Towing Icebergs By Don Calbreath
WHILE DESALINATION HAS BEEN A PRACTICAL REALITY FOR MILLENNIA, THE IDEA of towing icebergs is relatively young. It has been around for a couple of centuries— although not always as a means of providing fresh water to thirsty places.
Starting in 1825, proposals to move icebergs were floated in England and Chile to equalize the
Earth’s temperatures and chill beer, respectively. The sinking of the Titanic in 1912 after it col-
lided with a massive iceberg stimulated interest in towing icebergs to prevent future tragedies.
If you’ve never heard of towing icebergs for their water, it’s probably because, as a 2011
article in The Atlantic put it, the idea “exists in a kind of technological purgatory.” But
ambitious dreamers have kept it alive over the years.
The modern movement of towing icebergs is attributed to the late John Isaacs, who
was a professor at the Scripps Institute of Oceanography in La Jolla, Calif. In 1948, he
first proposed the idea of towing icebergs to water-strapped parts of California.
Why icebergs float
In 1977, a prince from Saudi Arabia—the country that relies the most on desalinated water—sponsored an international conference to explore iceberg towing. At that
time, it was estimated that towing a 100-million-ton iceberg across 11,500 kilometers
(7,100 miles) of open water would cost $100 million.
In one of the most recent iterations of this idea, French engineer
Georges Mougin, a longtime advocate of towing icebergs, formed
a partnership in 2011 with a French design firm to put modern-day
computing power to the task.
The firm simulated moving a 7-million-ton iceberg from an area
near the Canadian province of Newfoundland to the Canary Islands
off the coast of northwestern Africa. Some of the variables
included the size of the iceberg, the number and towing power
of the tugboats, and wind and ocean current flows that could
either help or hinder the movement of the iceberg.
Melting would be a serious problem. With the temperature of
the ice at 0 °C and the surrounding water at 15 °C to 20 °C, heat would flow from the
water to the ice, causing it to melt en route. To trap this precious water rather than let
it flow into the ocean, the researchers anticipated wrapping a skirt around the iceberg.
An iceberg’s weight is supported by displacing
about 89.5% of its volume in water, leaving just
10.5% of the glacial block to rise above the
water’s surface. Why is that? For one thing,
when water freezes, it
becomes less dense.
At 0 °C, the density
of pure ice is 0.917
g/cm3, and the
density of water is
1.000 g/cm3. This lets
ice cubes clink and float
in your glass of water. At
1.025 g/cm3, salt water is
even denser than your
The simulation showed that the
project would indeed be physically
possible—if not financially viable.
It would take 141 days, and an
estimated 38% of the ice would
melt during its journey. No cost
estimates were made public, however, and the project was never
In 2017, yet another plan to
move icebergs was announced
by oil-rich but water-starved
United Arab Emirates. We may
yet see this interesting idea come
Madrigal, A. C. The Many Failures and Few
Successes of Zany Iceberg Towing Schemes.
The Atlantic, Aug 10, 2011: https://www.theatlan-
Zax, D. Watch a Tugboat Drag an Arctic Iceberg to
Parched People Half a World Away [Video], Fast
Company, May 31, 2011: https://www.fastcom-
Bellware, K. Global Water Shortage Risk Is
Worse Than Scientists Thought, Huffington
Post, February 15, 2016: http://www.huff-
Among other things, engineers planning to tow icebergs have
to worry about preventing rollover.
Don Calbreath is a science writer who lives in
Spokane, Wash. This is his first article in
C-CORE; THINKSTOCK; SHU TTERS TOCK
NARASOUZA, ENVIROCIENCE INC.; NOAA; BARRY H. ROSEN
14 ChemMatters | APRIL/MAY 2018