Use of Night Lighting Continues to Grow

December 11, 2017

From 2012 to 2016, Earth’s artificially lit outdoor area grew by 2.2% per year, with a total radiance growth of 1.8% per year, reports an article published in the journal Science Advances. Continuously lit areas brightened at a rate of 2.2% per year. Researchers observed large differences in national growth rates, with lighting remaining stable or decreasing in only a few countries. These data are not consistent with global scale energy reductions, indicating instead greater light pollution, with negative consequences for flora, fauna, and human well-being.

Historically, increases in luminous efficacy have led to greater light use rather than energy savings, notes the article. A critical question for sustainable development is whether the use of outdoor light will continue to grow exponentially or whether developed countries are nearing saturation in demand.

The researchers question whether, if demand saturation has not been reached, the increasing luminous efficacy made possible by the solid-state lighting revolution (12) will increase light emissions instead of saving energy.

The research was conducted using data from Visible Infrared Imaging Radiometer Suite Day-Night Band (VIIRS DNB), which came online just as outdoor use of LED lighting began in earnest. This sensor provides the first-ever global calibrated nighttime radiance measurements in a spectral band of 500 to 900 nm, which is close to the visible band, with a much higher radiometric sensitivity than previous methods. This improved spatial resolution allows for neighbourhood (rather than city or national) scale changes in lighting to be investigated .

Results

The data show that over the period of 2012-2016, both lit area and the radiance of previously lit areas increased in most countries in the 500–900-nm range, with global increases of 2.2% per year for lit area and 2.2% per year for the brightness of continuously lit areas. These factors decreased in very few countries.

Many large cities had decreases in DNB radiance in the city centre but increases in outlying areas. These decreases can often be directly attributed to replacement of older lamps with LEDs. This is vividly demonstrated by photographs of Milan, Italy, taken by astronauts on the International Space Station in 2012 and 2015. The streetlights in the city changed from yellow/orange (sodium vapour) to white (LED), whereas the surrounding areas remained yellow/orange. As a result, the radiance observed by the DNB decreased because of the sensor’s lack of sensitivity to light in the range of 400 to 500 nm

Discussion

Two major arguments for changing to LEDs for outdoor lighting are cost savings and reductions in energy consumption. These goals have been realized in many cities, so decreases in observed DNB radiance likely indicate local energy savings. However, on a global and often national scale, these local decreases are outweighed by increases in radiance in other areas, most likely because of additional lighting being installed. The “energy saving” effects of outdoor LED lighting for country-level energy budgets are therefore smaller than might be expected from the increase in luminous efficacy compared to older lamps

Large differences in per capita light use compared to per capita GDP suggest that in brightly lit countries, major decreases in energy consumption for outdoor lighting could potentially be achieved through reduced light use.

In the near term, it appears that artificial light emission into the environment will continue to increase, further eroding Earth’s remaining land area that experiences natural day-night light cycles. This is concerning, because artificial light is an environmental pollutant. In addition to threatening the 30% of vertebrates and more than 60% of invertebrates that are nocturnal, outdoor artificial light also affects plants and microorganisms, and is increasingly suspected of affecting human health. In the longer term, perhaps the demand for dark skies and unlit bedrooms will begin to outweigh the demand for light in wealthy countries

Read the study here: http://advances.sciencemag.org/content/3/11/e1701528.full

Related Articles


Changing Scene

  • LEDVANCE Expands Ontario Presence with New Specification Agent

    LEDVANCE Expands Ontario Presence with New Specification Agent

    LEDVANCE is pleased to announce the appointment of Sterling Architectural Products Ltd. (Sterling Lights) as their new specification agent in Ontario. This partnership strengthens LEDVANCE’s presence in the region and reinforces their commitment to serving the professional lighting design and specification community with innovative, reliable lighting solutions. With decades of experience and a service-driven mindset,… Read More…

  • May 29, 2025 - Eureka Wins Three 2025 Red Dot Awards for Product Design

    Eureka Wins Three 2025 Red Dot Awards for Product Design

    Eureka is pleased to announce that its Velia, Cirra, and Junction luminaires have each received a 2025 Red Dot Design Award for Product Design. It is the 11th consecutive year that Eureka products have been honored with this prestigious award, which is a testament to the company’s consistency and relentless drive to design exceptional luminaires.… Read More…


Design

  • The Difference Between Accent, Ambient & Task Lighting: Ultimate Guide

    The Difference Between Accent, Ambient & Task Lighting: Ultimate Guide

    In interior design, lighting is not just about brightening the room. Sensitive lighting layout is the key in the whole aesthetic atmosphere. An outstanding lighting solution will not rely on one type of fixture. Rather, it is through the combination of different types of lighting. Accent, ambient, and task lighting are three basic types of… Read More…

  • Graphic Office Interiors Enhance Their Office Space, Incorporating State-Of-The-Art Lighting Solutions

    Graphic Office Interiors Enhance Their Office Space, Incorporating State-Of-The-Art Lighting Solutions

    Graphic Office Interiors, a renowned office design and furnishings company serving Vancouver Island since 1966, embarked on a unique lighting project for their personal office in Saanichton, BC. This project marked the first collaboration between Kelly Inglis of Mac’s II Agencies and Graphic Office Interiors’ in-house registered interior designer, Laura Harlos. Known for their exclusive Steelcase furniture line, modular moveable… Read More…


New Products

  • Amico: SOLAR ECLIPSE – 2X4 Multi-Functional Luminaire

    Amico: SOLAR ECLIPSE – 2X4 Multi-Functional Luminaire

    The Solar Eclipse Series provides a multi-functional luminaire that supports the demands of the hospital environment. The sleek and modern design merges architectural aesthetics with exceptional lighting performance to improve patient comfort while maximizing clinical efficiencies. This architectural patient room fixture offers reading, ambient, and exam functionalities and an optional night light. Multi-functional capabilities provide… Read More…

  • Signify: Unleash Colors from Your TV Screen with New WiZ HDMI Sync Box

    Signify: Unleash Colors from Your TV Screen with New WiZ HDMI Sync Box

    Signify has announced the release of new TV sync features and products for its smart lighting brand WiZ, enabling users to effortlessly immerse themselves in a world of dynamic colors and moods. With the new WiZ HDMI Sync Box with TV backlight, users now have an easy and affordable way to sync lights to their… Read More…