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Growing Glaciers -

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Growing Glaciers (01/04/2010)

TRANSCRIPT

Dr Paul Willis

Glaciers around the world are retreating but this one and a couple of others in New Zealand are
doing something different. And it's telling us something unique about climate change.

NARRATION

The west coast of the South Island of New Zealand, and Andrew and Alice and Brian are preparing to
escort me up the front face of Franz Josef Glacier. They want to know how big it is. It's a subtle
measure of the effects of changing global climate.

Dr Paul Willis

And so you guys are intending to go right up over the top? How far up the glacier are we going
today?

Andrew Mackintosh

Yeah up onto the flat section up there. You you can probably just see it.

NARRATION

And climbing a glacier with experiments and other gear on our backs is no mean feat. It's cold, wet
and steep.

Dr Paul Willis

For Andrew, Alice and Brian, this is their laboratory. It's got fantastic views, but they really
should adjust the air conditioning.

NARRATION

The complication is that this glacier is constantly changing shape so measuring it is a constant
job. Only a week ago, when Brian put this measuring pole in, the top was flush with the top of the
glacier. In that short period, almost a metre of ice has melted away. With such a high turnover in
ice, new measuring poles need to be regularly drilled into the glacier. And they drill into the
glacier with steam.

Andrew Mackintosh

This work is to drill stakes vertically into the glacier. And it allows us to work out how much
melt is occurring.

NARRATION

But historical data for the Franz Josef and nearby Fox glaciers only take the team back a couple of
hundred years.

Dr Paul Willis

The terminus of Fox Glacier is about a kilometre up this valley but you can tell from the scratches
on the rocks behind me that the glacier was here once upon a time. In fact, if I was standing on
this spot in 1894, I'd be under a couple of hundred metres of ice.

NARRATION

Coming to terms with what the glaciers were up to in prehistoric times means looking at the rocks
they've left behind. Dating moraine is the subject of Alice's doctoral thesis.

Alice Doughty

As soon as the rock is exposed to the atmosphere it's bombarded by cosmic rays and over time um, a
isotope called beryllium accumulates and we can take a sample of the rock and measure the amount of
beryllium that's in that rock... Before you can really understand how the climate system works you
need to understand what's happened in the past and possibly what's caused climate to change in the
past.

NARRATION

In collaboration, the team have put together a computer model of how these glaciers ought to work.

Brian Anderson

There's kind of two sides to it. There's... the balance between the amount of snow that falls on
the glacier... And then the other component is actually getting the way the the glacier transports
that mass from high elevations down to low elevations. And it's really those two processes that
control the response of a glacier to climatic changes.

NARRATION

But when they plugged in the measurements that they had taken into the model they had built, they
found something unexpected: both Fox and Franz Josef glaciers are very sensitive.

Andrew Mackintosh

They move fast, you know kilometres per year. The front can really change very dramatically. I mean
I come here several times a year and every time I come back it looks different.

NARRATION

These two glaciers are abnormal. Whereas most glaciers around the world have been in steady retreat
for most of the last 200 years, Franz Josef waited for a while before starting a decline and then,
amazingly, it started to grow again.

Andrew Mackintosh

Here, even though we've had a few advancing glaciers recently, the overall retreat has been
dramatic.

NARRATION

The west coast of the South Island is one of the wettest places on earth. Franz Josef collects
around five meters of rain a year. And a lot of that ends up feeding into the Fox and Franz Josef
glaciers. And, as high pressure systems over south-eastern Australia have become more common, they
feed more rain from the southern ocean onto New Zealand's west coast. Fed by even more rain, the
glaciers grew. But there's only so much bucking of the global trend that these glaciers are capable
of. If the computer model is right, Fox and Franz Josef glaciers are also under threat from climate
change.

Andrew Mackintosh

We've established that these glaciers are so responsive to temperature changes, even small amounts
of warming will cause these glaciers to retreat dramatically. So we know in New Zealand it's likely
to get say two degrees warmer within the next century. We've seen four kilometres of retreat during
the twentieth century. During the twenty-first century we might see double that. It's, it's really
going to change a lot around here if the global warming predictions come to pass.

NARRATION

The sheer size of these glaciers might give them an appearance of permanence but they are dynamic
systems, constantly changing and reacting to the environment. Although tucked away in remote New
Zealand,they are just as susceptible to the ravages of a global climate change as any living
creature.