Antarctica Without Ice?

December 29, 2008

by JonB

On another amazingly warm blue-sky day I’m standing on a low hill looking out over Neko Harbor. Across a narrow bay is a wall of glaciers, behind me is soft hills covered by deep snow. In the far distance in three directions are long lines of tall mountains covered by snow and ice, some of it tens of thousands of years old. Just a few slivers of hard, dark granite peek out, reminding me there is land – a continent! – beneath all of this white. (At Vostok, a Russian base on the eastern side of Antarctica, scientists have measured the ice to be 14,000 feet thick, nearly three miles.)

It is hard to imagine this place without ice and snow, but of course it has been. Roughly 125 million years ago what we know as South America and Africa began to separate; then, the Antarctic Peninsula where I stand was still connected to South America. From 38 to 29 million years ago the Antarctic continent moved south. During that Cretaceous period, circa 144 to 65 million years ago, the continent was covered by forest, including tree ferns, cycads, palms, conifers and deciduous trees, and was home to freshwater fish, dinosaurs, reptiles and the predecessors of the penguins we see here now, though they were somewhat different. In that they were the size of an average man and weighed 300 pounds.

The continent has frozen and thawed since, but has been completely covered by ice and snow since the last Ice Age, about 11,000 years ago. Today, even at the height of summer, only two percent of Antarctica is ice-free; the continent contains 75 percent of the fresh water on earth.

It is clear the Peninsula is evolving, changing … warming. Analysis suggests the rapidity of warming in the northern Peninsula is unmatched over the last 2,000 years. Temperatures along the Peninsula during summer have climbed on average five degrees in the past 50 years; its average winter temperatures have risen by ten degrees, twice as fast as anywhere on Earth in the past century.

If even a small part of the Ice Cap were to melt, world sea levels would rise from several feet to several yards, inundating most coasts. If the whole Ice cap were to melt, as it has in past ages, sea levels around the world would rise an estimated 260 feet, destroying a number of low-lying countries. Since sea levels have risen only 8.6 inches in the past century, the three-foot rise projected by the year 2080 is serious. Many millions will become refugees, depopulating the long U.s. coasts up to 50 miles inland, including all of southern Florida and the Mississippi Delta, also much of Bangladesh, the Philippines, Southeast Asia, the coasts of Africa and innumerable Pacific atolls.

Antarctica without snow and ice? Seems impossible, right? Here’s what the continent would look like without ice. It has been weighed down by heavy ice for so long that part of it is submerged. They would gradually climb back above sea level if free of ice, though that would take tens – hundreds? – of thousands of years.