Possible Iceberg Wrangling in the Southern Ocean

[AbruptSLR]

Hansen et al. (2015) (see the discuss in the Consequence folder of this forum at the first link below), have cited some of the possible positive feedback mechanisms and negative consequences of the ice sheets abruptly losing ice mass this century.  In that "Hansen et al paper: 3+ meters SLR by 2100", I speculated on the possibility of wrangling Southern Ocean icebergs to both reduce the positive feedback mechanisms and the negative climate consequences cited by Hanse et al. (2015).  As it seems inappropriate to explore this topic in the "Consequence" folder, I open this thread on "Possible Iceberg Wrangling in the Southern Ocean" in this "Policy and solutions" folder, in order to discuss: (a) the nature of Southern Ocean icebergs both now & in the future; and (b) the feasibility of wrangling Southern Ocean icebergs either as a future freshwater source and/or as a form of geoengineering.

http://forum.arctic-sea-ice.net/index.php/topic,1327.250.html


As most readers are likely unfamiliar with the nature of Southern Ocean icebergs, I begin with the first link to NASA Earth Observatory that discusses how the U.S. National ice Center (NIC) tracks icebergs adrift off the coast of Antarctica that meet the 19-kilometer minimum criteria for tracking (see the associated image of iceberg B-34 breaking off the Getz Ice Shelf and associated extracts).

http://earthobservatory.nasa.gov/IOTD/view.php?id=85727

Extract related to the first image: "On March 6, 2015, the U.S. National Ice Center (NIC) discovered a new iceberg adrift off the coast of Antarctica. Measuring 27 kilometers (17 miles) long, iceberg B-34 meets the 19-kilometer minimum required for tracking by the NIC.
The berg appears to have fractured from West Antarctica’s Getz Ice Shelf and moved out into in the Amundsen Sea sometime in mid- to late-February 2015. The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra and Aqua satellites acquired these images spanning the calving event. The first image (left) shows the iceberg on February 16, when it was still attached to the ice shelf. By February 28 (middle), it appears to have separated somewhat. By March 5 (right), it is floating freely."


Extract: "B-34 is the 34th iceberg from the “B” quadrant of Antarctica (located between 90 degrees East and 180 degrees) to be tracked by the NIC. The new berg is still smaller, however, than the much older B-15T—a fragment of B-15 that initially broke off from the Ross Ice Shelf in March 2000.
Large icebergs can have large-scale impacts on the Southern Ocean. For example, as the bergs melt, the addition of cold, fresh water to the saltwater ocean can affect ocean currents and circulation. Researchers have shown, however, that even more fresh water comes from the melting of smaller and much more numerous bergs.

References
•   NASA Earth Observatory (2015, April 12) Iceberg B-15T Still Adrift. Accessed April 20, 2015.
•   Tournadre, J. et al. (2015, March 26) Large icebergs characteristics from altimeter waveforms analysis. Journal of Geophysical Research: Oceans, 120 (3), 1954-1974.
•   U.S. National Ice Center (2015, March 6) Iceberg B-34 Found in the Amundsen Sea. Accessed April 20, 2015."

The next link leads to a US Coast Guard site that tracks the location of icebergs (focused on the North Atlantic) which provides the second attached image showing the location of large Southern Ocean icebergs in 2011, and I note that such large icebergs can stay adrift for decades while they slowly melt.

http://www.navcen.uscg.gov/?pageName=IcebergLocations

Caption for Second image: "Typical distribution of icebergs around the Antarctic continent"

[AbruptSLR]

The following August 2011 article cited by bligh8 both chronicles some of the economic failures and some of actual accomplishments for iceberg wrangling through the centuries.  The following selected extracts beginning by citing how in the mid-1800's icebergs were successfully towed for decades along the coast of Chile, the cites some slightly more modern conceptual schemes including the RAND Corporations concept shown in the attached image, and concludes by citing that as of 2011 well over 4 million tonnes of icebergs have been economically wrangled by oil companies operation in Canada:


http://www.theatlantic.com/technology/archive/2011/08/the-many-failures-and-few-successes-of-zany-iceberg-towing-schemes/243364/

Extract: "Mid 1800s: According to the Encyclopedia of Antartica, small icebergs were towed from southern Chile up to Valparaiso as part of the brewery supply chain. A Chilean researcher said, "The icebergs were towed by ships of the conventional type. Sometimes the icebergs were supplied with sails to utilize the prevailing winds. The ice was used for refrigerating purposes in the breweries and was generally substituted for artificial ice." Apparently, the business continued until about the turn of the century."

…

October 1973: The RAND Corporation dives 96 pages deep on "Antarctic Icebergs as a Global Fresh Water Source" for the National Science Foundation. By far the most comprehensive scheme to date, J.L. Hult and N.C. Ostrander went far beyond previous speculations to create an actual paper model of how an "iceberg train" could work. This is classic RAND work with lots of math and appendices. It made them a national media story. "Bringing icebergs to where the water is needed was suggested by John Isaacs of Scripps Institute of Oceanography in the 1950s," Hult told the AP. "It is our job to show how practical it is." Their scheme was inspired more by theoretical least-cost equations more than common sense. For example, they suggested sending a floating nuclear power plant to provide power for the operation.

…
January 3, 2007: Everyone's got an angle on iceberg towing, I always say. An Environmental Protection Agency report on climate change suggests, "Experiments such as towing icebergs into warmer water could also be undertaken to provide additional insights into the behavior of glaciers under radically different conditions." I really would like to see that suggestion given to Republican Congressmen.

