Recent events of the BP Deepwater Horizon and Fukushima have shown that man-made designs, guided by the assurance of traditional risk modeling, have greatly underestimated the degree of system complexities (Kampf & Haley, 2011). While these events do not yet call for a blanket application of the most stringent form of the Precautionary Principle, they do point to the need for a com-mensurate gravity – an ethic of gravitas – especially in large-scale environmental design. In contrast to the prevalent design ethos that perceives environmental design as instrumental to new spatial possibilities and social hope, the ethic of gravitas instead posits an accompanying duty to this practice by recognizing that irreversible changes made to the environment are costly and design should not be invoked lightly. In other words, in a world where planners and designers have the capacity to do many things and perhaps even anything, there should also be a commensurate capacity to ask the question, ‘ought we do it?’ (Silman, 2007). This ethic of gravitas in environmental design is anticipated to become more important in an era increasingly characterized by the negative externalities of anthropogenic impacts on the environment.