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.
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
Professor Roger Barry
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:
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.
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.
Why has no one mentioned one possible causes of the melting/sliding of the
major and thick Greenland's ice sheet could be due to the minute
temperature changes (primarily, warming up) of the earth/ground beneath ?
Or have I missed out on this ?
On Tue, Nov 17, 2009 at 7:04 PM, John Nissen <j...@cloudworld.co.uk> wrote:
> 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.
> *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*
> Professor Roger Barry
> 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 Baseline for cuts Black carbon Boxer-Kerry bill Business
> as usual Cap and trade Carbon capture and storage (CCS) Carbon dioxide
> (CO2) Carbon dioxide (CO2) equivalent Carbon intensity Carbon leakage Carbon
> neutral Carbon offsetting Carbon sequestration Certified Emission
> Reduction (CER) Clean Coal Technology Clean Development Mechanism (CDM) Climate
> change CFC CO2 COP15 Dangerous climate change Deforestation Emission
> Trading Scheme (ETS) EU Burden-sharing agreement Fossil_fuels Geological
> sequestration Global average temperature Global energy budget Global
> dimming Global warming Greenhouse gases (GHGs) Greenhouse effect IPCC Joint
> implementation Kyoto Protocol Major Economies Forum on Energy and Climate
> Methane Mitigation Natural greenhouse effect Non-annex I countries Per-capita
> emissions Pre-industrial levels of carbon dioxide REDD Stern review Technology
> transfer UNFCCC Waxman-Markey energy bill 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.
> 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.
> [image: 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:
> --
> You received this message because you are subscribed to the Google Groups
> "geoengineering" group.
> To post to this group, send email to geoengineering@googlegroups.com.
> To unsubscribe from this group, send email to
> geoengineering+unsubscribe@googlegroups.com<geoengineering%2Bunsubscribe@go oglegroups.com>
> .
> For more options, visit this group at
> http://groups.google.com/group/geoengineering?hl=.
I am pretty sure the term is already included in models, and I don¹t know of
any reason to think that it is increasing‹certainly not in comparison to the
increased heat from the surface due to warming and the meltwater that in
flowing down into the ice sheet is carrying heat (i.e., meltwater) well down
into the ice and likely all the way to the base.
Best, Mike MacCracken
On 11/18/09 7:12 AM, "Raymond Law" <r2007...@gmail.com> wrote:
> Hi everybody,
>
> Why has no one mentioned one possible causes of the melting/sliding of the
> major and thick Greenland's ice sheet could be due to the minute temperature
> changes (primarily, warming up) of the earth/ground beneath ? Or have I
> missed out on this ?
>
> Comments and advices, please !
>
> Raymond Law
> On Tue, Nov 17, 2009 at 7:04 PM, John Nissen <j...@cloudworld.co.uk> wrote:
>> 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.
>> 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 >> Professor Roger Barry
>> 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 Baseline for cuts Black carbon Boxer-Kerry bill Business as
>> usual Cap and trade Carbon capture and storage (CCS) Carbon dioxide (CO2)
>> Carbon dioxide (CO2) equivalent Carbon intensity Carbon leakage Carbon
>> neutral Carbon offsetting Carbon sequestration Certified Emission Reduction
>> (CER) Clean Coal Technology Clean Development Mechanism (CDM) Climate change
>> CFC CO2 COP15 Dangerous climate change Deforestation Emission Trading Scheme
>> (ETS) EU Burden-sharing agreement Fossil_fuels Geological sequestration
>> Global average temperature Global energy budget Global dimming Global warming
>> Greenhouse gases (GHGs) Greenhouse effect IPCC Joint implementation Kyoto
>> Protocol Major Economies Forum on Energy and Climate Methane Mitigation
>> Natural greenhouse effect Non-annex I countries Per-capita emissions
>> Pre-industrial levels of carbon dioxide REDD Stern review Technology transfer
>> UNFCCC Waxman-Markey energy bill 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.
>> Suggest additions <http://news.bbc.co.uk/1/hi/sci/tech/8329823.stm>
>> Glossary in full <http://news.bbc.co.uk/1/hi/sci/tech/8314171.stm>
>> 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.
>> 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.
>> --
>> You received this message because you are subscribed to the Google Groups
>> "geoengineering" group.
>> To post to this group, send email to geoengineering@googlegroups.com.
>> To unsubscribe from this group, send email to
>> geoengineering+unsubscribe@googlegroups.com
>> <mailto:geoengineering%2Bunsubscribe@googlegroups.com> .
