Light Pollution. Shaina Meyer

Transcription

1 Light Pollution Shaina Meyer

2 What is light pollution? The alteration of the natural quantity of light in the night environment due to the introduction of excess artificial light Should be able to see around 2,500 stars under normal nighttime conditions New York City Types Light Trespass Glare Over-illumination Sky Glow

3 Hong Kong

4 source: The World At Night

5 Effects of Light Pollution Wastes energy Causes adverse health effects in humans Obscures view of the stars Interferes with astronomical observatories Disrupts ecosystems Black-Capped Chickadee

6 Effects on Animal Behavior Light Pollution Disrupts visual orientation and ability to navigate Stimulates unusual behavior for season/time of day Studies have shown these effects in: Insects Salamanders Frogs Turtles Birds green turtle hatchling

7 Migratory Bird Navigation Birds find their way by Using the position of the sun during the day, the stars at night Sensing magnetic north Using other clues such as visual layout of the land smell (ex. sea) sound (ex. waves on shores, winds through mountain passes) *Scientists do not really know which migration technique birds rely on most Location, route, and maybe techniques of migration are hard-wired into their brains We are learning more about migration w/ better technology satellite transmitters GPS units

8 Light Pollution & Birds Hundreds of species of migrating birds fly at night including most songbirds and shorebirds Rely on constellations to guide them during seasonal migration Problems: Sky glow reduces view of constellations Flying near bright lights of urban areas may short-circuit steering sense Birds fly off course toward lights on buildings, towers, lighthouses Birds attracted to light Reasons unclear possibly use light as a reference When birds suddenly reach light s source, become confused/blinded Cause birds to slam into windows, walls, floodlights, the ground Problem particularly acute w/ bad weather like rain or fog

9 Tribute in Light In constant lights birds circle and hover in and around lights Believed to be trying to orient their flight to the light which they mistake for the moon or stars Over time build-up of migrants all trying to adjust course Increase chance of hitting each other or falling from exhaustion The white streaks in this image are in fact birds trapped in the "Tribute in Light" spots at the Ground Zero Memorial on September 11, 2004.

10 North America At Night source: North American Migration Flyways source:

11 FLAP Fatal Light Awareness Program (FLAP) Toronto organization trying to publicize problem Estimate at least 100 million birds killed annually by manmade structures Believe songbirds most at risk b/c they fly at low altitudes dominated by artificial light Song Sparrow

12 Bird Casualties Fall 2004 source:

13 Average Number of Migratory Birds Collected ( ) Migratory Birds Collected Year Spring Migratio n Fall Migratio n Graph shows the average number of migratory birds collected on each day of the year (numbers calculated using data compiled over 7 years) source:

14 Solutions Increasing awareness about the consequences of light pollution will encourage people to Use different types of lighting Shielded Motion sensors Reduce amount/intensity of lighting Block lighting from outside environment ex. Genzyme *International Dark-Sky Association (IDA) at How this helps birds: Research in Toronto and Washington, D.C. shows when building lights dimmed/turned off number of bird fatalities drops dramatically Tower without lights causes bird collisions but at least not attracting more birds Birds & Light Pollution Model

15 What is already being done to reduce light pollution? Light pollution credit for LEED Green Building Rating from the USGBC The intent of this credit is to minimize light trespass from the building and site, reduce sky-glow to increase night sky access, improve nighttime visibility through glare reduction, and reduce development impact on nocturnal environments. FLAP launched 12-step bird-friendly program that encourages buildings to turn down lights during migrations Adopted at 100 buildings in downtown Toronto since 1997 Trying to raise awareness in Chicago and New York as well Educational drives to publicize impact of light on turtle hatchlings and seabird fledglings Sponsored by National Park Service in Hawaii and county governments in Florida Lawmakers in hundreds of communities passed ordinances restricting lighting types, power, use States including Texas, New Mexico, Arizona, Connecticut, Maine, California implement statewide light restriction programs National impact of programs is minimal, but it s a start