June 28, 2007—Pretty soon, there will be no "road less traveled" to take.
As of 1995 only 17 percent of Earth's land remained free of direct human influence, as seen in this map of the vast networks of shipping lanes and roads that crisscross the planet.
In the rush to stock food supplies, keep safe from predators and natural disasters, and improve trade and commerce, people have domesticated entire landscapes and ecosystems—often to their detriment, a new study says.
The study authors, led by Peter Kareiva of the Nature Conservancy, studied global maps and defined human impact using several criteria, including the presence of towns or cities and nighttime lights that are detectable by satellites.
"On average, the net benefits to humankind of domesticated nature have been positive," the authors write in tomorrow's issue of the journal Science.
For instance, leaps and bounds in agriculture have increased food supplies and made for easy access to energy-rich, easily stored grains.
But the study also found that people have converted about 50 percent of the world's surface area to grazed land or cultivated crops, felling about half of Earth's forests in the process.
"We have, of course, made mistakes," the authors write, "... leaving few, if any, truly wild places on Earth."
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