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Do Bright Lights Mean a Big (Economic) City?

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Take a look at this map depicting the U.S. at night. What should be immediately obvious is that there are a lot of bright lights exactly where the richest people live: the East Coast megalopolis from Boston through Washington, D.C., Midwestern burgs such as Chicago, Southern cities such as Atlanta and the West Coast conurbation that goes by the name Los Angeles.

Inspired by this association—and others revealed in night time images that stretch back to the mid-1960s taken by the U.S. Department of Defense—economists, sociologists and other scientists with an interest in economic development have begun to explore whether nighttime lights might help reveal the relative richness of regions for which standard economic data is lacking. With that in mind economist William Nordhaus of Yale University and sociologist Xi Chen of Quinnipiac University parsed "luminosity" data from 1992 to 2008 for a wide range of countries world-wide—and even sub-regions within those countries.

In order to determine whether the extent of night lighting provided accurate economic data, the researchers first compared lighting levels with other economic statistics from countries that provide relatively reliable information, such as Australia, Canada and the U.S. Luminosity matched up well with other statistics and, therefore, failed to add much "new" information to existing economic statistics for those nations even at the regional level.

But for 29 countries—including, for example, the Democratic Republic of Congo, which is war-torn and has no reliable statistics despite covering more land than Western Europe—luminosity proved a revealing indicator of economic progress that was otherwise unknown.

Of course, there are countries that have some level of economic activity despite a lack of significant night lights. For example, when spending the night in Dandong on the Chinese-North Korean border, you would notice that an array of bright neon lights color the night, even extending across the two countries’ Friendship Bridge from China to North Korea. But the North Korean side is dark, except for the occasional floodlight to detect those who would ford or swim the Yalu River. That doesn’t mean that there is no economic activity in North Korea, just that North Korea’s government starves its people of electricity as well as food. Alleviating such "light" (read: energy) poverty—endured by roughly one billion people on the planet—remains a key development goal for those interested in ending human suffering.

More than 70 percent of the globe falls into this "dark" category by landmass, where man-made light goes largely undetected by satellites. That means luminosity may not prove useful for the most benighted places on the planet, but could help begin to pierce the darkness surrounding the economic activity of those countries struggling to develop.

Image: Courtesy of NOAA


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  1. 1. seanacoy 7:32 pm 05/17/2011

    Light as a measure of wealth or development also raises questions about light pollution, energy/light wastage, and even less public policy about light than about climate change, chemical pollution, and construction efficiency. First, with the exceptions of areas around airports and astronomical observatories, there seems to be little concern about lights which do not illuminate spaces for human use. (Although municipalities have been cutting down on vertical light spillage somewhat.) Undoubtedly, this is an area ripe for conservation, although tricky. European staircases used to be illuminated on timers. Theoretically, highways could be illuminated only when there are cars on them. But in the big cities, they are always in use. Much of the light comes from headlights that, while more efficient than predecessors, still seem overbroad. Second, the aesthetic of darkness is rarely raised. The stars and Milky Way are rarely visible in urban areas in the US. Should they be? Third, can night-time vision in some circumstances be fruitfully, economically, and safely enhanced to allow for lower levels of illumination? Fourth, can subtle and fundamental changes be made in external illumination, based on the sciences of perception and traffic flows, that allow for more effective illumination with less energy and less light? Are fewer or more lights along a sidewalk or highway better or not? Is comparably illumination along such a path more important than heightened illumination at intersections (the dark-light-dark phenomenon which suburban drivers frequently have to contend with)? Fifth, should there be regulation of light that escapes structures? Finally, do more thoughtful (lightly-speaking) communities send less light to space and is that factored into statistics based on light captured by satellites?

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  2. 2. electric38 6:37 pm 05/19/2011

    Bright lights concentrated in an area could come to mean that man has harnessed energy and squeezed the efficiency to a point that would tolerate an overflow.
    The desert city of Las Vegas is a case in point. As this city adopts more solar for its rooftops and small businesses and utilizes LED’s. The measurable light seen from space could be taken as an excess of privilege, or just a smart way to use the overabundance of sunlight they have available on a daily basis.
    Solar landscaping lights are popping up at a very inexpensive cost around the country. These are a good example of it not being necessary to turn them off, as they are only using the power generated by the free sunlight.
    Germany and now the UK have adopted aggressive FIT’s that are reducing the cost of rooftop solar for many low income, senior and disabled individuals. We may soon be seeing brighter lights from the smarter parts of our planet, rather than the wealthiest.

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  3. 3. Wayne Williamson 5:46 pm 05/20/2011

    Looks to me like it reflects the consentrations of people and not their richness…

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