Impact of climate scenarios on vulnerability and Impact of climate scenarios on vulnerability and copingcoping

or

“How does the climate modeler fit in the picture”Bruce Hewitson

University of Cape Town, South Africahttp://www.csag.uct.ac.za

Climate change projections and seasonal forecasting

span the time scales for adaptation strategies.

Adaptation is inherently dependant in understanding

and the system, and credible projections to inform /

determine action

End of the month storage in the Western Cape System

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Start Restrictions

end Oct 2000

Impact of climate scenarios on vulnerability and Impact of climate scenarios on vulnerability and copingcoping

or

“How does the climate modeler fit in the picture”Bruce Hewitson

University of Cape Town, South Africahttp://www.csag.uct.ac.za

What future, what adaptation,What coping strategy?

??

Coping strategies and adaptation predicated

on:a) Appropriate projections / forecasts of climate impactb) Quantifiable skill / probability of the forecastc) Effective communication

No usable forecast / projection No effective adaptationNon-effective forecast projection dangerous strategies

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Consequence

Likelihood

RISK

From: ???

Coping strategies and adaptation predicated

on:

a) Appropriate projections / forecasts of climate

impact

Appropriate to impact sector

Relevant variables

Applicable spatial / temporal resolutions

b) Quantifiable skill / probability of the forecast

Error bars / statistical significance

Probability (conditional)

Hit rates / skill scores

c) Effective communication

Language / terminology barriers

Accessibility and visibility

Guidelines / caveats / limitations

A Real-time development

environment: Seasonal

forecasting

Appropriate projections?

CSIRO PPT JFM 2002

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Current projections (SARCOF)

Current projection

s (UM)

10 simulation ensemble mean from simulations at University of Cape Town. Dashed lines enclose regions where the projected

anomaly is statistically different at 90% significance

Current projections (South African Weather Service)

Adoption examples:

Commercial farmers general view “not useful”Lack of spatial detail (large area average)Inappropriate temporal resolution (3-month average)Difficult to interpret

Subsistence farmers show variable adoptionProblem of sustaining trustDifficult access / communicateDifficult to interpret

Other sectors – variable adoptioneg: Water resource managers dangerous adoption

Naïve acceptance of seasonal forecasts to deep skepticism of climate change projections

Climate change projection: Multi-model mean Δ precipitation

4 of 6 agreement on sign… but which models are correct …

Climate change: the situation worsens

Annual mean change in daily precipitation(2070-2099) – (1970-1999)

HadCM3Baseline perturbation

ECHAM4Baseline perturbation

Nonetheless:

Observed trend coarsely matches GCM projections

Usable for developing adaptation strategies?

Temporalresolution

N a tiveo r rec o rd edre so lu tion

Skill oravailableresolution

Nativeor recordedresolution

Skill or availableresolution

Achieving Spatial requirement

Achieving temporal requirements

Spatialresolu tionPoint

resolution

E nve lope ofuser needs

Downscaling and tailoring: a necessary post-processing

Key issue: delivery of and access to probabilistic products appropriate to user needs.

Appropriate coping strategies for effective adaptation

are, in part, conditional on tailored probabilistic

projections

and

Understanding by climate community of user community needs

Understanding by user community of climate projection limitations

Within-country capacity (local knowledge) to generate tailored products

Effective communication / language

Concluding statements