…

Present: Iceberg towing is now commonplace in the Arctic near oil rigs. There are fairly standard procedures for dealing with all sizes of bergs and some upwards of 4 million tonnes have been towed successfully, according to a Canadian government report. "

[AbruptSLR]

Per the attached Sentinel 1a satellite image of the ice mélange just west of the Thwaites Ice Shelf taken on September 3 2015, calved icebergs from the Thwaites Glacier that are forming the mélange are almost exactly the size of icebergs assumed by the RAND Corporation for their iceberg train concept.  If Pollard et al. (2015) are correct and cliff failures accelerate for the Amundsen Sea Embayment, ASE, marine glaciers; then most future icebergs from the ASE will fall into this relatively towable size category.

Edit: I note that as Hansen et al. (2015) indicate that current iceberg melting in the Southern Ocean is currently resulting in a positive feedback promoting global warming, it would not seem unreasonable for a coalition of governments (say the USA, Chile, Australia and Brazil) to demonstrate the practicability of capturing and towing such iceberg trains to: Chile, Western Australia and to Brazil, using prevailing wind and ocean current patterns to facilitate the towing activity.

[bligh8]

What is being suggested, .towing a ice berg out of the southern oceans is simply not feasible.  Between the outer edges of the Amundsen  Sea to the western edge of the Humboldt Current is about 1500 miles across the most inhospitable place on Earth.
There is an 18% chance daily that one would encounter a storm/gale, understandable since storms have been circling Antarctica, in modern day terms, forever.

The logistics involved in towing something so massive in such conditions are the main reason it’s never been tried.  Even in calm waters moving a small berg is daunting, in a storm the ship would be forced to disconnect or suffer a broken tow line. 

In the North Atlantic they do deflect bergs early to avoid collision with oil rigs.
They are also prepared to move the rig when it’s not feasible to deflect the berg.

This is something that’s been talked about for centuries in a limited capacity, but moving a berg from south of 65deg South in such extreme violent conditions….I’ll agree with the Rand assessment…..a nuclear device would be in order.

In every picture you have ever seen when someone is setting-up or towing a berg the surface waters are always nearly flat. In the southern oceans with a constant parade of violent storms, it’s not feasible and will never happen,  just my opinion. I’ve seen what it is down there, a unimaginable senseless fury bent on the destruction of life.

http://www.bom.gov.au/australia/charts/viewer/index.shtml?type=mslp-precip&tz=AEDT&area=SH&model=G

[TerryM]

In WWII, Canada was developing an iceberg aircraft carrier. Perhaps with modern drone tech. a pilotless, nuclear powered iceberg could be coaxed away from the southern seas. I can't imagine such a project ever being priced reasonably, but perhaps if a long term drought made economic considerations mute & millions of thirsty people made something similar a necessity?


Sorry ASLR, I just can't contemplate it ever being attempted, as bligh8 notes, thats a bunch of nasty water.


Terry

[AbruptSLR]

The hardest thing about fighting any aspect of climate change is finding sufficient human will power to face a challenge.  Certainly, it would be better for everyone to have reduced GHG emissions 30-years ago; however, as the ASE marine glaciers are past their tipping point, this approach (while helpful) is no longer sufficient to prevent trillions of dollars of damage for WAIS ice mass loss.  Therefore, while I gain no benefit from arguing for wrangling Southern Ocean icebergs, in the interest of showing a little human initiative I will point out that:

(a) Large icebergs typically circumnavigate Antarctica several times; which means at some time they are north of 60S to pass through Drakes Passage, so at least it seems reasonable about nudging such icebergs north into the Humboldt Current.
(b) Russia uses nuclear powered icebreakers on a routine basis, so I don't think that we should be coloring RAND's concept as extreme.
(c) If a storm comes (and with modern satellites there is adequate warning) there is absolutely no problem with releasing an iceberg or even a train of icebergs, as it will still be recoverable when the storm is past.

If one believes Hansen et al. (2015) then it would make sense for some government (& I am thinking the US federal government) to practice nudging such icebergs northward out of the Southern Ocean, as this would decrease the positive feedback mechanism that Hansen et al. (2015) identify.

If one does not believe Hansen et al. (2015) then waiting until the ASE marine glaciers start to retreat rapidly just means that a bigger effort would be required to avoid the trillions of dollars of damage associated with the extremely high potential planetary energy imbalance identified by Hansen et al (2015).  However, if making an effort is too much bother then we can all just pass these problems forward to future generations.

Edit: (1) In my Reply #2 I show a Sentinel 1a image of an iceberg mélange associated with the Thwaites Glacier. I note that while currently this mélange is kept from dispersion by the presences of both the Thwaites Ice Shelf (and by the temporarily grounded large iceberg shown in the upper-left (northeast) corner of the image; once these features collapse I expect the mélange of icebergs (the size contemplated for towing by the RAND Corp) to more out into the Southern Ocean and from there directly towards Drakes Passage.
(2) I note that there is a port at Punta Arenas in the Straits of Magellan that could provide logistical support for any vessels (nuclear powered icebreakers or not) that might be deployed to nudge icebergs either into the Humboldt  Current, or northward along the eastern coastline of Argentina.
(3) The following link shows a video of the approximately 20.5 miles long, 12.4 miles wide and  1,640 feet thick iceberg B31 moving out of the ASE into the Southern Ocean (so it is not just my imagination that future icebergs will move out of the ASE into the Southern Ocean and then to Drakes Passage).


