The Ecological Ceiling
The ecological ceiling is the outer boundary of the doughnut, constructed from the planetary boundaries framework developed by Johan Rockström and colleagues at the Stockholm Resilience Centre in 2009 and subsequently updated. The framework identifies nine Earth-system processes that regulate the stability of the biosphere — the conditions within which human civilization developed over the past ten thousand years. For each process, a boundary marks the threshold beyond which the risk of destabilization increases sharply and, in several cases, irreversibly. As of the most recent assessment, humanity has transgressed six of the nine boundaries.
In The You On AI Field Guide
The ceiling's power in Raworth's framework is that it is not negotiable. It is not a policy preference or an ideological position. The boundaries are biophysical thresholds beyond which the Earth's systems behave differently — less predictably, less hospitably, less compatibly with the conditions under which civilization developed. An economy that transgresses