>> For more options, visit this group at
>> http://groups.google.com/group/geoengineering?hl=.
>> --
>> You received this message because you are subscribed to the Google Groups
>> "geoengineering" group.
>> To post to this group, send email to geoengineering@googlegroups.com.
>> To unsubscribe from this group, send email to
>> geoengineering+unsubscribe@googlegroups.com.
>> For more options, visit this group at
>> http://groups.google.com/group/geoengineering?hl=.
Your Question: Why has no one mentioned one possible causes of the melting/sliding of the major and thick Greenland's ice sheet could be due to the minute temperature changes (primarily, warming up) of the earth/ground beneath? Or have I missed out on this?
I yesterday responded with this e-mail below to some recipients. As you raised the issues, please find my reply re-enclosed.
CHANGE IN HEAT TRANSPORTATION: SEASONAL MOULINS TO ACCUMULATIVE MOULINS
The key problem (as per Greenland) is the recent switch-over from Seasonal Impact Moulins at the periphery of Greenland's ice sheet to Accumulative Impact Moulins. that reside at the high altitude, atop Greenland's sub-glacial interior depression.
Until recently, virtually all moulins and crevasses formed along the margins of Greenland Ice Sheet where sub-glacial ground inclination is always seaward. Melt-water that falls through moulins or crevasses into ice takes with it the heat in it. At the edge of ice, this melt water (and heat in it) is quickly drained away from beneath ice sheet as the melt-water creeks soon poured out, taking the water and heat back to the sea when melting season comes to its end.
Today, most melt is perhaps located across the sub-glacial water-divide that takes any water falling through the ice ever deeper towards Greenland's interior bowl. The dentures and crevasses on Greenland's sub-glacial bedrocks and soils get filled with this water and ice above starts to float on top of these ponds of water that conveniently smoothens the trajectory the bottom of Greenland's Ice Dome moves along the rock surface.
As ice is an extremely good insulator, summer-time heat that falls with melt water stays under the ice here virtually forever (at least for all practical purposes). Therefore, these are Accumulative Impact Moulins and Crevasses as heat builds up summer-after-summer and is the only process where the greenhouse effect reaches 100% heat-retention.
David de Rotschild suggested me a project to pump water out from beneath ice sheet to increase friction, reduce the spatial reach of the separating layer of water from between ice and rock. This would not only improve the ice sheet anchorage, or mooring, to the bedrocks, but pumping water out would, in theory, also help removing the heat as well:
TRANSFORMATION OF POTENTIAL ENERGY OF MELT WATER TO MECHANICAL ENERGY
As sad as it might be to think melting Greenland ice destabilising, we must also be remembered that we have also been blessed by the same processes from the past:
When moulins and crevasses drain and generate, thin but, high-speed water jets under the ice dome, these water jets then cause the cavitation process to pulverise bedrocks, which has created plenty of sand for the builders.(1.)
On other occasions, large layers of water penetrate suddenly through ice when large melt water lakes drain themselves very suddenly through entire height of Greenland ice sheet: the plucking takes place where the rapidly falling water meets the bed rocks at the bottom of ice. Instead of pulverising the bed rocks into fine-grain sands, the massive blasts of highly pressurised water lifts the entire ice sheet up much more than a steady creeks originating from a moulin with steady water input. The ice rises and a tall temporary cavern allows a thick blanket of the fast-moving water create a blast of rapidly moving flash-floods under Greenland ice. The plucking is a rapid erosion force that quickly creates immensely large pieces of rock that are often seen as post-ice age huge boulder piles or fields. The boulders often get stuck again into the bottom of ice sheet when the temporary cavern spreads further out and the thins away. These boulders can then be carried away much further than by any stream of water alone could quickly do. These huge boulders created by plucking under ice sheet may become ice-embedded and transported hundreds of miles away by the sliding ice sheet.
Sometimes underwater tornado-like currents form under ice that leads to the kolking, which (just like tornado in the air) can lift and remove large chunks of the underlying material. Persistent turbulent currents under the ice sheet create the giant's cauldrons and potholes (water pouring via moulins over extended periods of time, when drainage out is stable, can create localised plucking and kolking which drill these formations into hard granitic rocks).
Where ice crashes without any pressurised, high-speed water jets, like at the terminus of glaciers (or sides of a glacier), moraine forms from the abrasive mixture of soil and moraine that is slowly pushed forward into piles, or ridges, by the moving glaciers.(1)
IMPORTANCE OF SUB-GLACIAL LAKES OVER SPILLING WITH ICE SHEET FAILURE AS RESULT
So, when Greenland Ice Sheet collapses by the various processes? The accumulation of melt water by the Accumulative Impact Moulins and Crevasses is absolutely vital factor.
