Why Should Your Town or City Worry about Light Pollution?
Energy Waste and Carbon Emissions
In an average year in the U.S. alone, outdoor lighting uses about 120 terawatt-hours of energy, mostly to illuminate streets and car parks. That’s enough energy to meet New York City’s total electricity needs for two years!
DarkSky International estimates that at least 30 percent of all outdoor lighting in the U.S. alone is wasted, mostly by lights that aren’t shielded. That adds up to $3.3 billion and the release of 21 million tons of carbon dioxide per year! To offset all that carbon dioxide, we’d have to plant 875 million trees annually (see our Light Pollution and Energy Waste page).
Negative Effects on Wildlife
Numerous studies have shown that artificial light at night has numerous negative and deadly effects on many types of wildlife including birds, amphibians, insects and mammals. The evidence and research is also growing to demonstrate that nocturnal pollinators are being hit hard by thoughtless lighting.
What about Crime and Safety?
There is no clear scientific evidence showing that increased outdoor lighting deters crime. While brighter lighting may make us feel safer, poor outdoor lighting can actually reduce our personal safety. A study conducted by the city of Chicago found a correlation between increased crime and brightly lit alleyways. A study prepared by the U.S. National Institute of Justice concluded: “We can have very little confidence that improved lighting prevents crime.”
In fact, glare from bright lights creates shadows where criminals can hide. Some crimes like vandalism and graffiti thrive on lighting. Glare can also be dangerous to pedestrians and drivers. It shines into our eyes, constricting our pupils, which diminishes our ability to adapt to low-light conditions.
A Problem that has Simple Solutions
The good news is that your town can have it all – environmentally responsible lighting that helps keep citizens safe. When lighting is shielded, it’s directed down on the ground where it’s needed, which minimizes glare, light pollution and carbon emissions, and saves money.
Why Outdoor Lighting Policies Matter
Outdoor lighting policies are a great tool for ensuring that towns and cities implement good, safe outdoor lighting. A well-written policy, with proper lighting installed, will save the public money and increase safety. DarkSky International, in collaboration with the Illuminating Engineering Society (IES), created the Model Lighting Ordinance (MLO) to make it easier for municipalities to adopt good lighting plans. This is a USA-based policy but forms a good foundation for policy and legislation in the UK.
LEDs and Outdoor Lighting
Many towns and cities are replacing older, conventional, lighting systems with new, energy-efficient, light-emitting diodes (LEDs). However, energy efficiency is just one piece of the puzzle in improving outdoor lighting at night.
DarkSky International has developed a set of recommendations for towns and cities considering the installation of LED lighting systems. These recommendations take into account a number of important considerations and provide guidance for selecting outdoor lighting that increases energy and cost savings, enhances safety and security, protects wildlife, and preserves the nighttime environment.
