We’re taking too much from the earth, pushing the planet beyond its limits. With our unfettered greed for natural resources and our slovenly despoiling of our environment, we’re digging our own grave.
That’s the argument of many in the environmental movement (WWF for one). It’s far from new. Impending doom from exhausting planetary limits has been the refrain from Malthus in the 1800s to the Club of Rome’s seminal 1972 publication, Limits of Growth, and now the popular Planetary Boundary concept from the Stockholm Resilience Centre.
The worry that we are rapidly exhausting the natural resources on which we all depend continues to occupy the minds of the fearful and has been eagerly adopted as a rallying call by environmental campaigners. Only One Planet. No Planet B. Saving the Planet One (choose your issue) at a Time.
The concept of planetary boundaries is, largely, accepted as The Great Truth. But is it? Helen Fisher, investigates.
Are we exhausting our planet?
In 2008, a group of researchers met in a small Swedish town called Tällberg to start answering this complex question. They discussed the idea of Planetary Boundaries. These are biophysical thresholds within which exists a “safe operating space” for humans, and beyond which there could be significant destabilisation of the Earth System – with potentially severe consequences for our own species, not to mention thousands of others.
Led by Johan Rockström at the Stockholm Resilience Centre, the group’s work was published a year later in Nature. They characterised planetary boundaries for nine processes – updated in 2015:
- Climate change
- Change in biosphere integrity (biodiversity loss and species extinction)
- Stratospheric ozone depletion
- Ocean acidification
- Biogeochemical flows (phosphorous and nitrogen cycle)
- Land-system change (e.g. deforestation)
- Freshwater use
- Atmospheric aerosol loading (microscopic particles in the atmosphere)
- Introduction of novel entities (e.g. organic pollutants, radioactive materials, nanomaterials, microplastics)
Defining the limits
For each of these processes, the team identified one or two parameters — e.g. atmospheric carbon dioxide concentration – calculating the pre-industrial value, the current value, and the proposed boundary. A fixed threshold is hard to define for nonlinear processes that interact with each other, so each boundary sits within a broader zone of uncertainty. Stay out of that zone, and we’re pretty safe. Enter the zone and the risk of destabilisation is increasing. And beyond that, we’re in high risk territory.
The 2015 update to this work suggests we’re already past the boundary and into the zone of uncertainty for climate change and land-system change, and that we’ve shot far beyond this for biosphere integrity and biogeochemical flows. What’s more, two of these – climate change and biosphere integrity – are classified as “core boundaries”. Significant alteration to either is likely to drive the whole Earth System into a new state, which risks deterioration of human wellbeing on a global scale.
Well received
The Planetary Boundaries framework has been generally very well received. It’s the foundation for Kate Raworth’s doughnut economics model and WWF’s One Planet approach. The previous UN Secretary General urged world leaders to apply planetary boundaries thinking, and the Stockholm Resilience Centre is partnering with a number of corporates to look at sector-specific boundaries. Sustainability reports based on the planetary boundaries are emerging, starting with Swedish sportswear company Houdini.
But there’s also been plenty of criticism of the Planetary Boundaries – through the peer review process and media articles such as this from the New York Times.
Some of the common criticisms are that it’s pointless to establish boundaries for processes where global thresholds are unknown, there’s no scientifically robust way of specifying boundaries, and the framework doesn’t account for the range of influence and interaction between the different processes.
Unknown thresholds
The authors are quick to point out that it can be challenging, but not impossible to set boundaries where thresholds are unknown – the zone of uncertainty just has to be set wider, and will narrow as understanding improves. They also admit that their work is unfinished, and that there are still many gaps in knowledge around aspects such as timescales and interactions between the boundaries. They’ve updated the boundaries once already, drawing on input from more than 60 published articles scrutinising the framework and the latest advancements in earth science. And Planetary Boundaries 3.0 is in the pipeline.
This is an approach focused on the science, painting an evolving picture without dictating what should be done with it. But clearly – as many of its critics point out – working out the governance structures and the practical, local implications of the Planetary Boundaries are perhaps its biggest challenges.
Wider discussion
The authors position the framework as a contribution to a wider societal discussion and note that effective governance strategies based on their work are at early stages. The Stockholm Resilience Centre is increasingly engaging with various governance options, including through membership of the Earth System Governance Project. How this evolves, and how learning will be taken from the global approach to carbon emissions, will be interesting to watch.
For now, it seems sensible to think of the Planetary Boundaries framework as a set of lighthouses guiding our navigation. The air is foggy in a few places and the craggy shore might sometimes be unmapped, but it’s better to stay well clear of the rocks than risk catastrophe. And when the fog of unknowns lifts, it’s essential we work towards achieving a global, equitable approach to steering Earth Systems into a sustainable future.
Perhaps that future will see a shift from the current human destructive dominance of the Anthropocene era towards a new Symbiocene, a time when life and the planet is nurtured by humans.
Attaining such nirvana may depend on the level of scientific rigour of Planetary Boundaries 3.0. Until then our future remains very much a work in progress.
