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Dr. Walt Meier: In this animation, we're taking Arctic sea ice

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into the third dimension. Here we're looking at the 

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ice age, which is an indication of thickness. Generally older ice is

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thicker ice. And so what you see in this animation is first of all, the ice

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pulsing out and in with the seasons.

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In winter the ice grows out and expands outward, and in summer it contracts inward as it

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melts. in addition, you see the whiter ice 

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which is the older ice, moving around the Arctic, being pushed around

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by winds and currents that move the ice. And what you can see is over the years

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the ice pulses around and moves around towards the top

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of the coast of Greenland. You see that the older ice eventually moves out of the

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Arctic and into the north Atlantic where it melts.

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But the ice gets replenished within the Arctic because some of the ice survives 

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each summer and grows older. And particularly, 

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in the region north of Alaska called the Beaufort Sea where the ice

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spins around in a clockwise direction, called the Beaufort Gyre

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and that ice can keep spinning around, often times for several years, and gradually getting older

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and thus getting thicker.

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Eventually, the ice will spin out of that gyre and go out through Fram Strait.

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But in the past, what is happened, we've always had enough ice growth

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and ice aging, enough ice surviving the summers, to 

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replenish the older ice that's lost. But in recent

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years, we've seen less replenishment. There's been more melt

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during the summer and so the ice that goes out through Fram Strait has not been

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compensated by the ice growth. In addition,

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especially in recent years, we've seen some pretty remarkable things

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in the Beaufort Sea, where that area that used to be a nursery 

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for the development of older ice, allow the younger

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ice to age and mature, what we've seen instead

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is the ice is now more broken up, more scattered, and 

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that's allowing the older ice to melt within the Beaufort Sea.

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So we're seeing the Beaufort Sea go from a nursery to a graveyard

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for older ice. And as we get towards the

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more recent years, much of that oldest ice, the ice that's older than five years

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old in the bright white is almost virtually disappeared 

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from the Arctic Ocean, and the Arctic is now dominated by younger, 

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and thinner ice.