Transcript Slide 1

Scenarios and
Decision Support Systems
Monika Zurek
FAO, Rome
Greg Kiker
University of Florida
GECAFS Caribbean Meeting, 30 Aug 05
Overview of the talk
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Looking into the future
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What are scenarios? Why use scenarios?
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Decision Support Systems
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The GECAFS scenarios component
Looking into the future
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Out of curiosity
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For scientific exploration
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For decision-making
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Decisions are based on expected outcomes and the
trade-offs they imply
Decisions involve uncertainty about how the future will
unfold
For planning purposes/strategic planning exercise
Sources of Uncertainty when thinking
about the Future
Ignorance
Understanding is limited
Surprise
The unexpected and the novel can
alter directions
Volition
Human choice matters
Source: P. Raskin
Methods for looking into the future
Predictions are seen by the public and
decision makers as things that will happen
no matter what they do.
Forecast is the best estimate from a particular
method, model, or individual.
Projections are heavily dependent on
assumptions about drivers and boundary
conditions; they often assume that these
will not change. Projections lead to "if this,
then that" statements.
Scenarios……
Scenarios, predictions & projections?
The probability that …
Facts
Causality
known
What if?
Prediction
Scenarios
Projection
unknown
low
Uncertainty
high
(data availability)
Source: modified after R. Leemans 2003
Scenario Definitions
Plausible stories about how the future might unfold
from existing patterns, new factors and alternative
human choices. The stories can be told in the language
of both words and numbers (Raskin, in press).

Plausible descriptions of how the future may develop,
based on a coherent and internally consistent set of
assumptions about key relationships and driving forces
(Nakicenovic 2000).
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A tool for ordering one’s perceptions about alternative
future environments in which one’s decision might be
played out (Schwartz 1996).
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Plausible alternative futures, each an example of what
might happen under particular assumptions (MA).
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Why use scenarios?
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Purpose of scenarios:
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Information dissemination
Scientific exploration
Decision-making tool
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Understanding all factors influencing the future
Robust strategies that work under different worlds
 Different process of stakeholder involvement in
scenario development
Understanding and communicating the main
assumptions on which people base their notion of
the future
‚Good‘ scenarios should ...
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... be plausible (or ‘not implausible‘)
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... be internally consistent and coherent
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... be constructed with rigour, detail & creativity
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... meet the goals of scenario exercise!!!
Decision Support Systems
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Many definitions, many visions, many
versions…
DSS Integrate Tools
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Models
Databases
Visualization (GIS, graphics, charts…)
Decision analysis (MCDA, trade-off analysis,
linear programming)
User-Defined
“Slow and Fast”
Time Steps
Example DSS: QnD System
Management Options
Reset Button
“Warning Lights”
Tabbed panes with several
time series charts
Mouse-driven
Chart and Text
Display
Spatial Maps of Ecosystem Indicators
Challenges in Building DSS
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DSS almost always focus on one
sector’s (or discipline’s) tools and
concepts
Model integration is difficult and
technically challenging
Not helpful in unearthing assumptions
Transparency versus Ease of Use
Integration with scenario planning “More gaps than links”
Socio-Economic Drivers
CARSEA Scenarios
• Neo-Plantation Economy
• Quantity Over Quality
• Growing Asymmetries
• Diversify Together
Tourist visits, foreign investment,
external prices, etc.
QnD:Jamaica Version 0.0
• Stochastic relationships
• Time series values
• Incremental change
Climatic Drivers
QnD Scenarios
Climate Scenarios
• Precipitation
• Hurricane Intensity/ Frequency
• Sea Level Rise
• Neo-Plantation with mild Climate Change
• Neo-Plantation with intense Climate Change
• Etc…
GECAFS – research focus
1.
2.
3.
4.
Classifying and characterizing the major food
systems existing today for GEC studies,
Investigating the vulnerability of existing food
systems to GEC and its consequences for
different parts of society,
Sketching plausible future changes in
environmental and socioeconomic conditions
that will effect food systems,
Based on the analysis of plausible futures,
devising decision support systems for the
formulation of diverse policy-instruments to
adapt global food system to GEC.
Scenarios Component Research
Questions
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What are plausible future changes in environmental
and socio-economic conditions that will affect food
systems?
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What elements of global scenarios are most
important for regional-level food system analyses?
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How best can global scenarios be linked to the
regional scale in order to capture regional-level
factors relevant to food systems?
Linking global and regional scenario
exercises
Global Scenarios
Preparatory
phase
Feedback
IGP
CAR
Regional
GECAFS
Scenarios
SAF