Geoscience Reference
In-Depth Information
providing water, sewer, heating, and elec-
tricity in the high north, but it could save
one of North America's few remaining sub-
sistence societies.
lagoon are usually one to two meters (three
to seven feet) above sea level.
Paul Kench, a New Zealand geologist,
points out that atolls are dynamic but
change at a slower pace than barrier islands
(discussed below). Atolls widen as storm
debris piles up and they lengthen as sand
and gravel moves along beaches. Storms
open new inlets between islands while of-
ten simultaneously closing other inlets.
The process responsible for driving peo-
ple off the islands will most likely be the sa-
linization of groundwater. Already in some
communities in the Marshall Islands, crops
are being grown in ifty-gallon oil drums to
avoid salty soils. The Carteret Islands near
Papua New Guinea have already been aban-
doned, and Tuvalu, a nation of five atolls
with a population of just over twelve thou-
sand, has made arrangements to relocate to
New Zealand.
Perhaps the most famous atoll nation is
the Maldives, a group of twenty-six atolls
and more than eleven hundred islets in the
Indian Ocean with a total population in ex-
cess of 300,000, making it by far the most
populated atoll nation. The people of the
Maldives have recognized the hazard of sea
level rise in a big way. In 2009 the members
of the Maldivian legislature donned scuba
gear and held a session under water at a
depth of nine meters (thirty feet) to draw
attention to the sea level rise. The nation is
currently contemplating the possibility of
purchasing land in Sri Lanka or India and
moving the entire nation to a new site.
atolls
Atolls are mid-ocean rings of coral rock that
surround a lagoon. The origin of atolls was
famously first described by Charles Darwin
on the voyage of the
Beagle
. The islands be-
gan as a fringing reef completely ringing a
volcano, and as the volcano slowly moved
into deeper water (because of sea floor
spreading), the reef grew upward and even-
tually extended above the now submerged
mountaintop. These tiny islands became
populated with Polynesians, the world's
most impressive navigators, capable of tra-
versing in outrigger canoes across thou-
sands of miles of open ocean and finding
new islands based on wave patterns. The
islands became icons of song and romance
and then of the battles of the Second World
War. Now they have become the icons of
the coming sea level rise catastrophe.
At 475 square kilometers (184 square
miles), the largest atoll is Christmas Is-
land, part of the Kiribati atoll nation. Most
atolls have just a few square miles of land
area and are very low in elevation. Usually
the highest points are three to four and
a half meters (ten to fifteen feet) above
sea level along the open ocean shoreline,
where storms pile up debris from the coral
reef offshore. The living areas next to the
