Transcript IPCC approach - Global Environmental Change and Food Systems

SRES Approach to Scenario Formation
Linda O. Mearns
NCAR/ICTP
GECAFS Meeting
Reading, UK
August 2003
Intergovernmental Panel on Climate Change
(IPCC)
• Established by WMO and UNEP in 1988
• Purpose: to assess the scientific and socio-economic information
regarding climate change
• The IPCC has three Working Groups:
•Working Group I: Science of the climate system
•Working Group II: Impacts, vulnerability and adaptation
•Working Group III: Options for limiting greenhouse gases
• There have been three full assessments: 1990, 1995, 2001
Purpose of Scenarios
• WGI - provide emissions scenarios for
driving Atmosphere-Ocean GCMs
• WGII – provision of climate change scenarios,
and background scenario information
(demographics, economic conditions,
technology) for determining impacts of
climate change on various resource systems.
• WGIII - need information on socio-economic
settings for determining potential mitigation
policy/strategies
Basis of Scenarios
• Extensive assessment of driving forces and
emissions in the scenario literature,
alternative modeling approaches, and an
“open process’’ that solicited wide
participation and feedback.
• Open process refers to use of multiple
models, seeking inputs from wide community,
and making results widely available for
comment and review. There was an open
SRES website.
Basis 2
• No preference provided for any one
scenario, not assigned probability of
occurrence, not to be taken as policy
recommendations
• Do not include assumption of
implementation of UNFCCC or targets
of the Kyoto Protocol
Process of Scenarios
Development
• Four qualitative story lines developed
Basic features and driving forces
• Teams modeled and quantified different
storylines
• Resulted in the 40 emissions scenarios
• Six IA type models used to generate the
scenarios:
Asian Pacific Integrated Model (AIM);
Atmospheric Stabilization Framework (ASF);
Development 2
• Models (cont’d):
Integrated Model to Assess the Greenhouse
Effect (IMAGE);
Multiregional Approach for Resource and
Industry Allocation (MARIA);
Model for Energy Supply Strategy
Alternatives and their General Environmental
Impact (MESSAGE);
Mini Climate Assessment Model (MiniCAM)
Main Scenario Driving Forces
• Population - exogenous input to models
7-15 billion by 2100
• Economic Development - US$197-550
trillion by 2100 (gross world product)
• Structural and Technological Change –
represented by energy and land use
Four Macro-regions
• OECD90 – countries belonging to
OECD (Annex I countries), developed
• REF - countries undergoing economic
reform – Eastern Europe and FSU
• ASIA – all developing countries in Asia
• ALM – all other developing countries,
Latin America, Africa, Middle East
SRES Emissions Scenarios
The Four Major Story Lines
•
•
•
•
A1 – characterized by very rapid economic growth, global population
peaking in mid-century, and then declining, and rapid introduction of
new, efficient technologies. Three different subgroups in the A1
storyline are defined that present alternative changes in technology:
fossil intensive (A1FI), non-fossil (A1T) and balanced across sources
(A1B).
A2 – characterized by heterogeneity. Self reliance and local identities
are emphasized. Population increases continuously. Economic
development is regionally oriented, and economic and technological
growth is relatively slow, compared to other storylines.
B1 – a convergent world, having the population growth of the A1 story
line. Economic structures change rapidly toward a service and
information economy, clean and resource-efficient technologies are
introduced, with emphases on social and environmental sustainability.
B2 – local solutions to economic, social and environmental
sustainability is emphasized. Global population grows continuously, but
at rate lower than that of A2.
IMAGE 2.2 - 1970 Land Cover
5 - Regrowth (tim ber)
11 - Tem perate M ixed F ores t
17 - S avan na
0 - Ocean
6 - Ice
12 - Tem perate Decid Forest
18 - Tropical W oodland
1 - Agri cult ure
7 - Tundra
13 - W arm M ixe d Forest
19 - Tropical Fores t
2 - Exte ns ive grass land
8 - Wooded Tundra
14 - G ras s/S tep pe
No D ata
3 - C plantation - NU
9 - Bo real Fo re st
15 - D esert
4 - Regrowth (aban don)
10 - C ool C o nifer
16 - S crubland
IMAGE 2.2 Land Cover Types
IMAGE 2.2 - A2: 2100 Land Cover
5 - Regrowth (tim ber)
11 - Tem perate M ixed F ores t
17 - S avan na
0 - Ocean
6 - Ice
12 - Tem perate Decid Forest
18 - Tropical W oodland
1 - Agri cult ure
7 - Tundra
13 - W arm M ixe d Forest
19 - Tropical Fores t
2 - Exte ns ive grass land
8 - Wooded Tundra
14 - G ras s/S tep pe
No D ata
3 - C plantation - NU
9 - Bo real Fo re st
15 - D esert
4 - Regrowth (aban don)
10 - C ool C o nifer
16 - S crubland
IMAGE 2.2 Land Cover Types
Total Cumulative Carbon Dioxide Emissions (GtC)
3000
2500
A1F1
2000
High > 1800 GtC
A2
Medium High 1450-1800 GtC
A1B
1500
Medium Low 1100-1450 GtC
1000
B2
A1T
Low < 1100 GtC
B1
500
0
1990
IS92
Range
2000
2010
2020
2030
2040
2050
2060
2070
Cumulative Emission 1990-2100, CtC
2080
2090
2100
AOGCM Simulations
Change in Sea Level Rise
Projections of Future Climate
Spatial Scale of
Uncertainty
T
?P
T
P
T
??P
Downscaling the SRES
Scenarios
TGCIA Activities
Moving from aggregate to
decision-maker relevant
scales
• SRES reported data on the level of the
4 macro-regions
• Many of the IA models produced results
at higher resolutions
CIESEN has collected high res. data –
and made it available
• CIESEN also formally downscaled
socio-economic data to nation level
Plans for Next IPCC Assessment
IPCC: 2002 to 2007
• 3 Working groups maintain same scope as in
last 5 years:
– WG1: Physical climate system
– WG2: Impacts and Adaptation
– WG3: Mitigation
• Fourth Assessment Report (AR4) to be
completed in 2007
• Planning and scoping: 2003, 2004
Drafting and reviewing: 2005, 2006.
IPCC AR4: Proposed Themes
• More careful approach to describing
uncertainties - consistent across WGs
• Integrating mitigation and adaptation
• Identifying key vulnerabilities in regions
and systems
• Putting climate change in the context of
sustainable development
• Adopting a consistent regional approach
across WGs.
IPCC WG1: Likely issues (1)
• Avoiding the “tyranny of the global mean” –
greater regional focus
• Updating climate change scenarios for
impact studies
(particularly for vulnerable regions: polar,
monsoon, coral reefs,… )
• New focus on Climate – Water issues
• Climate Sensitivity – how do we reduce the
1.5oC to 4.5oC range !
IPCC WG1: Likely issues (2)
• Emission scenarios
–
–
–
–
rely mainly on existing scenarios, but…
black carbon emissions
climate change feedbacks on natural emissions
harmonizing SRES scenarios with the 1990 –
2005 period
• Direct influence of aerosols on the
hydrological cycle