The Ice Sheet
is of great interest to geoscientists due to its size and northern location, which means that it reacts quickly and dynamically to climate change.
And, of course, that's going to increase the drainage of the Greenland ice sheet
and contribute to rising sea level," he said.
Acting like glacial conveyor belts, tidewater glaciers are the primary mechanism for draining ice sheet
interiors by delivering icebergs to the ocean.
But a Nasa team was surprised when they lowered a video camera to get the first long look at the underbelly of the ice sheet
Research has shown the 1.7 million kilometre square ice sheet
could melt entirely over several thousand years if temperatures continue to rise unchecked, causing sea level rises of up to seven metres.
That means global temperatures may have a much faster effect on the formation of ice sheets
than previously thought.
The lake covered 5.7sqkm near the western edge of the ice sheet
and took about 24 hours to drain.
"If the trends we're seeing continue and climate warming continues as predicted, the polar ice sheets
could change dramatically," said Jay Zwally, lead author of a new, comprehensive NASA satellite survey.
But sophisticated new measurements made by two orbiting satellites have shown the ice sheet
is slowly melting away.
The vast ice sheets
of the Ice Age reached as far south as Wisconsin.
During that time, the scientists predict that half of the Arctic's summer sea ice will melt, along with much of the Greenland Ice Sheet
, which contains enough ice to raise sea level by some 23 feet.
He declared with particular reference to the Permian glacials present in the tropics of India and Africa, that 'it will now be necessary to explain not only the former presence of the great ice sheet
in the tropics but marked alternations of seasons too.' Any theory of glaciation, Coleman wrote in 1926, 'must account for a world-wide refrigeration affecting all zones of both hemispheres at the same time' (p.