Week 6: Planetary Boundaries Framework Pt. 1 - Post 2

Planetary Boundaries Framework Pt. 1

          Humanity has entered the Anthropocene. Humans are at the drivers seat of the changing climate. The question remains: how does humanity keep Earth in a Holocene like state so development may continue? The answer resides in planetary boundaries. The exponential pressures humans put on the Earth has the ability to cause catastrophic and irreversible tipping points within the Earth system. Understanding the thought process behind each planetary boundary helps to understand what they are. First scientists define which Earth system processes take part in regulating the Earth's ability to remain in a Holocene like state. An example of this is the climate system, which regulates global climate. Then, for each of the Earth systems scientists try to identify a control variable. These control variables put a quantitative boundary beyond which, if feedback shifts, thresholds, and tipping points are reached the Earth will enter a new and undesired stable state. This planetary boundary concept relies on three pillars of scientific inquiry. The first one, as Professor Johan Rockstrom decribes it "is understanding the planet as a self-regulating biogeochemical system where interactions occur all the time between the biosphere, the atmosphere, the cryosphere, the hydrosphere and the climate system, and that we are safely enveloped within the stratospheric ozone layer. The second line of inquiry is research advancements. Understanding the connection between human needs and the Earth's capacity to deal with that. The final line of inquiry is the Domain of Resilience theory. Which covers nonlinear dynamics in complex ecosystems and biomes. Understanding that these systems can actually cross tipping points and change completely. The key difference between planetary boundaries framework and any other Earth system assessments is that it separates itself from humanity. This gives an entirely scientific basis and reasoning behind the boundaries. The science makes no assumptions of human needs or human innovation capacity. It liberates the possibility of making underestimates or overestimates of humanity's ability to react. The result of planetary boundary framework is nine boundary processes. Three have evidence of progressing towards large scale tipping points: the climate system, the stratospheric ozone layer, and ocean acidification. There are four boundaries operating on a little bit of smaller of a scale: biodiveristy, land use, nutrients, and freshwater. And two boundaries which are very much anthropogenically caused: air pollution, or aerosol loading, and chemical pollution. As these regulating systems have been established, the real challenge lies in defining the boundary past which the Earth's stable state is in danger of tipping into an entirely new undesired state. The climate system is a good example. For this boundary there are two defined control variables; the number of watts per square meter of increased heat in the atmosphere and the concentration of greenhouse gasses in the atmosphere. Once the control variables are established scientists try to identify the quantitative point at which evidence suggests the system can be pushed no further. Going with the example of the climate system, if the concentration of carbon dioxide in the atmosphere goes higher then 350 parts per million (ppm) the climate is at risk of unsafe temperature rise. Within each of these boundaries scientists place a zone of uncertainty or a standard deviation of science. Meaning that somewhere within this uncertainty range lies the threshold, or the point at which the system reaches a tipping point. Planetary boundary framework is essentially a set of control variables, assigned to the most important Earth systems, with quantitative limits set on them, which if crossed will push the Earth into a new and undesired state.
          Planetary Boundaries are incredibly important to determine sustainability pathways going forward. If science can be used to define the boundary levels beyond which the Earth is pushed outside of its current state, humanity can monitor and keep track of of how close people have pushed the Earth towards all those boundaries. Finding ways to provide a sustainable future is really built upon the foundation of planetary boundaries framework.