2014
As snow continually falls, but rarely melts in Antarctica, the weight of its ice sheets constantly increases, while the weight of the air bubbles in the ice are squeezed out and the ice crystals enlarge, making the ice appear blue. Along the coasts, the glaciers/ice shelves slowly crack off, calving as icebergs; due to their displacement, about 90% of all icebergs are actually below the ocean’s surface.
Small amounts of new ice appear to be white because they contain plenty of air bubbles, while small quantities of water appear to be colorless. But as ice continues to form, the pressure of the added weight squeezes out the air bubbles, increasing the ice’s density. And just as large quantities of water appear to be blue, since they absorb other colors more efficiently than blue, a large piece of compressed ice – a glacier – can also appear blue.
Until recently the Antarctic Ice Sheet had been considered to be fairly stable in how it retreated. A recent study by Peter Clark, a climate scientist at Oregon State University, concludes however, that “New evidence shows that the ice sheet is much more dynamic and episodic, and contributes to rapid sea-level rise.” Published in the journal Nature, his study includes measurements at Antarctica’s largest glaciers – Thwaites and Pine Island – proving that during a warming trend which occurred 14,600 years ago – these ice sheets launched enough icebergs into the ocean that the sea level rose 6.5 feet in just 100 years. This evidence of dramatic melting in Antarctica’s past supports predictions for its future: that so many of Antarctica’s melting glaciers are now on the brink of a similar massive retreat.
Icebergs are fascinating, as they can be as big as mountains, or islands, or as small as very small chunks of ice, of any shape, and having any texture; and they can range from very blue to quite white, depending on the sunlight or lack of it; and the nearly 90% that is underwater can either be somewhat visible, or not visible at all.
So often in nature, when concentrating on one scene or object – such as a mountain, or a cloud, or an iceberg, it is fascinating how often one can see in one’s own mind – recognizable shapes – pareidolias – if you will: Dancing, Passing by, Two Critters, Penguin in Repose…
