Why are planetary boundaries important?
In the first ever S & S decoded, we grappled with the complexities of climate science. One of the most useful tools to contextualise our earth’s current state is using the framework of planetary boundaries.
So, what are planetary boundaries? These are essentially the preconditions for human development. This new approach was provided by scientist and sustainability expert, Johan Rockström.
This structure sets the safe operating space for humanity with respect to the Earth’s systems and is associated with the planets biophysical subsystems or processes.
It’s an immensely helpful contribution and tool to understand how we can discourage the acceleration of the hockey stick effect and crossing of biophysical thresholds.
What are the different planetary boundaries?
The concept of planetary boundaries has 9 linear, delicately interconnected specific conditions:
1.Climate change
2. Rate of biodiversity loss (terrestrial and marine)
3. Interference with nitrogen/phosphorus cycles
4. Stratospheric ozone depletion
5. Ocean acidification
6. Global fresh water use
7. Change in land use
8. Chemical pollution
9. Atmospheric aerosol loading
As of 2020, we have crossed the first three thresholds. For those wondering, the consequences of surpassing all nine planetary boundaries holds irreversible repercussions for the planet and future generations. As we overstep each threshold and boundary, it subsequently jeopardises the rest.
For example, land use changes in the Amazon can immediately impact fresh water sources in faraway lands. Additionally, the extent climate change as a planetary boundary is violated depends on our ability to maintain freshwater, land, aerosol, nitrogen, phosphorous, ocean systems and stratospheric boundaries. This interlinking means exceeding one has an impact, we are still not yet aware of.
On a more optimistic level, if we are able to keep in check the remaining thresholds there is no reason we cannot pursue long term social and economic development. Such a trajectory is outlined by the United Nations through the clear agenda of the 2030 Sustainable Development Goals to address these challenges.
Explained: Which planetary boundaries have we crossed?
Evidence of how have we crossed 1, 2, and 3 you ask?
- Climate Change
As outlined by the hockey stick acceleration graph, this includes melting of polar ice sheets, rising sea levels, destruction of forest/ecosystems away from Holocene and the doubling in level of CO2 of its pre-industrial rate.
For those unfamiliar, Holocene refers to a 10,000 year period in life of the planet following the ice age that was characterised by high stability in environmental and ecological conditions that saw a relatively stable climate and allowed the evolution of humanity.
2. The Rate of Biodiversity Loss
Witnessed through the rate of animal extinctions, increased vulnerability of terrestrial and aquatic ecosystems and erosion of ecosystem resilience. Exceeding this boundary is also highlighted by the acceleration of climate change which has seen the rate of extinction of species 100-100 times more than what is considered natural. Rockström sees the change in our systems could mean that up to 30% of all mammal, bird and amphibian species will be threatened with extinction this century.
3.The Nitrogen/Phosporous Cycles.
Catalysed by modern agriculture which require fertilizers for food production. Per year, these convert to approximately 120 million tonnes of nitrogen intro reactive forms which pollute water ways, coastal zones and accumulate in land systems.
Phosphorous from mining has eroded into lakes and oceans in turn raising levels of toxicity. Annually, 20 million tonnes are mined and a substantial 8.5-9.5 million of these find their way into our oceans. Through extensive research, Rockström and his team approximate this cannot exceed 11 million tonnes per year if we want to avoid mass extinctions of marine life.
The current status of planetary boundaries
Although published over a decade ago in 2009, Rockström estimated proposed boundaries, current status’ and the pre-industrial boundary which are sighted below.
More on planetary boundaries
Here’s the link to the full analysis and PDF article.
With such a framework, it is clear to see how the planet is often neglected as a crucial stakeholder with its delivery of ecosystem services that provide natural resources including food, fresh water, fibre, timber, regulatory functions and cultural societal benefits.
This value, which we often overlook, is highlighted by the loss of ecosystem services from 1997-2011 due to land use. This change cost approximately $4.3-20.2 trillion a year according to Robert Costanza, a leading ecological economist.
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