Light Exposure Part 1: A Silent Killer at Planetary Scale

A flurry of recent research has uncloaked a lingering threat to biodiversity: light pollution, a silent killer at planetary scale.

Among investigators, the menace is known under an unassuming name: ALAN – Artificial light at night (ALAN). The extent of the havoc wreaked by light pollution upon terrestrial, aerial and marine ecosystems boggles the mind.


  • untracks migratory birds in-flight significantly lowering arrival rates [1]
  • stunts coral reproduction sabotaging vital marine reef ecosystems [2]
  • decimates earth‘s bug biomass triggering ecosystem-wide cascade effects [3]
  • makes pathogen-carrying mosquitos more aggressive [4]
  • blots out the stars in the night sky at an accelerating pace of > 10 % per year (»skyglow«) [5]

The pervasive roll-out of indoor and outdoor LED lighting has compounded the problem of hazardous light.

Light emission from LEDs harbours a nefarious peak in the blue wavelength, the band in the light spectrum that is most energy-laden and chemoactive, and to which the senses of many living organisms are most acutely attuned to.

It is the concealed blue light radiated by 1.9 million street lights in Germany that lures away unsuspecting insects from their beacon lights in the sky – the moon and the stars –, killing an estimated 3,6 billion insects every night.

This staggering loss of biomass trickles down the food chain, thwarting pollination and starving animals.

Mitigation of light pollution is an underrepresented cause among biodiversity advocates.

Decarbonisation efforts alone won’t revivify biotopes under assault by unchecked light pollution.

In an upcoming content series we will spotlight how impact investors, nature markets, scientists and companies such as Mimotype Technologies can co-ordinate efforts to improve well-being across the entire biosphere by returning to natural light.


[1] Cabrera-Cruz et al., Light pollution is greatest within migration passage areas for nocturnally-migrating birds around the world. Sci Rep 8, 3261 (2018).

[2] Ayalon et al., Coral Gametogenesis Collapse under Artificial Light Pollution,Current Biology, Volume 31, Issue 2, 2021, ages 413-419.e3.

[3] Avalon et al., Light pollution is a driver of insect declines, Biological Conservation, Volume 241, 2020, 108259, ISSN 0006-3207.

[4] Rund et al., Artificial Light at Night Increases Aedes aegypti Mosquito Biting Behavior with Implications for Arboviral Disease Transmission, Volume 103: Issue 6, Page(s): 2450–2452.

[5] Kyba et al., Citizen scientists report global rapid reductions in the visibility of stars from 2011 to 2022, Science, Vol 379, Issue 6629, pp. 265-268.

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