World Climate Research Programme Climate Information for Decision Making

Ghassem R. Asrar Director, WCRP

Outline

• – – –

Science Based Decision Making

World Climate Conference-3: Climate info. for better future OceanObs09: Ocean observations for society ICSU visioning: Environment & sustainable development • – – – –

WCRP Contribution

Seasonal Predictions Decadal Predictions Regional climate predictions Sea Level variability and change

Seasonal Climate Prediction

• WCRP, through its

Working Group on Seasonal to Interannual Prediction (WGSIP),

– Launched the Climate-system Historical Forecast Project (CHFP) a multi-model and multi-institutional experimental framework for sub-seasonal to decadal complete physical climate system prediction

http://www.clivar.org/organization/wgsip/chfp/chfp.php

• CHFP will provide: - A baseline assessment of seasonal prediction capabilities using the best available models of the climate system and data for initialization

Seasonal Climate Prediction Challenges

• • • • •

Quantifying Forecast Uncertainty Due to Uncertainty in Model Formulation

– Multi-Model Helps, but Ad-Hoc

Quantifying Forecast Uncertainty Due to Uncertainty in Observational Estimates

– Initial Condition Problem

Model Error

– Need for International Coordinated Effort at Improving Models

(Multi-Model is Not an Excuse for Neglecting Model Improvement)

Climate System Component Interactions

– Coupled Ocean-Land-Ice-Atmosphere – External Forcing vs. Natural Variability

Quantifying the Limit of Predictability

Seasonal Prediction-South Africa Rainfall forecast issued in Dec. 2008 by a multi-model operational Seasonal Forecast by the South African Weather Service.

10%

Decadal Climate Experiments

WCRP, through its

Working Group on Coupled Modelling (WGCM)

additional predictions Initialized in ‘01, ’02, ’03 … ‘09

has developed the

coupled model intercomparison project

(CMIP5) that coordinates the decadal predictability/prediction experiments

prediction with 2010 Pinatubo like eruption 10-year hindcast & prediction ensembles: initialized 1960, 1965, …, 2005 30-year hindcast and prediction ensembles: initialized 1960, 1980 & 2005

- will provide the foundation for the simulations to be assessed as part of the IPCC AR5

prescribed SST time slices alternative initialization strategies

Decadal Climate Predictability

Observed decadal climate variability in Pacific and Atlantic sectors (left) and first attempts to make decadal predictions (right)

Regional Climate

The need for climate information at the regional-to-local scale is one of the central issues within the global change debate.

In 2008 WCRP established a Task Force on Regional Climate Downscaling (TF-RCD) , whose mandate is: – to summarize the shortcomings, difficulties and

scientific basis of existing downscaling methods

to serve as guidance to the climate change assessment community; – to develop a

framework for evaluation and intercomparison

of regional downscaling techniques .

Regional Climate

Schematic depiction of the primary uncertainties in regional climate change projections.

RCD Configuration (Multiple models) AOGCM Configuration (Multiple AOGCMs) Systematic Errors (Model eval./impr.) Uncertainty in regional climate projection Regional cover (Multiple regions) Internal variability (Multiple realizations) Emis./Conc.

(Multiple Scenarios) RCD approach (Multiple RCD methods)

Regional Climate:

Africa - Example January-February March mean precipitation for 1998-2008 period.

Regional Climate:

Africa - Example July-August-Septmeber mean precipitation for 1998-2008 period.

Sea-Level Variability and Change

The main challenge is to address the uncertainties in the projection of future sea-level changes due to recently discovered processes in the Greenland and Antarctic regions.

The joint WCRP/IOC Task Group on Sea-Level Variability and Change (TF-RCD) was established with the mandate to: – Improve further our ability to monitor, explain and predict changes in global and regional sea level and associated environmental factors.

– Make available this information for stakeholders and policy makers

Climate variability affects the regional distribution of sea-level rise.

Sea-Level Variability and Change:

Regional Impacts CSIRO - Australia

Sea-Level Variability and Change:

Regional Impacts

•

20 th Century sea level rise has already caused a significant increase in extreme events three-fold increase post-1950.

•

By 2100, 1 in 100 year events are projected to happen several times a year!

2.35

2.30

2.25

2.20

2.15

2.10

2.05

2.00

0.1

20

th

Century – Fort Denison

Post-1950 Pre-1950 +0.08m

x3.1

1 10 Return Period (Years) 100

Conclusions

WCRP will continue to:

– Provide

Scientific Knowledge

on climate variability and change.

– Facilitate research on

predictions climate projections and

on centuries, decades and seasons.

– Place a major emphasis on

regional climate variability and change

with special attention to

extreme events.

– Support development and delivery of

climate information for decision makers.

– Sponsor

training and development

of next generation of

regional and global

climate experts.