nearby: even the winter sea ice is much reduced (due
to the thin ice being as easily compressible into pack ice as a
deflating harmonica folds upon itself).
In the past the old multi-year sea ice did not pile-up so easily as
this year's thin sea ice. I remain of the opinion that 2010 might see
Arctic sea ice gone by the end of summer due to the ice pile-up, larger
waves &, sea winds scattering ice onto open and warmed-up seas.
Perhaps much more important than the melting volume in Greenland is
where it occurs:
If the ice melts in Greenland's periphery, all melt water (and heat in
it) drains away quickly when the melt season ends. (These are seasonal-impact moulins and
crevasses.) However, now the melting occurs much higher on the ice dome
where the sub-glacial ground surface inclination turns inward and where
the melt water sinks ever deeper into Greenland's interior depression,
filling the uneven dentures and crevasses by water. This lifts up ice
dome as it floats above rough surfaces: mooring to the ground is
quickly replaced by sailing on the ground. Mooring of the ice then
located at the downstream obstacles only.
As ice is a very good insulator (we Finns, like Greenlanders, build
snow-houses!): the heat that is taken down with the water that pours in
through moulins and crevasses takes heat with it for ever. (These are accumulative-impact moulins and
crevasses - a greenhouse effect with 100% heat retention
as most of this water takes thousands of years to make its way
ultimately towards and out of Melville Bay depression in North West
Greenland.)
The tipping point in Greenland's ice mooring has been crossed as each
year a new gulp of warm water is added to the base of ice sheet (since
the start of accumulative impact moulins and crevasses started to form
at higher altitudes in Greenland the last few years).
Because of this loosening of the footing of Greenland's ice dome by
melt water incursion, we monitor the coastal barrier stability at
Melville Bay by GPS meters in case the increased pressure destabilises
this section and "ice sheet thrust" re-occurs to break ice loose here.
We are also looking at sub-glacier high
velocity water jets that cause
cavitation, plucking and kolking under the ice shelves that are feeding
turbidic mud and rock flows into Melville Bay basin and how these cause
fast erosion on the rock barrier holding back the ice sheet.
We either fly in with military helicopters from Thule-Pituffik base in
extreme North West, or use civilian aircrafts from Ilulissat airport
that is south from Melville Bay. We think there are several sections
that are already in a macro-scale movement towards the sea and our aim
is to capture this movement by GPS. We aim for an amicable settlement
with the Danish authorities and co-operation (rather than deploy
undercover journalists to observe this).
I am almost certain that we do reach agreement over this matter soon as
it is no interest of the Danish government try to stop our United
Nations'-based enquiries even if they think Greenland ice sheet land
containment failure by "ice sheet thrust" at
Melville Bay is no risk.
We also have a great deal of support internally in Greenland to
challenge idea that the ice melts 15,000 years or 1,000 years, and
support from the World Indigenous Nations that the sea floods do occur
suddenly as the ice domes loose their footing and slide into the seas.
215,000 euros on this matter will keep us afloat. We do hope the
Indians are wrong and the Western idea of the ice sheets melting
peacefully in situ over many millennia would be right. But for us
Greenland appears as the snow roof of the world and when spring comes,
only few drops of water comes out and then the whole snow sheet falls
down from roof.
Thus, if the ice age in Greenland ends soon, it is sad to see us so
unprepared for this big flood and associated rapid "the Last Dryas"
cooling as the United Nations' General Assembly was warned by the First
Nations of the North America under the auspices of World Indigenous
Nations Summit as its closing plenary investigation request plea for
the UN.
Let's see if the Danish have guts to delay our geophysical experiments
further, although no one wish to see the indigenous people's idea (or
fear) of "ice sheet thrust" occuring to bring the ice age in Greenland
to its end: less
than 1% melts, more than 99% slides out.
With kind regards,
Veli Albert Kallio, FRGS
HH Plenipotentiary Scientific Ambassador,
the Global Environmental Parliament Group
Indianice Geophysical Experiment Group,
First Nations' UNGA 101292 Case Hander
International Guru Nanak Peace Prize Nominee for 2008:
sea level rise risk to global security & economic stability
Date:
Tue, 17 Nov 2009 11:04:49 +0000
From: [email protected]
To: [email protected]
CC: [email protected]; [email protected];
[email protected]; [email protected]
Subject: [geo] Greenland ice sheet - tipping in progress
Hi all,
Professor Mike Hulme gave a talk at the RGS yesterday evening [1], in
which the Greenland ice sheet was shown as a tipping point, along with
a dozen others on a map of the world [2].
The BBC article below shows how positive feedbacks are building up in
the Arctic. What is not discussed is whether the whole sections of ice
sheet could become unstable and slip off into the sea, causing a
massive step change in sea level, as shown to have happened from time
to time in the geological record of the Ice Ages [3]. If we are to
avoid a complete tipping of this system, sooner or later giving us 7
metres of sea level rise, there seems to be no alternative to
geoengineering to cool the Arctic. And the sooner we start the
geoengineering, the more likely we are to succeed in halting the
tipping process.
>From http://news.bbc.co.uk/1/hi/sci/tech/8357537.stm
---
The Greenland ice sheet is losing its mass
faster than in previous years and making an increasing contribution to
sea level rise, a study has confirmed.
