This is a very practical project that can be done cheaply. We should be keep it simple; putting up the 10 km cable and testing its effects on the climate, warming of the icebergs, melt rate etc.
A slightly more complicated idea would be to put more cables north of the first cable every time they advance northward and the channel to the south opens up. They can be corralled into a dense ice pack north of the cables. This might reverse the glacier breakup. On Oct 2, 9:17 am, Veli Albert Kallio <[email protected]> wrote: > Reply: > > Mike MacCracken wrote: > > What about doing this across Jakobshaven and other fjords that allow ice > streams to flow rapidly? > > Mike > > There would be benefits from constraining a flow of ice bergs from Ilulissat > (Jacobshavn) Ice Fjord and then storing them on off shore enclosures nearby > or in front of the mouth of the ice fjord: in Antarctica it has been seen > that ice shelves are constricting the flow of ice from behind. Thus, if a > sufficient collection of ice bergs is accummulated, the flow of ice from > Ilulissat ice fjord would be reduced - just like the breaking ice shelves are > doing the opposite. > > This matter has already been extensively reported by Helsingin Sanomat (a > Finnish correspondent news sheet to The Times or New York Times) where Risto > Isomaki of Atmosmare discussed the matter of collecting ice bergs extensively > from Jakobshaven Ice Fjord. I only summarise his main points below, the link > is below but I don't see point translating it in all its entirety. > > http://www.hs.fi/artikkeli/Luomakunnan+toivo/1135238269674 > > Key Points in Ice Berg Management: > > The out put of ice bergs in Jakobshaven Ice Fjord has trebled over the decade > as the melt water accummulation under its ice stream reduces the contact of > ice with the base rocks as a growing layer of water separates the two from > each other, producing a lubrication effect. > > The main observation of Risto Isomaki is the huge number of ice bergs calving > off the ice fjord. Currently Jacobshaven Ice Fjord discharges 27 km3 of ice > annually which obviously produces enormous number of ice bergs in course of a > year. The mouth of the ice fjord is over 15 kilometres wide. Although new ice > bergs are forming at slow rate to naked eye, the number of ice bergs emerging > each day is a huge one. > > If the ice bergs can be successfully schooled by tug boats and placed into an > enclosure (constrained by suspension cabling or some other form of barrier) a > problem remains: as more and more ice bergs emerge the ice berg enclosure > will automaticlly grow ever bigger and bigger. In the end it would form a > very large artificial ice shelf kept in place by cabling and nets and managed > by a fleet of tug boats. > > Ilulissat (nearby) is one of the most important business and transport > logistics hubs in Greenland which serves the Central and North Greenland and > is the main container and oil port that serves the Northern Greenland. The > port of Ilulissat (the old Danish name "Jacobshavn" translates as "Jacob's > Port") is only a few kilometres from the mouth of the ice fjord and is every > now and then blocked by a stray drifting ice bergs. This port cannot be > relocated easily as the towns livelihood depends entirely on it and it being > a key employer as well. > > The management issue besides funding the tug boats and the cabling also must > take into consideration of the storm events when the winds might overtake the > suspension cabling and the tug boats capability to anchor and manage the > artificial ice berg enclosure consisting not a solid ice shelve, but a > mismash of broaken ice that might be thrown against Iluiissat and blocking > off its port until all accummulate ice is cleared. The more successful the > artificial ice shelve, the larger its collection of ice bergs, the more > problematic would it become if stray ice bergs escaped at once and were > thrown towards and around Ilulissat and the other towns. The ice bergs > (unlike sea ice) has a large wind facing edge, as they are often as tall as > they are wide (unlike sea ice which is flat). > > The risk management issues (risks to human life in handling the ice bergs and > the impact of possible large scale ice berg strays) and the cost - benefit > analysis needs to be conducted whether this could help preserving the ice in > Greenland by slowing down the ice flow in the fjord. > > My concern is the large amount of work and environmental impact involved, > whether there is enough benefits, and also the warming climate which may make > it ineffective as Greenland's ice sheet will destabilise in other ways as > climate warms up (See below: UK Meteorological Office's model released this > week that the mean annual temperature of the entire Arctic to raise +15.2C, > the Arctic Basin to see the mean temperature rise between +16C and +20C). > > http://www.metoffice.gov.uk/climatechange/news/latest/four-degrees.html > > Dr Betts said: “Four degrees of warming, averaged over the globe, translates > into even greater warming in many regions, along with major changes in > rainfall. If greenhouse gas emissions are not cut soon, we could see major > climate changes within our own lifetimes.” > > High-end temperature change > > Fig 1. Comparison of surface temperature projections from