Light Pollution: Earth Has Become 16% Brighter in Eight Years, According to a Study

The Night Sky Grows Brighter: A 16% Increase in Artificial Light

The planet is becoming increasingly illuminated at night. According to a scientific study published in the journal Nature and reported by Science & Vie, the artificial brightness of Earth surged by 16% between 2014 and 2022, largely due to the widespread adoption of LED lighting and the proliferation of light sources in urban areas.

Observations made from satellite images reveal that cities now emit a bluish-white glow, gradually replacing the characteristic orange halos of older sodium lamps. While this shift contributes to reduced energy consumption, it also leads to an increase in light pollution.

LEDs: More Efficient, Yet More Abundant

Thanks to their low energy consumption and long lifespan, LEDs have become the standard for public lighting around the globe. However, the lower costs associated with these lights have prompted many municipalities to install more light points or to increase their intensity, which partly explains the rise in brightness noted from space.

Researchers also believe that this 16% increase might be underestimated, as current satellites are less effective at detecting blue light, which is prevalent in LED lighting.

Impacts on Biodiversity and Health

The rise in light pollution raises several environmental concerns. Excessive exposure to artificial light at night disrupts the biological rhythms of many animal species, including migratory birds, nocturnal insects, and bats.

For humans, this nighttime light can also affect the production of melatonin, the hormone that regulates sleep, potentially impacting rest quality and long-term health.

Towards Smarter Lighting Solutions

In light of these challenges, several cities are experimenting with more responsible lighting solutions. The latest generations of connected streetlights can automatically adjust their brightness based on traffic levels, time of day, or current conditions.

Researchers estimate that these technologies, when combined with public policies aimed at limiting light pollution, could achieve a balance among energy efficiency, public space safety, and the preservation of nocturnal ecosystems.