Teasing out a poor country’s economic statistics from satellite photos of nighttime lighting

Economists have a problem when they attempt to track the economy of a poor country: Accurate statistics are hard to come by. Either the numbers are unreliable or the government itself is unreliable – for whatever reason, it’s difficult to monitor the economic health of a poor country. Yet economic indicators are important to know if conditions are improving or deteriorating.

Researchers at Brown University decided to forego relying on the country’s government for economic numbers and turned instead to satellite pictures showing a country’s use of artificial lighting. Here’s an article in New Scientist detailing the study. There are several comments from readers following the article, with some of the commenters questioning the validity of the approach because variability in efficiency of lighting used would be too great.

Several months ago I posted about research presented by  Jeff Tsao, a researcher at Sandia National Labs who posited that, because light has historically been a fixed percentage of the world’s GDP, increasing lighting efficiency will result in more lighting used, rather than a decrease in power usage. This is called, among other things, the Rebound Effect.

Here’s the interesting part that relates directly to the Brown University method of measuring a country’s economic health: There’s a direct link between a country’s gross domestic product (GDP) and lighting. Over the past 300 years the world has spent a constant 0.72% of its GDP on artificial lighting. So, Tsao’s research would seem to support tracking lighting use from space as a valid economic indicator. The Rebound Effect isn’t mentioned in the New Scientist article, and the paper is behind a subscription wall so I can’t tell if the Brown researchers cover it.

(To learn more about lighting efficiency and solid-state lighting, register here to attend EDN’s Designing with LEDs Workshop in Chicago on October 6, 2009.)

From the New Scientist photos page, here is a nighttime satellite photo of the US:

… Europe as well as Northern Africa:

…and  Asia. What’s missing for all three is on overlay of population densities.