Global Warming May Give Oceans the ‘Sound’ of the Cretaceous
Global temperatures directly affect the acidity of the ocean, which in turn changes the acoustical properties of sea water. New research suggests that global warming may give Earth’s oceans the same hi-fi sound qualities they had more than 100 million years ago, during the Age of the Dinosaurs. The reason for this surprising communication upgrade is that whales vocalize in the low-frequency sound range, typically less than 200 hertz, and the new research predicts that by the year 2100, global warming will acidify saltwater sufficiently to make low-frequency sound near the ocean surface travel significantly farther than it currently does — perhaps twice as far.
“This knowledge is important in many ways,” said David G. Browning, lead scientist on the research team. “It impacts the design and performance prediction of sonar systems. It affects estimation of low frequency ambient noise levels in the ocean. And it’s something we have to consider to improve our understanding of the sound environment of marine mammals and the effects of human activity on that environment.”