The resource potential of Antarctic icebergs

Abstract

The possible use of Antarctic icebergs as a source of water and electrical power is discussed. We review the history of the idea, the development of concepts of iceberg use from the 1950s onward, and the physical properties of icebergs which determine their susceptibility to decay and thus their likely survival time under tow. The elements of an iceberg utilization scheme are discussed, including potential destinations, iceberg detection and selection, propulsion, protection, and processing. An "Icetec" scheme which combines water utilization with power generation via ocean thermal energy conversion would seem to offer the best economic prospect for iceberg use, but many technical problems remain unsolved while fundamental physical processes affecting an iceberg tow have yet to be examined experimentally. this, was (1.63 _ 0.10) x l0 •5 kg yr -1, by Shumskiy et al. [1964]. A more recent estimate is by Orheim [1984], who makes use of the large observational data set collected by ships of opportunity and transmitted in standard format to Norsk Polarinstitutt. From 33,000 sightings of icebergs he used statistical arguments to derive an estimate of 2.3 x l015 kg (i.e., about 2.7 x 103 km 3) for the mean annual iceberg flux, which would give the Antarctic ice sheet a negative mass balance. This, then, is the maximum freshwater volume avail-able annually. By comparison, the mean flow rate of the Amazon River is 5.7 x 103 km 3 yr -•, roughly double the Antarctic iceberg flux [Dietrich et al., 1980]. Therefore icebergs could make a significant addition to the world's water supplies, but only if most of those produced were captured. Since the annual flux represents about 5000-10,000 individual bergs, this is an impossible task; so the global contribution of icebergs to the world's usable water can only be a minor one. However, iceberg water is available in a ready-packaged form, and as we shall see, there are a number of destinations and types of iceberg water scheme which may be economically attractive and technically feasible. HISTORY OF THE IDEAThe economic use of natural ice as a refrigerant has a very long history [Reynolds, 1979[Reynolds, , 1983. The Romans used ice from Alpine lakes, which was transported in straw to Rome. By the early nineteenth century the use of lake ice was widespread throughout Europe and North America. Ice was cut from lakes during winter and stored in insulated ice houses for summer use. Thoreau [1854] gives a classic description of ice cuttingon Walden Pond. Where a nation such as Great Britain needed ice for refrigeration (the preservation of fish, in particular, required large quantities) but was unable to supply it herself, an export trade developed from more northerly countries. Norway began exporting glacier ice to Britain in 1822, and by 1898, 550,000 tons were being exported annually to Britain, France, and Germany. The ice was taken from ice caps such as Folgefonni (southwestern Norway) and JOkulfjordbreen near Troms½ and was mined either by the use of explosives

Arctic ice management

“…Given that it seems possible to produce a surplus of ice, it may be worth revisiting the older, provocative idea of harvesting icebergs to supply drinking water to areas of the U.S. or elsewhere that face intense drought. Early assessment of the icebergs for drinking water idea was premised on the idea of harvesting ice in Antarctica and towing it to southern California [ Hult and Ostrander , ], an idea further explored by Wadhams []. This idea appears feasible, although a major consideration is melting losses during transit.…”

Towing icebergs to arid regions to reduce water scarcity

“…However, if the iceberg is left offshore while it is harvested, the model indicates that it will entirely melt after 44 days. Precisely how icebergs will be harvested remains a largely unanswered question, although ideas include open-cast mining, melting in a dry-dock, or breaking into smaller fragments 9 , 15 , but it needs to be done quickly.…”

“…From what has already been written it appears that at the turn of the nineteenth century small icebergs were towed from Laguna San Rafael (~ 45°S) to Valparaiso, Chile (~ 33° S), and Callao, Peru (~ 12°S) for refrigeration. The idea of using icebergs as a source of drinking water, however, is most often credited to a seminar John Isaacs gave at the Scripps Institution of Oceanography in 1949 1 , 9 , 10 . Several decades later a series of technical papers appeared on this subject 11 – 13 and soon after, the first Iceberg Utilization conference was held at Iowa State University 14 .…”

Media Environments

“…The group of engineers at Dassault was joined by select oceanographers, meteorologists, and glaciologists invited by Mougin. Amongst them was Peter Wadhams, a professor of ocean physics at Cambridge University, and a long-term advocate of Mougin's plan (Wadhams 1990).…”