In Search of Dark Sky -
The Effect of Light Pollution on Nature and Wildlife
I am drawn to the night!
Yes, it can be tiring, it can be scary to be out alone in darkness and
my vigilance is heightened as I listen to the sounds of the night.
But the silence also lets me reflect on many issues as I wait for my camera
to capture the night landscape under a brilliant sky and moon.
There is beauty in the night.
Unfortunately, as city dwellers and suburbanites we mostly don’t see the millions of stars overhead since light pollution blocks out what the Universe has to offer.
Tracking light pollution over the last ~60 years, the below image shows how much light has been added to the landscape by cities and even rural areas. And check out the projections for 2025 – dark sky will almost vanish in most of the US sky.
When we zoom into the Silicon Valley and the greater Bay Area, it’s hard to find areas of ‘dark sky’ where we may observe the movement of the stars and gaze at the milky way.
The next image shows how much we are missing in light polluted areas (left side) and how many stars and planet are visible without light pollution (right side).
Light Pollution and its Effect on Nature and Wildlife
But light pollution does not only hinder us to see the stars, it also has a profound effect on nature and wildlife.
We all have seen how moth and insects are drawn to light even to their death by an open flame.
It confuses baby turtles that are programmed to run towards the light, but that light often comes from hotels and parking lots, rather than reach the ocean to start their long life. Below is a graph that depicts the confused wondering of loggerhead hatchlings. They may never reach the water or their prolonged path may result in more hatchlings loosing their lives to predators prior to reaching the ocean.
Tracks of disoriented loggerhead (Caretta caretta) hatchlings, Melbourne Beach , Florida
Photograph by Blair E. Witherington.
Photograph by Blair E. Witherington.
[Source: Florida Marine Research Institute Technical Report TR-2. 73 pages, 1996.]
It has been found that frogs that mate at night will seize to mate in areas of light pollution.
It is known that big cities with their bright high-rises and reflecting glass will draw migrating birds from their ancient migration routes and they perish.
Here is a quote from Bart Kempenaers of the Max Planck Institute for Ornithology in Germany :
"In comparison to chemical and noise pollution, light pollution is more subtle, and its effects have perhaps not received the attention they deserve," said Bart Kempenaers. "Our findings show clearly that light pollution influences the timing of breeding behavior, with unknown consequences for bird populations." It is these unknown consequences over the long term that needs to be understood.
[Source: Current Biology, 16 September 2010, Volume 20, Issue 19, pages 1735-1739. 10.1016/j.cub.2010.08.028.]
And unfortunately the list goes on and on with lots of information available with a quick search on the web.
But what can be done? We all have responsibilities to take care of the planet Earth and we all can become more cognizant of how our actions influence our environment. Just as example: Turning off outside lights when we go to bed at night, installing lights that are directed downwards and that are on automatic shut-off when not necessary, supporting city street lights that are minimizing light pollution; these are all small but important contributions to the bigger issue.
I would like to conclude with a very informative video: ‘Our Vanishing Night’ by AstroGirlWest
[Source: http://physics.fau.edu/observatory/lightpol-environ.html]
“Light pollution: its real, destructive consequences are seldom recognized, but it is a problem with easy solutions that make economic sense. All living creatures rely on the Earth's regular rhythm of day and night to regulate internal cycles. Many use the protection of darkness to safely forage and mate. We exist in a balance with our environment, a delicate balance that we are shifting. In the process we are also losing our connection to the night sky and the universe beyond.”
Til next time,
Meggi