As more and more warm water pours in and warms ice sheet's base cumulatively, further melt is ever easier by the Accumulative Impact Moulins pouring water in year-on-year. A situation would eventually arrive where Greenland's Ice Dome base below sea level would all be turned into water, topped by ice. But the melt water lake cannot indefinitely thicken under the ice sheet without this system becoming rapidly chaotic and unstable.
The melt water lake within Greenland's interior depression bowl, under the ice dome, need not reach sea table, nor exceed it, for the "ice sheet thrust" to occur: the bottom of Greenland's ice dome will never sail atop a flat water table. If it were so, we would be safe and have several centuries to await for the instability to occur if all bottom half of ice had to melt to the level of sea table and this flat pool of water was topped by the remaining ice sheet neatly floating on a flat water surfaces as if occurring on open seas or lakes. No.
As the melt water is created from the bottom of ice sheet, the edges of this subglacial melt lake water is pushed very rapidly and firmly up, the surface of this subglacial lake bent along its edges inside Greenland interior bowl, along the interfaces of rock and ice.
Just like the ice bergs swim in open water only 1/8 above surface. Once started, the rise of water table on this sub-glacial melt-water lake (that is squeezed between bed rock and ice) rises extremely rapidly along the ice-rock interface as the layer of water is not thick, but spread out in three dimensions along the interface. Very soon, this melt water lake surface reaches and exceeds the sea level when the final ice sheet slide out occurs.
What once may appear that there is huge amount of depth left in this thin melt water lake under the ice sheet, it is very quickly pushed up to sea level and above on the very limited space of the ice-rock interface before the ice sheet land containment failure finally occurs.
This is not matter of centuries, but years, once melt-water warmed Greenland ice sheet starts a rapid melt water accummulation along its very bottom...
The drainage of water should help. I have not yet come up mechanism how to pump water out enough which some geoengineering people (with better mind than mine) ought to resolve. If you have any queries, or need clarification, please let me know.
With kind regards,
Albert
-----
copy of yesterday's e-mail:
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
...
>> "I am pretty sure the term is already included in models, and I don’t know of any reason to think that it is increasing—certainly not in comparison to the increased heat from the surface due to warming and the meltwater that in flowing down into the ice sheet is carrying heat (i.e., meltwater) well down into the ice and likely all the way to the base. <<
Hi,
In our models the disequilibrium between the West Antarctic Ice Sheet which is losing weight, and the East Antarctic Ice Sheet that is gaining weight is creating ice sheet balance disequilibrium. In our view, this raises ground pressure under East Antarctica and decreases it under the West Antarctica. As the volume beneath the East Anatrctica is under increased compressional stresses, the displacement of liquids should drive these towards the West Antarctica if suitable conduits and connectivity between areas exists. If so, there should be volcanic activities increasing under the West Antarctic ice sheet.
I have suggested that the Pine Island Glacier might be a recipient of displaced volcanic liquids beneath its ice sheet as it has less pressure while the East Antarctica has more and would have a tendency to drive out liquids from beneath ground, if they can find way out. When volcanism under ice sheet melts ice away, and the water drains to sea, more displaced volcanic rocks could move in and melting of the ice sheet like Pine Island is very fast and could end up in a sudden burst of lava flood.
In our UN complaint, one issue is the isostatic ground-carrying-capacity being exceeded by ice accummulation (as in case of ice sheets there is a lack of geological driver, tectonic uplift, to support accummulation of tall grounds). When isostatic ground carrying capacity is exceeded, the base and grounds under ice sheets rapidly sink down. This leads the periphery of ice sheet (where ice is much thinner) starting to bulge out at the time when the ground-carrying-capacity under the thicker parts of the ice dome have been lost by excessive ground pressures. The interior subsidence of ice sheet creates a temporary tectonic uplift on the thin edges of ice sheet. This according to World Indigenous Nations' complaint, fed volcanic materials and caused the 'rapid ice age'. (The initial ice sheet was lost due to geothermal heat penetration from crevasses within fractured bed rocks leading to Eemian Interval. I do not elabore full view of the First Nations ideas of the fast ice age.) Only in Antarctica which is very large area in size for glacier, the middle was forced to bulge up generating Gamburtsev rise, while the pressure on the edges were down. Greenland is smaller and its edges gave away just like in Scotland, Norway and Kara Sea.
