So far the researchers have not heard any
telling signs that climate change is
affecting Antarctica.
Image: iStockphoto
The greatest warning of impending climate catastrophe could also be one of the most spectacular — the sound of millions of tonnes of ice breaking away from the giant icesheets of the South Pole.
Using acoustic sensors thousands of kilometres away, scientists from Curtin University of Technology have been able to listen to the break-up of ice from the Antarctic ice shelves.
The main aim of the research, conducted by Dr Alexander Gavrilov and PhD student Binghui Li, who will be presenting their research paper at a conference in Europe in late June, is to investigate whether it is actually possible to detect and monitor significant changes in the disintegration rate of the Antarctic ice shelf through the monitoring of ice breaking noise.
So far the results do not show any evidence of climatic change on the ice shelves, but according to Dr Gavrilov, it is still early days in the research process.
“This is very promising research which may provide a practical and cost-effective way of monitoring the impact of climate change on Antarctica,” Dr Gavrilov said.
“We analyse the sounds of the breaking ice from two remote underwater listening stations based off the coast of Cape Leeuwin in Western Australia and the Chagos Archipelago in the middle of the Indian Ocean.”
In a poignant example of beating swords into ploughshares, the sensors used are those that monitor nuclear weapons testing by the Comprehensive Nuclear-Test-Ban Treaty Organisation.
More than six years ago, Dr Gavrilov suggested that these sensors could be used for another important task — to watch one of the best indicators for global temperature change, the Antarctic ice shelf.
“Each station consists of three receivers placed in the middle of the natural ocean acoustic channel, where underwater sound propagates over large distances without interaction with the sea surface and the sea floor,” he said.
“Each station is cabled to the shore, so sea noise data can be processed in real time.”
More than 100 signals from Antarctica are detected weekly at the Cape Leeuwin station.
To examine the origin of these signals, sea noise data was recorded by researchers from the Australian Antarctic Division on an autonomous acoustic logger installed for a year on the Antarctic continental shelf. This information was analysed alongside the data collected from the station off the Australian coast.
This confirmed that the noise the Curtin team was listening to was definitely from ice breaking away from the Antarctic Shelf.
According to Dr Gavrilov, an analysis of the data obtained from the Cape Leeuwin station over the past six years has revealed a strong seasonal cycle in the intensity and frequency of noise events located in Antarctica.
However, despite these impressive results, so far there has been no evidence of climate change impacting the intensity of Antarctic ice noise.
“More than six years of observation has not revealed any significant climatic trends,” Dr Gavrilov said.
“I guess we could see this as good news.”
However, Dr Gavrilov is not going to take these results for granted.
“There has been a lot of speculation about the nature of climate change, supported by a great deal of research,” he said.
“Six years of results is not long in the scheme of things, so we will keep watching. Antarctic ice could be the canary in the Earth’s climatic coal mine.
“This monitoring process is a very promising way to watch the climate in action and we will continue to do so.”
Dr Gavrilov is a researcher at Curtin’s Centre for Marine Science and Technology, which is an affiliate research centre of the Australian Sustainable Development Institute (ASDI).
Officially launched by Curtin in 2009, ASDI consolidates existing research institutes and centres based at Curtin to intensify research and teaching in the area of sustainability. It also provides leadership in policy, and professional training to government, industry and the wider community.
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