Introducing the planetary boundaries framework
The theory and the evidence behind the Anthropocene and social-ecological resilience, so you now have a very firm floor to explore the opportunities and the tools to navigate the Anthropocene. So this was the end of the first cluster and now in the fourth module we’ll be taking us into the new cluster on Planetary Boundaries.
The last module in this cluster on Planetary Boundaries will be introducing the three large processes, the three large planetary boundaries with global scale tipping points: climate change, ocean acidification, and ozone depletion.
To do this in the best way, we’ve invited Professor Kevin Noone from the Department of Applied Environmental Sciences at Stockholm University who also is a co-author of the Planetary Boundaries research who is joining us for this week.
In this lecture we’ll be exploring the origins of the planetary boundary framework. And it emerges from fantastic advancements in Earth system science over the past 30 years, and it’s the result of the collision of two pieces of scientific enquiry.
The first one is the insight that we’ve entered the Anthropocene; the exponential pressures on the Earth system that we now have become a geological force of change at the planetary scale, which collides with the insight that we can no longer exclude catastrophic, irreversible tipping points in the Earth system.
Now when you combine these two you have to conclude that we now need to consider the following very dramatic question. Could we as humanity push the entire Earth system outside of its current stability domain?
Which is illustrated in this graph showing that the planet can actually reside in multiple stable states separated by a threshold.
But to start that enquiry we must first ask ourselves: what is our desired state?
And science shows very clearly, as shown in this following graph, which shows ice core data over the past 100 000 years, that the Holocene, the past 10 000 years of extraordinarily stable interglacial conditions on Earth, is in no doubt humanity’s desired stable state which has enabled our modern civilizations to develop as we know them.
This is the period when we’ve had extraordinarily stable climate, varying with only 1 degree Celsius up and down over the entire period. This is a period where we know the global carbon cycle, the global nitrogen and phosphorus cycle, all the biogeochemical processes that regulate the stability, which has enabled Earth to stay in the Holocene.
So the starting point of thinking around a planetary boundary framework is the recognition that the stable desired state of the planet is the Holocene, and therefore our endeavor is to try and define what are the Earth system processes that regulate the Earth’s ability to remain in a Holocene equilibrium, in a Holocene desired state?
If we can identify those environmental processes, the next question is: can we for each one of those try and identify a control variable and put a quantitative science-based boundary beyond which we risk feedbacks, interactions, and surprise that could risk the entire system to move over a tipping point and push the system outside of the Holocene?
So that in a nutshell is what the planetary boundary framework is about. It’s recognizing that today we are potentially moving in this direction where put very, very eloquently and sharply by Ban Ki-moon, Secretary-General of the United Nations, “We have our foot on the accelerator driving towards a threshold or an abyss,” meaning that we see signs that we might actually be approaching tipping points in several of the Earth system processes that regulate the stability of the entire planet.
Now, I’d really like to emphasize that this work, which was published in 2009 in Nature with a large group of highly recognized Earth system scientists across the world, covering expertise from the climate system, the cryosphere, oceans, hydrology, ecology, this work was based upon empirical advancements in research over the past decades. So it’s really the next incremental stage of advancements in research such as the understanding that we can no longer exclude tipping elements and climate; understanding that we have ecological capacities which define the stability of many of our ecosystems, which means that the planetary boundary concept resides on three pillars of scientific enquiry.
The first one is clearly the Earth system understanding of the planet as a self-regulating geobiochemical system where the interactions occur all the time between the biosphere, the atmosphere, the cryosphere, the hydrosphere and the climate system, and that we are safely enveloped around the stratospheric ozone layer.
The second line of enquiry is the work residing or coming back all the way to the early 1960s around ecological footprints, Herman Daly’s work on steady state economy, Kenneth Boulding’s thinking around Spaceship Earth, ecological economics research, the research advancements understanding the relationship between human needs and the capacities of our biosphere to support humanity.
And the third line of enquiry is the enormous advancements we’ve made in understanding the nonlinear dynamics in complex ecosystems and biomes, the whole domain of resilience theory, complex systems research where we’re understanding increasingly that systems can actually cross tipping points and change very rapidly.
So planetary boundary theory and its framework originates from these three lines of enquiry and is a natural next step in our understanding. But it differs very significantly from many of the previous concepts that we’ve been exploring.
So you’re probably familiar with different concepts such as limits to growth, carrying capacity, guardrails for climate, or tipping elements in the climate system. But the most famous of these is the limits to growth.
And I really want to emphasize that even though they complement each other, they’re distinctly different, because limits to growth, which was developed by Dennis and Donnella Meadows and was part of the Club of Rome report that came in 1970s, in the early 1970s, was based on the following analysis.
It tried to estimate the resource base that we have in the Earth system, natural resources, everything from soil to metals to oil to finite fresh water resources, and then made assumptions regarding technology and tried to estimate human needs. And then it compared the resource base, basically what Earth could provide, the supply side, and humanity’s demand side. And when the demand side exceeded supply we were in overshoot.
And then the analysis made assumptions around how that overshoot could play out in future risks, for example, the climate system. But it had to make assumptions on technology and human demands. Same for carrying capacity analysis, which always are based on assumptions on technology and human needs.
Now history shows that these analyses tend to underestimate human ability to innovate, that we tend to be more clever in terms of, for example, ensuring the capacity to feed ourselves despite resource constraints.
The planetary boundary framework does this very differently. It backs off in terms of humanity and simply tries through scientific enquiry to interview planet Earth and see whether Mother Earth could answer the question, “If you were left alone, and if you would like to answer for us, what are the Earth system processes that determine your ability to stay in the Holocene, what are these processes?
And for each one of these processes how far can we push you beyond which you will move yourself outside of the Holocene?”
So the planetary boundary framework decouples itself from humanity in the diagnostic and the definition of the boundaries. This gives us a safe operating space, which is entirely biophysical. It makes no assumptions of human needs, no assumptions on human innovation capacity. And then you can put back humanity inside that safe operating space.
So it liberates ourselves from the risk of making underestimates, overestimates of our ability to develop. And therefore I believe that the planetary boundary framework is so useful in support of our endeavor of enabling and ensuring human prosperity in the Anthropocene, because it’s entirely a science-based enquiry of what it will take for the Earth system to remain resilient and stable in the desire Holocene-like condition.
And then we can take the enormous challenge of finding solutions, exploring technologies, addressing ethics, addressing a fair distribution of remaining ecological space, and addressing the very, very complex questions around democracy, ethics, transparency, governance, economic growth, etc. But that comes inside the safe operating space, it’s not being challenged and it’s not normative in terms of its definition of the boundaries.