Scientists 'flabbergasted' at Arctic melting
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American scientists studying the Arctic icecap say the area covered by sea ice has shrunk for a fourth consecutive year.
A joint study by NASA and the National Snow and Ice Data Centre (NSIDC) found that at the current rate of shrinking the icecap could completely disappear within 60 years.
The scientists say they are recording the lowest extent of polar ice cover for more than 100 years and warn that global warming could be accelerating.
Dr Mark Serreze from the NSIDC says he is alarmed that sea ice levels are not fluctuating like they used to.
"I'm flabbergasted, to be honest," he said.
"What we all typically see in the Arctic is we'll have a low sea-ice year, but we'll recover for next year - just natural variability.
"But we're not. Every year has less and less sea-ice."
Alaska-sized loss
His NSIDC colleague, Julianne Stroeve, says their satellite observations have been showing that Arctic sea ice is rapidly declining.
"This year in 2005 we reached our all-time minimum since we began the satellite observations in the late 1970s," she said.
"We had sea ice this year that was about 22 per cent below the long-term mean and that's roughly the size of Alaska in terms of how much ice we've lost, in terms of what is normally seen over summer period in the Arctic."
She says the trend is accelerating.
The last four years have seen increasing warm temperatures in the Arctic over the summer months, causing the ice to shrink further and further.
"It's not coming back," she said.
"And this winter was also unusual in that normally, even though in 2002, 2003 we had these really low ice years. After the 2004 minimum, which was the third consecutive year of low ice conditions, we didn't see the winter icecap refreeze, or not quite as rapidly.
"It came back, but was much lower than what we'd seen in the past.
"In the past, the temperatures would be cold enough to freeze the ice and the ice would grow again. This last winter, that didn't happen. We had record lows every month since last September, except during May."
Cause unclear
While scientists say this sort of warming is consistent with what will happen as a result of climate change, Ms Stroeve says it is hard to tell whether the melting is due to a natural occurrence, or if can it blamed on increased emissions of greenhouse gases into the atmosphere.
"But it's hard to deny the fact that we're emitting a lot of gases into the atmosphere that are causing warming and the Arctic is certainly warming," she said.
"What we believe is that there's these feedbacks from the systems that are occurring in the Arctic appear to be sustaining this continual decline in the sea ice cover.
"So it might not be possible for it to recover any more."
Global implications
The shrinking ice will reduce the living space for Arctic animals like polar bears, who depend on the ice sheets to hunt seals.
But Ms Stroeve says the changes to the Arctic will have more far reaching consequences for the entire planet.
"The Arctic is a huge heatsink, it helps keep the planet cool, and it also drives our circulation because the heat graded between the poles and the equator is what drives our atmospheric, our ocean circulation.
"And what we're doing is we're changing the heat in the Arctic, and it's warming up.
"It's going to have an impact on all our atmospheric patterns. Exactly what the consequences will be, it's hard to say.
"All we know is that our global climate is tied to the Arctic climate as well and so any changes that are occurring there are going to be impacting the rest of our environment."
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