http://mashable.com/2014/04/25/an-iceberg-6-times-the-size-of-manhattan-is-drifting-into-southern-ocean/

[AbruptSLR]

The following linked (2014) articles discuss paleo-evidence about iceberg-rafted debris (IBRD) from the Scotia Sea from eight events of increased iceberg flux from various parts of the AIS between 20,000 and 9,000 years ago that passed through Drakes Passage.  This IBRD evidence proves that large flotillas of icebergs have passed through Drakes Passage, and may do so again:

Trevor Williams, (2014), "Climate science: How Antarctic ice retreats", Nature, doi:10.1038/nature13345

http://www.nature.com/nature/journal/vaop/ncurrent/full/nature13345.html


Summary: "New records of iceberg-rafted debris from the Scotia Sea reveal episodic retreat of the Antarctic Ice Sheet since the peak of the last glacial period, in step with changes in climate and global sea level."


M. E. Weber, P. U. Clark, G. Kuhn, A. Timmermann, D. Sprenk, R. Gladstone, X. Zhang, G. Lohmann, L. Menviel, M. O. Chikamoto, T. Friedrich & C. Ohlwein, (2014), "Millennial-scale variability in Antarctic ice-sheet discharge during the last deglaciation", Nature, (2014), doi:10.1038/nature13397


http://www.nature.com/nature/journal/vaop/ncurrent/full/nature13397.html


Abstract: "Our understanding of the deglacial evolution of the Antarctic Ice Sheet (AIS) following the Last Glacial Maximum (26,000–19,000 years ago) is based largely on a few well-dated but temporally and geographically restricted terrestrial and shallow-marine sequences. This sparseness limits our understanding of the dominant feedbacks between the AIS, Southern Hemisphere climate and global sea level. Marine records of iceberg-rafted debris (IBRD) provide a nearly continuous signal of ice-sheet dynamics and variability. IBRD records from the North Atlantic Ocean have been widely used to reconstruct variability in Northern Hemisphere ice sheets, but comparable records from the Southern Ocean of the AIS are lacking because of the low resolution and large dating uncertainties in existing sediment cores. Here we present two well-dated, high-resolution IBRD records that capture a spatially integrated signal of AIS variability during the last deglaciation. We document eight events of increased iceberg flux from various parts of the AIS between 20,000 and 9,000 years ago, in marked contrast to previous scenarios which identified the main AIS retreat as occurring after meltwater pulse 1A and continuing into the late Holocene epoch. The highest IBRD flux occurred 14,600 years ago, providing the first direct evidence for an Antarctic contribution to meltwater pulse 1A. Climate model simulations with AIS freshwater forcing identify a positive feedback between poleward transport of Circumpolar Deep Water, subsurface warming and AIS melt, suggesting that small perturbations to the ice sheet can be substantially enhanced, providing a possible mechanism for rapid sea-level rise."

See also (with extract):

http://news.discovery.com/earth/global-warming/antarctic-iceberg-flotilla-caused-huge-sea-level-rise-140528.htm

Extract: "Antarctica's melting glaciers launched so many icebergs into the ocean 14,600 years ago that sea level rose 6.5 feet (2 meters) in just 100 years, a new study reports. The results are the first direct evidence for dramatic melting in Antarctica's past — the same as predictions for its future.

"The Antarctic Ice Sheet had been considered to be fairly stable and kind of boring in how it retreated," said study co-author Peter Clark, a climate scientist at Oregon State University. "This shows the ice sheet is much more dynamic and episodic, and contributes to rapid sea-level rise.""

[sidd]

i cannot resist putting up one of my favorite pics from the Galileo spacecraft of the four or five storms constantly present around antarctica. (This is a "fake" image, there is no terminator ...)

[bligh8]

Careful with the “fake” image, one could end up on the wrong platform potentially heading in the wrong direction! A train of ensuing errors…

[AbruptSLR]

i cannot resist putting up one of my favorite pics from the Galileo spacecraft of the four or five storms constantly present around antarctica. (This is a "fake" image, there is no terminator ...)

I have no interest in downplaying the severity of the Southern Ocean's storm activity; nevertheless, the linked article indicates that despite this severity the Southern Ocean is still overfished, including currently for krill, which serves predominately as feed for farmed fish or omega-3 nutritional supplements for humans.  If something as cost competitive as fish food can finance fishing fleets that can routinely operate in the Southern Ocean, then I think that it is safe to assume that nuclear powered icebreakers could also routinely operate there:


http://www.asoc.org/advocacy/antarctic-wildlife-conservation/southern-ocean-fisheries

Extract: "It is true that Southern Ocean experiences less fishing activity than many other parts of the world. Due to the dangerous conditions, fishing in Antarctica is difficult and expensive.
But as with fisheries everywhere, Antarctic fisheries have still experienced overfishing, data uncertainties, and illegal, unreported, and unregulated (IU) fishing.

…

Today, the primary species targeted by commercial fishing operations are Antarctic krill and toothfish, both the Patagonian and Antarctic species. Antarctic krill is mostly processed into feed for farmed fish or omega-3 nutritional supplements for humans, although some human food products are made from krill.

Krill has always been a species of interest to fishing operators because of its high biomass, but a combination of improved fishing and processing technology and new uses for krill have renewed commercial interest in the fishery. Unfortunately, this increased interest comes at a time when the krill population appears to be in long-term decline."

