Science Friday

What The Sounds Of Melting Glaciers Can Tell Us

December 11, 2025

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  • The sounds of melting glaciers, such as bursting air bubbles, provide valuable data for researchers to better understand the rate of climate change and glacial meltwater impact. 
  • Glacial calving events, particularly dangerous submarine ones, generate low rumbles that can help researchers estimate the volume of ice lost and its impact on fjord circulation. 
  • Glaciologist Dr. Erin Pettit utilizes a complex, multi-stage robotic system involving a remote-controlled boat, an ROV, and a drilling mechanism to safely collect close-range data on glacier melting processes. 

Segments

Introduction to Glacial Sounds
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(00:01:28)
  • Key Takeaway: Glacier melt releases pressurized air bubbles that create distinct sounds, like trickling water or sizzling.
  • Summary: The sound initially played resembles trickling water but is actually tiny air bubbles bursting from melting glacier ice. These sounds are a potential source of data for understanding climate change rates. The bubbles are trapped during snow compression into ice and pop as they melt out, having traveled long distances within the glacier.
Acoustic Data Collection Rationale
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(00:03:37)
  • Key Takeaway: Acoustic monitoring is preferred over close physical proximity due to the inherent danger of approaching calving glacier termini.
  • Summary: Sound travels effectively in water, allowing oceanographers and glaciologists to listen from a safer distance near glaciers. The terminus of a glacier is dangerous due to calving cliffs and icebergs, making remote acoustic monitoring essential. Bubble sounds are proving to be as informative, if not more so, than monitoring calving events alone.
Sound Intensity and Melt Rate
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(00:05:34)
  • Key Takeaway: Faster melting rates generally correlate with louder acoustic signals due to a higher volume of bursting air bubbles.
  • Summary: A faster melt rate results in more bubbles emerging per unit time, leading to a louder sound compared to slower melting. While variability exists due to ice shape and iceberg presence, the principle suggests a direct relationship between sound intensity and ice melt speed. This relationship is crucial for modeling future ice loss.
Analyzing Submarine Calving Events
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(00:06:42)
  • Key Takeaway: Submarine calving events begin with deep, low-frequency rumbles originating from fractures at the fjord bottom.
  • Summary: A large calving event starts with a deep rumble caused by fractures at the bottom of the glacial fjord, which then rises as the ice tumbles. These submarine events are particularly dangerous to boats as they are not visible from above the water surface. Listening helps quantify the size of the event and its impact on fjord circulation, which influences additional melting.
Robotic Monitoring System Deployment
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(00:12:07)
  • Key Takeaway: A four-person team deploys a nested remote system—boat, ROV, and drilling platform—to gather simultaneous acoustic, visual, and melt rate data.
  • Summary: The system involves a remote-controlled boat carrying a tethered ROV, which in turn deploys a drilling mechanism that screws itself into the glacier. This platform stays fixed for hours, hosting hydrophones, measurement devices for melt rate and currents, and video cameras. This setup allows for the collection of small-scale physical process data crucial for scaling up climate models.
Melancholy and Scientific Fascination
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(00:16:48)
  • Key Takeaway: While the sounds represent accelerating, non-recovered ice loss, the underlying complexity of glacial physics remains a source of profound scientific fascination.
  • Summary: The current sounds reflect ice loss that is not being replenished by upstream snowfall, lending a melancholy quality to the recordings. Glacial melting is a natural process, but the current accelerated rate is concerning. Despite the sadness, the realization of how much remains unknown about these systems provides a rich, fascinating area for continued study.
Antarctic Under-Ice Acoustics
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(00:19:03)
  • Key Takeaway: Acoustics recorded beneath the Thwaites Ice Shelf are quieter, lacking the typical bubble sizzle due to high pressure and rapid dissolution of air.
  • Summary: The team drilled through 1,000 feet of ice into the water beneath Antarctica’s Thwaites Glacier, known as the Doomsday Glacier. This environment is characterized by eerie quietness, distant seal calls, and ice fracturing sounds rather than the frequent bubble popping heard in other regions. The high pressure causes bubbles to dissolve quickly, resulting in a very different acoustic profile.