In 1978, satellites began continuously observing the polar regions,
and the dynamic beauty of the Arctic sea ice was revealed.
What we expect to be a solid mass of ice is actually
in constant motion.
As researchers continue to seek a deeper understanding of this region,
new information about how the sea ice changes is coming to light.
[Dr. Walt Meier] In this animation, we're taking Arctic sea ice into the third dimension.
Here, we're looking
at the ice age, which is an indicator of thickness. Generally older ice is thicker ice.
[narrator] That's the voice of Dr. Walt Meier, Senior Research Scientist at the National Snow and
Ice Data Center.
[Meier] What you see in this animation is the ice pulsing out and in with the seasons.
In winter, the ice grows out and expands outward; in summer, it contracts inward as it melts.
You see the whiter ice which is the older ice, moving around the Arctic, being pushed
around by winds and currents that move the ice.
Over the years the ice pulses around
and moves around towards the top along the coast of Greenland.
The older ice eventually moves out of the Arctic and into the north Atlantic where it melts.
The ice gets replenished within the Arctic because some of the ice survives each summer and grows older.
And particularly, in the region north of Alaska, called the Beaufort Sea, where the ice spins
around in a clockwise direction, called the Beaufort Gyre,
and that ice can keep spinning around, often times for several years,
gradually getting older and thus getting thicker.
Eventually, the ice will spin out of that gyre and go out through Fram Strait.
In the past, we've always had enough ice growth and ice aging, enough ice surviving the summers,
to replenish the older ice that's lost.
But in recent years, we've seen less replenishment.
There's been more melt during the summer and
so the ice that goes out through Fram Strait has not been compensated by the ice growth.
In addition, especially in recent years,
we've seen some pretty remarkable things in the Beaufort Sea,
where that area that used to be a nursery for the development of the older ice,
allow the younger ice to age and mature,
what we've seen instead is the ice is now more broken up, more scattered,
and that's allowing the older ice to melt within the Beaufort Sea.
So we're seeing the Beaufort Sea go from a nursery to a graveyard for older ice.
And as we get towards the more recent years,
much of that oldest ice--the ice that's older than five years old in the bright white--
is almost virtually disappeared from the Arctic Ocean,
and the Arctic is now dominated by younger and thinner ice.