A scenario is an internally consistent view of what the future might turn out to be -
not a forecast, but one possible future." Michael Porter
"Scenario planning is that part of strategic planning which relates to the tools and
technologies for managing the uncertainties of the future." Gill Ringland
Scenario planning is not about predicting the future. It is about exploring the future. If you are aware of what could happen, you are more likely to be able to deal with what will happen.
Scenario planning exercises involve identifying trends and exploring the implications of projecting them forward - probably as high, medium and low forecasts. These can include political, economic, social and technological. As different trends are chosen and different combinations of forecast levels are combined, a whole spectrum of possibilities can be identified.
Well known examples include the end of the Berlin Wall, OPEC oil price rises, bombs and terrorist attacks. Asking the great What if? Identifying risk.