The historical, current and future international practice of cumulative effects assessment and management (CEAM) is addressed. The 'context' of CEAM is explained and challenges from scientific and policy issues and numerous uncertainties are described. A six-step generic process for carrying out CEAM is provided. Opportunities for mitigation and management are highlighted, with emphasis given to 'collaboration' as a foundational element for dealing with cumulative effects. This state-of-practice review concludes by noting six 'ugly lessons' which result from lack of appropriate attention, eight 'bad lessons' which reflect practices that need improvement, and 12 'good lessons' which can be used to articulate good practice principles related to CEAM. In many situations some modification of EIA methods and tools may be necessary. In summary, the practice of CEAM is growing out of its infancy. As experience is accrued, it is anticipated that good practice principles will be further articulated and utilized on an international basis.Keywords: EIA, CEAM, methods and tools, mitigation, management, best practices HE GOAL OF THIS REVIEW is to concisely summarize the state of the professional practice of cumulative effects assessment and management (CEAM). Both authors have experience related to university-level teaching about environmental impact assessment (EIA) and CEAM, and in conducting related sponsored research and advising graduate students in their research. They also have independently and collaboratively taught professional-level CEAM short courses for government agencies and the private sector. Further, they both have consulted on the planning and conduct of CEAM studies, and have prepared relevant sections or chapters in subsequent environmental impact statements (EISs) or environmental assessments (EAs). Finally, they both have reviewed impact study documents and provided suggestions for improvement. The second author has also served on several EIA review panels for the Canadian government. As a result, both authors have planned, reviewed and conducted comparative evaluations of the CEAM features within prepared compliance documents, or as separate study documents (Baxter et al, 2001;Ross, 1998;Cooper and Canter, 1997). Such reviews with similar findings have also been conducted in the UK (Cooper and Sheate, 2002). As a result, this state-of-practice review primarily encompasses accrued experiences from both the USA and Canada -two countries which have been devoting considerable attention to CEAM over the last two decades, and particularly since 2000.Included herein is a brief historical perspective on the practice of CEAM. Early practice focused on T Larry Canter is Principal, Environmental Impact Training, PO Box 9143, Horseshoe Bay, Texas 78657, USA, and also Professor of Civil Engineering and Environmental Science (Emeritus) at the University of Oklahoma, Oklahoma 73019-0470, USA; Email: envimptr@aol.com. Bill Ross is Professor of Environmental Science (Emeritus), Environmental Design, University of Calg...
