Even though plans to extract from one dates back to the
1950s, can Antarctic icebergs ever be a viable source of low cost fresh water?
By: Ringo Bones
Young Turks these days may have only heard of the scheme
from a 2012 Dassault Systèmes advert often aired on the BBC but believe it or
not, the idea of obtaining low cost fresh water from icebergs dates as far back
as the 1950s. After complex logistical issues are taken into account do
icebergs – as in Antarctic icebergs – really provide low cost drinking water
for our increasingly thirsty civilization?
During the 1950s, the US state of California’s number one
community problem – and still probably is today – is where to get a low cost
supply of fresh water fit for both domestic and industrial use. Back then, an
oceanographer from the Scripps Institution of Oceanography named John Isaacs
has suggested that icebergs be fetched up from the Antarctic to ease the state
of California’s local water shortage. Even though the idea seems too fantastic
at the time (and even for this day and age) – Isaacs’ colleagues from the
Scripps Institution says not at all when they made the requisite mathematical
calculations and found, somewhat to their astonishment, that it is the one
dreamboat that might really float.
Being formed from glaciers, icebergs are completely
salt-free and unlike their smaller North Atlantic variety, Antarctic icebergs
are big enough to make the idea worthwhile – as in economically viable. A good
sized Antarctic iceberg is typically 10 miles long, half a mile wide and 600
feet thick can even be considered “small” when talking about Antarctic
icebergs.
Using 1950s era slide rules to crunch the numbers, the
scientists of the Scripps Institution of Oceanography together with John Isaacs
calculated that in two months time, three ocean-going tugboats could work a 10
mile long, half a mile wide iceberg drifting in the Antarctic into the Humboldt
Current running up the west coast of South America. Where the Humboldt Current
slows down off Peru and Ecuador, the tugboats would steer the icebergs into
other favorable ocean currents that would lead it in a long, lateral loop
almost to Hawaii and eventually to Los Angeles.
Given that these favorable currents move at around 2 to 3
knots, the whole trip would take about a year and along the way the iceberg
might lose as much as half of its vast bulk. But it would still represent about
300 billion gallons of fresh water. Authorities could ground the iceberg on an
offshore shoal and surround it with a floating dam extending about 20 feet or
so below the surface. This would keep the fresh water penned in around the
iceberg as the ice melted.
Because it is lighter, the fresh water would stay on top of
the surrounding salt water and the city of Los Angeles could just pump it out
as needed through pipes leading to the mainland. One iceberg that was
originally 10 miles long when it was toed back from the Antarctic would be
enough to supply the city’s then normal needs of fresh water for about a month
– using 1950s water consumption figures.
Back in the 1950s, the total cost of the water so delivered
– mainly the then rate of one million US dollars for a year’s hire of the three
ocean going tugboats – works out to be something like one-third of a US cent
per thousand gallons, a minute fraction in comparison to what the city of Los
Angeles pays back in the 1950s for its regular source of drinking water.
Calculated to be financially feasible for California using 1950s prevailing
costs, this method of “outsourcing” fresh water might still be appropriate for
the water needy arid regions of the Southern Hemisphere – like South Africa,
Australia and the Peruvian desert communities.
