Geoscience Reference
In-Depth Information
The FuTure oF Ice 5
The World's Great Ice Sheets
rate. All indications are that they will con-
tinue to melt and that the melting rate will
continue to accelerate.
Greenland is an island of 2.165 million
square kilometers (836,000 square miles)
with an ice cover of 1.753 million square
kilometers (677,000 square miles), con-
sisting of 2.868 million cubic kilometers
(688,000 cubic miles) of ice up to three
kilometers (two miles) thick. The ice that
covers Greenland was probably first formed
about two million years ago at the start of
the Pleistocene epoch. In this epoch the
Earth entered a period of cool atmospheric
temperature, perhaps 6 degrees Celsius (11
degrees Fahrenheit) cooler on average than
when the dinosaurs were kings of the ani-
mal kingdom. It is possible that the Green-
land ice completely disappeared several
times during interglacial times. Greenland
is surrounded by the Atlantic Ocean to the
southeast, the Greenland Sea to the east,
the Arctic Ocean to the north, and Baffin
Bay to the west. The weight of the ice has
depressed the central part of Greenland
into a deep basin a thousand feet deep.
Thus if the ice were suddenly removed,
The world has three great ice sheets: the
Greenland Ice Sheet in the northern hemi-
sphere and the East and West Antarctica ice
sheets in the southern hemisphere. Each
consists of a large central mass of ice ringed
by a series of outward and seaward-flowing
outlet glaciers. Glaciers are large masses of
ice, which are frozen year-round and flow
slowly and continuously down slope. The
ice is created by the compaction and recrys-
tallization of snow.
Ice sheets are the eight-hundred-pound
gorillas of global climate change, because
they will likely be the major drivers of sea
level rise and changes in ocean currents,
which in turn will have a large impact on
global climates. No one really knows for
certain what the future holds for these ice
masses. For example, the amount of ice
formed by future winter snowfall in the in-
terior of the ice sheets remains an educated
guess. Warming temperatures could lead to
increased precipitation in the interiors. At
present, however, the ice sheets are losing
mass and melting at an ever-increasing
Search WWH ::




Custom Search