So, without taking the base heat discussion too much to the First Nations complaints at the United Nations, I would like to point to the possibility that the ice sheet mass balance can cause liquid displacements where there is movement of equilibrium states.
Kr, Albert
Date: Wed, 18 Nov 2009 09:18:21 -0500
Subject: Re: [geo] Greenland ice sheet - tipping in progress
From: mmacc...@comcast.net
To: r2007...@gmail.com; j...@cloudworld.co.uk
CC: Geoengineering@googlegroups.com; john.dav...@foe.co.uk; oliver.tick...@kyoto2.org; m.hu...@uea.ac.uk; albert_kal...@hotmail.com
I am pretty sure the term is already included in models, and I don’t know of any reason to think that it is increasing—certainly not in comparison to the increased heat from the surface due to warming and the meltwater that in flowing down into the ice sheet is carrying heat (i.e., meltwater) well down into the ice and likely all the way to the base.
Best, Mike MacCracken
On 11/18/09 7:12 AM, "Raymond Law" <r2007...@gmail.com> wrote:
Hi everybody,
Why has no one mentioned one possible causes of the melting/sliding of the major and thick Greenland's ice sheet could be due to the minute temperature changes (primarily, warming up) of the earth/ground beneath ? Or have I missed out on this ?
Comments and advices, please !
Raymond Law
On Tue, Nov 17, 2009 at 7:04 PM, John Nissen <j...@cloudworld.co.uk> wrote:
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.
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 Professor Roger Barry
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 Baseline for cuts Black carbon Boxer-Kerry bill Business as usual Cap and trade Carbon capture and storage (CCS) Carbon dioxide (CO2) Carbon dioxide (CO2) equivalent Carbon intensity Carbon leakage Carbon neutral Carbon offsetting Carbon sequestration Certified Emission Reduction (CER) Clean Coal Technology Clean Development Mechanism (CDM) Climate change CFC CO2 COP15 Dangerous climate change Deforestation Emission Trading Scheme (ETS) EU Burden-sharing agreement Fossil_fuels Geological sequestration Global average temperature Global energy budget Global dimming Global warming Greenhouse gases (GHGs) Greenhouse effect IPCC Joint implementation Kyoto Protocol Major Economies Forum on Energy and Climate Methane Mitigation Natural greenhouse effect Non-annex I countries Per-capita emissions Pre-industrial levels of carbon dioxide REDD Stern review Technology transfer UNFCCC Waxman-Markey energy bill 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.
Suggest additions <http://news.bbc.co.uk/1/hi/sci/tech/8329823.stm> Glossary in full <http://news.bbc.co.uk/1/hi/sci/tech/8314171.stm>
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.
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
...
> 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.
> _____
> From: John Nissen [mailto:j...@cloudworld.co.uk]
> Sent: 18 November 2009 14:32
> To: Oliver Tickell
> Cc: 'Veli Albert Kallio'; m.hu...@uea.ac.uk; 'John Davies';
> christ...@christianclot.com; 'Edward Hanna'; 'R.D. Schuiling'; John Latham;
> Geoengineering; P. Wadhams; Mark Serreze
> Subject: Re: [geo] Greenland ice sheet - tipping in progress
> 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.
> Oliver Tickell
> Kyoto2 - for an effective Climate Protocol
> www.kyoto2.org > --
> 379 Meadow Lane
> Oxford OX4 4BL
> From: Veli Albert Kallio [mailto:albert_kal...@hotmail.com]
> Sent: 17 November 2009 16:31
> To: m.hu...@uea.ac.uk
> Cc: John Davies; oliver.tick...@kyoto2.org; christ...@christianclot.com;
> Indianice FIPC; John Nissen; Edward Hanna
> Subject: RE: [geo] Greenland ice sheet - tipping in progress
> 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
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.
From: John
Nissen [mailto:jn@cloudworld.co.uk] Sent: 18 November 2009 14:32 To: Oliver Tickell Cc: 'Veli Albert Kallio'; m.hulme@uea.ac.uk; 'John Davies';
christian@christianclot.com; 'Edward Hanna'; 'R.D. Schuiling'; John
Latham; Geoengineering; P. Wadhams; Mark Serreze Subject: Re: [geo] Greenland ice sheet - tipping in progress
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.
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.
Oliver Tickell
Kyoto2 - for an effective Climate Protocol www.kyoto2.org
--
379 Meadow Lane
Oxford OX4 4BL
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
|
