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Definition of Scenario:
A plausible, simplified, synthetic description of how the future of a system might develop, based on a coherent and internally consistent set of assumptions about key driving forces and relationships among key variables[1].
Scenarios are neither predictions nor projections and sometimes may be based on a 'narrative storyline'. Scenarios may be derived from projections but are often based on additional information from other sources.
This is the common definition for Scenario, other definitions can be discussed in the article

Why Scenarios?

Scenarios - alternative, ‘what if?’ visions of the future – and the process of generating them can be used as a key part of the ICZM Process. Scenarios can be used to:

• Provoke debate about common futures

• Expand the range of options

• Expose contradictions and conflicts

• Clarify and communicate the technical analysis

• Expose uncertainties for future developments

• Evaluate policies in the face of an uncertain future

Scenarios and the process of scenario development should engage the imagination of both the planners and the stakeholders. Their value should be to widening the participant's perception of possible future events and possibilities and encourage 'thinking the unthinkable'.

Scenarios can be generated from a combination of factors, such as demographics or economic growth, with plausible alternative political, social, technical, legal and environmental trends as key driving forces. Climate change scenarios will add an additional ‘control’ dimension to the process.

Asking what actions are required to mitigate the negative or reinforce the positive aspects of the likely scenarios can then inform the formulation of strategies.

There are many variations of the scenario process, but they can be placed between two extremes:

1. A limited number of top-down scenarios generated formally by the planning team and subject to a formal consultation – often consisting of ‘high’ and ‘low’ scenarios centred on a ‘do nothing’, ‘business as usual’ or median option.

2. A fully participative process involving facilitated workshops etc. at which few constraints are placed on the number or range of alternative scenarios generated; whether objective or subjective, driving forces and outcomes are given equal weight.

Extreme 1 requires the least effort, but is self-limiting in the quality or innovation of options. It also largely self-fulfilling in terms of stakeholder response and the resulting strategy. A structured version of 2 offers the most creative way forward in terms of the selected outcomes and, more importantly, taps in to local knowledge and encourages the ‘ownership’ of the outcomes.

The indicators can be used to help ‘measure’ the impacts of the alternative scenarios in terms of costs and benefits – recognising and accepting that in many cases these will be speculative. The degree of sophistication applied to the technical evaluation of alternatives through, for example, coast-benefit analysis, will be dependent on the resources and expertise available.

Techniques & Tools

The literature contains many scenario tools for sustainability. No one technique is prescribed here for the coast, rather the precise techniques used will vary with local cultures, social and administrative complexity, local capacity and other contextual factors. In all cases however, the added value of participation should be maximised.

See ‘Imagine a Systemic and Prospective Sustainability Analysis


  1. Millennium Ecosystem Assessment (2005) Ecosystems and Human Well Being: Scenarios, Island Press