Wednesday, September 23, 2009

A safe operating space for humanity

Nature 461, 472-475 (24 September 2009) | doi:10.1038/461472a; Published online 23 September 2009

Johan Rockström1,2, Will Steffen1,3, Kevin Noone1,4, Åsa Persson1,2, F. Stuart Chapin, III5, Eric F. Lambin6, Timothy M. Lenton7, Marten Scheffer8, Carl Folke1,9, Hans Joachim Schellnhuber10,11, Björn Nykvist1,2, Cynthia A. de Wit4, Terry Hughes12, Sander van der Leeuw13, Henning Rodhe14, Sverker Sörlin1,15, Peter K. Snyder16, Robert Costanza1,17, Uno Svedin1, Malin Falkenmark1,18, Louise Karlberg1,2, Robert W. Corell19, Victoria J. Fabry20, James Hansen21, Brian Walker1,22, Diana Liverman23,24, Katherine Richardson25, Paul Crutzen26 & Jonathan A. Foley27

Identifying and quantifying planetary boundaries that must not be transgressed could help prevent human activities from causing unacceptable environmental change, argue Johan Rockström and colleagues.


  • New approach proposed for defining preconditions for human development
  • Crossing certain biophysical thresholds could have disastrous consequences for humanity
  • Three of nine interlinked planetary boundaries have already been overstepped
Although Earth has undergone many periods of significant environmental change, the planet's environment has been unusually stable for the past 10,000 years1, 2, 3. This period of stability — known to geologists as the Holocene — has seen human civilizations arise, develop and thrive. Such stability may now be under threat. Since the Industrial Revolution, a new era has arisen, the Anthropocene4, in which human actions have become the main driver of global environmental change5. This could see human activities push the Earth system outside the stable environmental state of the Holocene, with consequences that are detrimental or even catastrophic for large parts of the world.

During the Holocene, environmental change occurred naturally and Earth's regulatory capacity maintained the conditions that enabled human development. Regular temperatures, freshwater availability and biogeochemical flows all stayed within a relatively narrow range. Now, largely because of a rapidly growing reliance on fossil fuels and industrialized forms of agriculture, human activities have reached a level that could damage the systems that keep Earth in the desirable Holocene state. The result could be irreversible and, in some cases, abrupt environmental change, leading to a state less conducive to human development6. Without pressure from humans, the Holocene is expected to continue for at least several thousands of years7.

No comments: