There is a certain type of pollution that most people don't think twice about - light pollution. Ecologists assess in a new study just how various lights at home like the gate light, garden lights, and sensor lights, are harmful to wildlife and people alike.
Theresa Jones, an Australian ecologist from the Urban Light Lab at the University of Melbourne said, 'We're seeing the impact of light at night in different species across all life on Earth.' They have tracked how migratory species of birds, turtles, and moths have been impacted by light pollution.
Similar to early sailors, traders, and other travelers, migratory animals use the stars as a guide for their journey. Urban lights, or skyglow, from factories, streets, buildings, and houses have resulted in animals losing their way.
Turtle hatchlings head towards land instead of the water, seabirds get blinded by lighthouses, and moths swarm into unwanted places. Nocturnal animals, like bat species, are some of the most disturbed animals when bright lights affect their feeding patterns. They are also at risk of crashing into walls or buildings and become an easier target for predators.
The Tammar wallaby in Australia is also disturbed by unnecessary bright lights kept on at night. With their sleep disturbed, causing them to sometimes stay up all night, results in producing less young during the breeding season.
Lights and Sounds
Part of Dr. Jones' study also showed the correlation between sound at night and light pollution. The team compared several bushland sounds, such as the willie wagtail, a native Australian bird.'
The little willie wagtail that's on your cricket fields or footy fields that wags its little tail, and flushes out insects, is a prolific nocturnal singer," Dr. Jones explains. Light disturbance affects the males' ability to make sweet tunes. Less singing means fewer chances of attracting a female for mating. Humans are not exempt from light pollution.
People's body clocks may become inconsistent depending on melatonin secretion levels, which is a result of light exposure. 'We've got this new light pollution because we're changing all our lights to these white lights now which means we get more blue in the environment,' explained Dr. Jones.
LED lights are energy savers and in the blue spectrum, they emit shorter wavelengths. While species that are sensitive to blue light benefit from this, like turtles, for some bird species like pigeons and swans, warm-toned lights are a problem. Dr. Jones expressed that scientists initially thought that getting rid of blue lights would help the environment, yet 'that's clearly not the case.'
Flick the Switch
Australia used to have much more dark space until urbanization expanded along coasts and the mining industry built factories. The government is also very limited in making assessments as they only 'consider each facility in isolation, said Kellie Pendoley, a conservation biologist.
She is currently working on a light pollution project at a turtle site in Queensland. The biggest issue is that the city's 'coast is just one big strip of light.'
Her team makes continual efforts to work with local authorities to track light pollution using a network of sky glow sensors. Their goal is to educate people about how visible their light is in the sky. 'What it shows, and what's been difficult to try to get people to understand, is that measuring light in the sky is really, really complicated,' Pendoley explained. Light pollution has three contributing factors - 'light shining upwards and bouncing off clouds and particles in the atmosphere, direct glare, and indirect reflection off surfaces.'
One issue that Landon Bannister, a lighting expert, said is that the light business sells people the idea that they need all these lights for safety reasons and aesthetics. Alongside the Glenorchy City Council, he is working to create good lighting that is safe for people and wildlife. This includes facing lights downwards toward the ground, using warmer lights, shielding lights to lessen the glare, and using light only when necessary.
The problem with LED lights is that it only targets efficiency. 'Unfortunately, we've focused just on the carbon reduction and not actually what the light is doing,' said Bannister. 'With light pollution, you literally flick the switch and suddenly the problem disappears,' said Dr. Jones.
