Change occurs slowly in Antarctica. Even those dramatic and astounding moments when it seems the very earth is breaking apart are insignificant when the scale of the continent is considered. And yet locked in Antarctic ice are tales of a landscape beset by cataclysms and ravaged by the metamorphosis of extreme time.
We are in Neko Harbour, and I am watching a mere whisper of Antarctica’s story – an inconsequential few seconds that, when added to others, result in incomprehensible change on a clock that has been ticking for billions of years. But I feel as if I am witnessing the birth of the oceans.
One hundred million years ago, I would be standing in a cool forest not unlike those that exist in present day South America (Frozen in Time, Prehistoric Life in Antarctica). Petrified tree trunks and carbonized leafs found on Seymour Island tell this chapter of Antarctica. Even before this, dinosaur fossils found in the Antarctic are prologue to the breakup of Gondwana, the great southern supercontinent. There are rocks in Antarctica that have been dated at 3.8 billion years old (Antarctic Peninsula, A Visitor’s Guide).
Looking across Neko Harbour in the present day, two glaciers silently meet at the water’s edge; the scene appears as frozen in time as the ice that makes up these unlikely rivers. Any movement is imperceptible to my eye, yet great buckles in their otherwise smooth surface speak of the tortured ground over which these glaciers flow. They can advance up to one-hundred meters a day, and to a depth of sixty meters, their ice is brittle and fractures, creating seemingly bottomless crevasses. Below this depth, ice flows over and around obstacles just like a pliable plastic (Antarctica, Global Science from a Frozen Continent).
With an average annual precipitation of just thirteen centimeters per year, Antarctic is a desert. Like any desert, there is much that is hidden, waiting to be discovered. But in this case, it is hidden by ice.
One sits down on a desert sand dune, sees nothing, hears nothing. Yet through the silence something throbs, and gleams… – Antoine de Saint-Exupery
The topography of the ground beneath the ice can usually be discerned by what happens as ice moves – except when the depth of that ice is measured in miles. Over forty million years, the East Antarctic ice sheet has accumulated ice that is, in places, three miles thick. There are entire mountain ranges, replete with 8,000 foot peaks, which lie beneath endlessly flat ice fields.
Since the average age of ice in East Antarctica is just 125,000 years (Earth, Portrait of a Planet), over time, a lot of ice has been dumped into the Southern Ocean. The usual depository method is via glacier or ice sheet. There are moments when city-sized ice bergs splinter into the sea. There are also moments when ice is blasted into the atmosphere.
There is a sub-glacial volcano in the Hudson Mountains (another mostly buried mountain range) near the Pine Island Glacier. This glacier drains about ten-percent of the West Antarctic Ice Sheet. Steam has been noticed to vent through cracks in the ice. Ice cores drilled in the area by scientists from the British Antarctic Survey show that a significant eruption occurred here some 2,200 years ago which blasted ash seven miles high. Lava still flows under the ice. In 2013, an iceberg (named B31) the size of Singapore broke off the glacier. It is now drifting into the Southern Ocean.
The glaciers I am watching at Neko Harbour generate bergs that are mere ice cubs compared to B31. Nevertheless, they form an impressive and impassible wall two miles wide. A moment later, two cannon shots echo across the Bay, and newly born icebergs tumble into the water. Near the shore, this poses a minor inconvenience for some Gentoo penguins as waves wash over the cobble stone beach. The Ioffe repositions herself as an older berg moves threateningly towards her.
Antarctic ice is critically important to human life and not just because of what it can do to sea levels. The oceans are the Earth’s most important carbon sink, and Antarctica helps drive the process. Since carbon dioxide dissolves in water, it is removed from the atmosphere by the oceans. When winter comes to Antarctica, the continent doubles in size as water freezes. The saline content of the unfrozen, carbon laden water increases, making it heavier and taking it to the bottom of the Southern Ocean. In the spring, when the ice thaws, this global pump begins again.
O! how shall summer’s honey breath hold out,
Against the wrackful siege of battering days,
When rocks impregnable are not so stout,
Nor gates of steel so strong but Time decays?
– Shakespeare, Sonnet 65
See Part VI – Wilhemina Bay