Global light pollution is skyrocketing and currently affects about 80% of the planet. Increasing urbanization and technological advancements push artificially lit areas at an estimated annual expansion rate of 2.2%, reports the World Economic Forum.
Although lighting is a sign of human progress, shifting away from natural light cycles has relevant consequences for the environment and our cities. The impacts range from wildlife and biodiversity to human health and global energy efficiency.
Many studies proved that light pollution interrupts wildlife patterns and harms biodiversity: birds, bats, and insects are the most affected species, but even the blossoming of flowers is at stake.
As far as human health is concerned, the excess of artificial light has negative acknowledged effects on the body’s biological clock and sleeping cycles, depriving individual and collective quality of life. Some independent research even found overi llumination to be correlated to some forms of cancer such as lung, breast, colorectal and prostate cancers.
Light pollution is also linked to energy efficiency and climate change. “Increasing sky brightness is a sign we are doing lighting wrong. It’s a sign we are using energy inefficiently, wasting money, exacerbating climate change, and increasing environmental impacts,” stated the International Dark Sky Association (IDA).
Data from IDA and the US Department of Energy show that, when not adequately managed, 99% of outdoor lighting ends up in energy and money waste. As streetlights are useful and necessary, IDA advises cities for responsible outdoor lighting.
How can cities promote a smarter and more intelligent streetlighting? The technology and tools already exist to light our districts differently, both at daytime and nighttime.
By connecting lamps and controlling them from remote, cities can define customized lighting patterns for single streets and areas. Streetlights can be turned on/off and dimmed according to programmed schedules (ie. setting a default combination for working and festive days, for residential and industrial areas, etc.), changing them whenever necessary to mirror specific local circumstances or events.
Specific sensors allow brightness to be adjusted upon ambient light levels. Lamps may also be integrated with motion sensors, vehicle counters, tilt sensors, and other devices, triggering condition-based dynamic lighting. This is particularly useful in low-traffic areas, where lights may be further dimmed only when no vehicle or pedestrian is passing by.