Cool Science in Action

Scientists have recorded a rapid melting of sea ice in the Arctic in recent years which matches a small increase in temperatures across the globe. But in parts of Antarctica sea ice has been increasing. If scientists can understand why this is happening they can better predict the future effects of climate change.

The Arctic and Antarctic

The Arctic and the Antarctic are very different. The Arctic is an area of frozen ocean surrounded by land while the Antarctic is an area of frozen land surrounded by ocean. This means that they respond to climate change differently.

Antarctica has ice shelves – giant slabs of ice that float above areas of seawater called seawater cavities. Some of these ice shelves are very large. The Ross Ice Shelf is about the same size as France.

What other differences are there between the Arctic and the Antarctic?

In both the Arctic and Antarctica ocean temperatures have increased slightly due to global warming. When this slightly warmer water comes into contact with ice shelves it causes melting. 

Why is the area of sea ice around Antarctica increasing?

While the total area of sea ice is increasing, it is not increasing everywhere. This is because the ocean around Antarctica is different in different regions.

Changing winds are thought to affect ice growth in some regions. 

The K131 team are interested in how ice shelves and the ocean affect each other. Ice shelves are made of fresh water so when they melt they release very cold, fresh water into the sea.

This water is so cold it can be below its freezing point and is called supercool. This supercool water tries to form new ice. As this water refreezes it forms ice crystals.

It is possible that increasing growth of sea ice over winter in Antarctica is partly caused by ice shelves melting. One form of ice is being replaced by another. 

Why could more sea ice be a problem?

Sea ice changes a lot between winter and summer. If there is less ice over a period of years there could be a problem. Ice is white and reflects sunlight. Without a cover of ice the ocean will absorb the sun’s energy as heat causing it to warm more.

Sea ice is also an important home for sea ice algae and other animals which are part of the ocean food web in this region.

If the ice shelves keep melting then the sea level will rise in the future.

Less ice means higher sea levels.

When a lot of ice melts the water that was stored as ice goes into the ocean causing the sea level to rise.

What the scientists will be measuring

Fifteen kilometres away from Scott Base the K131 science team will set up a field camp on the sea ice near the Ross Ice Shelf. The Ross Ice Shelf is the size of France. Measurements and observations will be collected on;

• Supercooled water
• Changes in seawater temperature
• Salinity (saltiness)
• Turbulence (movement of water)
• Ice crystals

By collecting this data scientists hope to get more information about changes in the ice shelf and sea ice. This data will be used by computer models that help show the impacts of climate change.