We we are on a hazardous route for some time:  exceeding the safe limits of greenhouse gases emissions, pollution and other forms of extracting the planet’s resources as well as throwing the remains of our activities on its atmosphere, water and soil.

Sérgio Abranches

What we take from Earth and what we deposit on the planet environment has been called our footprint. And we know that our footprint has ceased to be sustainable a long time ago.

We have created several imbalances, and they have become increasingly more acute, through an intricate feedback system. Now, Gaia is taking its revenge, James Lovelock has said. Its air is clogging us, water is becoming scarce, soil eroded, dust choking large populations in Asia and Africa, and covering whole villages. And the planet is warming faster than ever.

We know all that. Some don’t want to believe it. Some don’t care. The majority of us are deeply concerned.

A fresh view of this process has just been forwarded by a group of outstanding scientists, including Nobel Laureate Paul Crutzen, plus Hans Joachim Schellnhuber, Will Steffen, Katherine Richardson, Jonathan Foley, and the lead author of the paper, Johan Rockström, Executive Director of the Stockholm Resilience Centre.

This new approach, the Journal Nature tells us on a splendid feature article, has been proposed to define preconditions for human development. “Crossing certain biophysical thresholds could have disastrous consequences for humanity”, Nature explains. The authors concluded that “three of nine interlinked [identified and quantified] planetary boundaries have already been overstepped.”

How did they come to their conclusion? An article from the Stockholm Resilience Center, “Tipping towards the unknown”, tells us how. “The scientists first identified the Earth System processes and potential biophysical thresholds, which, if crossed, could generate unacceptable environmental change for humanity”. The thresholds allowed them to identify the “boundaries” that should be respected in order to reduce the risk of crossing them.

Nine planetary boundaries were identified, including 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.

The authors “estimate that humanity has already transgressed three planetary boundaries: for climate change, biodiversity loss and changes to the global nitrogen cycle.” Moreover, “planetary boundaries are interdependent, because transgressing one may both shift the position of, or result in transgressing, other boundaries.” The study contends that “social impacts of transgressing boundaries will be a function of the social-ecological resilience of the affected societies.”

As they say, in the summary of the research paper, “Planetary Boundaries: Exploring the safe operating space for humanity”, the “concept of ‘planetary boundaries’ lays the groundwork for shifting our approach to governance and management, away from the essentially sectoral analyses of limits to growth aimed at minimizing negative externalities, towards the estimation of the safe space for human development.” These planetary boundaries define, the ‘planetary playing field’ for humanity, “if we want to be sure of avoiding major human-induced environmental change on a global scale.”

The authors conclude saying that: “There is little doubt, that the complexities of interconnected slow and fast processes and feedbacks in the Earth System provide humanity with a challenging paradox. On the one hand these dynamics underpin the resilience that enables planet Earth to stay within a state conducive to human development. On the other hand they lull us into a false sense of security, because incremental change can lead to the unexpected crossing of thresholds that drive the Earth System (…) abruptly into states deleterious or even catastrophic to human well-being. The concept of planetary boundaries provides a framework for humanity to operate within this paradox.”

Extraordinary innovative, ground-breaking study. A recommended read.