Australians to retrieve 500 year climate record from Antarctic ice core

5 October 2004

Australian scientists sail from Hobart today for Antarctica to bring back an ice core that will shed some light on global climate change and climate interactions between northern and southern hemispheres over the past 500 years.

Australian Antarctic Division glaciologist Dr Mark Curran and a team of scientists and support personnel will drill a 110-metre ice core at Law Dome 110 kms inland from Australia's Casey station and the site of ongoing climate research.

Dr Curran said that the core would be used to produce a detailed climate record covering the past 500 years.

"During that period changes have occurred in Earth's climate. These include natural variations during the so-called Little Ice Age in the Northern Hemisphere from the 16th to the 18th Centuries and also including the subsequent warming that has taken place during the era of human industrialisation.

"The extent to which the Little Ice Age may have had global climate impacts is not well understood and the focus of this new research is to study changes in Antarctica during this period and into the time of recent warming.

"One key climate indicator is the extent of frozen sea ice around the Antarctic. Each winter, an area comparable to the size of the continent itself is covered by a layer of frozen ocean. Variations in the extent are thought to be a reflection of climate change.

Dr Curran said that studying this variation in the past had been difficult because of limited observations.

"Most research to date has used satellite data, ice edge records from whaling ships and even the observations of Captain Cook.

"Last, year, however, our group reported a new way to track past sea ice by measuring a chemical tracer ? known as methanesulphonic acid or MSA - that can be detected in ice cores from the continent," Dr Curran said.

MSA is an atmospheric aerosol produced as a result of phytoplankton activity at the surface of ocean waters. Phytoplankton are small single-cell ocean plants that are a major food source for species such as krill and other grazers.

Researchers believe that a 110-metre ice core they plan to drill will reveal a comprehensive picture of climate as far back as 500 years.

Dr Curran said that measurements would be used in the field to identify major volcanic eruptions, detectable in the ice core, to help in refining this estimate.

Two very large events can be seen - the eruption in 1815 of Tambora in Indonesia, the greatest eruption in history and Kuwae, Vanuatu in the late 1450s.

Dr Curran said that it was the Kuwae eruption in particular that would be a key to determining the desired 500 year mark.

The team sails this evening aboard the Antarctic research ship Aurora Australis at 5 o'clock.

Law Dome is located on the Antarctic Coast adjacent to Australia's Casey station. It has been a focal point for Australian glaciological research since the 1960s. Snow that fell on Law Dome summit more than 80 thousand years ago now lies buried near the base of the ice sheet, 1200m below the present day surface. This archive of past snowfall provides ice core records of climate and environmental changes over this period.

This page was last modified on 5 October 2004.