Dear EarthTalk: Has anyone calculated the energy wasted at night by unnecessary lighting in and around buildings? What can we do to reduce our light footprint? — Bill Rehkamp, via e-mail
Americans do squander a lot of electricity keeping things lit up at night while most of us sleep. This light blocks our view of the night sky and stars, creates glare hazards on roads, messes with our circadian sleep-wake rhythms, interrupts the patterns of nocturnal wildlife, and is by and large annoying. It also takes a financial toll: The federally funded National Optical Astronomy Observatory (NOAO) reports that poorly-aimed, unshielded outdoor lights waste $2 billion (17.4 billion kilowatt-hours) of energy in the U.S. each year.
NOAO has monitored outdoor lighting levels across the U.S. and beyond for the past six years through its GLOBE at Night program whereby citizen-scientists track nearby outdoor lighting levels over a two-week period beginning in late March and submit their observations to NOAO electronically. A simple star map provided by NOAO is all that participants need to track their slice of sky. “All it takes is a few minutes for a family to measure their night sky brightness by noting how many stars are missing from an easy-to-find constellation like Leo (in the northern hemisphere) or Crux (in the southern hemisphere),” says GLOBE at Night project director Connie Walker. “This tells us how much light is directed upwards into the sky.”
Over the last six annual campaigns, participants from 100-plus countries have contributed almost 70,000 measurements, giving project organizers a detailed picture of light pollution globally. Unfortunately, analysis of the data shows that participants have seen brighter skies and fewer stars over time, meaning that light pollution is a growing problem. The free and publicly-accessible data gathered by the project is not only useful for educational purposes but can also help inform planners and policymakers on decisions about increasing public safety, reducing energy consumption and even identifying parks and green spaces that can serve as “sky oases” where city dwellers can appreciate the night sky from a safe, dark place.
According to the McDonald Observatory’s Dark Skies Initiative (DSI), the solution to light pollution is 90 percent education and 10 percent technology. “We can reclaim vast amounts of energy currently wasted inadvertently into the night sky…by using light fixtures that are shielded to reflect light down where it is needed, as well as using the smallest number of lights and lowest wattage bulbs necessary to effectively light an area,” says DSI. Leading by example through the installation of downward-pointing outdoor light fixtures is a great place for home and building owners to start: “Once people see it in action, and understand its implications for cost savings and enhanced visibility, they are far more likely to adopt good lighting practices on their own.” Another group committed to reducing light pollution, the International Dark-Sky Association, maintains a list of distributors that sell approved fixtures to prevent light pollution.
Some cities have instituted standards to limit outdoor night lighting to protect citizens against unwanted light (or “light trespass”). The International Dark-Sky Association has developed a set of model lighting ordinances that cities and towns can adopt and modify to suit their needs accordingly. Also, the U.S. Green Building Council has incorporated a credit for buildings seeking to reduce the amount of light trespass and sky glow through its Leadership in Energy and Environmental Design (LEED) program.
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Dear EarthTalk: I read that CO2 in our atmosphere is now more than 300 parts per million. Doesn’t this mean that we’re too late to avoid the worst impacts of climate change? — Karl Bren, Richmond, VA
Actually the amount of carbon dioxide (CO2) in the atmosphere today is roughly 390 parts per million (ppm). And that’s not good news. “Experts agree that this level cannot be sustained for many decades without potentially catastrophic consequences,” reports the Geos Institute, an Oregon-based non-profit and consulting firm that uses science to help people predict, reduce and prepare for climate change.
While we’re unlikely to get atmospheric CO2 concentrations down as low as they were (275 ppm) before we started pumping pollution skyward during the Industrial Revolution, climate scientists and green leaders agree that 350 ppm would be a tolerable upper limit. Prior to 2007 scientists weren’t sure what emissions reduction goal to shoot for, but new evidence led researchers to reach consensus on 350 ppm if we wished to have a planet, in the words of NASA climatologist James Hansen, “similar to the one on which civilization developed and to which life on earth is adapted.”
The non-profit 350.org, launched in 2008 by writer and activist Bill McKibben and others to raise awareness about global warming, has circled the proverbial wagons around the cause of reducing atmospheric CO2 to 350 ppm. The group has enlisted the help of thousands of student volunteers around the world to mobilize public support for reducing humanity’s carbon footprint.
McKibben, whose 1989 book The End of Nature detailed the potential effects of climate change and remains one of the most influential environmental books of all time, believes that 350 ppm is attainable. “We’re like the patient that goes to the doctor and learns he’s overweight, or his cholesterol is too high. He doesn’t die immediately—but until he changes his lifestyle and gets back down to the safe zone, he’s at more risk for heart attack or stroke,” says McKibben. “The planet is in its danger zone because we’ve poured too much carbon into the atmosphere, and we’re starting to see signs of real trouble: melting ice caps, rapidly spreading drought. We need to scramble back as quickly as we can to safety.”
“Scrambling back” will entail nothing short of transforming our energy infrastructure, including how we transport people and goods and power our structures. According to 350.org, it means building solar arrays instead of coal plants, planting trees instead of cutting forests, increasing energy efficiency and reducing waste. “Getting to 350 means developing a thousand different solutions—all of which will become much easier if we have a global treaty grounded in the latest science and built around the principles of equity and justice,” the group reports. “To get this kind of treaty, we need a movement of people who care enough about our shared global future to get involved and make their voices heard.”
The group is working to create an international grassroots movement to influence political dynamics and implement solutions that show the benefits of moving to a clean energy economy. 350 ppm, while merely a number, represents humanity’s potential capacity to solve the most pressing problem it has faced; it also represents a target for international negotiators to aim for in forging an effective global warming treaty.