By Graeme Shannon, Bangor University
Noise pollution, generally an unintended byproduct of urbanisation, transport and industry, is a key characteristic of human development and population growth. In some cases, it is produced intentionally, for example when seismic surveys are being carried out using powerful airgun arrays to explore and map the seafloor, or active sonar, which uses sound waves to detect objects in the ocean.
All of this noise – whether intentional or not – has the ability to alter the acoustic environment of aquatic and terrestrial habitats. This can have a dramatic effect on the animals that live in them, perhaps even driving evolutionary change as species adapt to or avoid noisy environments.
Rising noise levels
The dramatic and comparatively recent rise in noise levels is marked in both magnitude and extent, with an estimated 30% of the European population exposed to road traffic noise levels greater than 55dB (decibels) at night, well above the 40dB target recommended by the World Health Organisation. Even remote natural areas do not escape the reach of anthropogenic, or manmade, noise. One study across 22 US national parks demonstrated that this kind of noise was, on average, audible more than 28% of the time.
Noise is not just irritating; we have known for some time that it can have direct human health impacts. Indeed, chronic exposure to noise levels above 55dB dramatically increases the risks of heart disease and stroke, while aircraft noise has been shown to impact the development of reading skills in children attending schools close to busy airports. The WHO estimates that in Europe at least a million healthy life years are lost every year due to traffic noise.