Published in the journal Science, it has also given scientists a
clearer view of why the sheet is shrinking.
The team used weather data, satellite readings and models of ice sheet
behaviour to analyse the annual loss of 273 thousand million tonnes of
ice.
Melting of the entire sheet would raise sea levels globally by about 7m
(20ft).
For the period 2000-2008, melting Greenland ice raised sea levels by an
average of about 0.46mm per year.
![]() |
![]() If you
multiply these numbers up it puts us well beyond the IPCC estimates for
2100 ![]()
|
Since 2006, that has increased to 0.75mm per year.
"Since 2000, there's clearly been an accelerating loss of mass [from
the ice sheet]," said lead researcher Michiel van den Broeke from
Utrecht University in the Netherlands.
"But we've had three very warm summers, and that's enhanced the melt
considerably.
"If this is going to continue, I cannot tell - but we do of course
expect the climate to become warmer in the future."
In total, sea levels are rising by about 3mm per year, principally
because seawater is expanding as it warms.
Sea change
Changes to the Greenland sheet and its much larger counterpart in
Antarctica are subjects commanding a lot of interest within the
scientific community because of the potential they have to raise sea
levels to an extent that would flood many of the world's major cities.
CLIMATE CHANGE GLOSSARY
Select a term from the
dropdown:
Glossary
Adaptation
Annex I countries
Annex II countries
Anthropogenic climate change
Atmospheric aerosols
Bali action plan
Bali roadmap
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Carbon dioxide (CO2)
Carbon dioxide (CO2) equivalent
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CO2
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Dangerous climate change
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(ETS)
EU Burden-sharing
agreement
Fossil_fuels
Geological
sequestration
Global average
temperature
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effect
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Per-capita emissions
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dioxide
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Weather
Climate
change - A pattern of change affecting global or regional
climate as measured by yardsticks such as average temperature and
rainfall, or an alteration in frequency of extreme weather conditions.
This variation may be caused by both natural processes and human
activity.
Global warming is one aspect of climate change.
The 2007 Intergovernmental Panel on Climate Change (IPCC) report
projected a sea level rise of 28-43cm during this century.
But it acknowledged this was almost certainly an underestimate because
understanding of how ice behaves was not good enough to make reliable
projections.
By combining different sources of data in the way it has, and by
quantifying the causes of mass loss, the new study has taken a big step
forwards, according to Roger Barry, director of the World Data Center
for Glaciology at the University of Colorado in Boulder, US.
"I think it's a very significant paper; the results in it are certainly
very significant and new," he said.
"It does show that the [ice loss] trend has accelerated, and the
reported contribution to sea level rise also shows a significant
acceleration - so if you multiply these numbers up it puts us well
beyond the IPCC estimates for 2100."
Professor Barry was an editor on the section of the IPCC report dealing
with the polar regions.
|
On reflection
An ice sheet can lose mass because of increased melting on the surface,
because glaciers flow more quickly into the ocean, or because there is
less precipitation in the winter so less bulk is added inland.
The new research shows that in Greenland, about half the loss comes
from faster flow to the oceans, and the other half from changes on the
ice sheet itself - principally surface melting.
![Artist's impression of Grace satellite in orbit]()
The Grace satellites provide a twin eye
on gravity at the Earth's surface
|
Another analysis of satellite data, published in September, showed that
of 111 fast-moving Greenland glaciers studied, 81 were thinning at
twice the rate of the slow-moving ice beside them.
This indicates that the glaciers are accelerating and taking more ice
into the surrounding sea.
Melting on the ice sheet's surface acts as a feedback mechanism, Dr van
den Broeke explained, because the liquid water absorbs more and
reflects less of the incoming solar radiation - resulting in a heating
of the ice.
"Over the last 10 years, it's quite simple; warming over Greenland has
caused the melting to increase, and that's set off this albedo feedback
process," he told BBC News.
"Quite likely the oceans have also warmed, and it's likely that
explains the [acceleration of] outlet glaciers because they're warmed
from below."
Data provided over just the last few years by the Grace satellite
mission - used in this study - is giving researchers a closer view of
regional variations across the territory.
Grace's twin satellites map gravity at the Earth's surface in
unprecedented detail; and it is now possible to tease out from the data
that most of the mass is being lost in the southeast, southwest and
northwest at low elevations where the air will generally be warmer than
at high altitudes.
Professor Barry cautioned that the Grace mission, which has produced
valuable data about Antarctica as well as Greenland, has only a further
two years to run, and that no replacement is currently scheduled.
---
For graphic illustration of what we're facing, I can recommend James
Balog's time-lapse photography:
http://www.ted.com/talks/james_balog_time_lapse_proof_of_extreme_ice_loss.html
Cheers from Chiswick,
John
[1] RGS lectures
http://www.rgs.org/WhatsOn/London+Lectures/Monday+night+Lectures.htm
[2] Tipping points map
http://web.me.com/stewartbrand/DISCIPLINE_footnotes/Tipping_points.html
[3] Hansen on scientific reticence and sea level rise
http://www.iop.org/EJ/article/1748-9326/2/2/024002/erl7_2_024002.html
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