There was a time when people would go to bed at sunset because there were no light bulbs around, and it actually became dark at night. As artificial lighting (torches, fires, oil lamps, eventually light bulbs) became used, people stayed up longer, often whether they needed to or not. We can probably all remember our parents telling us to go to bed, that we need our sleep, etc. It turns out they were right! There are subtle, insidious consequences for disrupting our circadian rhythms with light pollution.
Light Bulbs at Night
Studies have shown that artificial light at nighttime interferes with the production of melatonin, a chemical our body makes which promotes healthy sleep. With sub-optimal levels of melatonin and excess light polluting our every view, the quantity and quality of our sleep is diminished. This affects animals, too, but even more significantly. From disrupting the migration of birds to the hatching of sea turtles on beaches, light pollution is a serious. As good as light bulbs are for us, they have a negative side as well.
Light bulbs may have allowed us to do far more than we could have ever done without them, but there is a caveat. That caveat is that we need to use them responsibly, and we haven't really done that. If you live in a city, try to find somewhere where there is no artificial light. It's nearly impossible to do! Street lights and security lighting contribute a great deal to light pollution. Poorly designed and implemented street and security lighting can do the opposite of what they are intended to do. If a security light is not covered and pointed at the ground, chances are it is blinding people and hindering identification of potential hooligans.
Use Energy Efficient Light Bulbs Responsibly
These days our lighting and light bulbs are continually becoming more energy efficient. Hopefully this new energy efficiency doesn't beget a new slew of light pollution infractions as people and businesses use more lighting simply because they can. Excess seems to be human nature, but light bulbs and lighting are a couple things we need to avoid using to excess.