Grey sound in a green economy

The ocean absorbs more CO2 than it can handle. What about sound?

So, we are heading towards an electric world with zero emission. That is good. The downside is that there will be a lot of noise. Not figuratively or politically, but actual damaging sound.

The soundtrack of the sea is becoming more and more a cacophony, or anthropophony, of man-made sound.

The sound problem was pointed out many years ago, but the current pace of electrifying the world amplifies the problem.

New Soundscape

Occasionally we hear about whales that have stranded on beaches. Narwhal stuck in the ice. One of the explanations is that they have gone off course because the sounds they normally have to orient themselves by are disturbed. Whales can probably hear both ultrasound and infrasound at a distance of several hundred kilometers.

But noise disturbance is not just a curiosity for animal rights activists who love whales.

And it’s not just our noise that is the problem. Over fishing and less life in the sea means that the sound balance is changed. It disturbs everything from invertebrates to blue whales. There will be more noise from humans, fewer animals to make noise, but also more noise from ice melting and storms, due to climate change.

In this video you can see and hear how human sounds affect life in the sea.

Silence after terrorist attack

A research project carried out between 2001 and 2005 suggests that underwater noise has a negative effect on whales. Following the terrorist attack in the United States on September 11, 2001, shipping traffic to the East coast was reduced for security reasons. For the whales that stayed in Fundy Bay in Canada, the silence also subsided. Researchers examined whale poop for stress hormones and found that stress hormone levels dropped when noise levels dropped. The researchers believe that high stress levels can negatively affect the whales’ immune system and reproductive ability.

The researchers also point out that not only are marine mammals able to hear, fish can also perceive sound waves even if they do not have an ear opening. The fish have a lateral line organ that perceives vibrations and changes in water pressure. The lateral line organ is closely connected to the inner ear of fish.

Pressure waves can travel 340 m/s through air, while in water the sound travels four times faster. The noise can therefore spread over a larger area under water than in air. Sperm whales, for example, can communicate with each other at a distance of 6,437 kilometers.

Construction sound

Sound from ships, sonar and seismic surveys. Acoustic deterrent devices to keep seal and whales away from underwater construction sites. All of this can do damage far beyond the areas where it operates because the sound carries so far through water.

Any country with a coastline is looking for opportunities to invest in offshore wind. With president Joe Biden the US is also back on the climate scene investing in offshore wind.

Two years ago, in 2019, China had 45 offshore wind projects, either planned, started or completed. Germany had 28, Japan and the US 1. At the beginning of 2022 these figures are: 347, 179, 129 and 164 respectively., according to the consultancy firm 4Coffshore.

Offshore wind turbines make low-frequency sound that disturbs whales and other large marine mammals. This can lead to both collisions with boats and stranding with consequent death.

Electric cables that run along the seabed can also disturb animals such as eels, stingrays and sharks, as they can perceive electromagnetic fields. This affects the species’ ability to orientate themselves. Fish that spawn can also be disturbed by the offshore wind turbines that are often planned in central spawning grounds.

Subsea Mining

Battery demand for electric vehicles will grow 40 times the next 20 years. And the overall demand for minerals, 30 times, according to the International Energy Agency. Cobalt demand will increase by 70 times and manganese 58 times by 2040.

Cobalt is by far the most expensive and prices are unpredictable. The quest for more cobalt has created 19th century style brutal competition. Mass electrification will have to happen without cobalt dependency.

The demand will unavoidably lead to more traditional mining. Cobalt, manganese and nickel are among the minerals on the ocean bed, and deep sea mining is by many seen as good money and as part of the solution.

How much noise is this going to produce?

The sound of silent coral reefs

Coral reefs that die have less life and thus also make less noise. Great Barrier Reef, for example. Animals that depend on the sound of coral reefs have lost much of the sound map they need. No Google Maps to help them down there. They struggle to find food and places to reproduce.

The sea with and without sound

Cover photo: A fish staring into the camera during one of my morning swim in Havana, Cuba, 2012.