Wildlife

Circadian Disruption and Animal Welfare: Light Pollution Effects

Artificial light at night disrupts the circadian rhythms of billions of animals, causing measurable health and welfare harm.

Key Facts

Light pollution now affects 83% of the world's population and most wildlife habitats
Migratory birds navigate by stars; artificial light causes fatal disorientation
Sea turtle hatchlings navigate by moonlight on ocean; beach lights cause them to head inland
Firefly populations are declining partly due to light pollution disrupting mating signals
Bats, moths, and insects are disrupted by artificial light with cascading ecosystem effects

Welfare Considerations

Circadian disruption in animals causes immune suppression, reproductive failure, sleep deprivation, and disorientation leading to death. Sea turtle hatchlings drawn away from the ocean by beach lights die of dehydration or predation. Migratory birds collide with lit buildings en masse during migration. The welfare dimension of light pollution is rarely considered alongside its ecological impacts but is equally significant.

What You Can Do

Use amber or red outdoor lighting that is less disruptive to wildlife
Shield outdoor lights to point downward rather than into the sky
Turn off unnecessary lights at night especially during bird migration seasons
Support dark sky ordinances and lighting standards in your municipality
Advocate for turtle-safe lighting on coastal beaches during nesting season