Scenario Studies
Many different types and characterisations of scenarios can be found in the literature. These range from short-term, trend-extrapolating, quantitative projections to long-term, contrasting, sometime normative, purely qualitative narratives. Depending on the focus of the analysis at hand, two types of scenario studies can be distinguished in IMAGE studies in the last few years, namely "multiple baseline" scenarios and "single incarnation of the future" scenarios.
Multiple baseline scenariosOn the one, hand are the multiple baseline scenarios combining narratives and quantitative data and models, starting with the set of IPCC scenarios in the Special Report on Emissions Scenarios (SRES) (IPCC, 2000). In the same category scenarios were elaborated for the GEO-3 study of UNEP, the Millennium Ecosystem Assessment of the World Bank and the Sustainability outlook "Quality and the future". The scenarios represent structurally different futures, including assumptions on prevailing values and preferences of society with their associated policies. The underlying narratives or storylines provide the basis for constructing coherent sets of assumptions from which model parameters and settings are derived. Variants can be developed from one or more of the baselines by assuming additional interventions not foreseen in the baseline, geared to improve on selected outcomes such as climate change. Single incarnation of the future scenariosThe second approach aims to identify a single incarnation of the future as the point of departure for the analysis. This can take different forms such as a no-new-policy baseline or a best guess development under Business-as-Usual conditions. Uncertainties can then be explored by varying the central assumptions in the reference. If done systematically, the compounded effect of uncertain inputs will result in distributions of end results rather than point estimates. Alternative policy interventions can be tested against the single baseline to see how effective and efficient they are, what undesired side-effects they may have, etc. More information on multiple baseline scenarios
More information on scenario studies
More information examples of single incarnation of the future scenarios
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