28 November 2005

Ice Conference Heats Up

World experts see sea ice as climate-change indicator

Sea ice responds very quickly to climate change, shrinking or expanding accordingly, so it is a critical climate-monitoring tool.

The trouble is, no one has yet figured out a way to accurately measure the thickness of sea ice remotely by satellite. Just how to do this is one of the big questions confronting the International Glaciological Society’s symposium on sea ice, taking place at the University of Otago from 5 – 9 December.

One hundred and thirty delegates from countries such as Finland, Russia, Japan and the United States will converge on Dunedin to discuss a range of issues about sea ice.

Organiser Dr Pat Langhorne of the University’s Physics Department says the symposium has attracted specialists in a wide range of fields, from researchers working on the crystalline structure of sea ice, to those focusing on the global picture.

“It’s a very good opportunity to see things from the other end of the spectrum,” she says. “If you’re working on minutiae, it’s important to talk with people exploring the larger regional picture. It expands your vision!”

The other big issue being considered is the so-called ‘albedo feedback effect’ -- an acceleration of ice melt. Usually, because the ice is white, it reflects most of the sunlight. Ice therefore doesn’t heat up, and so melts slowly.

“However, with the sea ice’s response to climate change, there is already an increase in sea ice melting, which makes the sea ice darker, which in turn means the ice absorbs more light, so that it warms more, and melts more,” Dr Langhorne explained. “This melting of the sea ice is of particular concern in the Arctic where it is already happening, but it has the potential to be a problem in Antarctica also.”

Notable conference delegates include Dr Stephen Ackley from Clarkson University in New York State and Dr Ian Allison who is a programme leader from the Australian Government’s Antarctic Division.

Dr Ackley, who has researched aspects of sea ice for nearly 30 years, is currently focusing on the dynamics of sea ice ecology. Dr Allison is the co-chair of the International Polar Year Committee which is sponsored by the International Council of Science and the World Meteorological Organisation.

The committee is planning a range of research activities to commemorate next year’s 50th anniversary of the involvement of 80,000 scientists from 67 countries in the International Geophysical Year 1957/58. This event is remembered in New Zealand because of Sir Edmund Hillary’s first crossing of the Antarctic continent.

ENDS