Uncertainty, climate scenarios and adaptation

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Uncertainty, climate scenarios and adaptation

• Suraje Dessai
• Tyndall Centre for Climate Change Research, UK
  and
• School of Environmental Sciences
• University of East Anglia, Norwich, UK
• CLIMATE CHANGE KIOSK EVENT CALENDAR
• GLOBAL CLIMATE SCIENCE

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Uncertainty in climate change
Source Carter, 2000
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Why might we need probabilities of climate
change?

• To assess the seriousness of impacts we need to
  know how likely they are to occur (Schneider,
  2001, 2002).
• Probabilities represent uncertainty explicitly
  and thus better fit a risk assessment framework
  the reason for quantifying risk it to make
  coherent risk management decisions under
  uncertainties and within resource constrains
  (Pate-Cornell 1996) this allows decision-makers
  to hedge the risk of climate change
• Several communities (water resource managers and
  engineers) demand it!
• The central role played by prediction in guiding
  decision-making.

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What are the problems in estimating
probabilities?

• Probabilities only one method to represent
  uncertainties
• Confusion about probabilities, risk and
  uncertainty (various definitions and typologies)

Incomplete vs unknowable knowledge Epistemic vs
stochastic uncertainty Subjective vs aleatory
uncertainty Type B vs type A uncertainty Reducible
vs irreducible uncertainty
Stirling (1998)
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Different types of uncertainty in the context of
climate change
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Sensitivity of adaptation decision-making
Adaptation decisions A Alternative supply
required B Build new storage C Operations
management changes D No changes required E
Operations management changes F Develop small
infrastructure G Develop big infrastructure
Probability
Climate variable
A B C D E F G
Decisions
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Sensitivity of adaptation decision-making
Adaptation decisions A Alternative supply
required B Build new storage C Operations
management changes D No changes required E
Operations management changes F Develop small
infrastructure G Develop big infrastructure
Probability
Climate variable
A B C D E F G
Decisions
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Further reading

• Dessai and Hulme (2003) Does climate policy need
  probabilities? Tyndall Working Paper 34
• http//www.tyndall.ac.uk/publications/working_pape
  rs/wp34.pdf