Monster waves to blame for Arctic ice break-up

A buoy to measure waves is lowered on to sea ice. Photo / Rob Johnson

Niwa finds waves affect sea ice on larger scale than thought, decreasing ocean barrier

Large waves are apparently to blame for breaking up sea ice on a larger scale than thought, explaining a rapid decrease in Arctic ice.

The finding by Niwa scientists comes from researching how the Southern Ocean's biggest waves were affecting Antarctic sea ice.

Raw video: Monster waves caused Arctic break-up

Their data showed that large waves in the Southern Ocean - those bigger than 3m - were able to break sea ice over greater distances than previously believed.

This process may explain the increase in Antarctic sea ice, while Arctic sea ice is decreasing.

The findings were published this week in the scientific journal Nature.

Co-author Alison Kohout said their work had suggested that the role of large waves was more relevant that previously assumed.

"In the Arctic there is a lot of evidence of sea-ice retreat, yet scientists have been unable to reproduce the acceleration of sea-ice retreat in their modelling. This suggests something is missing from the models." Sea ice plays a critical role in moderating the global climate system and the state of the sea ice was an indicator of how climate was changing around the poles, said Dr Kohout. Co-author Mike Williams said new equipment had made the measurements possible.

Ice-breakers

• Big waves are breaking up sea ice more than previously thought.

• New technology allowed researchers to obtain wave data.

• Sea ice plays a key role in moderating global climate.

Watch: Animation: Melting of West Antarctica's glaciers