[AbruptSLR]

Probably the strongest argument that sidd, bligh8, & Terry have against the feasibility of wrangling Antarctic icebergs is that the economics don't currently work (compared to desalination) without government subsidies and currently no government is going to subsidize such an effort (now or in fifteen years).  This is a strong argument as people will heavily discount the trillions of dollars of future losses to about zero motivation in today's dollars.  Thus if this concept is going to have any prospect of being realized, then it would seem that I will need to dabble in the economically uncertain market for freshwater from such icebergs circa 2030 (note that iceberg B-31 contained about 16 cubic kilometers of fresh water when it calved).

In this regard, while the linked article focuses on the water needs of Central Asia starting by mid-2030, comparable statements could be made for large parts of the world in that timeframe.  Furthermore, circa mid-2030 fossil fuel should include carbon pricing thus increasing the cost of desalination; which could represent a window of opportunity for Antarctic icebergs to penetrate the water supply markets in at least: Africa, South Asia, Australia and South America.  In future posts I will endeavor to discuss means to improve the economics of freshwater supply from Antarctic icebergs after 2030:

http://www.azernews.az/analysis/87483.html

Extract: "Around the world, 748 million people lack access to a clean drinking water source, while billions more lack drinking water that barely meet safety standards, according to a UN report released in 2015.
The Food and Agriculture Organization (FAO) forecasts that more than 4 billion people will be living under serious water shortages by the mid-2030.
With its limited water resources, the Central Asia states may also face sharp decreases in water supply in about 35 years as a result of global warming and drought.
The water resources will decrease after 2050 in some regions of Central Asia, estimates professor Martin Hoelzle of the Alpine Cryosphere and Geomorphology Research Group at the University of Fribourg (Switzerland).
Glaciers high up in the mountains hold an enormous share of the overall drinking water sources of Central Asia. Up to 85 percent of Kyrgyz's water reserves, for example, come from glaciers. However, the fresh water reserves in Kyrgyzstan are significantly declining on an annual basis.
Kyrgyzstan’s main reserves of fresh water concentrate in its glaciers, which hold about 750 billion cubic kilometers of fresh water.

…

The total volume of water on the Earth is about 1.4 billion cubic kilometers, 2.5 percent of which is fresh water, totaling 35 million cubic kilometers.
As many as 75 percent of the world reserves of fresh water are contained in glaciers and icebergs.
Currently, more than 80 countries lack adequate water supply, and it is becoming urgent to many regions of the world due to demographic growth, global warming, and a range of other reasons.
Brazil leads with 19 percent of the world's fresh water reserves, while Russia contains 10 percent and Canada, Indonesia, China each hold 7 percent.
The replenishment of fresh water basically depends on evaporation from the surface of the oceans.
Over 500,000 cubic kilometers evaporates from the oceans annually, while more than 70,000 cubic kilometers evaporates from land sources."

See also:

http://www.livescience.com/51876-asia-glaciers-rapidly-shrinking.html

http://www.businessinsider.com/r-business-as-usual-will-create-a-thirsty-planet-in-15-years-says-un-2015-3

[AbruptSLR]

The first two related links lead to a discussion of Georges Mougin’s plan to tow icebergs for freshwater supply; which has proven to date to be uneconomical compared to desalination.  Mougin's scheme uses a floating geotextile skirt (which I concur with) around the perimeter of the iceberg (see the first two images) to both reduce the rate of ice melting in transit, and to retain a freshwater pool that can then be piped to shore:

http://www.3ds.com/icedream/
http://www.3ds.com/icedream/documentary/

In order to improve the economics of Mougin's scheme I propose that once the nuclear powered icebreaker has nudged tabular icebergs out of the Southern Ocean, then a much smaller vessel could be used to tow such icebergs relatively long distances using series parachute drogue(s) (or para sea anchors) for main propulsion by using winches on the deck of the smaller vessel and a tender vessel to periodically re-deploy the series parachute drogue(s) in front of the iceberg.  The third image shows at typical series drogue (see also the following Wikipedia link & extract)


https://en.wikipedia.org/wiki/Drogue


Extract: "Retired aeronautical engineer Don Jordan tested what is now known as the series drogue, originally conceived and patented by E.J. Pagan and later patented by Sidelnikov in 1975; however, before his tests, numerous mariners had experimented with pulling several large drogues in series. Like Sidelnikov, Jordan expanded upon this idea, and affixed a large number of small parachute drogues to a nylon rope with a weight at the end. The large number of smaller drogues results in there always being a drag force on the line; it does not have to be adjusted to be in phase with the waves as the drag is spread out over many waves. Because the drogue line is prevented from becoming slack there is no jerking or snapping of high loads on the line. This prevention reduces damage to deck fittings and reduces the chance of breakage. The number of small parachutes, the length and thickness of the line, and the size of the end weight are all matched to the displacement of the boat. Another key design feature is the V-bridle. The two attachments should be made at the outer corners of the transom with the lengths of the two bridle lines being 2.5 times the width between the attachment points. According to Jordon, special reinforcement is required for the bridle attachment since Jordon projects that forces of 7,000 lb. to 27,000 lb. and even higher can occur with a breaking wave strike. With this deployment no steering of any kind is needed.
The series drogue does not have to be adjusted during a storm. Neither do other storm drogues if they are fully deployed and they adhere to the constant rode tension theory. As sea conditions requiring a drogue are usually hazardous to be on deck, it’s usually smart to fully deploy all of the rode associated with a storm drogue. Also, the series drogue can be deployed safely with one hand from the cockpit as can any other storm drogue. Recovering a series drogue before the storm abates takes effort, but the process is safe and straightforward. It can be winched in on sheet winches if the cones are small enough to travel around the winch drum without jamming. The series drogue is currently made by three manufacturers, one in Australia, one in the United States and one in the United Kingdom. Any sailmaker can make one and you can make one yourself, though it is a tedious job."

