Silencing the seas: climate change is irrevocably altering the sound of our oceans

Oceanographer Kate Stafford says that decreases in Arctic sea ice are drastically altering the underwater environment

In the dead of winter, bowhead whales sing beneath Arctic sea ice. It is a sound few of us will ever experience in its true, haunting beauty and, in the future, it's a sound that might be lost forever.

Beyond the variable weather and melting ice caps, climate change is claiming its next victim as it silences the seas. Research has found that the sounds of the ocean are changing with the climate and waters that were once rich with life are being altered beyond recognition.

Oceanographer Kate Stafford explored the effect of human activity on human noise in her recent TED Talk. Stafford has studied marine habitats across the globe and has explored the diversity of the ocean from the tropics to the poles. While some view the Arctic as an inhospitable desert, Stafford remarks on the abundance of life hidden just beneath its frozen exterior.

"There is no place on Earth I would rather be," Stafford says, describing the Arctic as the embodiment of a "disconnect between what we see on the surface and what's going on underwater."

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Whilst most people rely on sight to inform their impression of the world, sound is the sense by which marine mammals see,and the tool they use to communicate with each other. These sounds are valuable warnings - echoes of ice patches or open water. The joined sounds of Arctic marine mammals produces an orchestra of song; one that can be recorded on hydrophones thanks to a low level of ambient sound.

But this low-level of ambient sound is shifting due to greenhouse gas emissions. As temperatures rise, levels of seasonal sea ice fall. These decreases range from four weeks to six months, leading to an increase in open water seasons and drastically altering the habitats of marine mammals.

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With less sea ice, sub-Arctic species are moving North. Fin whales and humpback whales have been monitored moving further North in what Stafford terms an "invasion of the Arctic". Oceanographers and marine biologists don't know what this will mean for the future of Arctic animals. It could lead to increased competition for food sources, or lead to new diseases among groups that have weaker or no resistance to certain illnesses.

Furthermore, warmer temperatures are leading to an increase in human use of the Arctic. This has seen an increase in oil and gas exploration and extraction, with new opportunities for tourism and commercial shipping. The noises and sounds of industry throughout the Arctic have been proven to increase the stress levels and even change the swimming and vocal behaviour of whales. The noise is effectively drowning out the sound of natural life in the ocean, and altering the very way these animals view the world.

In fact, whales and other marine animals are being confronted with a level of noise pollution that is akin to the droning sounds of a packed cityscape.

There are currently no international standards to regulate noise pollution in our seas. It was previously thought noise pollution would have no effect on marine animals, however, it has been found to be of paramount importance to their communication and navigation abilities. With pollution above sea level leading to a warmer and more tumultuous climate, the Arctic is now seeing an increase in storm activity.

Stafford states that it is up to humans to "do the hard work of reversing or at the very least decelerating human-caused atmospheric changes." If not, the ocean will soon become unrecognisable.

This article was originally published by WIRED UK