16

This paper explains the scientific reasoning that led us to institute the “night environment” as new interdisciplinary research topic from a social-ecological perspective. Sociocultural, ecological and health costs of artificial light at night (ALAN) have been gradually highlighted since the second half of the twentieth century in a range of scientific fields, from astronomy to medicine through ecology and energy. At the same time an environmentalist movement was emerging: the “dark-sky movement” which condemns “light pollution” and carries its demands within local, national or international arenas. In the 1990s, the requalification of urban lighting as light pollution gave rise to the ill-defined notion of night environment. This notion aims to understand the systems, both human and non-human, that are functionally related to the night and darkness. Building on medium and long-term observations of the processes of construction, legitimation and territorialization of the nocturnal environment, we demonstrate that this notion enables to establish a junction between the different strongly compartmentalized meanings and approaches of the roles, functions and effects of ALAN, and more specifically of urban lighting. We propose to approach its study based on the social-ecological systems framework. This requires creating strong interactions between the different approaches of ALAN: those of the social sciences and those of the experimental, life and health sciences.