Planetary boundaries : Governing emerging risks and opportunities

The climate, ecosystems and species, ozone layer, acidity of the oceans, the flow of energy and elements through nature, landscape change, freshwater systems, aerosols, and toxins—these constitute the planetary boundaries within which humanity must find a safe way to live and prosper. These are thresholds that, if we cross them, we run the risk of rapid, non-linear, and irreversible changes to the environment, with severe consequences for human wellbeing. The concept of planetary boundaries, though recent, has already gained traction in scientific and in some policy circles, and is generating debate more broadly. Nevertheless, despite decades of talk on sustainable development, reform of international governance and institutions has not kept pace with the scale and urgency of the global environmental crisis. The notion of planetary boundaries can be seen as a way to frame governance reform. This discussion introduces key elements of governance in a world with boundaries: deep reform of international governance, such as the United Nations system and trade treaties; emerging ecological concepts and principles in international law; the role of economics for the biosphere; and, the need to integrate different kinds of knowledge—from the local to the global. The literature is rich with ideas for solutions and real-world experiences. One recent example from south-eastern Australia demonstrates innovative approaches to knowledge sharing and communication between scientists, urban planners, and local communities for sustainable development in a changing climate. Finally, there is need for a mobilizing narrative: a story grounded in the concept of planetary boundaries, uniting the solutions, and framed in such a way as to offer opportunities for learning, innovation, and creativity at all levels, in both the North and South. There are no simple solutions to what are complex problems involving politics and trade-offs. Ongoing debate and discussion—in academia, in policy circles, and in society at large—is healthy, but we should not allow debate about the precise nature of planetary boundaries to stymie progress. Exploring these issues and the interface between different fields is a challenging task, to be sure. Still, it is essential if the concept of planetary boundaries is to fulfill its potential as a guide for human action in the Anthropocene.