Light pollution, which is the excessive, inappropriate, or disruptive use of artificial light at night, is not usually thought of in the same context as air or water pollution but it still has an adverse effect on the environment. We are talking about lighting from buildings and offices (interior and exterior), advertising signage, street lighting and public spaces like sports fields.

There are a few different types of light pollution:

• sky glow, when areas (for example, cities and suburbs) are overly bright at night;

• light trespass, when light lands where it is not planned or needed (for example, streetlights spilling through a bedroom window);

• clutter, which is when light sources are bright, excessively clustered, and/or confusing and jarring;

• and glare, which is basically excessive brightness.

One of the primary concerns of light pollution is the impact it has on wildlife.  Research has shown that sky glow can cause animals to travel or migrate differently and find themselves where they shouldn’t be. It can also interfere with sleeping and feeding patterns and expose some animals to predators. Nocturnal animals need night to be dark and in our urban environments, it just isn’t. A range of wildlife are specifically affected including bats, turtles, wallabies, various birds and insects, whose declining populations have been linked to light pollution.

From a climate perspective, excessive lighting consumes energy and, as lights generate heat, they increase the temperature of their environment. On top of that, research indicates that light pollution can induce trees to bud, an event that is indicative of disruption to the delicate balance of not only day and night but also the seasons themselves.

Research also suggests that light pollution adversely impacts human health, again due to the suppression of melatonin production and disruption of circadian rhythm.

Light pollution is increasingly being considered one of the more pervasive types of environmental pollution and as much of the developed world is affected by light pollution (up to 80% according to the World Atlas of Artificial Night Sky Brightness,) it is becoming a global issue.

You can see for yourself what your local light pollution looks like by using NASA’s Blue Marble Navigator.

The good news is that we each have some level of control over light production – whether it is by only using lighting in our home environment (internal and external) when it is absolutely necessary, ensuring all outdoor lights are directed downwards and shielded to contain the light, using curtains and blinds to stop any light spilling out from inside the home or, when safety is a concern, converting outdoor (and maybe even indoor) lights to motion sensors or setting timers.  If you can influence the lighting in your work environment or community, even better. 

Lastly, choosing lower intensity bulbs can reduce energy use and carbon emissions, not to mention saving money on the way. You can read more about light pollution and things that can be done to help, here and how to take action on a wider level, here.  For detailed information about the impact of light pollution on wildlife and how to mitigate it, the Australian Government has published the National Light Pollution Guidelines for Wildlife. It’s well worth a read.

Planet Ark does not take responsibility for the accuracy of the original information and encourages readers to check the references before using this information for their own purposes.