StandbildBremerhaven
Overview
• Coupled model intercomparison project
• Coupled model intercomparison project
Definition: Scenario
• Image of future • Neither forecast nor prediction • Each scenario is one possible future
– Set of scenarios possible future developments of complex systems
• Useful tool for not fully understood complex systems, whose prediction is impossible e.g. population growth, use of fossil fuels and GHG
emissions
1970s Scenarios used to explore natural resource sustainability
1988 GCM simulations using time-dependent scenarios
1990 IPCC AR1 uses equilibrium climate scenarios
1990 IPCC SA90 emission scenarios
1992 IPCC IS92 emission scenarios
1995 IPCC AR2 uses equilibrium climate scenarios
1999 IPCC Special Report on Emission Scenarios (SRES)
2001 IPCC AR3 uses IS92 scenarios
2007 IPCC AR4 uses SRES and IS92 scenarios
2009 Representative Concentration Pathways (RCPs)
2014 IPCC AR5 will use RCPs
GCM = General Circulation Model
• Used in IPCC AR4
• Main driving forces of future emissions: 1. Population prospects 2. Economic development 3. Energy intensities and demand, structure of its use
4. Resource availability 5. Technological change 6. Prospects for future energy systems 7. Land-use changes
different future developments
GHG total emissions
40 different scenarios
Future: 100 years
Storylines of scenarios
– rapid economic growth – low population growth – rapid introduction of new and more
efficient technologies
– regional economic development – high population growth – slow technological change
– rapid changes in economic structures – low population growth – introduction of clean and resource-
efficient technologies
– intermediate economic development – moderate population growth – less rapid and more diverse
technological change than in the B1 and A1 storylines
A1
A2
B1
B2
A1B Balanced emphasis on all energy sources
A1T Emphasis on non-fossil energy sources
A1FI A1B
Emissions
A1 A2 B1 B2
• socio-economic conditions
• ‘rare’ events
Climate model
Climate model
Climate model
CMIP: Coupled Model Intercomparison Project
• Program for Climate Model Diagnosis and Intercomparison (PCMDI)
• standard experimental protocol for coupled atmosphere- ocean general circulation models (AOGCMs)
• Since 1995
• Phase 3: ‘realistic’ climate scenarios
– CMIP3 models used for IPCC AR4
• Phase 4: testing climate models for forecasting abilities
• Phase 5: improved Phase 3
– CMIP5 used for IPCC AR5
Range of global surface warming
warming (°C) in 2100
Multi model average of global surface warming relative to 1990
Range of regional surface warming
Aerosols
to concentrations • Uncertainties caused by models
– Parameterizations (e.g. clouds, snow processes)
– Constant land ice
RCP: representative concentration pathways
• New scenarios – updated data – different needs – mitigation included – max. 2°C global mean surface temperature
• Representative: 4 scenarios • Pathway
– long-term until 2300 – short-term focus until 2035 – resolution – extreme events
Range of global surface warming
warming (°C) in 2100
Multi model average of global surface warming relative to 1990
RCP: representative concentration pathways
• New scenarios – updated data – different needs – mitigation included – max. 2°C global mean surface temperature
• Representative: 4 scenarios • Pathway
– long-term until 2300 – short-term focus until 2035 – resolution – extreme events
RCPs
Pathway
RCP6.0 ~ 850 at stabilization after 2100 stabilization without overshoot
RCP4.5 ~ 650 at stabilization after 2100 stabilization without overshoot
RCP2.6 peak at ~ 490 before 2100 and then declines
peak and decline
• standard experimental protocol for coupled atmosphere- ocean general circulation models (AOGCMs)
• Since 1995
• Phase 3: “realistic” climate scenarios
– CMIP3 models used for AR4
• Phase 4: testing climate models for forecasting abilities
• Phase 5: improved Phase 3
– CMIP5 used for AR5
• Idealized experiments – E.g. aquaplanet robust climate responses
• Usage of RCPs
– Emission scenarios – Emissions to concentrations – Models – Unknown or not fully understood mechanisms and
feedbacks
• Robust findings – Anthropogenic source of warming – Geographic pattern of warming – Slow down of MOC by 2100
• Continuous improvement
– Emission scenarios – Emissions to concentrations – Models – Unknown or not fully understood mechanisms and
feedbacks
• Robust findings – Anthropogenic source of warming – Geographic pattern of warming – Slow down of MOC by 2100
• Continuous improvement
Thank you!
Folie 1
Storylines of scenarios
Uncertainties in emission scenarios
Aerosols