"Recognizing that each additional disturbance in a region can represent a high marginal cost to the environment, there is an increasing awareness of the need to better assess and manage cumulative environmental effects. Yet, cumulative effects are one of the most perplexing issues in environmental assessment and natural resource management, and the practice of cumulative effects assessment has been falling significantly short of its promise. Practiced largely in the context of project-based decision making, the current approach to cumulative effects assessment does not provide the results needed to understand broader environmental change or to make longer-term decisions concerning the sustainability of current and future development actions. This paper attempts to unpack the current approach to cumulative effects assessment, and to identify a means to move toward more meaningful practice. It argues that cumulative effects assessment requires a much more integrative and strategic framework than what is currently practiced, operating at a regional scale and both informing and informed by higher level policies and plans and lower level project actions. In order for this to happen, we must rethink our assumptions about the nature of cumulative effects; move toward the integration of assessment, science, and management; and invest in the capacity needed to implement and sustain cumulative effects assessment systems and practices."