Conceptually, such a series parachute drogue could look like a series of parachute sea anchors as shown in the fourth image (where winches would be on the deck of the vessel shown and an iceberg would be towed behind the vessel) from the following Sea-Guardian website:

http://sea-guardians.weebly.com/

Propulsion using such a series parachute drogue should be more efficient than using conventional propeller propulsion; thus improving transit economics.

[bligh8]

Economics is not my problem it’s feasibility.  I’ve already stated the challenges of towing a berg North from 65S to a small degree.  But in addition one cannot tow a tabular berg, they simply cannot withstand the sheer forces involved and would break up in short order, in those conditions.

In addition any sea anchor deployed in a major ocean current would quickly sink the vessel it would get caught in the current and drag the vessel under. Those devices are designed to stop the forward momentum so that a vessel can hold position and not struggle to stay afloat in a heavy seaway. One would find precautions upon opening the packaging about this as in…”Do not deploy in major ocean currents”

A series drogue is designed to slow a smaller vessel (mounted off the stern) so that it does not race down the face of a large wave and bury the nose of the vessel in the trough resulting in the vessel pitch poling (end over end).

Neither of the two devices outlined are designed for propulsion; they are designed for slowing or stopping a vessel. 

I’ve used a para tech sea anchor and they work well allowing the boat and crew to bop up and down comfortably without some terrifying surfing down the front of some giant wave.   They are however very very difficult to retrieve and I would not deploy one again unless I felt there was an immediate threat of losing the vessel.  I’ve also use a sea drogue
And they also work very well pinning down the stern accomplishing two things, no surfing down a wave nor slewing the vessel around sideways and rolling over, they are a little easier to handle and retrieve.

Then again this entire discussion hinges on our ability to tow a berg from south of 65deg south which is impossible, ok, maybe not impossible on the off chance we might get one small berg, but this idea sadly aligns itself with the notion that we could construct a pipeline from the great lakes to southern California for irrigation and drinking water.

Additionally fishing is one thing, hooking and towing a giant piece of ice is an entirely different game.

I read and agree, water across much of the planet is and will become more problematic as agw moves forward.

[P-maker]

ASLR,

suggest you change the topic of this thread to (Im)possible Iceberg Wrangling in the Southern Ocean.

Cheers P

[ritter]

Eh, why tow it. Just set up a water dehydrating factory and bring the stuff back in cans... 

[AbruptSLR]

Eh, why tow it. Just set up a water dehydrating factory and bring the stuff back in cans... 

In a blog we can all talk about what we want, so you can talk about dehydrated water, and I can provide the following linked information about the Gullfaks C offshore oil drilling platform; which was the most massive structure (1.5 million tonnes) moved by man; which was towed from Norway into the North Sea (see the three accompanying images).

See:
https://en.wikipedia.org/wiki/Offshore_concrete_structure

https://en.wikipedia.org/wiki/Gullfaks_oil_field

[AbruptSLR]

This 2013 article says that melting the iceberg is the most challenging technical issue for an iceberg water supply system; but that this can be over-come by using waste heat from a power plant:

http://www.industrytap.com/tapping-90-of-earths-fresh-water-frozen-in-glaciers-and-icebergs/2607

Extract: "The big technological challenge is the terminal conversion of icebergs into fresh water. This may prove to be the most expensive part of the process. When idea is to melt ice using low-grade waste heat from electrical power generation. It is estimated that waste heat from 10,000 MW power plant could melt about 1,000,000 acre-feet of water equivalent ice in one year."

[AbruptSLR]

Here is a link to a pdf of the 1973 RAND Corp report on the feasibility of using Antarctic icebergs as a source of freshwater:

http://www.rand.org/content/dam/rand/pubs/reports/2008/R1255.pdf

[AbruptSLR]

The following linked research indicates that about 1/3 of the world's great aquifers are currently being rapidly depleted (see images).  Perhaps, freshwater from icebergs could be piped by gravity feed in order to replenish some of these depleting aquifers:

Alexandra S. Richey, Brian F. Thomas, Min-Hui Lo, John T. Reager, James S. Famiglietti, Katalyn Voss, Sean Swenson and Matthew Rodell (July 2015), "Quantifying renewable groundwater stress with GRACE", Water Resources Research, Volume 51, Issue 7, Pages 5217–5238, DOI: 10.1002/2015WR017349


http://onlinelibrary.wiley.com/doi/10.1002/2015WR017349/abstract


Abstract: "Groundwater is an increasingly important water supply source globally. Understanding the amount of groundwater used versus the volume available is crucial to evaluate future water availability. We present a groundwater stress assessment to quantify the relationship between groundwater use and availability in the world's 37 largest aquifer systems. We quantify stress according to a ratio of groundwater use to availability, which we call the Renewable Groundwater Stress ratio. The impact of quantifying groundwater use based on nationally reported groundwater withdrawal statistics is compared to a novel approach to quantify use based on remote sensing observations from the Gravity Recovery and Climate Experiment (GRACE) satellite mission. Four characteristic stress regimes are defined: Overstressed, Variable Stress, Human-dominated Stress, and Unstressed. The regimes are a function of the sign of use (positive or negative) and the sign of groundwater availability, defined as mean annual recharge. The ability to mitigate and adapt to stressed conditions, where use exceeds sustainable water availability, is a function of economic capacity and land use patterns. Therefore, we qualitatively explore the relationship between stress and anthropogenic biomes. We find that estimates of groundwater stress based on withdrawal statistics are unable to capture the range of characteristic stress regimes, especially in regions dominated by sparsely populated biome types with limited cropland. GRACE-based estimates of use and stress can holistically quantify the impact of groundwater use on stress, resulting in both greater magnitudes of stress and more variability of stress between regions."

