In the last decades, sustainability became a key part of design at different scales. In spite of this, the relationship between architectural design and sustainability remains a complex and problematic one. Sustainability is, as a matter of fact, a mobile target. As knowledge about the tangled relationship between humans and their environment expands, its boundaries widen and move. Thus, the balance point between the need for sustainable development and the need to physically transform the environment is constantly shifting. Moreover, the rich complexity of the subject requires specific, context-based solutions, while general solutions are often ineffective.
This essay seeks to investigate this topic from two related perspectives. From a more general viewpoint, it explores the link between sustainability and spatial design through the relationship between humans and their environment - a debate lately renewed by the evident blurring between nature and artifice, and by concepts, like the 'Anthropocene', stressing the importance of the deep global changes caused by humans.
Under a more specific point of view, the text examines the importance of design as a relevant tool to investigate the subject. It describes several case studies where the traces of previous settlements - remnants of former colonisations of the environment - become cornerstones of new spatial organisations, and architectural exercises to deal with the inherent contradictions behind the demand for sustainability.

Francesco Spanedda is university researcher and assistant professor at the Alghero School of Architecture, Department of Architecture, Design and Urban Planning, University of Sassari. He also runs a research-based practice in Italy. The combination of scholarship and design opens up the investigation of uncommon topics. Before starting his own practice he worked to a large series of built projects throughout Europe.