Antarctica is the fifth largest continent, covering 5.4 million square miles. There are three ice sheet covering about 98% of the continent, the Antarctic Peninsula Ice Sheet, the West Antarctic Ice Sheet, and the East Antarctic Ice Sheet. This is the largest single mass of ice on Earth, covering an area of over 5 million square miles, and containing over 60% of the Earth’s fresh water. In spite of that, Antarctica is a desert with only about 8 inches of precipitation per year along the coast, and less inland. There are numerous lakes and rivers, even a mountain range, under the ice.
There are hundreds of glaciers on Antarctica, and the weight of the ice has caused the continent to sink by .3-.6 miles. Most of what we saw was from the Antarctic Peninsula Ice Sheet. This ice sheet is widely regarded as sensitive to climate change due to its small size, and because this region has been warming rapidly. Several ice shelves have collapsed in recent years. An ice shelf is the floating portion of a glacier.
I just read a fascinating article on EcoWatch about the ice “singing” to the researchers monitoring vibrations on the Ross Ice Shelf. According to Rick Aster, professor of Geosciences at Colorado State University, “the tones in these signals shift when the surface of the ice shelf is disturbed by changes in surface dunes or near-surface melt.” The noises result when winds blow across snow dunes on the ice shelf. It’s possible that scientists may be able to predict when ice shelves are about to collapse.
There was a very large iceberg, over 62,000 square feet, that broke off from the Larsen C ice shelf just a few months after our trip. In fact, we had been monitoring the news while we were there, since we knew that this calving was imminent.
In mid-October, 2018, NASA photographed a tabular iceberg that had calved off of the Larsen C ice shelf, that looks like a perfect rectangle, with 90 degree angles. It is rare, but not unheard of, to see an iceberg that looks so perfectly carved as this one.
We saw a small fraction of the glaciers on this continent, yet that was so much more than we’d seen anywhere else. We sailed east and north past Anvers Island, where Palmer Station is located. Palmer is one of three permanent stations on Antarctica maintained by the United States.