The Ecology Book

252

DARK SKIES

ARE NOW

BLOTTED OUT

LIGHT POLLUTION

A

ccording to some ecologists,

light pollution—the amount

of artificially generated light

in the world—could be the most

damaging pollutant of all. Around

80 percent of humanity lives under

skies saturated with light. In 2017,

a major German study of light

pollution, carried out by ecologist

Franz Hölker and others using

satellite data, showed that the area

of Earth illuminated artificially

grew 9 percent between 2012 and

2016. The brightening is most

intense in industrializing countries

in South America, Africa, and Asia,

but it also continues to increase

in the already well-lit countries

of Europe and in the US.

Astronomers were among the

first to notice light pollution because

it interfered with their ability to see

IN CONTEXT

KEY FIGURE

Franz Hölker

BEFORE

1000 ce The first organized

system of street lighting

(by oil lamps) is introduced

in Muslim Spain.

1792 Scottish-born engineer

William Murdock invents the

gas light. Over the next half

century, many cities introduce

gas street lighting.

1879 American inventor

Thomas Edison demonstrates

the first commercially viable

electric light bulb.

1976 High-brightness,

high-efficiency, LED lights

are introduced.

AFTER

2050 The date by which

Hölker and others predict that,

with the global population set

to exceed 9 billion, Earth’s

total illuminated area will have

doubled since 2016.

A map of light pollution across

North America (white and red indicate

where it is highest, black where it is

lowest) explains why 99 percent of

Americans cannot see the Milky Way.

US_252-253_Light_Pollution.indd 252 12/11/18 6:25 PM