3. Climate Projections: Contribution to adaptation pathways

1. Climate Change Projections:
Contribution to adaptation pathways
Dr Bertrand Timbal
Centre for Climate Research Singapore
Meteorological Service Singapore
ASEAN Specialized Meteorological Centre

2. Physical Science
Basis
Mitigation
Impacts, Vulnerability,
Adaptation
Climate Science: The IPCC • 5th AR (2013-2014)
• 6th AR (2021-2022)
What is the IPCC?
• International body to assess the science: scientists volunteer time and expertise
• ARs provide the scientific basis for governments at all levels to develop climate
related policies  Policy Relevant not policy prescriptive

3. Climate Change information and data
• Global Climate database: Coupled Model Intercomparison Project: CMIP (currently 6)
 Understand the response of the global climate system
• Regional Climate Models: CORDEX (WMO sponsored program as part of WCRP)
 Accessing VIAs compatible regional data (high resolution: 10-40km)
• National projections: National Meteorological & Hydrological Services (NMHSs)
 Information tailored to National Adaptation Planning
International effort to coordinate and stream line delivery of climate information
 Global Framework for Climate Services (GFCS) supported by WMO

4. Full CMIP5 archive from the international
community (4 RCPs & 40+ GCMs)
“Illustrative” scenarios selected
(RCP 4.5 & 8.5)
9 GCMs selected: “suitable”
for Singapore climate
RCM Downscaling:
century-long simulations
12km resolution
Convection
Permitting RCM
10 years
“time-slices”
Bias corrected
local
projections
•Anthropogenic forcing:
Plausible future paths of
socio-economic development
•Global Climate System:
Different modelled responses
to the anthropogenic forcing
•Downscaling linkage:
Response of the regional climate
to global climate change(s)
•Convective Process resolved:
Response of localized weather
systems to regional climate change
•Local Information:
Statistical adjustments to provide
local information for quantities
of relevance to users
Numerical Modelling Tools Uncertainties Considered
The cascade of uncertainties

5. An holistic approach to adaptation
Courtesy of Singapore
Water management agency
Changes in
• Rainfall
• Sea Level
• Temperature
Changes in:
• Mean
• Variability
• Extreme frequency
• New extremes
 Science based!

6. Adapt to Climate Change or Variability?
Climate Variability:
natural variations in the
average climate on
different time scales
(some understood)
Climate Change:
more ‘persistent’
variation over a long
period of time 
indicate a change in the
climate: mean,
variability or extremes
1500
2000
2500
3000
3500
4000
1860 1880 1900 1920 1940 1960 1980 2000 2020
MacRitchie (Singapore) annual rainfall
Is this
Climate
Change ?
Or is this
Climate
Variability ?
 Climate Change vs. Climate Variability is a timescale issue
Annualrainfall(mm)

7. Adaptation: variability (now) & change (future)
Singapore’s Temperature Dashboard
Emission scenarios:
• Mid-term (2030-2050): no real impact
• Critical by end of century: decision is now!
Monitoring tool:
• Climate is changing
• Variability & change
• Envelop of risk is evolving

8. Adapting to uncertain future(s)
Differing extent of change for different climate
scenario:  Climate Change Projections
Range of results for different
climate models
• All models provide plausible climate futures
• Median model does not equate to the most likely change
• Not feasible to plan for worst case in every aspect affected by climate change
• Not advisable to treat extremes as outliers and remove them when planning for climate change
Source: 2nd National Climate Change Projections for Singapore, 2015
Stakeholder Report

9. Source: Mekong River Commission (MRC), 2017:
Technical Report of Climate change impacts on hydrology of the Lower Mekong Basin
Chiang Sean
Vientiane
Adapting to uncertain future(s)

10. Lessons learnt from ASEAN community
• Need for a centralised approach
– Coordinate studies on projections and data consolidation activities
– Provide guidance on: generation and usage of climate models
• Region-specific guidance document
– Standardisation of technique for intercomparability  synthesise different studies
– Provide regional perspective on robust scientific understanding  optimisation
• Early user engagement  communicate uncertainties & packaging of information
• Probabilistic projections still not common  translation to risk
• Not all NMHSs are tasked to generate climate projections
•Regional
workshops on:
•Best practices
•Climate extremes
Discuss
•Science: CORDEX-SEA
•Applications to
sector specific users
Design •South-East Asia
RCC-Network
•Delivery of
Climate Services
Deliver

11. • One-stop portal for accessing, analyzing and visualizing GCM outputs
CDAAS – Climate Data Access and Analysis System
Regional data portals (I)

12. Pacific Climate Change Data Portal
For the upload, analysis
and visualisation of
homogenised climate data
in the Pacific
Approx. 100 station
records for 23 countries
and territories (excluding
the Aust. and NZ mainland)
Data can be
updated/modified by
participating national
meteorological services
Regional data portals (II)