Antarctica — Old Air Is Trapped in the Ice

Snow pressed into ice traps air

It does not rain in Antarctica; it only snows. The snow does not melt but piles up one layer a year, and the weight above presses the layers below into ice.

As it is pressed, the air between the snowflakes fails to escape and is trapped as bubbles. Each year's air is sealed into each year's ice.

One layer a year, so the deeper you go the older the air — like the rings of a tree. Dig down and you travel back.

So the ice is drilled

A long hollow drill bores into the ice and the column is pulled up whole. This is an ice core. The deepest so far is over three kilometres, and the ice at its foot froze eight hundred thousand years ago.

The remarkable part is this. Thermometers are a few centuries old and written records a few thousand years. The ice was keeping its own record long before either. We have only just opened the diary.

Why Antarctica

Because the ice there is the oldest and thickest. The continent lies under ice averaging two kilometres deep; most of the world's fresh water is frozen there.

And it is the cleanest. With no factories or cities, whatever is in the air is the world average. A value measured in Antarctica can stand for the whole planet.

A little further in

Coring ice means fighting the ice

The deeper the drill goes, the harder the ice squeezes the hole shut under the weight above. So the hole is filled with a fluid whose density matches the ice, and it holds.

A core that melts is lost. It is kept below minus twenty, shipped home, and cut in a cold store. One short piece holds several years of air; nothing is wasted.

Three stations and a ship

Korea keeps two stations in Antarctica and one in the Arctic. King Sejong sits on an island off the Antarctic Peninsula, comparatively reachable; Jang Bogo stands on the mainland, where in winter the sun does not rise at all.

1. King Sejong Station (1988) — King George Island. Korea's first Antarctic base.
2. Jang Bogo Station (2014) — the Antarctic mainland. Glaciers, meteorites, space observation.
3. Dasan Station (2002) — Svalbard, Arctic. Arctic climate and sea ice.
4. Araon (2009) — the icebreaker that carries people and supplies to all three.

The Jang Bogo crew live four winter months without daylight, in minus forty outside and winds of typhoon strength, and keep the observations running all year.

Where the ice goes when it melts

If all of Antarctica's ice melted, the sea would rise about sixty metres. That is not about to happen; how fast the edges are melting is the biggest question in polar research today.

To measure it you need to know how warm the sea is beneath the ice, so holes are drilled and instruments lowered into the water below. Satellites see only the surface.

What you would study to do this

It is not only scientists who go. A station winters with around twenty people, and half of them are not scientists.

1. Someone who reads the ice and the climate — earth science, atmospheric science, oceanography.
2. Someone who keeps the station alive — generators, heating, communications, heavy plant. If the generator fails at minus forty, everyone is in danger.
3. Someone who sails the ship — the icebreaker's officers and engineers. Ice navigation is its own trade.
4. Someone who feeds everyone — the cook, four months without resupply.
5. Someone who heals — the doctor, alone with every decision, months from a hospital.

The second line is this field's unexpected job. The most valued person at an Antarctic station is the one who can fix the generator and the loader — a straight road from a technical high school in mechanics or electrics.

This work belongs to the Korea Polar Research Institute in Songdo, Incheon.

The question that remainsIf we are now reading a diary the ice has kept for eight hundred thousand years — what line are we writing in it?