WEBVTT FILE 1 00:00:00.030 --> 00:00:02.190 2 00:00:02.210 --> 00:00:07.130 July 16th, 2012 - the Petermann Glacier in northwest Greenland 3 00:00:07.150 --> 00:00:12.470 lost a massive iceberg, for the second time in three years. 4 00:00:12.490 --> 00:00:16.660 As the ice floating in the fjord broke up, the ice island was carried by the current 5 00:00:16.680 --> 00:00:21.550 down the glacier's outlet channel and toward the Nares Strait. 6 00:00:21.570 --> 00:00:25.220 Known as Petermann Ice Island 2012, 7 00:00:25.240 --> 00:00:30.400 it is bigger than Manhattan island - and floating at one kilometer per day. 8 00:00:30.420 --> 00:00:35.980 NASA's Aqua and Terra satellites made multiple passes each day over the polar regions, 9 00:00:36.000 --> 00:00:41.470 allowing scientists to track the ice island - whenever clouds didn't block the view. 10 00:00:41.490 --> 00:00:46.060 Scientists have been watching this crack develop since 2001. 11 00:00:46.080 --> 00:00:50.200 Ocean temperatures are one factor determining when glaciers will calve an iceberg. 12 00:00:50.220 --> 00:00:54.330 Warmer water destabilizes the ice. 13 00:00:54.350 --> 00:00:59.990 14 00:01:00.010 --> 00:01:06.540 After two months at sea, Petermann Ice Island 2012 had begun to fragment as it floated down the strait. 15 00:01:06.560 --> 00:01:10.600 16 00:01:10.620 --> 00:01:19.993