I had just finished reading Southwest Editor Annette McGivney's article on night hiking ("Looking at Night in a Whole New Light," June), when some friends and I set out on a short hike on the Bay Area Ridge Trail in California. With Annette's observations and advice fresh in mind, I wondered what great nighttime adventure I would have. Would I see a mountain lion? Would I see the landscape through a new perspective? Perhaps a meteor would streak through the sky to give me something to wish upon.
Unfortunately, the weather closed in and the skies yielded no visual delights. And, except for a skunk that showed up to investigate my companion Jerry in the wee hours of the morning, the wildlife was all tucked away against the impending storm.
But we were skunked in another way, too. About 2 a.m., I suddenly realized that it had never gotten fully dark. San Francisco and its sprawling suburbs were bouncing massive amounts of light off the low-lying clouds. Even though we were nestled far below the ridgeline on the mostly unpopulated side of the coastal range, the glowing sky made it hard to forget just how close we were to a major population center.
True, what else should I have expected so close to an urban area? But I've seen the same problem beginning to pop up in plenty of true backcountry areas in California, Colorado, Utah, and Washington.
Under ideal conditions, you can expect to see as many as 15,000 stars in the night sky with the naked eye. In a typical suburb, only 200 to 300 will be visible. And in a major metropolitan area, you're lucky to see two dozen stars on a clear night. Welcome to the world of light pollution, aka skyglow.
Don't think that light pollution is an issue that has nothing to do with wilderness and backcountry. Consider this: the National Parks and Conservation Association (NPCA) in March issued a comprehensive study on how light pollution affects the National Park system. Among the more disturbing facts uncovered:
- National parks experience light pollution from city lights more than 100 miles away.
- Artificial light pollutes nearly two-thirds of the country's national parks that allow overnight stays.
- Only 12 percent of the affected parks have taken steps to reduce light pollution.(For more information, go to NPCA's Web site: www.npca.org/readaboutit/nightskies.html.)
Armed with NPCA's study and spurred by my experience on the Bay Area Ridge Trail, I delved into the topic of light pollution. After several weeks of study, two facts stood out: (1) at least 30 percent of the energy that powers outdoor lighting in the United States is wasted, and (2) we could save $1.5 billion if we eliminated that waste.
But this issue of light pollution is not simply about energy reduction. It causes other problems. Light that isn't focused down onto the ground results in unnecessary glare. Have you ever stood on a peak that overlooks a city at night? All the light you see from below is pure glare, and the energy used to create it is wasted. And if you can see that light from more than 40 feet away, it reduces your ability to see at night.
So how do you find places to hike that aren't spoiled by light pollution? One way is to point your Web browser to www.darksky.org/ida/darksky/. While the information there is based partially upon subjective data, it's probably the most accurate predictor of skyglow available. For example, when I selected the site on the Bay Area Ridge Trail I had hiked, I got, "Milky Way invisible. Passing clouds are easily seen due to being lighted up from surrounding lights." Compare that to what I found when I selected another place I'd recently hiked, Capitol Reef National Park, Utah: "Much structure is visible in the Milky Way. Passing clouds appear as dark moving masses as they block the natural skyglow or the Milky Way. A few sources of skyglow are still visible."
Note that last line: "a few sources of skyglow are still visible." That doesn't have to be. Here's what you can do about light pollution:
- Make sure your home's outdoor light fixtures aren't wasting energy. All your lights should have "sky caps" to focus light downward. With the correct fixtures, you won't be sending light skyward, and you'll be able to use a lower wattage lamp to achieve the same effect, saving electricity in the process. See www.darksky.org/ida/gnol.html for sources of appropriate fixtures. And when you're shopping for outdoor fixtures at your local building supply center, look for ones that focus light down into a confined area. (A fixture that has open glass sides is usually inefficient, even if it has a reflector in the top. Look instead for ones that have reflective "snouts," or shields on all but the bottom.)
- Consider motion detection-activated security lights instead of dusk-to-dawn lighting.
- Minimize your use of purely decorative lighting. Do you really need to have Christmas lights blinking at 4 a.m.? Instead, put 'em on a timer, or simply unplug them when you go to bed.
- Help the parks by writing to your congressional representatives asking them to adopt the NPCA's primary recommendations: use of light shields, high efficiency fixtures, and low-sodium lights, enforcement of the Clean Air Act to reduce pollution's impact on light scattering, and enactment of tougher outdoor lighting ordinances in communities near parks.
It's good to know that skyglow is a solvable problem each of us can do something about. Now if you'll excuse me, I've got to go change a few light fixtures on my townhouse.