Regardless of impacts on the planet, the human condition has likely never been better in terms of material prosperity. The question is: “How do you continue to improve the human condition?” Foley asks. “How can we sustain a world that will reach nine billion people without destroying the planet? At least knowing a bit where the danger zones are is a really important first step.”
There are grounds for hope. Humanity has crossed one of these thresholds before—namely, diminishing levels of stratospheric ozone caused by emissions of ozone-destroying chemicals (the “ozone hole”). We pulled back thanks to international cooperation and the 1989 Montreal Protocol. “We did manage to move ourselves away from the ozone boundary and have made serious efforts at regional levels to protect biodiversity; reduce agricultural pollution, aerosols and water demand; and slow land conversion,” points out environmental scientist Diana Liverman of the University of Arizona, one of the authors of the new thresholds. “This provides some hope that we can manage our planetary impact if we choose.”
Note: This article was originally printed with the title, "Setting Boundaries."
*Erratum (1/25/10): The correct conversion is 264 billion gallons.
This article was originally published with the title Setting Boundaries.