Planetary boundaries & sustainability

written by Dinali

I have been mulling over how to present the Planetary Boundaries framework and the underlying concepts without being too scientific or making it too overwhelming an issue to address. Yet I do think it is an important framework to understand as it, like the ecological footprint concept, gives a good outline of the impacts we are having on our planet. It also highlights how crucial it is that we understand that climate change is not the only pressing environmental issue of our times and that we need to be looking at more than just reducing our carbon footprint.

It is now generally accepted in science that the planet is a single complex, integrated system. For the whole of human existence, the planet has been in what geologists call the Holocene epoch. We have evolved and adapted to the current conditions including the climate, atmospheric composition and plants and animals (our source of food) of this epoch. Yet these conditions were not always present on the Earth and some scientists are suggesting that current human activities may have such a large impact on the planetary system so as to severely disrupt it and push the planet into a different state that may not be viable for humans.

The Planetary Boundaries is a framework that has been developed over the past decade to define certain boundaries that should not be passed if we are to maintain the current human friendly conditions of this Holocene epoch. The boundaries are:

• Biosphere Integrity – Rate of biodiversity loss measured by extinction rate
• Climate Change – measured by atmospheric carbon dioxide concentration
• Nitrogen cycle – measured by amount of N2 removed from the atmosphere for human use
• Phosphorous cycle – measured by quantity of phosphorous flowing in the oceans
• Stratosheric ozone depletion – measured by concentration of ozone
• Ocean acidification – measured by global mean saturation state of aragonite in surface sea water
• Global freshwater use – measured by consumption of freshwater by humans
• Change in land use – measured by percentage of global land cover converted to cropland
• Atmospheric aerosol loading – measured by overall particulate concentration in the atmosphere, on a regional basis
• Chemical Pollution – measured by a number of measurements including the concentration of organic pollutants, plastics, endocrine disrupters etc.

Read full description of planetary boundaries in my previous blogs (Planetary Boundaries  and Planetary Boundaries: defining safe operating space for humanity)

Of these identified boundaries it is thought that we are in the danger zone with current rates of species extinctions (see previous blog A wilder world  for more on the sixth great extinction period we are experiencing) and changes in flow of Nitrogen and Phosphorus (both used in synthetic fertilisers). We are also pushing acceptable limits in changes to the levels of carbon in the atmosphere (climate change) and use of land.

While this may seem overwhelming, the point is that we still have a planet that we can live on and so it is not too late to act. What this framework highlights is there is more than one environmental issue that needs to be considered for our future sustainability and that these issues are all interconnected. For instance, stabilising the climate system requires not only a reduction in carbon emissions but also conservation of forest and ocean ecosystems. We need to move away from the single problem-solution mindset of classic reductionist scientific thinking and start looking at the connections and interactions of the various environmental problems we face.

With a stronger understanding of the interconnectedness of everything (including humans) on this planet then perhaps we can begin to move away from human societies that value profit making and individualism above all else to societies that value the connections to each other and the larger connected web of life on this planet and accordingly take responsibility for our impact on our home planet. Perhaps a way to start would be to consider possible impacts of a proposed solution to the problem we are working on be it climate change, food security or conservation etc, on other planetary boundaries.

References

Steffen et al. Planetary boundaries: Guiding human development on a changing planet. Science 2015

Stockholm Resilience Centre www.stockholmresilience.org/planetary-boundaries