See also:
http://www.jpl.nasa.gov/news/news.php?feature=4626

[AbruptSLR]

The linked website gives the current location of Antarctic icebergs and indicates that today there are three major icebergs north of 65deg South which are: a56, b15r and c24.  If someone wanted to practice wrangling, one of these three would be the one to practice on.

http://www.scp.byu.edu/current_icebergs.html


See also:
http://www.mers.byu.edu/long/papers/DeepSeaResearchII_2011.pdf

[sidd]

A little far from the Humboldt. Perhaps the Agulhas, for some totally crazy crew to try.

[bligh8]

The Agulhas and Good Hope are not to be trifled with, Good Hope or so apply named “Cape of Storms” by the Dutch in the 15th Century is a Mariners nightmare, possibly the most dangerous body of water of the planet. What happens here is a large low pressure system from the deep southern oceans collides with the semi permanent high pressure presence over South Africa and carves it up into a string of intense low pressure systems that form a necklace along the south and east sides of the African continent. These lows travel just east of north along the east coast pushing south west winds against the Agulhas creating near vertical wave patterns.  A mere 40 knts results in what the British call “deplorable” conditions. It is here along the 600 meter line, the apex of the current, where the infamous freak waves are born and cut large bulk freight (coal) carriers in half. The Agulhas follows the African continent south then west and dissipates into the Agulhas banks, a formation of rock and shallow (80 meters) ledges that create totally unpredictable & powerful current eddies and did in the days of the great sailing ships, caused many wrecks along the southern coast. I just cant imagine a ship of any kind towing an ice berg north against the Agulhas.

https://en.wikipedia.org/wiki/Agulhas_Current

[AbruptSLR]

A little far from the Humboldt. Perhaps the Agulhas, for some totally crazy crew to try.

First, these icebergs are migrating eastward with the circumpolar current so with a small amount of planning one could schedule a wrangling expedition for when such a northerly iceberg is in a favorable location (note that once such icebergs have migrated northward they seldom migrate southward very far).

Second, I concur with bligh8 that your suggestion to consider towing against the Agulhas current is sub-optimal.

[AbruptSLR]

To expand on Georges Mougin’s concept of using a floating geotextile skirt to both reduce ice melt in transit and to contain water that does melt, by designing "skirt" as an adjustable space frame incorporating:
(1) The "skirt" could contain a flexible surface deck (see the first attached image of an aquiculture fish pen for Bluefin tuna) as both a work platform, and the top ring-flange of an adaptive/flexible space frame integrated with the geotextile "skirt".  Furthermore, I believe a bottom ring-flange for the "skirt", bearing against the lower portions of the iceberg, would be warranted.
(2) Circumferential & radial scissoring modules (see the first image of an onshore scissoring lift with a double-acting hydraulic ramp [which for offshore use could employ a nitrogen charge in the fluid chamber to accommodate shocks]) that would allow the "skirt" to adaptively/flexibly bear against the peripheral face of an iceberg, thus allowing the "skirt" to:
     (a) Adjust its size to accommodate different quantities of meltwater; as the meltwater could be periodically shipped by water tankers both during transit and when grounded at the destination site;
     (b) Accommodate propulsion units [either winches on the deck with series drogues in the water, or electric engines with propellers].
(3) Consider using concentrated solar power, CSP (see the following Wikipedia link, extract and third figure), modules temporarily mounted on the top of a space-frame "skirt" stabilized tabular iceberg (note that the surface deck/top ring-flange could incorporate cranes for lifting the modules), to:
     (a) Melt the iceberg in a controlled pattern using the waste heat from the CSP power plant (which would likely improve the thermal efficiency of the power plant via the latent energy of melting the ice);
     (b) Provide energy for propulsion of the iceberg (particularly if the "skirt" contains propulsion units);
     (c) Provide marketable electrical power, and waste energy for melting the ice, once the iceberg is grounded at its destination.


https://en.wikipedia.org/wiki/Concentrated_solar_power

Extract: "A study done by Greenpeace International, the European Solar Thermal Electricity Association, and the International Energy Agency's SolarPACES group investigated the potential and future of concentrated solar power. The study found that concentrated solar power could account for up to 25% of the world's energy needs by 2050.

… CSP was improving and how this would result in a drastic price decrease by 2050. It predicted a drop from the current range of €0.23–0.15/kwh to €0.14–0.10/kwh."

I also note that two alternating grounded space frame/skirt stabilized tabular icebergs could also serve as an alternating deepwater port facility for transshipment of goods from deep-draft vessels to smaller shallow draft coast/inland vessels (say at the mouth of the Mississippi River, [the fourth attached image shows that 400m of water depth occurs near the river delta], etc).

