We don't give light pollution much thought since we're born into a world of bright night lighting. In some cities there is really no distinction between night and day. Yet our circadian clocks and those of all plants and animals have evolved over the eons to a rely on a dark night and a bright day Living things need the darkness at night for their well being.
Darkness is Good for All Living Things
By robbing living things of a dark night, we disrupt normal physiology and the production of the night time hormone melatonin, present in all living things.
Light at night prevents melatonin secretion and melatonin is needed to tell all organisms how to best regulate physiology.
In humans, melatonin is an anti-cancer hormone that requires darkness for its secretion by the human pineal gland. Melatonin is now known to protect the human body from the proliferation of human breast cancer cells. (Blask, DE et al; Cancer Research 65, 11174-11184, December 1, 2005 ) http://cancerres.aacrjournals.org/
Quality of Life Issues
One can use lower wattage bulbs by shining light downward where it belongs, not upwards or sideways where the light is wasted. There is no reason to have photons land on every surface of pavement for "security". The human eye can see well into the shadows between light sources when the eye is not insulted by glare from unshielded fixtures.
We Need to See the Stars
We are made of star dust. We find a fascinating connection to the stars and the universe, but only when we can clearly see the stars.
Left to grow one light at a time, light pollution will eventually erase the lovely stars over the islands, the same stars that the courageous Polynesian voyagers used to navigate the Pacific Ocean to find their way to Hawai'i and all of Polynesia http://www.pvs-hawaii.com/ .
Astronomy in Hawai'i must succeed for UH and for its affiliated partners to remain leaders in imaging the universe. The observatories on Maua Kea and Haleakala are finding it more and more difficult each year to filter out the light pollution from the roadways and towns below.
We welcome you to browse these pages and then become an advocate for dark skies over Hawai'i by supporting dark sky ordinances in the state and in your local county.
Stephen M. Pauley MD
UH Sea Grant