The paper proposes a contribution to the reflection on the effectiveness of the SEA instrument as a process of environmental sustainability integration in planning choices in general, and, in particular, for some policy areas (adaptation to climate change) characterized by lack of methodological and operational tools. To this end, the experience of the SEA of the Calabria Region Transport Plan is analyzed in the light of the open questions in the international scientific debate. The SEA conducted is described by illustrating the used methodologies in relation to the type of approach adopted in the process. The reflection highlights how, even in the presence of constructive approaches, as defined in the reference literature, the integration of environmental sustainability is not immediately verifiable, since it is postponed to the subsequent implementation phases. This difficulty is even more evident in relation to the application to the policies on adaptation to climate change, an area characterized by the lack, at national and regional level, of well-structured and operationally defined reference instruments. In this case, even if adopting a constructive approach, the achieved result is limited, necessarily, to general indications, typical of a compliance approach with respect to the policy itself. [ABSTRACT FROM AUTHOR]