Heard Island: Australia's bellwether on climate change

• Andrew Darby, Hobart
• The Age, January 16, 2009
• http://www.theage.com.au/national/heard-island-australias-bellwether-on-climate-change-20090115-7i6p.html

THE latest bulletin is in from Australia's home of rapid polar environmental change, and it says the pace is hot.

On Heard Island in the Southern Ocean the temperature is up, rapid glacial retreat is unabated, and a peninsula has been split by the sea to create a new island offshore.

Every few years Australian scientists have a chance to measure wholesale changes to the volcanic island, which lies 2200 nautical miles south-west of Perth.

In the most recent visit aboard the ship Aurora Australis last month, they confirmed its place beside the Antarctic Peninsula as a climate change outpost as ice sheets collapse and glacial melting speeds up.

Automatic weather stations on Heard Island have recorded a 1.3 degree temperature rise. Brown Glacier, one of the island's major glaciers, retreated 1.2 kilometres between 1947 and 2004, and there is reason to believe that today the pace is just as fast.

On a two-day stop on the island, scientists used Australian Antarctic Division helicopters to take video and still images to record the highly dynamic landscape.

"We have 80 gigabytes of images to analyse, but the team noticed that melt lagoons at the foot of the glaciers appear to be larger than when they were last mapped," said the division's Heard Island expert, Ewan McIvor.

"Over 50 years, there has been a retreat in total ice cover at Heard from 80 per cent of the island to 70 per cent."

Mr McIvor said what immediately stood out was the creation of a one-kilometre-long island where inundating seas had cut into the end of a 10-kilometre peninsula known as Elephant Spit. He said an island had appeared there in the past, as wind and waves reshaped the gravel spit.

Bleak weather relented to reveal what was happening at Heard Island, but nearby McDonald Island, perhaps the most active new land form in Australia, remained shrouded. In 2004, remote sensing showed volcanic activity doubled McDonald's size from about one square kilometre to 2.5 square kilometres over only a few years.