摘要：This paper outlines the qualitative components (the storylines) of the Millennium Ecosystem Assessment (MA) scenarios. Drawing on a mixture of expert knowledge, experience, and published literature, we have explored plausible consequences of four trajectories for human development. The storylines have been designed to draw out both benefits and risks for ecosystems and human well-being in all four trajectories with enough richness of detail to allow readers to immerse themselves in the world of the scenario. Only a summarized version of the storylines is presented here; readers are encouraged to read the more detailed versions (MA 2005). Together with the quantitative models (Alcamo et al. 2005) the storylines provide a base from which others can consider implications for policy and practice in more depth, adding their own interpretations, experience, and imagination. This is the purpose of the following papers in this volume.
