Why Darkness Matters | Please dim a light.
Darkness is a Habitat - join the 2025 Global Dark Sky Party June 20th 2025
As a special event within the 2025 World Congress
During June 16 - 22 2025, our global community hosts the second annual World Congress on Planetary Health, focusing on education and community-led action that has deep and positive cascading effects throughout our planet.
As part of our 2025 June event, our community gathers - around the world - to celebrate darkness in a special event - 2025 Global Dark Sky Party.
On June 20th 2025, the Summer Solstice- from dusk to dawn - dim a light.
When was the last time you truly saw the stars?
For wildlife — and for us — natural darkness isn’t a luxury. It’s a vital, life-sustaining part of our shared ecosystem.
This June, join a worldwide movement to honor, protect, and restore the night.
Our Global Dark Sky Party invites you, as part of your local community, from where ever you are on the planet, from anywhere around the world —> dim a light for one evening, reconnect with natural darkness, and take a small, meaningful action to protect night-time ecosystems.
You and your family can participate in this event from anywhere in the world - a small action that makes immediate and potent positive change for the nocturnal creatures that share your space. To participate - dim a light.
Also, if you’re hungry for community connection, education content around nocturnal habitats, and star gazing tutorials - join our virtual community to celebrate and learn together. Our community will gather in our virtual meeting space from 6:30-8:30p MT.
Through the support of the Care for the Healer nonprofit - this event is free to the community. There is no cost for this event.
Set the sliding payscale to $0 when registering.
Why Darkness Matters - for all animals INCLUDING humans.
Dark skies are essential for ecosystem balance — from moths pollinating at night to frogs signaling through their calls. Light pollution disrupts migrations, feeding, and reproduction in birds, insects, amphibians, and mammals.1
Animals need the dark. From bats to beetles, frogs to owls, countless species rely on natural darkness to hunt, migrate, pollinate, and survive. 30% of all vertebrates and over 60% of all invertebrates are nocturnal. 2
Human health is affected too. The circadian rhythms of all mammals - including humans - are set by the transition between light and dark throughout the day and the seasons. Excessive artificial light affects human sleep, hormone cycles, and mental health. Read this letter from the Chair of DarkSky International - John Garvey, Colorado Timnath resident on the negative effects of light pollution on human health.
Planetary health includes the night sky. Light pollution disrupts more than sleep — it distorts ecosystems, confuses wildlife, and exacerbates damage to biodiversity in fragile environments.
Darkness is a habitat. Preserve it — dim a light.
Do you really need that light?
Can you go without one light for one night? - June 20th is the 2025 Summer Solstice - the shortest night of the year - what unneeded light pollution can you stop during this shortest night.
What light can you turn off ?
How You Can Participate:
Dim a light — prioritize dimming a porch, garden, or street-facing window
Talk to your neighbors - how many lights can you dim when working together? Here is a flyer that you can share!
Host your own local Dark Sky Party! Here’s our list of local community events, including our local Colorado events, from around the globe - find your neighbors and connect. Let us know about your own event to be added to the list.
June 20 6:30 - 8:30p MT. Join our virtual community (but shield your device screen! - see below for instructions) for $35 educational sessions, star gazing tutorials, and community discussions.
How to Protect the Night from your phone:
How to turn your iPhone screen red for astronomy (Sky at Night Magazine)
New Android App Makes it Easier to Use Your Phone While Stargazing (Universe Today)
Hacking a Redlight (Autodesk Instructables)
Join us in protecting night-time ecosystems - dim a light on June 20th 🐸
What is Light Pollution?
Light pollution is the human-made alteration of outdoor light levels from those occurring naturally.3 The National Geographic Society defines light pollution as "the excessive or inappropriate use of outdoor artificial light.”
Did you know that light can be as much a pollutant of habitats as harmful substances in air, water, or in soil? Dark Sky International, an advocacy group dedicated to restoring the nighttime environment, lists these terms and definitions to better describe and facilitate conversations and problem-solving toward solutions to light pollution.
Glare — excessive brightness that causes visual discomfort
Sky glow — brightening of the night sky over inhabited areas
Light trespass — light falling where it is not intended or needed
Clutter — bright, confusing, and excessive groupings of light sources
How is light pollution is affecting you?
80% percent of the world’s population lives under sky glow. In the United States and Europe, 99% of the human population can not experience a natural night.45
Are you aware of the subtle losses in sleep quality, physiologic rhythms, and mental health resiliency caused by the loss of nighttime around you?
How must other, more light- and rhythm-sensitive, animals near you also be affected?
Human health, and the health of ecosystems around us are closely networked together. All species - including you! - deserve freedom from pollution - including unnecessary and unconscious pollution of light into the nighttime sky.
🔦 Nocturnal Pollinators Decline
Moths avoid lit areas—leading to reduced pollination and fewer seeds in night-blooming plants.
Source: Knop et al., Nature, 2017
🐢 Sea Turtle Hatchlings Get Lost
Beachfront lights disorient baby turtles, drawing them away from the ocean.
Source: NOAA National Ocean Service
🦉 Predator–Prey Balance Shifts
Lights give predators an advantage—exposing prey and disrupting food chains.
Source: Longcore & Rich, Ecological Light Pollution, 2004
🌿 Amphibian Mating Calls Diminish
Frogs and toads stop calling under bright lights, affecting breeding success.
Source: Perry et al., 2008
🦇 Melatonin Suppression in Wildlife
Even non-human animals need darkness to regulate sleep, immunity, and seasonal cycles.
Source: Dominoni et al., 2013
🌳 Forest Regeneration Disrupted
Light-sensitive pollinators and dispersers vanish—changing how forests regrow.
Source: Bennie et al., 2015
Join us on the Summer Solstice - June 20 2025 - Global Dark Sky Party.
Wherever you are in the world, from dusk to dawn on the solstice - dim a light and take action to protect night-time ecosystems. If you’re interested in engaging in community discussion or educational sessions - join us virtually from 6:30 -8:30p MT.
https://www.researchgate.net/publication/328497950_Light_pollution_biodiversity_What_are_the_levers_of_action_to_limit_the_impact_of_artificial_lighting_on_nocturnal_fauna
https://www.researchgate.net/figure/Percentage-of-extant-nocturnal-species-within-different-vertebrate-classes-and-orders_fig2_328497950
https://darksky.org/resources/what-is-light-pollution/
https://darksky.org/news/80-of-world-population-lives-under-skyglow-new-study-finds/
https://www.science.org/doi/10.1126/sciadv.1600377