Humans tend to be very visual animals—"seeing is believing," we say. But images can only tell us so much. Soundscape ecologist Bernie Krause has been recording the noises of natural habitats for years, and, through thousands of recordings, he’s been able to hear climate change happening.

“When I first began to record almost 50 years ago,” Krause says in the video above from Great Big Story, “I would put on a pair of earphones and go out into the field and sit and listen, because it made me feel good. It made me aware of the living world around me.”

A musician at the time, Krause managed to sell his nature recordings to Warner Brothers as a record called In a Wild Sanctuary. Decades later, Krause has become one of the world’s foremost experts in the new discipline of soundscape ecology, which uses the sounds of wildlife to monitor the state of ecosystems.

Audio input is incredibly important, he states in his book The Great Animal Orchestra: Finding the Origins of Music in the World’s Wild Places. “Our ear doesn’t lie,” Krause writes. “I like to say to my students, ‘While a picture may be worth a thousand words, a soundscape is worth a thousand pictures.’”

The pictures have not been pretty of late. Like a human heartbeat, a habitat’s soundscape is a good indicator of its health. But around the world, coral reefs, rainforests, and forests are in decline, and their soundscapes have flatlined. We have reached, as ecologist Rachel Carson famously predicted, a silent spring.

Scientists are in agreement: global warming is changing the world around us, and now is the time to take action. It would be wise of us to listen.

Header image courtesy of YouTube // Great Big Story.