WEBVTT FILE 1 00:00:00.100 --> 00:00:04.160 Dr. Walt Meier: In this animation, we're taking Arctic sea ice 2 00:00:04.180 --> 00:00:08.240 into the third dimension. Here we're looking at the 3 00:00:08.260 --> 00:00:12.340 ice age, which is an indication of thickness. Generally older ice is 4 00:00:12.360 --> 00:00:16.420 thicker ice. And so what you see in this animation is first of all, the ice 5 00:00:16.440 --> 00:00:20.530 pulsing out and in with the seasons. 6 00:00:20.550 --> 00:00:24.640 In winter the ice grows out and expands outward, and in summer it contracts inward as it 7 00:00:24.660 --> 00:00:28.750 melts. in addition, you see the whiter ice 8 00:00:28.770 --> 00:00:32.910 which is the older ice, moving around the Arctic, being pushed around 9 00:00:32.930 --> 00:00:37.070 by winds and currents that move the ice. And what you can see is over the years 10 00:00:37.090 --> 00:00:41.150 the ice pulses around and moves around towards the top 11 00:00:41.170 --> 00:00:45.270 of the coast of Greenland. You see that the older ice eventually moves out of the 12 00:00:45.290 --> 00:00:49.360 Arctic and into the north Atlantic where it melts. 13 00:00:49.380 --> 00:00:53.440 But the ice gets replenished within the Arctic because some of the ice survives 14 00:00:53.460 --> 00:00:57.560 each summer and grows older. And particularly, 15 00:00:57.580 --> 00:01:01.700 in the region north of Alaska called the Beaufort Sea where the ice 16 00:01:01.720 --> 00:01:05.830 spins around in a clockwise direction, called the Beaufort Gyre 17 00:01:05.850 --> 00:01:09.960 and that ice can keep spinning around, often times for several years, and gradually getting older 18 00:01:09.980 --> 00:01:14.130 and thus getting thicker. 19 00:01:14.150 --> 00:01:18.190 Eventually, the ice will spin out of that gyre and go out through Fram Strait. 20 00:01:18.210 --> 00:01:22.290 But in the past, what is happened, we've always had enough ice growth 21 00:01:22.310 --> 00:01:26.420 and ice aging, enough ice surviving the summers, to 22 00:01:26.440 --> 00:01:30.460 replenish the older ice that's lost. But in recent 23 00:01:30.480 --> 00:01:34.560 years, we've seen less replenishment. There's been more melt 24 00:01:34.580 --> 00:01:38.700 during the summer and so the ice that goes out through Fram Strait has not been 25 00:01:38.720 --> 00:01:42.840 compensated by the ice growth. In addition, 26 00:01:42.860 --> 00:01:47.020 especially in recent years, we've seen some pretty remarkable things 27 00:01:47.040 --> 00:01:51.120 in the Beaufort Sea, where that area that used to be a nursery 28 00:01:51.140 --> 00:01:55.180 for the development of older ice, allow the younger 29 00:01:55.200 --> 00:01:59.280 ice to age and mature, what we've seen instead 30 00:01:59.300 --> 00:02:03.410 is the ice is now more broken up, more scattered, and 31 00:02:03.430 --> 00:02:07.530 that's allowing the older ice to melt within the Beaufort Sea. 32 00:02:07.550 --> 00:02:11.660 So we're seeing the Beaufort Sea go from a nursery to a graveyard 33 00:02:11.680 --> 00:02:15.810 for older ice. And as we get towards the 34 00:02:15.830 --> 00:02:19.970 more recent years, much of that oldest ice, the ice that's older than five years 35 00:02:19.990 --> 00:02:24.150 old in the bright white is almost virtually disappeared 36 00:02:24.170 --> 00:02:28.250 from the Arctic Ocean, and the Arctic is now dominated by younger, 37 00:02:28.270 --> 00:02:35.247 and thinner ice.