A plausible and often simplified description of how the future may develop, based on a certain set of assumptions.
(Solomon et al., 2007, p. 951)
A scenario is defined a plausible and often simplified description of how the future may develop, based on a coherent and internally consistent set of assumptions about driving forces and key relationships. Scenarios may be derived from projections, but are often based on additional information from other sources, sometimes combined with a narrative storyline.
Solomon, S. et al. (eds.) (2007). Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge: Cambridge University Press. Retrieved on July 5, 2008, from http://www.ipcc.ch/ipccreports/ar4-wg1.htm.