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Scientists fear ice-free Arctic summer within -

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ELEANOR HALL: There are new warnings today that the Arctic will be free of ice in summer in the
space of a generation.

With summer drawing to a close in the Northern Hemisphere, it's clear that the melt this year
hasn't been quite as dramatic as it was in 2007.

But scientists say it would be a big mistake to assume that global warming is on the wane.

Instead, they argue, the cooler summertime temperatures should have halted the thaw by a much
greater degree.

Our reporter Simon Santow has been speaking to Walt Meier, he's a research scientist at the
National Snow and Ice Data Centre in Colorado in the United States.

WALT MEIER: It's the second lowest on record and far lower than any other previous year except for
2007.

SIMON SANTOW: So I was going to ask you, that there's no comfort for climate change sceptics who
would, who might argue look, there's less of an ice melt going on this year than last year so we
shouldn't be panicking.

WALT MEIER: Right, I mean, it's a little bit higher than last year but I would resist any
temptation to call it a recovery. We did have a little bit of a cooler summer this year, and
conditions weren't quite as favourable to melt, which makes it actually in some ways remarkable
that we went as low as we did given that we would expect more of a rebound from last year.

But the ice was so much thinner, that we still lost a lot of ice to summer, but the long term trend
is still downward and actually has been accelerating over the past few years and this year really
is simply reinforcing that.

And so we're still on a long-term track towards an ice-free summer in the Arctic Ocean at some
point in the future.

SIMON SANTOW: Would you speculate on when that might happen?

WALT MEIER: Well it's really hard to give any kind of definitive answer on that because a lot does
depend on whether you have a cool summer or two or whether you have a really warm summer, it could
accelerate things.

The consensus seems to be among sea ice scientists in the order of 2030, so in the next 20, 25
years, seems to be a reasonable estimate.

There have been some that have suggested earlier, as early as within 5 years, that's a little bit
extreme I would say, I would disagree with that. But it's not impossible, it's not a crazy idea by
any stretch.

Regardless of exactly when it happens, it's looking clearer and clearer and this year again only
reinforces it that at some point in the not too distant future we're going to have conditions where
the ice, the sea ice in the Arctic Ocean melts completely during the summer, and we'll have a blue
Arctic Ocean so to speak.

SIMON SANTOW: And what are the implications as far as that's concerned for the climate there?

WALT MEIER: Well when you are removing the ice cap, you're really changing your energy balance,
you're going to warm up the Arctic a lot more than it normally would because the sea ice reflects a
lot of the solar energy and doesn't absorb it. Whereas the ocean absorbs almost all of the incoming
solar radiation during the summer, in solar energy.

And so that's going to be adding a lot more energy to the Arctic region and going to heat things up
even more than what you would normally get. So it's kind of amplifying the greenhouse gas effect,
in the Arctic.

But the effects are going to felt much more widely than that, because the climate is a completely
inter-connected system. The Arctic and the connection between the Arctic and the lower latitudes
and the cold Arctic and the warmer lower latitudes help set up ocean and wind circulations and
essentially the weather pattern, things like the jet stream and so forth and storm system tracks
that you see, those are going to be changing.

At the very least, over the Northern Hemisphere, throughout North American and Europe and Asia and
that's going to have a pretty big impact on people's lives down the road as people have to adjust
to changing weather patterns. And there may be changes in for example, what you may be able to
plant and when you may be able to plant certain crops and so forth.

SIMON SANTOW: And if I can ask you about Southern Hemisphere, of course Australia will be going
into a summer over the next couple of months, do you expect there to be quite an ice melt in the
Antarctic?

WALT MEIER: Well the Antarctic is quite a bit different than the Arctic in terms of its general
environment. The Antarctic always has an extreme ice melt, it loses most of the ice cover, the sea
ice cover during the summer time, the summer melt.

And so we have seen some increasing trends in the Antarctic, in contrast to the Arctic, but these
trends are a fare bit smaller than the Arctic and are not as significant in terms of any climate
change signal because essentially the climate change signal is being delayed in the Antarctic
because the Antarctic is such an isolated place.

It's a continent on the bottom of the world surrounded by ocean and you get very strong ocean
currents and very strong winds that circle the Antarctic, that kind of act as a wall to prevent any
kind of interaction, or most of the interaction between the Antarctic and the lower latitudes
towards the equator.

And so you don't have that interplay between the lower latitudes and the poles that you do in the
Arctic, and so we expect that the response would be slower and that you might actually see some
increasing trends for a time.

Eventually that will turn around as the warming temperatures eventually kind of penetrate that
wall, but it hasn't happened yet, but it probably will before too long.

We have seen some areas of the Antarctic that have shown some considerable warming, most notably
the Antarctic Peninsula where we've seen a lot of warming in terms of the temperatures and we've
also seen some pretty dramatic decreases in sea ice, decreasing trends in sea ice in the western
side of the Antarctic Peninsula.

Though it's a more complicated, more mixed picture in the Antarctic but it doesn't offset what
we're seeing in the Arctic. The Arctic signal, is a very strong powerful signal with very big
climate impacts and whereas the Antarctic is a smaller signal with at least for the time being,
smaller impacts.

ELEANOR HALL: And that's Walt Meier, a research scientist at the National Snow and Ice Data Centre
in Colorado, speaking to Simon Santow.