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Frozen carbon twice previous estimates -

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Frozen carbon twice previous estimates

The World Today - Friday, 12 September , 2008 12:30:00

Reporter: Simon Lauder

ELEANOR HALL: An international team of scientists has concluded a three year study on the potential
for greenhouse gases to be released from previously frozen regions of the Earth and has found that
it is far more dangerous than previously thought.

Scientists from Australia, Russia, the US, the UK, Canada and Europe say if thawing occurs,
previously frozen vegetation could release twice as much CO2 and methane as scientists have been
predicting.

The findings have been published in the latest edition of the journal 'Bioscience'.

Dr Pep Canadell from the CSIRO is one of the report's authors and he has been speaking to Simon
Lauder.

PEP CANADELL: What's really new and I think that is most surprising is the fact that we have gone
through what we call soil profiles and sediment profiles of organic matter across Canada,
Scandinavia, Russia and basically all the countries where they have a significant permafrost in the
Northern Hemisphere, and found that with all this new data, that we have almost double the amount
of the carbon content of permafrost when compared to the estimates we have been using until
recently to do our projections of, you know, climate change and potential carbon releases into the
future.

SIMON LAUDER: In fact, you say there's 1,500 billion tonnes of the stuff?

PEP CANADELL: Yes, correct. And before, even the IPCC (Intergovernmental Panel on Climate Change)
was still considering that the amount of carbon locked in permafrost was around anywhere between
400 and 800 billion tonnes, so we're talking about here more than double.

SIMON LAUDER: There's no way of knowing whether any of this permafrost will actually thaw, is
there?

PEP CANADELL: The permafrost is actually already thawing now, it has been thawing for the last few
decades and it is closely linked to the human induced warming of the high latitudes, a layer of
frozen ground keeps going deep and deep into the soil, and that's very well measured.

Now, what's more difficult to really understand is what's going to happen when that soil has been
melted, how much of that carbon is going to be decomposed and how much is going to be released into
the atmosphere, and therefore impacting the climate change.

So these are the big questions, and we don't have an answer yet for that, either.

SIMON LAUDER: What would it mean if even a small fraction of the vast frozen reservoir of carbon
were to be released?

PEP CANADELL: Well, we have done our calculations ourselves, and if the scenario like 10 per cent
was going to melt, and so what we come up is that at the end of this century, we have about 80-90
parts per million more, and this is like almost 10 to 15 per cent more carbon in the atmosphere
than we would have otherwise, you know had not the permafrost melt. That's a substantial additional
to climate change.

SIMON LAUDER: So there's so much carbon and methane stored in permafrost, that if any of it melts,
you're saying it will rapidly accelerate climate change?

PEP CANADELL: There is no doubt about that, the big doubt is how much is going to be released.

SIMON LAUDER: Obviously it's a positive feedback scenario, though?

PEP CANADELL: It is always a positive feedback, it's whether how much is going to be released and
whether it's going to be released as methane largely, which is a very powerful greenhouse gas, or
carbon dioxide, which is less powerful but you know huge quantities.

So these things are big concerns, and our study does not offer any new insights on that.

ELEANOR HALL: Dr Pep Canadell from the CSIRO, speaking to Simon Lauder.