The Earth System

How does science define out common home and identify the risks to humanity if we degrade out home?

Scientists describe the Earth System as a single complex system consisting of interacting physical, chemical and biological cycles. It provides the common home for all of humanity. The planetary boundaries framework is a scientifically based approach to describing the critical processes that define the functioning of the Earth System, and the limits beyond which humanity should not push these processes if the Earth System is to remain in a favourable state.

Earth System science - A major paradigm shift in the way that science approaches and understands the natural world

In 1986 the International Geosphere Biosphere Program was formed and became the first major international scientific program to focus a world-wide research effort on understanding Earth as a single system. Earth system science attempts to understand and expand knowledge of how the planet works as a single, integrated system including the interacting physical, chemical and biological processes that make up the life-support system at the surface of the planet.

The Earth System includes humans, our increasingly technological societies, and the impacts of our actions, which means that we do not sit outside the Earth system but are an integral part of it. Thus, Earth System science includes the study, not only of the biogeophysical processes of atmospheric chemistry, oceanic circulation, biodiversity, ecosystem physiology and so on, but also, very importantly, of the complex interaction of human beings with the environment. A critical function of Earth System science is to understand what is required to retain the Holocene-like state that has fostered human development and well-being. With the recognition of the importance of interactions among the climate, the biosphere and human social and technological systems, there is now even more emphasis on interdisciplinary research on how the whole Earth System functions and how it is changing.

Planetary Boundaries, the Anthropocene and the "Safe Operating Space"

The Planetary Boundary framework grew out of Earth System science and the advent of the Anthropocene. It represents a major paradigm shift in the way that science approaches and understands the Earth as a single, interconnected system.

Planetary Boundaries define a ‘safe operating space’ for humanity based on our evolving understanding of the functioning and resilience of the planet. The physical conditions of the Holocene epoch have been recognized as most beneficial, and likely necessary, for human societies to thrive. It is only during the Holocene that most of our social and technological development has taken place in the stable global climate characterized by temperature remaining within a narrow band of plus or minus 1°. The Holocene environment has predictable and stable seasons and rainfall patterns within which humans have evolved from small nomadic hunter/gatherer groups to settled locations developing agriculture, then industrialization and now the technological age. The favorable state of the Holocene has supported human development, resulting in vast increases in human population numbers and rises in living standards in many parts of the world.

Planetary Boundaries define a ‘safe operating space’ for humanity based on our evolving understanding of the functioning and resilience of the planet. The physical conditions of the Holocene epoch have been recognized as most beneficial, and likely necessary, for human societies to thrive. It is only during the Holocene that most of our social and technological development has taken place in the stable global climate characterized by temperature remaining within a narrow band of plus or minus 1°. The Holocene environment has predictable and stable seasons and rainfall patterns within which humans have evolved from small nomadic hunter/gatherer groups to settled locations developing agriculture, then industrialization and now the technological age. The favorable state of the Holocene has supported human development, resulting in vast increases in human population numbers and rises in living standards in many parts of the world.

The Great Acceleration

The Anthropocene is therefore truly “the epoch of humans”. It is an exceptionally rapid, human-driven trajectory of the Earth System away from the stability domain of the Holocene and towards a state that is highly likely to be less hospitable to humans.

The Anthropocene represents arguably the most difficult challenge that humanity has ever faced. A continuing trajectory away from the Holocene could lead, with an uncomfortably high probability, to a very different state of the Earth System, one that is likely to be much less hospitable for the development of human societies. The Planetary Boundary framework aims to help guide human societies away from the current trajectory of the Anthropocene by defining a “safe operating space” in which we can continue to develop and thrive. It does this by proposing boundaries for anthropogenic perturbation of critical Earth System processes. Respecting these boundaries would greatly reduce the risk that anthropogenic activities could inadvertently drive the Earth system to a much less hospitable state.

Figure 3 is a visualization of the Planetary Boundary framework showing the current status of the nine boundaries. The green zone in Figure 3 represents the safe operating space. The yellow zone represents a zone of uncertainty or increasing risk and the red zone is a high-risk area. The planetary boundaries lie at the intersection between the green and the yellow zones. The boundaries are not set at the tipping points that could drive the Earth System into unknown states, but rather at a safe distance from possible tipping points or significant erosion of resilience. Determining a safe operating space obviously involves normative value judgments on how societies choose to deal with risk and uncertainty.

The legal challenge of the Anthropocene

The Anthropocene introduces a new dynamic into environmental policy, law and governance and how it should evolve because it heralds a new period of global human-driven environmental change. This change highlights the failure of the existing legal system to adapt to these changes. So far, environmental law has been largely problem specific rather than global in its focus and system-oriented.

Many of the human activities causing these large, complex, global environmental issues are neither socially unacceptable nor illegal. They are not criminal nor are they torts or civil wrongs. They do not violate national or international law, but they are deeply embedded in our contemporary way of life. Essentially the law is blind to these seemingly innocuous but profoundly damaging and disruptive activities. An obvious example is climate change. All of us contribute to increasing the greenhouse effect by increasing the levels of carbon dioxide in the air through the daily activity of driving our cars. (…) The Anthropocene therefore requires that we re-evaluate the normative approaches in law and governance towards the environment. (Bosselmann, K., Jone, K 2016)

However, what “Anthropocene” does achieve, along with the Planetary Boundaries framework, is a powerful way to conceptualise, and even to visualise, where we as a particular species and “we” as an entire “Earth community” now stand in terms of our own planetary life support system over a very long-term perspective. The Anthropocene might just be what’s required to build a system of management of our use of the Earth System, an integrated economic and legal system within the biogeophysical state of the planet.

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