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Name: James
Status: Other
Age: 30s
Location: N/A
Country: N/A
Date: N/A 


Question:
Three questions:
1) Can you confirm the report below; has the Arctic polar ice cap really melted?

2) Weren't there government measurements published just last November that suggested the ice cap would not melt for another thirty-five years?

3) Can you extrapolate this to predict how long it will take Antarctica to melt, please? What is your best current estimate?
I look forward to your answers!
Sincerely,
James Salsman



Replies:
James,

The polar ice has thinned some 30-50% in the last 40 years. This may be a result of warming of the atmosphere, but the warming in the past century has been so small (0.5 degrees C) that it cannot explain the thinning. A natural cause of another kind, such as a change in polar ocean currents is quite possible. Leads (openings in Arctic sea ice) are common in the summer, with the ice forming into essentially icebergs that move around and smash into each other with the Arctic ocean currents. That there was a lead a mile wide may be unusual, but is not impossible even in the coolest of summers in the Arctic. The report is overblown, as many media reports are.

An interesting sidelight to this is that at Barrow, Alaska it is pretty much ice-free this time of year, but a few weeks ago the sea ice closed in (early this year). So, you can see that it has not been a normal summer in the Arctic.

The article that you copied is undoubtedly inaccurate in stating that there hasn't been open water at the North Pole in 50 million years. The climate has been much warmer than now, much more recently than that. So, wide leads may have been fairly common during some of the warmer climate periods.

David Cook (a meteorologist working at Argonne National Laboratory)



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