Antarctic Glacier Sped Up As Its Ice Shelf Collapsed
Pine Island Glacier, one of the fastest-shrinking glaciers in Antarctica, hastened its slide into the sea when one-fifth of its associated ice shelf broke off as massive icebergs, a new study reveals. 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 Glacier ice shelf
00:06 caused the whole mass of ice to speed up on its slide towards the sea.
00:11 The images were captured by the Copernicus Sentinel-1 satellites,
00:16 which are operated by the European Space Agency and equipped with synthetic aperture radar,
00:22 which takes what looks like black-and-white photographs,
00:25 but actually captures radio waves rather than visible light.
00:30 Starting in 2015, the Copernicus Sentinel-1 satellites took snapshots of the Pine Island Glacier every 12 days,
00:37 and then after fall 2016, they began collecting data every 6 days.
00:42 Researchers examined all the images collected between January 2015 and September 2020,
00:49 and used the multitude of images to create detailed videos of the ice flow.
00:54 According to these videos and models that the team developed,
00:58 the loss of ice from the shelf allowed the glacier to speed up by about 12% between late 2017 and 2020.
01:06 The glacier sped up another time in recent history, between the 1990s and 2009,
01:12 when warm ocean currents ate away at the underside of the ice shelf,
01:16 destabilizing its structure and causing the glacier to accelerate toward open water.
01:22 But this time, this somewhat gradual, melt-driven process wasn't the primary cause for the speed-up.
01:28 Instead, the dramatic and sudden calving of icebergs from the shelf drove this acceleration.
01:34 These new findings hint that the entire ice shelf might collapse sooner than previously projected,
01:41 within decades rather than centuries.
01:43 This could hasten the whole glacier's collapse in turn.
01:46 But that said, we don't know exactly when that collapse might occur,
01:51 and for now, the observed changes shouldn't drastically change Pine Island Glacier's contribution to sea level rise.
01:58 At present, the glacier 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 millimeter.
02:08 In the words of the first author,
02:11 "The changes are rapid and concerning, but not immediately catastrophic.
02:15 Nothing's going to happen overnight."
02:18 [Music]