Light pollution is largely the result of lack of awareness by the public, governmental organizations, and the lighting industry. In particular, the lighting industry is similar in many ways to the tobacco industry - they make and market an environmentally deleterious and potentially unhealthy range of products where excessive amounts of light at night can lead to many negative consequences, but most people think (and have been told through marketing) it is good for them and are largely unaware of the environmental and health-related impacts.

There needs to be a paradigm shift where the latest research and education improves the understanding of the negative effects of excessive and detrimental outdoor lighting, and the lighting industry becomes better regulated so that these detrimental effects are mitigated and/or eliminated. As with other environmental pollutants, only when lighting manufacturers are restricted from producing inappropriate lighting for the consumer (public or private), and governmental agencies act to limit the use of adverse outdoor lighting - and promote environmentally appropriate lighting - will the problems associated with poor and harmful outdoor lighting be significantly addressed and solved.

Light pollution has a dramatic effects on energy use and therefore climate change. Studies have shown wasted light at night consumes over 60 billion kilowatt hours (kWh) in the US every year, representing over 11.5 million tons (23 billion pounds) of CO2 annually - and getting larger year after year. Globally this wasted light adds about 21 million tons of CO2 to the atmosphere - and would require the equivalent of 875 million trees to offset. 

Light pollution also has widespread direct and indirect detrimental effects across the natural environment, including affects on human health:​​

IMPACTS OF LIGHT POLLUTION ON HEALTH

The potential negative effects on human health from light pollution are caused by suppression of the hormone Melatonin which helps regulate our internal clock -- the Circadian Rhythm.
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The Circadian Rhythm is particularly affected by blue wavelength lighting, which is often found in outdoor lighting such as LED street lighting.​​ Even low intensity blue rich lighting can have the same effect as high intensity white lighting in affecting the circadian rhythm.
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The ​American Medical Association recently issued concerns for human health effects because of this widespread lighting with high blue content. Disruption of circadian rhythms can lead to sleep disorders, depression, reproductive disorders, and increases in metabolic conditions such as obesity and diabetes, and studies are now showing a connection between suppression of Melatonin and increased rates of breast and prostate cancer.

Artificial lighting at night has wide-ranging detrimental effects on many other species as well.

​Light Pollution has eliminated the view of the Milky Way for over 80% ​of the United States population. This interactive world map shows the global extent of light pollution.

Map of light pollution intensity for North America

Indoor Light Pollution

Because of the color temperature issue, the concept of light pollution has now entered our homes. With the increased use of computers and personal electronics - which give off a great deal of blue light - the negative health consequences have been getting increasing attention. The need to use warm light at night has also now found its way into your computer and cell phone displays.

​Besides adjusting imaging displays, the best way to "fight the blues" is to be sure to check the color temperature specification of your light fixtures, and preferably use only 3000K or less - a standard incandescent bulb of yesteryear had a color temperature of 2700 K. Besides, it feels right at night.
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The New Yorker - Lyn Hsu