[AbruptSLR]

As this thread is a bit speculative, and the cited concepts probably would not be implemented before 2030 (if at all); I might as well speculate about a possible desperation-level use tabular Arctic icebergs in the 2030 to 2050 time frame.  The first attached image shows a 1950's vintage Soviet concept for a 55-mile long dam across the Bering Strait in order to regular flow into the Arctic Ocean.  By the 2030 to 2050 time frame (following a BAU to 2030) the Arctic Sea Ice may be seasonally absent and the flow of warm ocean water into the Petermann Glacier fjord may have accelerated to the extent that period tabular icebergs many be available for wangling, by that time.  The second image show a 2014 sketch of the cross-sectional profile of the Petermann Ice Shelf, and the third image shows a plan view of the width and ice velocity of the Petermann Glacier circa 2009 (see the Greenland thread for more background), which indicates that icebergs from the Petermann Glacier many have a draft of from 100 to 200 meters and a width of something like 15 to 20 km.  The fourth image shows the bathymetry & currents in the Chukchi & Beaufort Seas near the Bering Strait; showing the proximity with which Greenland icebergs could be towed to and grounded in the Bering Strait in order to block some of the warm water flow into the Arctic Ocean.  As the icebergs melt they could be re-grounded closer to the narrow part of the Being Strait, where the icebergs could be used as temporary construction platforms for constructing infrastructure to regular flow into the Arctic Ocean as a form of geoengineering.  Today this certainly seems like a desperation level concept, but by 2050 it might seem preferable to other more radical forms of geoengineering.

https://en.wikipedia.org/wiki/Bering_Strait

Extract: "The Bering Strait is about 82 kilometres  wide at its narrowest point, between Cape Dezhnev, Chukchi Peninsula, Russia, the easternmost point (169° 43' W) of the Asian continent and Cape Prince of Wales, Alaska, USA, the westernmost point (168° 05' W) of the North American continent. Its depth varies between 30 metres (98 ft) and 50 metres (160 ft).


The following link leads to a 1954 Popular Mechanics article that includes discussion of a Soviet proposed 55-mile long dam across the Bering Strait:

https://books.google.com/books?id=QuEDAAAAMBAJ&pg=PA135&dq=1954+Popular+Mechanics+January&hl=en&sa=X&ei=jLnBT_OmOpT3gAfc2_WlBQ#v=onepage&q&f=true

[AbruptSLR]

First, I note that per the first image no nation claims the ASE so icebergs coming from there would not have any legal entanglement (also the USA does not recognize any other country's claim to any portion of Antarctica, so all icebergs may be free for the taking).

Second, the second image shows that near 0 degrees C, methane hydrates are stable in about 260 meters of water depth.  Therefore, icebergs coming from Antarctica with keel depths of 260 meters or more, may have methane hydrates present in the lower portions of the iceberg [at least for icebergs that calve directly from the ground-line of a marine glacier, rather than from an ice shelf that has under-gone basal melting].

[sidd]

"Therefore, icebergs coming from Antarctica with keel depths of 260 meters or more, may have methane hydrates present in the lower portions of the iceberg [at least for icebergs that calve directly from the ground-line of a marine glacier ..."

Methane hydrate at the keel of icefront will destabilize rapidly when exposed to seawater, evolving gaseous CH4. might be detectable with the underwater remotes they got nowadays.

[AbruptSLR]

"Therefore, icebergs coming from Antarctica with keel depths of 260 meters or more, may have methane hydrates present in the lower portions of the iceberg [at least for icebergs that calve directly from the ground-line of a marine glacier ..."

Methane hydrate at the keel of icefront will destabilize rapidly when exposed to seawater, evolving gaseous CH4. might be detectable with the underwater remotes they got nowadays.

While I concur that dealing with methane hydrate decomposition (whether in iceberg transport or in dragon breaths) is a real issue, it is easy to over generalize this issue.  In this regard, I point out that as the first image shows, it is not exposure of hydrates to seawater that meaningfully destabilizes them, rather it is water temperature (note the thermal gradient of the seawater in the first image).  This is confirmed by numerous natural outcropping of methane hydrates exposed on the seafloor for centuries as shown on the second & third images.  Inside the "skirt" the melt water in contact with any methane hydrates at the bottom of an iceberg would be close to zero degrees C and would be freshwater.

As a side note, I point out that in some of the videos of Jakobshavn calving, the icebergs roll 180 degrees, exposing the keels to the atmosphere, and in some of these images it is clear that there are methane hydrates steadily decomposing (which takes time for heat transfer and does not happen explosively).

[AbruptSLR]

While again acknowledging that this thread is speculative; nevertheless, if Hansen et al. (2015) are correct about a 10-year doubling time for SLR, then ports around the world could experience up to 5m of SLR by 2100; which might make some of this speculation worthwhile, including the following thoughts:

1) By the use of heating pipes/drill strings during capture & transport, hollowed-out chambers could be formed in the upper few hundred meters of such icebergs; which could: (a) minimize the risk of the iceberg rolling over; (b) reduce the risk of the iceberg fracturing in transit (if combined with NDT examination of the berg & fracture analysis by computer model), and (c) could provide storage room for cargo transport (say from Western Australia to Saudi Arabia, or Chile to California).  Once grounded at the receiving port, such chambers could help the iceberg with a space frame "skirt" to act as a temporary deep water port facility while the flooded existing port is re-built.  Furthermore, if floatable marine structures (like new floating wharves and piers) are built inside such chambers (using supplies delivered by ship to this deep water port), then they could then be launched selectively as the iceberg is melted by power plant waste heat.
2) Not only could the melt water be used to re-charge depleted ground water levels, but low elevation (or negative elevation) coastal surface reservoirs could be built for stock piling water supplies in the event of the interruption of iceberg supplies.
3) Icebergs could be used as temporary bridges (say in/to Indonesia) to facilitate construction, transport, or emergency relief, activities.

