1. Are we sure?
UNECE-workshop on uncertainty treatment in Integrated Assessment Modelling January 2002
Rob Maas

2. Learning Process 1 Denial of uncertainties
2 Acknowlegdement of uncertainties
3 Specification of types of uncertainty
4 Quantitative assessment of uncertainties
5 Specification of policy relevance
6 Uncertainty management in decision process

4. Types of uncertainty Lack of knowledge Variability
unreliable data: inexactness
lack of measurements
immeasurability
structural uncertainty: conflicting evidence
ignorance
indeterminacy
Variability
natural randomness
value diversity
behavioural variability
societal randomness
technological surprises

5. Uncertainties in NL-Projections
* In % more energy use than expected in 1990
* Surprises in societal developments: e.g lower energy prices
* But also: only 70% of the policy measures were actually implemented or enforced
Policy makers are an important source of uncertainty

6. Major open issues & bottlenecks
Quality of emission data (a.o. PM10)
Eulerian vs Lagrangian model
Effects of climate change / policy
Transcontinental fluxes (ozone)
Dynamic ecosystem effects
Health effects of PM-species
Scenario’s for energy & agriculture
Implementation of measures & costs

7. Aspects of uncertainty management
Lack of knowledge:
scenarios
Variability:
probability
Risk:
assessment

8. Scenario approach
Scenarios raise awareness of uncertainties and can test the robustness of different policy strategies
Scenarios can contribute to communicate the range of perceptions
The likelihood of a scenario is subjective and differs among various scientists and policy makers
Policy makers have to decide what economic and ecological risks are acceptable

9. Political Risk Aversion
Ecologic perspective
high economic growth
low efficiency change
low energy prices
partial implementation
high background level
all PMs are dangerous
Economic perspective
low economic growth
high efficiency change
high energy prices
full implementation
low background level
focus on most suspicious PMs

10. Policy-science interaction
Political preferences are constructed during the process.
Assessment and decision taking belong together.
Well designed procedures include stakeholder openness, disclosure of beliefs, willingness to understand the other (to go beyond the given perspective) and procedures to manage conflicts (both legally and scientifically).

11. Role of science
US: adversal; pluralistic; linkage with stakeholders; ‘innovative’
CLRTAP: consensus oriented;
learning process within the ‘group’
possible risks:
closed shop & lack of trust in science?
How to remain open to dissident views?