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An Age Defined by Human Impact?

By: Charlie Howe

Earthrise – As seen by Apollo 8 on Dec 24, 1968.
Image courtesy of NASA.

Astronaut William Anders was the first human to take a photograph of earth from space. People around the planet responded to the Earthrise image with awe. For the first time we could see the earth from beyond its atmosphere and understand that it is an isolated entity in space. Earthrise conveyed a sense of fragility. This photo and the imagery that followed raised environmental awareness in what some have deemed a golden age of environmentalism. In the next seven years, the United States passed the Clean Water and Endangered Species Acts with overwhelming support.
Forty-five years later, earth imagery has never been clearer; yet, it rarely drives the kind of environmental dialogue that it did in the years following Rachel Carson’s publication of Silent Spring. Data, literature, and conversation tell us that we are impacting the globe, but aside from zoomed-in images of specific events, we see the same earth that William Anders saw… at least during the day.

At night, city lights become the prominent feature on earth and, due to recent advances in nighttime imaging the NASA NPP satellite and the International Space Station, we now see the shadow side of the earth in great detail. The anthropogenic landscape comes to the foreground, and we can see a new physical quality of the earth—it glows.

The glow of city lights gives the earth a new physical quality.
Image courtesy of NASA.

Nighttime images of the earth are proof of concept for many scholars who believe the planet has entered an age defined by the impacts of humans. Since the release of the first images in 2000, the nighttime globe has accompanied writings and lectures on the anthropogenic age. Could new high-resolution and video imagery prove the next Earthrise?

Ecologist Erle C Ellis would undoubtedly say, yes. Ellis’s research shows that human land-use has profoundly changed the planet. Ellis has mapped 21 new global biomes defined by human population, land use, biota, climate, and geology. On his Anthropogenic Biomes map, wild areas account for a quarter of the land, intensive human use accounts for another quarter of the land, and the remaining half of the terrestrial surface supports partial-use biomes. Partial-use biomes are mosaics of different land uses; they include populated forests, populated cropland and residential rangeland. In daylight imagery, partial-use areas of the globe can be easily mistaken for wild; however, when seen at night they are clearly anthropogenic. Urban and dense settlement biomes align with the brightest areas of the globe at night. Wild areas correspond to cold regions and parts of the globe we know to be desert.

What does conservation look like in an anthropogenic world?

Conservation is not just about wilds. Ellis’s research describes a world where wild areas, especially high productivity ecosystems, like forests, are very rare. He elaborates, “Temperate forest is probably the most endangered type of ecology on the planet, there is virtually no wild temperate forest on the globe.” What does this mean for conservation and ecological restoration? Some have suggested a shift in focus from wild lands to the wise management of mosaic and urban habitats.

The highly publicized Central Park Effect is one example of the beneficial role urban habitat. Birds migrating along the densely populated Atlantic coast of the United States are funneled into New York’s Central Park as a stop-over on the Atlantic Flyway. Birds gather in the park in unusually high numbers to the delight of New York bird watchers. Even though these species breed and winter all across the continent, careful management of the park can help sustain their populations. Urban planners recognize the importance of urban restoration projects. The Central Park Conservancy recently selected Great Ecology to conduct a feasibility study for Central Park restoration projects. These projects will not simply restore a pre-Colombian landscape, but will create wildlife habitat fit to thrive in an urban context.

Nature is a land use. In Ellis’ words, “We live in a world that our ancestors created to get us here.” Many of the biomes he maps are the landscapes that support our population and are the result of social, political, and economic process. He implies what restoration practitioners know well–restoration efforts must fit the context.

Ellis’ North America Anthopogenic Biomes Map
Image courtesy of The Trustees of Columbia University.

1 Comment »

  1. Very cool article!

    Comment by MoniG — January 18, 2013 @ 9:41 pm

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