Pine Island Glacier, one of the fastest-shrinking glaciers in Antarctica, hastened its slide into the sea between 2017 and 2020, when one-fifth of its associated ice shelf broke off as massive icebergs, a study revealed.
Scientists studied the acceleration using high-res radar images, captured by satellites.
Scientists studied the acceleration using high-res radar images, captured by satellites.
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00:00 These high-resolution radar images show how recent collapses of the Pine Island
00:05 Glacier ice shelf caused the whole mass of ice to speed up on its slide towards
00:10 the sea. The images were captured by the Copernicus Sentinel-1 satellites, which
00:17 are operated by the European Space Agency and equipped with synthetic
00:21 aperture radar, which takes what looks like black-and-white photographs but
00:26 actually captures radio waves rather than visible light. Starting in 2015, the
00:31 Copernicus Sentinel-1 satellites took snapshots of the Pine Island Glacier
00:35 every 12 days, and then after fall 2016, they began collecting data every six
00:41 days. Researchers examined all the images collected between January 2015 and
00:47 September 2020 and used the multitude of images to create detailed videos of the
00:52 ice flow. According to these videos and models that the team developed, the loss
00:59 of ice from the shelf allowed the glacier to speed up by about 12% between
01:03 late 2017 and 2020. The glacier sped up another time in recent history between
01:10 the 1990s and 2009, when warm ocean currents ate away at the underside of
01:15 the ice shelf, destabilizing its structure and causing the glacier to
01:19 accelerate toward open water. But this time, this somewhat gradual melt-driven
01:25 process wasn't the primary cause for the speedup. Instead, the dramatic and sudden
01:30 calving of icebergs from the shelf drove this acceleration. These new findings
01:36 hint that the entire ice shelf might collapse sooner than previously
01:40 projected, within decades rather than centuries. This could hasten the whole
01:45 glacier's collapse in turn. But that said, we don't know exactly when that collapse
01:51 might occur, and for now, the observed changes shouldn't drastically change
01:55 Pine Island Glacier's contribution to sea level rise. At present, the glacier
02:00 contributes about one-sixth of a millimeter of sea level rise each year,
02:04 so even if that rate suddenly tripled, we're still talking about fractions of a
02:08 millimeter. In the words of the first author, "The changes are rapid and
02:13 concerning, but not immediately catastrophic. Nothing's going to happen
02:17 overnight."
02:19 [Music]