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4.2.2 PHASE 2: Identifying drivers of change in the case study ecosystem

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Having built the socio-ecological diagram and defined the temporal horizon of your scenarios (e.g. 2030), it is important to identify with stakeholders the possible changes in the system.

The changes in the system can be : environmental changes, uses and human activities, governance and management contexts, etc. Changes in the system may represent a risk or an opportunity, they can be influential or be influenced, they can show high or low flexibility.

These changes, also called variables, are:

  • The heavy trends, i.e. possible changes that are considered important and almost certain. Their evolutionary direction is known and will influence all the scenarios in a same way (e.g. climate change, demographic predictions).
  • The critical uncertainties, i.e. major possible changes but uncertain.
  • The weak signals, i.e. signal difficult to decode, or a signals which, after analysis, seem unlikely" [Vaughan, 2001] but can "announce future major changes" [Blanco and Lesca, 2003].
  • The seeds of change, i.e. elements that can cause a change.
  • The break possibilities, i.e. elements that can cause a break with the actual situation (e.g. an oil spill).
  • The development opportunities and main sectors driving innovation... [Fauchard and Mocellin, 2009]


Each possible change (e.g. variable) can then be associated with different evolutionary hypotheses, in general between 2 to 4 hypotheses per variable. The identification of variable and associated hypotheses can be conducted with the participation of stakeholders and experts during workshops, interviews and/or surveys.

It is useful to prepare a summary sheet for each variable to have a clearer view of all the possible changes. This sheet may contain the name of the variable, its definition, its descriptors, the past and future data and action levers. The variable sheets gather quantitative and qualitative data on which scenarios can rely, that enhance their credibility [Michel et al., 2013].

The variable sheets can be distributed to the participants at the beginning of a workshop to collect their suggestions/knowledge. The sheets can then be refined and used to select with the stakeholders 2 to 4 hypotheses per variable selected that will then be used to build the scenarios. The selection of variables and hypotheses must be justified and the reasons clear.


Advice: define at the start of the process a maximum number of critical uncertainties (e.g. 5 to 10 maximum). To identify these critical uncertainties it is useful to ask the following questions: "What determines the evolution of the system? On what can we act? ".


Tools that can be used to reach the objectives of this phase:

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DELPHI Glasses icon
REGNIER Glasses icon
DPSIR Glasses icon
PESTLE Glasses icon
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