Bryan Pijanowski has spent years traveling the globe and installing microphones everywhere from the rain forests of Borneo and Costa Rica to the Sonoran Desert and the streets of Chicago.
His travels are part of an ambitious project in which he will record every sound the planet makes.
Soon, sensors in Indiana will go online, and his collection of microphones will record oceans, birdsongs, insects, animals, traffic and every other sound on Earth for a full year.
Pijanowski, a "soundscape ecologist" at Purdue University, studies how environmental sounds interact, and he believes listening to the world can clue us in to the changing state of the natural world.
On Earth Day, he launched the Global Soundscapes Project and enlisted thousands of people to record their surroundings with the Soundscape Recorder smartphone app.
He says accumulating these audio files year after year will allow scientists to listen for patterns and measure changes in the environment.
Pijanowski isn’t the first person to study nature through its sounds. During the 1960s, musician Bernie Krause began making recordings of the natural world to be used in films, and he later founded Wild Sanctuary, an organization that records and archives the planet’s soundscapes.
As Krause listened to these soundscapes, he discovered there was an order to them. Birds with shorter calls fit their sounds in between those of birds with longer calls. Insects alternated their stridulations so they wouldn’t drown out the sound of other insects.
His observations led him to hypothesize that animals evolve to be heard over natural sounds like storms and rivers, as well as over man-made sounds, and he wondered if disruptions caused by deforestation, pollution and invasive species could be heard in an area’s soundscape.
He tested this idea in 1988 by taping the sounds of a Sierra Nevada forest for a full year. During that time, the area was selectively logged and Krause’s soundscape became virtually silent.
Since then, researchers have continued to expand on Krause’s ideas and have monitored the sounds of every type of landscape imaginable, from the mountains to the oceans.
Pijanowski says that over time, he’ll hear changes in these soundscapes because of the effects of climate change.
As Earth’s temperature rises, certain species will move to warmer regions and add their own noises to the soundscape. Temperature changes will also prompt insects to emerge earlier and add their sounds to the world at times they weren’t previously heard.
But to monitor these changes, first Pijanowski must first capture the planet’s sounds as they are now. Once he’s collected a year’s worth of earthly noise, an algorithm will sort it and ecologists will be able to study these varying soundscapes and listen for changes.
Stuart Gage, an ecologist who works with Pijanowski, compares the job of a soundscape ecologist to that of a doctor with a stethoscope.
“A doctor can use a stethoscope to tell 10 different things about your heart,” he told The Verge. “We’re holding a stethoscope up to nature. We’re listening to the heartbeat of the environment, whether it’s the heartbeat of a city or the heartbeat of a forest, it’s the heartbeat of the biosphere."
In the time-lapse video below, listen to a full day's soundscape at the Purdue Wildlife Area in Tippecanoe County, Indiana.