1. The Shared Socioeconomic Pathways (SSPs) - a new scenario framework to provide key narratives for different climate futures
Alexander Nauels, Zebedee Nicholls
Australian-German Climate & Energy College
University of Melbourne
Seminar, 4 April 2018

2. Australian-German Climate & Energy College
Pathway Pasta
IPCC FAR 1990
IPCC AR4 2007
IPCC SAR 1995
IPCC AR5 2013
IPCC SRES 2000
IPCC AR6 2021
???
IPCC TAR 2001
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Australian-German Climate & Energy College

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Content
Climate scenario history
SSP overview
SSP baseline scenarios
SSP-RCP matrix
SSP mitigation pathways
SSP pathways limiting warming to less than 1.5 °C
SSP extensions
2/12/2018
Australian-German Climate & Energy College

4. Scenario History – SA90 & IS92
A wide range of scenario families have informed the IPCC assessment reports over last decades:
IPCC First Assessment Report (FAR): four SA90 scenarios (Business-As-Usual, B, C, D) until 2100, same assumptions for economy and population, only varying future energy mix, one non-intervention scenario.
IPCC Second Assessment Report (SAR): six IS92 scenarios (IS92a to f) until 2100, varying population, income growth and fossil fuel resource assumptions, five non-intervention scenarios.
2/12/2018
Australian-German Climate & Energy College

5. Scenario History - SRES
IPCC TAR (2001) and AR4 (2007): In 2000, the Special Report on Emission Scenarios (SRES) provided 40 new pathways and six illustrative scenarios (all non-intervention) until 2100, covering four main narratives.
IPCC SRES 2000
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Australian-German Climate & Energy College

6. Scenario History - SRES
A1: rapid economic growth, global population peaking mid-century, rapid introduction of efficient technology (fossil intensive A1FI, non-fossil A1T, balanced A1B)
A2: heterogeneous world, self-reliance, increasing population, fragmented economic growth and technological change
B1: convergent world, A1 population, more rapid changes towards information and service based economy, clean technologies
B2: local solutions to economic, social, and environmental sustainability, lower continuous population growth than A2, less rapid, more diverse technological change than A1/B1
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Scenario History
From a Sequential Approach to a Parallel Process
Sequential Approach (SA90, IS92, SRES):
Socioeconomic
Storylines
Emission
Scenarios
Radiative
Forcing
Climate
Scenarios
Impact Assessments
Parallel Process (RCPs, SSPs):
Socioeconomic
Storylines
Emission
Scenarios
SSP
framework
Impact Assessments
RCPs
Climate
Scenarios
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Australian-German Climate & Energy College

8. Scenario History - RCPs
IPCC Fifth Assessment Report (AR5): Four Representative Concentration Pathways (RCPs) developed based on published emission trajectory assumptions (non-intervention):
2100 radiative forcing levels of 8.5, 6.0, 4.5 and 2.6 Wm-2 identified to cover broad range of climate outcomes.
RCP2.6 is consistent with keeping warming below 2°C relative to pre-industrial with a likely chance.
RCP extensions (ECPs) have been introduced until 2300 to allow for analysis of longer term climate responses.
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Australian-German Climate & Energy College

9. Scenario History - RCPs
IPCC WGI AR5 2013
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Australian-German Climate & Energy College

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SSP overview
The Shared Socioeconomic Pathways (SSPs) complement the RCPs by introducing five new socioeconomic storylines as part of the parallel scenario development process.
Integrated Assessment Models (IAMs) quantify the five narratives with consistent population, urbanisation, education, and GDP assumptions resulting in energy system, land use and GHG emission pathways.
The SSP framework separates non-mitigation baseline scenarios from pathways assuming different levels of climate mitigation.
Climate mitigation efforts are realised within each SSP narrative with a set of Shared Policy Assumptions (SPAs).
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SSP overview
SSP1: sustainable development
marker IAM: IMAGE
SSP2: 'middle of the road‘
marker IAM: MESSAGE-GLOBIOM
SSP3: regional rivalry
marker IAM: AIM/CGE
SSP4: inequality
marker IAM: GCAM
SSP5: high energy demand, fossil-fuel development marker IAM: REMIND-MAGPIE
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Australian-German Climate & Energy College

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SSP overview
O’Neill 2017
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SSP baselines - GDP pc
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14. SSP baselines - Inequality
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15. SSP baselines - Total Energy
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16. SSP baselines - Renewables
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17. SSP baselines - Fossil CO2
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18. SSP matrix illustrative CMIP6 ScenarioMIP pathways
Adapted from O’Neill 2016
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19. SSP Mitigation pathways
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SSP CMIP6 pathways
Rogelj et al. 2018
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Australian-German Climate & Energy College

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SSP pathways 1.5 °C
Primary Energy
Coal w/o CCS
CO2 Sequestration
Rogelj et al. 2018
Rogelj et al. 2018
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Australian-German Climate & Energy College

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SSP pathways 1.5 °C
Afforestation and
reforestation
Change in cropland
for agriculture
Rogelj et al. 2018
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Australian-German Climate & Energy College

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SSPs – data needed post 2100
Key climate variables like sea-level rise (SLR) respond slowly to changes in atmospheric GHG concentrations and call for a projection horizon well beyond 2100.
Nauels et al. 2017
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Australian-German Climate & Energy College

24. SSP extensions - Fossil CO2
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25. SSP extensions - Land use CO2
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Australian-German Climate & Energy College

26. SSP extensions - Fossil CH4
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27. SSP extensions - Land use CH4
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SSP 2300 GMT responses
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SSP 2300 SLR responses
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Australian-German Climate & Energy College

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Thank you!
The new SSP framework merges ten years of socioeconomic and climate scenario research to more comprehensively inform the upcoming assessment report of the IPCC due in 2021…
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Australian-German Climate & Energy College

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Upcoming Events
Monday 9 April 6:30pm - Discussion with Simon Corbell (Victorian Renewable Energy Advocate) co-hosted with Beyond Zero Emissions - Prest Theatre, Faculty of Business and Economics, 111 Barry Street
Wednesday 11 April 11:00am - Towards an improved methodology for Energy Return on Investment (EROI) for electricity supply - PhD Completion seminar - Graham Palmer - Climate College, Level 1, 187 Grattan Street
2/12/2018
Australian-German Climate & Energy College