AMSTERDAM -- Over the past 300 years, in an ever-accelerating process, humans have reshaped the terrestrial surface of the Earth. In doing so, humanity has scripted a scenario of global environmental change with impacts that promise to be at least as severe as global climate change, scientists reported here today, July 11.
Addressing an open science conference held under the auspices of the International Geosphere-Biosphere Programme, University of Wisconsin-Madison environmental scientist Navin Ramankutty and colleague Kees Klein Goldewijk of the Dutch National Institute of Public Health in Amsterdam, unveiled a historical global land-use inventory that chronicles the massive impact humans have had as they've remade the global landscape since the 17th century.
"We're hitting a threshold of available global natural resources," Ramankutty says. "We need to think about this issue before it's too late. There is no substitute for natural resources."
By far, the largest human influence on the global landscape is agriculture with 12 percent of the global land surface -- an area equivalent to the surface area of all of South America -- now under permanent cultivation, says Ramankutty.
Moreover, a global trend toward urbanization promises to "become one of the biggest consumers of land," predicts Ramankutty. "Historically, we lost forest to crop land. Now we are losing crop land to urban areas."
To take stock of how the Earth's land resources have been influenced by people over the past 300 years, Ramankutty and Wisconsin climatologist Jonathan Foley embarked on a massive study of historical records, combining such things as agricultural land surveys, tax rolls and census data, to sketch a portrait of global landscape change that, for the most part, has gone unrecorded in any direct way by the world's governments.
To augment the historical records, Ramankutty and Foley used growing repositories of satellite-derived land cover data s
Contact: Navin Ramankutty
University of Wisconsin-Madison