By Jonny Lupsha, Wondrium Staff Writer
An iceberg passing Antarctica almost took a chunk of the icy continent with it. The iceberg, designated A-74, was originally a piece of the continent but broke off in February. Antarctica is the world’s largest desert.
A major chunk of the Brunt Ice Shelf in Antarctica was nearly broken off of the continent when an iceberg, double the size of Chicago, struck it earlier in August. The 490-square-mile iceberg, called A-74, was a part of the continent until February when it broke off from the same area it recently struck. It spent nearly six months floating near its point of separation, until strong winds caused it to drift south and change course. Had it struck harder, the entire Brunt Ice Shelf could have broken off and would have become one of the world’s largest free-floating icebergs.
In his video series The World’s Greatest Geological Wonders, Dr. Michael E. Wysession, Professor of Earth and Planetary Sciences at Washington University in St. Louis, said that Antarctica is the world’s largest desert.
Antarctica by the Numbers
“Antarctica is big; it’s really big—it’s larger than Europe,” Dr. Wysession said. “In fact, it’s twice the size of Australia, but the population is so small. It’s about 1,000 in winter, 4,000 in summer. This really has the lowest population density of anywhere in the world. In the wintertime, it’s about one person per 13,000 square kilometers.”
Unfortunately, this large, silent wonder is difficult to reach. According to Dr. Wysession, the southern ocean that surrounds Antarctica has some of the worst weather, worst storms, and biggest waves of any part of the ocean. However, some tourist boats still brave the waters, bringing scientists and tourists to the frozen continent every summer.
“The volume of ice in Antarctica is about 25 million cubic kilometers,” he said. “This is so much ice, if it were to melt, the world’s sea levels would rise about 63 meters; that’s over 200 feet. A lot of continental area would be flooded—remember, about three billion people around the world live within 60 miles of a coastline.”
The largest and thickest ice is in East Antarctica and measures about three miles thick.
Wandering the Desert
Despite the amount of ice in Antarctica, it is technically the world’s largest desert. It earns this claim to fame by having such a low rate of precipitation, which it gets due to the air’s global circulation pattern.
“You [have] warm air rising up at the equator, coming down roughly at 30 degrees north and south, [which] is very cold, dry air, and [you have] another band of warm air rising up at about 50 to 60 degrees north and south, coming down at the poles,” Dr. Wysession said. “Well, it’s that cold, dry air coming down at the South Pole that just doesn’t bring any moisture with it.
“The average rainfall here is equivalent to about 16 centimeters of rain a year—that’s a little bit more than 6 inches.”
This rain falls mostly as snow, but stays around a long time because of the cold temperatures. The average temperature over the course of a year in Antarctica is -70 degrees Fahrenheit (-57 Celsius). The record low is -129 degrees Fahrenheit (nearly -90 Celsius), which is also the coldest temperature ever recorded on Earth.
Even still, warming temperatures and other factors destabilize Antarctic ice, leading to breaks like A-74, which in turn have the potential to take more ice shelves with them.