Mangrove ecosystems perhaps represent the most diverse combination of floral, faunal and physical elements among coastal habitats. Mangrove forests are globally widespread in the tropics and subtropics and provide a dynamic interface between the sea and the land. Mangrove ecosystems reflect the dynamics between climatic variations of coastal processes and biological interactions as well as interventions by human activities. This paper defines an assessment framework for mangrove ecosystems and elements for an assessment. The assessment process is illustrated using the potential effects of GCC on mangrove ecosystems as an example.