This could destabilize critical biophysical systems and lead to abrupt or irreversible environmental changes that would be damaging or even catastrophic for the welfare of human society.
Determining the extent to which human society has exceeded the planet’s natural limits is nothing new. In 1972 The Limits to Growth predicted the consequences of rapidly growing world population and finite resources for the future of humanity.
A recent review of the accuracy of the Limits to Growth’s predictions over the last 30 years discovered that changes in industrial production, food production and pollution are all in line with the prediction of economic and societal collapse in the 21st Century.
Other studies have shown that we are currently in ecological overshoot. In 2009 we used approximately 40 per cent more than nature can regenerate. We are currenlty living beyond our ecological means.
It is only recently that human activities have begun to affect the functioning of the Earth’s system. Since the industrial revolution human activities has progressively been pushing the planet outside the range of variability for many key processes which sustain life on Earth.
A 2009 study on planetary boundaries has attempted to quantify the safe biophysical boundaries outside which the Earth System cannot function in a stable state. Human pressure on the Earth’s ecosystem has reached a point where rapid global environmental change is possible. There are critical climatic, geophysical and ecological thresholds we must respect if we are to have a sustainable future.
In total nine planetary boundaries have been identified. These are 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.
Three of these planetary boundaries have already been transgressed: climate change, biological diversity and nitrogen input to the biosphere. Since the boundaries are strongly connected crossing one boundary may seriously threaten the ability to stay within safe levels of the others.
The extent to which human societies will be affected by transgressing these planetary boundaries will be dependent on their ability to cope with rapid environmental change. It is often poor communities with weak infrastructures and social support services which are most at risk.
The notion of planetary boundaries provides a first attempt at defining the limits for humanity. However, there are a number of uncertainties and gaps in knowledge that need to be addressed to improve this concept.
If we are to minimize the negative effects of human activities and ensure a safe space for sustainable human development, we need to take action to prevent crossing these planetary boundaries and avoid major human-induced global environmental change.
Planetary boundaries are further evidence that human society cannot continue business-as-usual. There is a need for a fundamental change to the structure of our society and way of life.
A transformation to a new “ecological age” where we live within planetary limits will require a change of the scale achieved in the industrial revolution. However, this time it will be drive by clean, efficient and renweable energy technologies and will be sustainable.
Assessments of the current state of the global environment and scientific predictions of future human and societal collapse provide the evidence on which to base policy.
We know the ecological consequences if we do not fundatmentally change our way of life. The big question is does anyone really care?
© Gary Haq 2010