Towards a Sustainable Circular Economy on a Full Planet : The Role of Thermodynamic Principles

The concept of a circular economy has instilled substantial hopes that it will help forging patterns of resource use compatible with Planetary Boundaries. Many countries are implementing circularity policies to reduce wastes and emissions, while also fostering economic growth. Research and action are mainly focused on micro- to meso-levels; from products, materials, companies, sectors, to recycling. Macro-level, system-wide implications of circularity strategies remain underappreciated. We synthesize thermodynamic and socio-metabolic principles to articulate boundary conditions for a sustainable circular economy. The 1st law of thermodynamics implies that virgin resource extraction is inevitable whenever societies’ material stocks in buildings, infrastructures and machinery grow. This even holds under the assumption of complete recycling, which is practically unattainable under the 2nd law. Furthermore, in a circular bio-economy, practices of biomass and land use must avoid, or ideally reverse, losses of natural carbon stocks in ecosystems, and close elemental cycles. While conceptually straightforward, especially for Ecological Economists aware of Georgescu-Roegen’s seminal work, these insights are widely underappreciated in circular economy research and implementation. We discuss how thermodynamics can help (1) prioritize and design circularity strategies, (2) avoid partial fixes, problem-shifting and rebounds, and (3) develop a systematic evidence base supporting policy-relevant priorities and guidelines