Sunday, January 18, 2015

Massive destabilization of the 'Earth System' could occur within century

Scientists: Human activity has pushed Earth beyond four of nine ‘planetary boundaries’

By Joel Achenbach, Washington Post, January 15

At the rate things are going, the Earth in the coming decades could cease to be a “safe operating space” for human beings. That is the conclusion of anew paper published Thursday in the journal Science by 18 researchers trying to gauge the breaking points in the natural world.

The paper contends that we have already crossed four “planetary boundaries.” They are the extinction rate; deforestation; the level of carbon dioxide in the atmosphere; and the flow of nitrogen and phosphorous (used on land as fertilizer) into the ocean.

“What the science has shown is that human activities — economic growth, technology, consumption — are destabilizing the global environment,” said Will Steffen, who holds appointments at the Australian National University and the Stockholm Resilience Center and is the lead author of the paper.

These are not future problems, but rather urgent matters, according to Steffen, who said that the economic boom since 1950 and the globalized economy have accelerated the transgression of the boundaries. No one knows exactly when push will come to shove, but he said the possible destabilization of the “Earth System” as a whole could occur in a time frame of “decades out to a century.”

The researchers focused on nine separate planetary boundaries first identified by scientists in a 2009 paper. These boundaries set theoretical limits on changes to the environment, and include ozone depletion, freshwater use, ocean acidification, atmospheric aerosol pollution and the introduction of exotic chemicals and modified organisms.

(Continued here.)

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