A lot of the reason is laziness and a lack of understanding. Most people don't even know that this problem exists. This leads to light pollution wasting energy and money. In 2002, the city of Calgary in Canada changed all of their lighting fixtures to direct their light at the ground. Since then, they have been saving an estimated 1.7 million dollars every year. The AMA calculates that over 10 billion dollars are wasted by bad lighting practices every year. That's more then half of NASA's annual budget! There are also other effects on wildlife and safety that can be improved simply by changing these lighting fixtures.
There's also another reason to care about light pollution. If you have seen the night sky in a big city, and from a remote spot in the middle of nowhere, you know the difference. If you haven't, the difference is a few thousand stars. The wasted light in a city washes out the fainter stars making them impossible to see with the naked eye. This is one of the reasons new observatories are often built in very remote locations. By improving the types of lighting fixtures we use we can greatly improve our view of the universe.
Just five days ago (on June 15th) the American Medical Association (AMA) passed a resolution regarding light pollution. The resolution has 3 parts.
RESOLVED, That our American Medical Association advocate that all future outdoor lighting be of energy efficient designs to reduce waste of energy and production of greenhouse gasses that result from this wasted energy use.
RESOLVED, That our AMA support light pollution reduction efforts and glare reduction efforts at both the national and state levels.
RESOLVED, That our AMA support efforts to ensure all future streetlights be of a fully shielded design or similar non-glare design to improve the safety of our roadways for all, but especially vision impaired and older drivers.For all of us amateur astronomers this is great news. One of the main reasons for the AMA's involvement is the growing link between light pollution and breast cancer. The AMA has a lot of power and influence in this country. It is inspiring to see such a large group support science, and help to make a more energy efficient society.
For more Information about light pollution check out the International Dark-Sky Association (IDA).
Source- Universe Today
Image Credit- NASA