1. Climate projections in the CSIS/CST: CMIP and CORDEX (Coupled Model Intercomparison Project) (Coordinated Regional downscaling Experiment) Clare Goodess with thanks to Bill Gutowski (CORDEX co-chair) Bruce Hewitson (my WCRP Working Group on Regional Climate co-chair) Fred Tangang (CORDEX Scientific Advisory Team) 1

2. Country requirements
Peru – want access to more CORDEX data to update national scenarios
Moldova – want access to CORDEX nodes & training – need to provide data for development of scenarios to national climate change office
Burkino Faso – want CMIP5/CMIP6 and CORDEX data – currently working with one GCM/RCM model
Bhutan – want to start working with CORDEX data
Tanzania – requests via modelling department – ‘statistical adaptations’, develop projections and research capacity
Papua New Guinea – university/others doing some work for Office of Climate Change – some involvement in the process
Dominica – no requirement currently
Decision-making context includes National Communications & National Adaptation Plans – so mitigation and adaptation

3. CMIP5 NetCDF standards Distribution via ESGF Most widely used:
GCM/ESM runs for
RCPs 2.6, 4.5, 6, 8.5
Some outputs also available from IPCC DDC – see TGICA CMIP5 fact sheet 3

4. VIACS (Vulnerability, Impacts, Adaptation and Climate Services) Advisory Board for CMIP6 (chaired by Alex Ruane and Claas Teichman) – CSIS representation?

5. The CORDEX vision is to advance and coordinate the science and application of regional climate downscaling through global partnerships.
Original experimental protocol (modified from Giorgi et al., 2009):
14 standard domains (each with contact points)
0.44 degrees (EUR also 0.11 degrees, i.e. ~12 km)
ERA and CMIP5-forced simulations
Historic
RCP4.5 and RCP
Core set of variables has to be archived – NetCDF
CORDEX is largely an unfunded activity –
of which expectations are very (too?) high – where are the boundaries?
IPOC hosted at SMHI – Director – Iréne Lake

6. Construction of climate projections from the CMIP/CORDEX building blocks & observations
Climate projections have been developed in a somewhat ad hoc fashion for different countries/regions, largely outside the oversight of the WMO
Some accepted good practices (e.g. use of multi-model ensembles) but no standard methods or guidelines for constructing projections (e.g. how to select and combine models)
A number of different institutions/bodies are involved in work on construction of climate projections: universities, research organisations and consultancies, as well as NMHSs and RCCs
Projections are fundamentally different to forecasts/predictions due to the unverifiable timescales (and their basis on emissions/land use scenarios etc) – this has implications for handling and communication of uncertainties across timescales 6

7. Utility and ‘usability’ - From data to information
NetCDF files and large multi-model ensembles
Model/experiment/run selection (from ensembles of opportunity)
Model evaluation
Validation vs obs is ‘necessary but not sufficient’
Added value of downscaling
Further downscaling and/or bias adjustment (not correction!)?
Consistency/links RCPs and SSPs (Shared Socioeconomic Pathways) etc
Representation of uncertainty/robustness of climate change signal
Projections not forecasts/predictions (so ‘different’ but need a consistent story for users and can learn by considering underlying physical processes and model performance on different timeframes)
Data distillation! 7

8. Physics / dynamics / processes Future
Past
Observations (probable)
GCM 1 data
GCM 2 data
GCM 3 data
GCM 4 data
GCM 5 data
GCM-n data
data
RCM 1
RCM 2
RCM 3
RCM 4
RCM 5
SD 1
data
SD 2
SD 3
SD 4
Contradictions and CHOICE: system uncertainty, structural differences, scientific error, limits of understanding
Bruce Hewitson, University of Cape Town

9. A real example
Projected changes from , for the ‘2030s’ ( ), the ‘2050s’ ( ) and the ‘2080s’ ( ). The average change is shown first with the uncertainty range across the models (in brackets – the 90% range).
How to communicate the information to a user? Is there “usable” information?
How to “improve” the information?

10. Climate information for regions
Climate information for regions is the primary issue and need for climate services. In this context, it is important to note the difference between 'data' and 'information' in terms of climate information for regions; information is not data, but is an understanding that builds messages of relevance to the concerned users that are backed by clear and robust physical scientific analyses. There are substantial gaps in climate data that constrains the ability to produce the climate information needed, particularly in some regions.

11. Application-inspired
Climate Information for Regions
“Leg 1”
Foundational Climate Science
(Curiosity-driven research/
Fundamental knowledge)
“Leg 3”
Trans-disciplinary
Engagement
“Leg 2”
Application-inspired
Climate Science
CORDEX
(Flagship Pilot Studies)
Working Group on Regional Climate (likely to transform into the Working Group on Information for Regions in April)
Climate
Services

12. “Leg 2” Application-inspired Climate Science
Climate Information for Regions
“Leg 2” Application-inspired Climate Science
 - Research to understand critical phenomena
- Use-inspired fundamental research
- Goal: Understanding of processes governing climate
Concept of Frontiers of Climate Information (FOCI) projects – to be approved in April….
A multi-scale process-based approach to ‘distillation’ – local to global: regional dynamics and local response to climate forcings
“Leg 3” Trans-disciplinary Engagement
 - Requires dialogue with “boundary” organizations
- Can view as translational science
- Goal: Provide climate information, not numbers, as an outcome of the engagement

13. Some proposed actions
If JSC approves the concept of FOCI projects, ‘we’ could propose that one should be based on one of the 8 countries (and involve NMHS, RCC) – should certainly be an eventual source of guidance for CSIS/CST
Explore extending the RCOF process to encompass climate projections
Fred/Clare to report back to CORDEX Science Advisory Team (SAT)
Raise awareness of the country needs expressed in Nanjing
Establish links between the countries & CORDEX domain POCs
Resolve access for countries with immediate needs – e.g., Moldova, Peru
Can the evident interest in CORDEX outputs be used to seek additional support/funding for CORDEX (e.g. getting more data into ESGF, Climate Explorer, other more user-friendly portals)?
Would it be helpful to have a CSIS representative on CORDEX SAT?
Linkages with Copernicus global/regional projection services?
Involvement in new tenders????; Provision of guidance/examples