00:00These high-resolution radar images show how recent collapses of the Pine
00:05Island Glacier ice shelf caused the whole mass of ice to speed up on its
00:10slide towards the sea. The images were captured by the Copernicus Sentinel-1
00:16satellites, which are operated by the European Space Agency and equipped with
00:20synthetic aperture radar, which takes what looks like black and white photographs
00:25but actually captures radio waves rather than visible light. Starting in 2015 the
00:31Copernicus Sentinel-1 satellites took snapshots of the Pine Island Glacier every
00:3612 days and then after fall 2016 they began collecting data every six days.
00:43Researchers examined all the images collected between January 2015 and
00:47September 2020 and used the multitude of images to create detailed videos of the
00:52ice flow. According to these videos and models that the team developed, the loss
00:59of ice from the shelf allowed the glacier to speed up by about 12 percent between
01:03late 2017 and 2020. The glacier sped up another time in recent history between
01:10the 1990s and 2009 when warm ocean currents ate away at the underside of the ice
01:15shelf, destabilizing its structure and causing the glacier to accelerate toward
01:20open water. But this time this somewhat gradual melt-driven process wasn't the
01:26primary cause for the speed-up. Instead, the dramatic and sudden calving of
01:31icebergs from the shelf drove this acceleration. These new findings hint that
01:37the entire ice shelf might collapse sooner than previously projected, within
01:41decades rather than centuries. This could hasten the whole glacier's collapse in
01:46turn. But that said, we don't know exactly when that collapse might occur and for now
01:52the observed changes shouldn't drastically change Pine Island Glacier's
01:56contribution to sea level rise. At present the glacier contributes about one-sixth of
02:01a millimeter of sea level rise each year, so even if that rate suddenly tripled,
02:06we're still talking about fractions of a millimeter. In the words of the first
02:10author, the changes are rapid and concerning but not immediately catastrophic.
02:15Nothing's going to happen overnight.
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