the high-end > emissions scenario, without carbon cycle feedbacks. Temperature increases > between 1961-1990 and 2090-2099, averaged over all high-end members. > > In some areas warming could be significantly higher (10 degrees or more). > > The Arctic could warm by up to 15.2 °C for a high-emissions scenario, > enhanced by melting of snow and ice causing more of the Sun’s radiation to be > absorbed. > > These temperatures +16-20C may well warrant the answer to the well > intentioned question by a member of public during "Arctic - Mirror of Life" > symposium in Greenland querying when the current rate of global warming might > be sufficient enough for people to start planting palm trees in their gardens > (there is a nostalgia of ancient fossilised palm trees found in the high > Arctic, and in few places people have made a mock-up plastic palm trees as > their garden decor in Alaska). > > Kind regards, > > Albert Kallio > > Date: Fri, 2 Oct 2009 10:42:21 +0100 > From: [email protected] > To: [email protected] > CC: [email protected]; [email protected]; > [email protected]; [email protected] > Subject: Re: [geo] Re: Robeson Channel Suitable for Suspension Cabling to > Block Prevent Southward Ice Movement > > Hi all, > > Some time ago, Albert and I discussed cables and barriers at length - and at > a length to cross straits. You really want a valve, that will let ice flow > in one direction (North) but not the other (South). It's quite difficult to > do that with a cable. > > My thoughts are that a floating barrier might be best. It can be rounded and > point into the ice, so that ice pressure becomes a compression of the > barrier. Basically what you want is to create an ice jam of ice flows (or > icebergs) on one side of the barrier which would then take most of the > pressure as the ice builds up. The barrier could be made across a fjord or > across straits. > > The barrier would be made of sections, so it could come apart to let ice flow > in the opposite direction (possibly in two sections, like canal lock gates). > The barrier could possibly be made out of pykrete [1], which has excellent > compressional strength (over twice as strong as normal ice) and good tensile > strength as well (much better than concrete) to give it rigidity, while > having a density less than water so it floats (just). > > One major problem with such a barrier (across straits) could be when the wind > is from the North, while the sea current is from the South, keeping the > barrier open. > > BTW, I've seen recent research suggesting that there is a stable weather > condition which can sit over the North Pole, with winds which tend to > disperse the ice. This condition is considered to have been instrumental in > the unprecedented sea ice retreat in 2007. Perhaps one of you can find a > reference, please. > > Cheers from Chiswick, > > John > > [1]http://en.wikipedia.org/wiki/Pykrete > > Mike MacCracken wrote: > > What about doing this across Jakobshaven and other fjords that allow ice > streams to flow rapidly? > > Mike > > On 10/1/09 9:25 AM, "Veli Albert Kallio" <[email protected]> wrote: > > Dear All, > > Please find enclosed a brief satellite animation on the Robeson Channel from > this summer which suggest that use of bridge-style suspension cabling could > hold ice in place and prevent it moving into the warm waters further along > the channel between Ellesmere Island and Greenland. The link attached below > which shows the summertime ice movements. > > The shortest suspension cables would be Ellesmere - Hans Island - Greenland > each stretch about 10 kilometres in length. (The concept is to create ice > congestion behind barrier that is self-locking jam of pack ice behind cable > that remains longer in the cold waters.) > > On the negative side, the ice amount south of any successful cable barriers > will decrease. The impact of cables for boats, whales and perhaps other large > fish and wild life would also have to be addressed. After melting, the > barrier cable is lowered to the seafloor when ice is on northward move or > there is a lack of ice, the barrier is raised up to surface whenever there is > ice flow moving southward. It is also raised up to surface for the winter > freeze. > > In Nunavut, the suspension cabling could help to keep the North West Passage > clear of thick sea ice floes that damage ships while preserving ice on the > north side of the channel. This might help justify such a system at least in > Nunavut. The profile of the Swalbard Islands and Franz Joseph Land could also > be enlarged by blocking the straights by cables. This would increase the ice > congestion behind these archipelagoes and decrease some sea ice escape from > the high Arctic Basin. > > I have not considered blocking of the Fram Staight due to its width, but > materially the largest amount of sea ice loss through escape will occur > there. The barriers can slow down ice movement and loss to the south due to > decreases in ice movements but if ice melts away due to warm weather behind > barrier, these measures become all but useless. > > Kind regards, > > Albert > > From: [email protected] > To: [email protected] > Subject: Greenpeace ... > > read more » --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "geoengineering" group. 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