STOCKHOLM, Sept. 24 /PRNewswire-Asia/ -- New approaches are needed to help humanity deal with climate change and other global environmental threats that lie ahead in the 21st century. A group of 28 internationally renowned scientists propose that global biophysical boundaries, identified on the basis of the scientific understanding of the Earth System, can define a "safe planetary operating space" that will allow humanity to continue to develop and thrive for generations to come. This new approach to sustainable development is conveyed in the coming issue of the scientific journal Nature where the scientists have made a first attempt to identify and quantify a set of nine planetary boundaries.
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"Human pressure on the Earth System has reached a scale where abrupt global environmental change can no longer be excluded. To continue to live and operate safely, humanity has to stay away from critical 'hard-wired' thresholds in Earth's environment, and respect the nature of planet's climatic, geophysical, atmospheric and ecological processes," says lead author Professor Johan Rockstrom, Director of the Stockholm Resilience Centre at Stockholm University. "Transgressing planetary boundaries may be devastating for humanity, but if we respect them we have a bright future for centuries ahead," he continues.
The group of scientists including Hans Joachim Schellnhuber, Will Steffen, Katherine Richardson, Jonathan Foley and Nobel Laureate Paul Crutzen, have attempted to quantify the safe biophysical boundaries outside which, they believe, the Earth System cannot function in a stable state, the state in which human civilizations have thrived.
The scientists first identified the Earth System processes and potential biophysical thresholds, which, if crossed, could generate unacceptable environmental change for humanity. They then proposed the boundaries that should be respected in order to reduce the risk of crossing these thresholds.
Nine boundaries were identified including climate change, stratospheric ozone, land use change, freshwater use, biological diversity, ocean acidification, nitrogen and phosphorus inputs to the biosphere and oceans, aerosol loading and chemical pollution. The study suggests that three of these boundaries (climate change, biological diversity and nitrogen input to the biosphere) may already have been transgressed. In addition, it emphasizes that the boundaries are strongly connected -- crossing one boundary may seriously threaten the ability to stay within safe levels of the others.
"What we now present is a novel framework through which our scientific understanding of the Earth System can potentially be used more directly in the societal decision making process," says co-author Katherine Richardson, Professor at the Earth System Science Center at the University of Copenhagen.
The scientists emphasize that the rapid expansion of human activities since the industrial revolution has now generated a global geophysical force equivalent to some of the great forces of nature.
"We are entering the Anthropocene, a new geological era in which our activities are threatening the Earth's capacity to regulate itself. We are beginning to push the planet out of its current stable Holocene state, the warm period that began about 10,000 years ago and during which agriculture and complex societies, including our own, have developed and flourished," says co-author Professor Will Steffen, Director of the ANU Climate Change Institute at The Australian National University. "The expanding human enterprise could undermine the resilience of the Holocene state, which would otherwise continue for thousands of years into the future."
Co-author Professor Hans Joachim Schellnhuber points out that the climate system has clearly started to drift away from the familiar domain where historic experiences apply. The risk of highly nonlinear changes in our environmental conditions is sharply increasing outside that domain.
"Observations of an incipient climate transition include the rapid retreat of summer sea ice in the Arctic Ocean, melting of almost all mountain glaciers around the world, and an increased rate of sea-level rise in the last 10-15 years," Professor Schellnhuber says. He is Director of the Potsdam Institute for Climate Impact Research.
The researchers stress that their approach does not offer a complete roadmap for sustainable development, but does provide an important element by identifying critical planetary boundaries.
"Within these boundaries, humanity has the flexibility to choose pathways for our future development and well-being. In essence, we are drawing the first -- albeit very preliminary -- map of our planet's safe operating zones. And beyond the edges of the map, we don't want to go. Our future research will consider ways in which society can develop within these boundaries -- safely, sanely and sustainably," says co-author Professor Jonathan Foley, Director of the Institute on the Environment at the University of Minnesota.
Feature article in Nature, September 24 issue: "A safe operating space for humanity," as well as individual commentaries and reader responses: http://www.nature.com/news/specials/planetaryboundaries/index.html
Full scientific article: "Planetary Boundaries: Exploring the safe operating space for humanity," and video interviews, graphics and further background material: http://www.stockholmresilience.org/planetary-boundaries
-- Press release by the Stockholm Resilience Centre at Stockholm University, Potsdam Institute for Climate Impact Research, The Australian National University, University of Copenhagen and University of Minnesota
