Introduction

From time immemorial, in the West as in Asia, scientists, naturalists and philosophers have studied nature, its components and its evolution. Awareness of the fragility of the planet's natural equilibrium and the increasing scarcity of resources is thus very old. However, while man's actions have always modified his environment (selection of species through hunting, clearing land to grow crops, etc.), it is only since the industrial revolution that the intensification of human activities in the agricultural, industrial and transport fields has disrupted the environment and the living world at a rate never before observed on a large scale.

On a global scale, the consequences of climate change are accelerating and intensifying: rising temperatures, heatwaves, droughts, floods, storms and more. This disruption is generating risks of food and water shortages, threats to human health (emergence of new diseases) and ecosystems (shrinking ranges of animal and plant species, etc.) - (Intergovernmental Panel on Climate Change - IPCC, 2023³).

Although the effects of this "great acceleration" have not always been perceptible, awareness of the issues at stake was already apparent at a very early stage. Fifty years ago, scientists were already alerting public opinion to the risks of depletion of natural resources and degradation of ecosystems, induced by unlimited economic growth. In 1972, the Meadows Report⁴ described the dynamics of complex systems and set out possible future scenarios, highlighting the planet's ecological boundaries.

In 2009, following on from this work, researchers at the Stockholm Resilience Centre identified nine planetary boundaries that must not be transgressed to preserve a "safe and just operating space for humanity". These nine boundaries are based on the evolution of nine complex, interconnected phenomena: climate change, biodiversity loss, biogeochemical cycles of nitrogen and phosphorus, land-system change, freshwater use, ocean acidification, stratospheric ozone depletion, atmospheric aerosol loading, and the introduction of novel entities into the biosphere. Exceeding the boundaries of "safe operation" for each of these phenomena can provoke potentially irreversible chain transformations, destabilizing the planetary equilibrium and rendering the planet uninhabitable for mankind.

In 2019, in its quadrennial report on the state of the environment in France, the CGDD chose to use the planetary boundaries analysis framework for the first time, in order to extend the environmental diagnosis of France beyond its borders. Following on from this work, and with a view to raising public awareness of these insufficiently-known concepts, it seemed important to deepen this exercise and produce a publication entirely dedicated to the concept of planetary boundaries.

With this in mind, this publication sets out to provide an overview of the approach to planetary boundaries in three complementary parts, in order to better grasp the issues at stake: the first part deals with the origin and general framework of the concept of planetary boundaries; the second part presents the nine planetary boundaries, with a focus on France's contribution to exceeding five of them (with reference to publications by the Stockholm Resilience Centre prior to 2023); the third part looks at the use that can be made of this framework, on the scale of a company and a territory, in a sustainable development perspective.

3 Giec, 2023. AR6 Synthesis Report. Climate Change 2023.
4 Meadows D. et al., 1972. The limits to Growth - A Report for the Club of Rome's Project on the Predicament of Mankind. New York: Universe Books.