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Climate change making frozen island green, sa -

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PETER CAVE: Heard Island near Antarctica is turning green as more and more of its normally snow
covered slopes are exposed.

Nay-sayers aside, scientists says it's not the island's active volcano that's melting the ice but
climate change, and that's why they are monitoring it from space.

The volcano called Big Ben dominates Heard Island, 4,000 kilometres south west of Western
Australia, and the latest eruption has left a crater the size of the MCG.

Felicity Ogilvie reports from Hobart.

FELICITY OGILVIE: It takes two weeks to sail from Hobart to Heard Island.

But scientists in Hobart are overcoming the tyranny of distance by monitoring the sub-Antarctic
island from space.

In his office at the University of Tasmania, Arko Lucieer, is looking at satellite images of Heard
Island on his computer.

ARKO LUCIEER: These satellites are in an orbit 700 kilometres above the Earth's surface and the
spatial resolutions, so the pixel size that we get out of these images, is in the order of 50
centimetres to 60 centimetres.

So that means we can see individual elephant seals on the beach. You can see right into the glacial
crevices.

FELICITY OGILVIE: Doctor Lucieer has even seen the island's volcano, Big Ben, erupt.

ARKO LUCIEER: We chose a very recent volcanic activity, and it shows a crater around the top of Big
Ben and the diameter of this crater is close 180 metres, which is roughly the same as the size of
the MCG stadium.

FELICITY OGILVIE: The satellite image of the volcano is pure white because Big Ben is covered in
glaciers.

Ewan McIvor from the Australian Antarctic Division says there's a good reason why the volcano is
covered in ice.

EWAN MCIVOR: The ice is just on the very surface obviously of the ground of the island and between
the ice and the channels where the lava might flow, there's a considerable amount of solid rock
which has fabulous insulating properties.

So where the lava flows come out, such as the crater where we're looking at, you might see some
melting in the snow and the ice; and where the lava flows down the hill.

But for the bulk of the island, the surface, the ground surface is very well insulated from any
lava underneath just by the bulk of rock that forms the island.

FELICITY OGILVIE: But the glaciers on Heard Island are melting and the scientists say the volcano's
not too blame. The culprit is climate change.

EWAN MCIVOR: We talk about Heard Island as our Southern Ocean sentinel for climate change, being a
largely unmodified location that is, hasn't been impacted greatly by local human activities. It's
akin to a natural laboratory.

So changes that are happening there, we're fairly sure are happening for reasons other than local
human impacts.

FELICITY OGILVIE: Arko Lucieer has been watching the glaciers shrink.

ARKO LUCIEER: We can see clear retreat of the Stephenson Glacier; pretty much from all the way down
to the coastline and all the way down to sea level to further up the mountain. The total length of
retreat between 2003 and 2008 appears to be around three kilometres, with a total area lost of 400
hectares.

FELICITY OGILVIE: The island is getting greener too. Tough sub-Antarctic plants are growing in the
land that's been exposed by the melting ice.

This is Felicity Ogilvie in Hobart for The World Today.