Info & News
Article by Denise Bester
For more than ten thousand years the earth has been in a relatively stable state - a unique period called the Holocene, which has allowed civilization to evolve into what it is today. This desirable state is now under pressure from what scientists say is largely human driven change. The question is: how far can we go before our actions cause disastrous consequences, or is it already too late?
With this question in mind, a group of 28 of the worlds leading scientists, led by Johan Rockström at the Stockholm Resilience Institute, have joined forces to determine which planetary systems are critical to sustaining human life, and what the “tipping points” for each are. What they’ve come up with is being hailed as a new approach to sustainable development. Called “planetary boundaries”, it aims to look at how humanity’s actions as a whole are stressing the entire Earth system, and develop a “safe operating space” for human life, rather than imposing “limits to growth”.
The research group has identified nine key systems, and proposed preliminary sustainable threshold levels for the following seven: climate change, ocean acidification, stratospheric ozone depletion, freshwater use, biodiversity, global nitrogen and phosphorus cycles, and land-use change. If the thresholds are surpassed, they say, we are at high risk of experiencing catastrophic effects. They have as yet been unable to identify the safe limits for either atmospheric aerosol loading, or chemical pollution, and say that we have already crossed the boundaries for the nitrogen cycle, the rate of species loss, and human-induced climate change.
Prof. Rockström says that to continue to live and operate in a “safe space”, we need to stay away from the threshold points, and in the cases where we have already overstepped them, back-pedal as a matter of urgency. While each system’s boundaries are very difficult to identify, they are all very strongly linked, and therefore transgressing any of them can have unpredictable impacts on all or some of the others, placing them at risk of being surpassed too. And once the interactions become more fully understood, the boundaries for human activity are likely to become smaller than currently predicted.
This new system has its criticisms, of course. For example, while globally we may be well within a particular threshold, local circumstances are often unique and these thresholds may be reached far sooner, causing small-scale destruction. Furthermore, while this type of framework is desperately needed by policy-makers, there is some debate over whether the use of thresholds may provide just another excuse to delay positive action, as we wait for the limits to be reached.
While by no means definitive, this new approach may indeed prove very useful in protecting life as we know it, and by linking back to ecosystem services, it strongly reinforces just how dependent we are on nature. As one of the 28 scientists, Professor Jonathan Foley, says, “This isn’t about hugging trees and hoping they stay here, this is about keeping the planet we know intact for future generations”.