The human footprint on Earth
Credit: Science
A review published this week in the journal of Science details how humans have been “taming” the home planet — clearing forests, growing crops, crisscrossing oceans, laying concrete and asphalt.
“We have domesticated vast landscapes and entire ecosystems,” wrote ecologist Peter Kareiva,
chief scientist of the Nature Conservancy, and three co-authors.
“Humans have so tamed nature that few locations in the world remain without human influence. Global maps of human impact indicate that, as of 1995, only 17 percent of the world’s land area had escaped direct influence by humans.”
One of the most intriguing angles suggested by their discussion may be what’s missing — and where. Check out the Far North on the map. Alaska and the Arctic remain one of the few global blank zones, where humans have not terraformed the ecology for safety, food and pleasure.
Almost half of Alaska’s 640,000 people may live in Anchorage, but this metropolitan bowl abutts vast open space that includes the third largest state park in the country. Brown bears forage for salmon inside city parks, and even roam suburban neighborhoods after crossing five-lane boulevards.
Shipping lanes and roads
Yet even the North has been etched with shipping lanes and road networks, as indicated by the second map worked up by the editors at Science.
Other details from the article:
- At least 50 percent of the world’s land area has altered for crops or grazing.
- More than 13,500 miles of European coast has been hardened with concrete or rock.
- Six times more water laps behind dams than rushes through free-flowing rivers.
- Invasive species carried on global transport cause $100 billion in damage in the United States.
- By 2030, the world’s cities will collectively cover an area the size of California.
With so little of the planet untouched by often devastating human influence, the authors urge people to take stock of the impacts and analyze what gets lost when ecosystems get remade.
A bulldozer clearing rainforests in Brazil.
Credit: Haroldo Palo, Jr./ The Nature Conservancy
But they also caution against the notion that “wilder is better.”
Indeed, apart from reproduction, the most natural of all human activities may be the domestication of nature. Some paths of domestication will result inimproved ecosystems both for people and for other species; other paths of domestication will result in ecosystems that are clearly better for humans but not for other species; and some paths of domestication will result in ecosystems that are too degraded to benefit people or other species.