Icebergs, among the most imposing natural phenomena in the oceans, generate some of the loudest and most distinctive underwater sounds. Scientists are now uncovering how these “ice songs”—produced during the formation, life, and demise of icebergs—can offer valuable insights into our changing climate.
A Frozen World Comes Alive
At the surface, Antarctica’s ice shelves appear as vast, lifeless expanses of white, occasionally fractured by deep cracks. These fissures sometimes grow large enough to release massive slabs of ice, creating icebergs that drift slowly into the Southern Ocean. While their movement above water seems nearly imperceptible, the underwater realm reveals a symphony of sounds.
Beneath the surface, the grinding and scraping of iceberg undersides against the seafloor or other icebergs create a haunting, rhythmic resonance. When adjusted to human-audible frequencies, these sounds resemble whale songs. Alexander Gavrilov, a professor at Curtin University in Australia, explains, “An iceberg plate works as a tuning fork. The song frequencies depend on the iceberg’s dimensions.”
From Song to Clang: The Life Cycle of an Iceberg
The acoustic journey of an iceberg mirrors its physical decay. Initially, as the iceberg drifts through colder waters, its song is steady and harmonic. But as it enters warmer regions, it begins to collapse, producing cacophonous clanging sounds that resonate across oceans.
This process is starkly different in the Arctic, where icebergs breaking off Greenland’s glaciers generate sharp, thunderous sounds rather than melodic tunes. These noises, combined with the crackle of bubbles escaping from melting glacier ice, provide a unique auditory snapshot of the Arctic environment.
Iceberg Sounds as Climate Clues
At both poles, scientists are harnessing the sounds of icebergs to study the effects of climate change. Advanced monitoring technologies, such as seismic arrays and hydrophones, have enabled researchers to track the calving, movement, and melting of icebergs more precisely than ever before.
“These are really powerful noises,” says Vera Schlindwein, a polar seismologist at the Alfred Wegener Institute in Germany. “Initially, research on iceberg sounds was driven by curiosity. But with modern tools, we’re now uncovering their potential to reveal environmental changes.”
Antarctica’s Changing Ice
The impact of climate change on Antarctica’s ice is complex and variable. While some areas are warming rapidly, others are experiencing growing ice shelves and seasonal sea ice. This variability directly influences the size and frequency of icebergs calving off the continent.
The noise levels produced by icebergs fluctuate daily due to tidal movements, seasonally with the transition between summer and winter, and even over decades. As large icebergs collapse in warmer months, they create deep booms and “bloops” that ripple across oceans. However, long-term acoustic trends remain elusive. For example, Gavrilov’s analysis of hydroacoustic recordings in the Indian Ocean between 2002 and 2022 found no consistent interannual patterns.
Challenges in Monitoring Iceberg Sounds
Tracking individual iceberg events through their sounds is challenging. Continuous songs, which were first detected in 2002, often emanate as background noise from Antarctica. To pinpoint specific events, scientists must rely on seismic or satellite data to correlate sounds with physical movements, such as when icebergs ground themselves on the seafloor.
Logistical hurdles further complicate direct studies. Deploying and retrieving seismic equipment near icebergs is costly and time-intensive. However, advancements in remote monitoring—like the systems installed at Ukraine’s Vernadsky Antarctic Station—are enabling scientists to gather data more efficiently.
Arctic Insights
In the Arctic, iceberg acoustics provide crucial data about climate impacts. Unlike Antarctica, Arctic icebergs don’t sing, but the noises they produce during calving and melting help scientists estimate ice loss and monitor temperature anomalies. For example, researchers in Svalbard, Norway, have linked underwater noise to sudden temperature spikes caused by extreme weather events, known as “weather bombs.”
A Symphony of Change
The sounds of icebergs serve as a poignant reminder of the interconnectedness between the natural world and climate change. By “listening” to these icy giants, scientists hope to unlock new ways of understanding and addressing the challenges posed by a warming planet.