Biogeoclimatic ecosystem classification (BEC) has underpinned terrestrial ecosystem management and conservation planning in British Columbia, Canada since the early 1970s, serving the province well for over 40 years as expectations for the use and management of the public land base have evolved. The system is now critically challenged because (1) BEC champions in government, academia, and the private sector are disappearing through retirement and layoffs; (2) BEC is based on outdated notions of climax ecosystems in equilibrium with climate; and (3) the contemporary relevance and intellectual richness of this approach to ecosystem science is not comprehended by a generation of scientists and resource managers grappling with accelerating rates of change in climate and other environmental drivers. This review addresses ways to ensure that BEC remains robust and useful in an uncertain future. The Author proposes that BEC embrace complex systems science. Through a dialectical analysis of alternative paradigms in ecology, it is argued that BEC's holistic, developmental view of terrestrial ecosystems is fundamentally compatible with complexity theory and provides the information content missing from contemporary ecosystem ecology. Two examples of nonlinear modelling (adaptive landscapes and agent-based) to illustrate how the classification system can adapt from a largely linear and equilibrium, to a nonlinear, nonequilibrium perspective of ecosystem dynamics. The BEC program itself must function as a complex adaptive system to survive government downsizing and guide ecosystem management during difficult times, and to challenge and enlighten a new generation of scientists and citizens. [ABSTRACT FROM AUTHOR]