[greylib]

Thought I remembered this thread on Scienceforums from way back:

http://www.scienceforums.com/topic/20906-harvesting-icebergs

The first link in the thread doesn't work - screwed by a forum update. This is the one:

http://www.cbc.ca/news/technology/massive-iceberg-spotted-off-australia-1.843586

Towing it the whole way by brute force is likely to be impossibly expensive (and probably dangerous, as pointed out upthread).

So... carve the front to make it a bit pointy and wave action will drive it forward. Not fast, but a lot faster than random winds and currents would do it. Keeping it pointed in the right direction could be done by tugs, or sails could be mounted on top. Me, I'd go for a remote-controlled sail system. 

[AbruptSLR]

Thought I remembered this thread on Scienceforums from way back:

http://www.scienceforums.com/topic/20906-harvesting-icebergs

The first link in the thread doesn't work - screwed by a forum update. This is the one:

http://www.cbc.ca/news/technology/massive-iceberg-spotted-off-australia-1.843586

Towing it the whole way by brute force is likely to be impossibly expensive (and probably dangerous, as pointed out upthread).

So... carve the front to make it a bit pointy and wave action will drive it forward. Not fast, but a lot faster than random winds and currents would do it. Keeping it pointed in the right direction could be done by tugs, or sails could be mounted on top. Me, I'd go for a remote-controlled sail system. 

The RAND Corp. calculations show that towing icebergs is not impossibly expensive, but today they are not economically competitive for supplying freshwater compared to desalination.

[bligh8]

The chart below is a grib file of the southern oceans, most of our readers have seen overhead shots of the never-ending storms that circle Antarctica but I might imagine
the effect of these storms on surface wind/waves is not some thing one sees quite so often.

Grib files are normally downloaded in an active format where one can select time increments for looking forward, essentially forecasting what’s in front of or coming-up behind the vessels location.

Fore the purpose of viewing I downloaded 95% of the Southern Oceans surface, to large of a file to be of usefulness to a mariner.

One can see the wind field on the East side of South American from about 35S extending south and west to nearly Madagascar, (about 6-7 thousand NM) this type of wind field on average contains wind speeds of force 6 to force 8. These storms are traveling east at about 25-30kts, so small breaks mean nothing to the wave patterns. The blue shading is either rain or fog.

The intense low south of cape hope with the condensed isobars is force 8 to force 10. With no landmass to interrupt the wind/wave patterns the seas grow to unimagined conditions, often times containing wave patterns from several directions, making navigation for the small vessel difficult.

This file was downloaded Fri Sept 11, 2100utc

[johnm33]

How about using a hang-glider type wing/sea anchor designed for use in the powerful cold currents that flow north, guided by a submarine vessel, to tow the bergs north of the raging storms? I guess the best time to move them north from their calving point would be to follow the freeze, given the winds down there ships driven by vertical axis wind turbines positioning the bergs to maximise the northward push on them by the wind and waves.
So selected icebergs carved by high pressure sea water jets to give them a bow, possibly shaped by the same method to increase their wind profile across the top. Fitted with skirts, driven north as the refreeze happens, hitched to 'flying' sea anchors when they reach the ice edge and piloted through the storm riven southern ocean by submariners.

[AbruptSLR]

The linked reference indicates that for the past 13 years (2002-2015) the Antarctic Research Supply Vessel Laurence M. Gould has made 20 passages (year round) per year across Drakes Passage, without missing any scheduled passage in that timeframe.  Per the attached image the Gould is only 230-ft long and can only deal with 1-ft thick sea ice. 

Therefore, I submit that if the Laurence M. Gould can reliably operate year-round in the roughest body of water in the world, then there is no need to talk about submarines, or about the impossibility of using surface vessels to deploy a "skirt" with a space frame and self-propulsion to capture an iceberg from the Southern Ocean:



David R. Munro, Nicole S. Lovenduski, Taro Takahashi, Britton B. Stephens, Timothy Newberger and Colm Sweeney (2015), "Recent evidence for a strengthening CO2sink in the Southern Ocean from carbonate system measurements in the Drake Passage (2002-2015)", Geophysical Research Letters, DOI: 10.1002/2015GL065194


http://onlinelibrary.wiley.com/doi/10.1002/2015GL065194/abstract


See also:
http://www.reportingclimatescience.com/news-stories/article/two-papers-highlight-southern-ocean-co2-sink.html

[AbruptSLR]

The linked article is entitled: "Icebergs to be towed from Antarctica to United Arab Emirates for drinking water".  The future is coming closer.

http://www.independent.co.uk/news/world/middle-east/uae-icebergs-drinking-water-from-antarctica-towed-united-arab-emirates-a7715561.html

Extract: "The National Advisor Bureau Limited company plans to provide a new source of freshwater for the region by towing the iceberg from Antarctica to the coast of the eastern emirate of Fujairah.

The Masdar city-based company then plans to mine the iceberg for drinking water.

An average iceberg contains more than 20 billion gallons of water, or enough for one million people over five years, Abdullah Mohammad Sulaiman Al Shehi, the company's managing director, told Gulf News."

[oren]

Larsen C is about to supply them a good specimen of iceberg.