Nature’s sounds are rapidly quieting down. The natural world risks becoming “acoustic fossils” if urgent steps are not taken to halt environmental degradation, international experts caution.
So, what’s the trend?
The variety of life on Earth in all its forms encompasses not only the vast number of organism types inhabiting the planet. Biodiversity also includes genetic variety and the diversity of ecosystems—communities of living beings where all members are closely interconnected, such as in forests, coral reefs, or wetlands. Today, researchers note numerous climatic, technological, economic, and other shifts that are diminishing life’s variety on Earth.
Natural Acoustics
With technological advancement, sound is becoming an increasingly vital means of gauging the health and biodiversity of ecosystems: Earth’s forests, soil, and oceans possess their own acoustic signals.
Scientists employing acoustics to examine habitats and species report that many familiar sounds are vanishing or diminishing in volume across the globe: the morning calls of birds, the rustling of mammals, and the summer buzzing of insects. This points to a decline in species density and variety.
According to Professor Steve Simpson of the University of Bristol, listening to certain ecosystems nowadays can reveal a “deadly silence.”
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Acoustic Fossils
Professor Brian Pybus from Purdue University in the USA has been monitoring natural sounds for 40 years and has made recordings from nearly every major ecosystem type worldwide. He observes: “The sounds of the past that have been recorded and preserved represent echoes of species that may no longer exist, and records of places that are no longer there. In that sense, they are already acoustic fossils.”
Numerous researchers are documenting how natural soundscapes are transforming, becoming disrupted, and fading away. A 2021 scientific paper analyzing 200,000 sites in North America and Europe found a “pervasive decline in acoustic diversity and intensity of soundscapes across both continents over the past 25 years, driven by changes in species richness and abundance.” The authors added: “One of the primary ways humans interact with nature is in chronic decline. This phenomenon could lead to widespread consequences for human health and well-being.”
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Coral Reef Soundscapes
Changes in ecosystem acoustics are occurring even underwater. During the Cold War, the US Navy utilized underwater surveillance systems to track Soviet submarines. Specialists found recording difficult near coral reefs due to the sounds they produced. In 1990, citizen scientists were able to review this data. Steve Simpson emphasizes: “Every time we approached a healthy reef, the acoustic cacophony we heard was overwhelming. It was a carnival of sounds.”
More than half of the world’s coral reefs have disappeared since 1950. If the Earth’s average annual temperature rises by 2°C, this figure could reach 99%. The researcher states: “A deadly silence is emerging. We swam around dead reefs and wept into our masks.”
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The Global Soundscape
“These sounds and the silence speak to us as if through a mirror,” says Hildegard Westerkamp, a Canadian researcher who has been recording acoustic landscapes for 50 years. During this period, wild animal populations have dropped by almost 70% on average.
She began the “World Soundscape Project” in 1973 to document vanishing ecosystems. Westerkamp notes: “The very act of listening can be both soothing and extremely disturbing. But most importantly, it connects us to a harsh reality.”
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