Status of research SB-20 21 June 2004

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Status of researchSB-20 21 June 2004
Xiaosu Dai, Michel den Elzen, Niklas Höhne
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Overview

1. Introduction to the MATCH processNiklas Höhne /
   Xiaosu Dai
2. Introduction of first joint paperMichel den
   Elzen / Niklas Höhne

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SBSTA 17 (Oct 2002)

• Work should be continued by the scientific
  community, in particular to improve the
  robustness of the preliminary results and to
  explore the uncertainty and sensitivity
• Be of a standard consistent with the practices of
  peer-reviewed published science.
• The process should be inclusive, open and
  transparent.
• Capacity building strongly encouraged Parties
  and institutions to facilitate capacity-building
  in developing countries, including by hosting
  scientists from developing countries
• Invited the scientific community, including IGBP,
  WCRP, IHDP and IPCC to provide information on how
  they could contribute
• Encouraged scientists to undertake further work,
  to make the results of their work publicly
  available and to report progress at SBSTA 20,
  June 2004 (side event).
• SBSTA decided to review the progress at its 23rd
  session (Nov 2005).

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MATCH process
UNFCCC process

• Two expert meetings
• Coordinated modelling exercise ACCC

• Ad-hoc group
• Initiated by Brazil and UK
• Two expert meetings so far

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MATCH process

• Objective
• Assess methods for calculating the contribution
  of different emission sources (e.g. regional,
  national or sectoral) to climate change and its
  impacts, taking into account uncertainties, and
  the sensitivity of the calculations to the use of
  different methods, models and methodological
  choices.
• Outputs
• Provide clear guidance on the implications of the
  use of the different scientific methods, models,
  and methodological choices
• Where scientific arguments allow, recommend one
  method/model/choice or several possible
  methods/models/choices for each step of the
  calculation of contributions to climate change,
  taking into account scientific robustness,
  practicality and data availability
• Organization of expert meetings, workshops and a
  coordinated modelling exercise
• Prepare papers to be published in peer reviewed
  scientific journals

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MATCH process

• Scientific Coordination Committee

Xiaosu Dai National Climate Center, China
Michel den Elzen RIVM, Netherlands
Jan Fuglestvedt CICERO, Center for International Climate and Environmental Research - Oslo, Norway
Jason Lowe Met Office, Hadley Centre for Climate Prediction and Research, UK
Joyce Penner University of Michigan, USA
Michael Prather (Chair) University of California at Irvine, USA
Cathy Trudinger CSIRO Atmospheric Research, Australia
Murari Lal IIT, India
José Domingos Gonzalez Miguez Interministerial Committee on Global Climate Change, Brazil
Niklas Höhne (Secretary) ECOFYS, Germany
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MATCH process

• Developing country participation
• Fund for travel costs of developing country
  experts sponsored by governments of Germany,
  Norway, UK (currently funds for further 15
  developing country expert trips)
• Support unit
• Ecofys under contract to UK Defra
• Information
• http//www.match-info.net

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MATCH-info.net

• Background
• Organization
• Papers
• Expert meetings
• File exchange
• Discussion forum

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Participation at last meeting
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Individual scientific papers

• Pinguelli Kahn (2001) The present, past, and
  future contributions to global warming of CO2
  emissions from fuels, Climatic Change
• den Elzen and Schaeffer (2002) Responsibility
  for past and future global warming Uncertainties
  in attributing anthropogenic climate change,
  Climatic Change
• Trudinger Enting (2004) Comparison of
  formalisms for attributing responsibility for
  climate change Non-linearities in the Brazilian
  Proposal approach, Climatic Change
• Andronova and Schlesinger (2004) Importance of
  sulfate aerosol in evaluating the relative
  contributions of regional emissions to the
  historical global temperature change attribution
  methods, Mitigation and Adaptation Strategies for
  Global Change
• den Elzen, Schaeffer and Lucas (2004)
  Differentiating future commitments on the basis
  of countries' relative historical responsibility
  for climate change uncertainties in the
  'Brazilian Proposal' in the context of a policy
  implementation, Climatic Change
• Pinguelli, Kahn, Muylaert and Pires de Campos
  (2004) Comments on the Brazilian Proposal and
  contributions to global temperature increase with
  different climate responsesCO2 emissions due to
  fossil fuels, CO2 emissions due to land use
  change, Energy Policy
• Höhne and Harnisch (2004) Calculating historical
  contributions to climate change discussing the
  Brazilian Proposal, Climatic Change

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Anticipated papers

• Paper 1
• Analysing countries contribution to climate
  change Scientific choices and methodological
  issues status of the work and first results 
• Paper 2
• Demonstration of credible alternative scientific
  choices and their effect on the emissions,
  concentration and climate change 
• Paper 3
• Formal assessment of uncertainties and clarify
  parameter space
• Paper 4
• Additional attribution calculations discussed in
  paper 1 by including the outputs from paper 2
  and paper 3
•  

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Schedule

• Meeting September 2003
• Formation of the ad-hoc group MATCH
• Agreement on terms of reference, scientific
  coordination committee, research questions

• Meeting May 2004
• Discussion of draft paper 1
• Discussion of development of further papers

June 2004 SB 20 side event

• Meeting December 2004 (tentatively 2/3 December
  in Brazil)
• Discussion of draft paper 2
• Discussion of development of further papers

Meeting May 2005 Discussion of draft paper 3
Meeting September 2005 Discussion of draft paper
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SB 23 November 2005 Presentation of results
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Remarks

• Challenges
• New research
• Resource requirements for contributing experts
• Links to other organizations and programmes
• Ambitious schedule
• Strong points of MATCH
• Participation of leading experts on the topic
• Joint research effort
• Results are peer-reviewed publications

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2. First joint paper

• Analysing countries contribution to climate
  change Scientific choices and methodological
  issues

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Main objective of paper 1

• to summarise the studies and results so far (i.e.
  the contributions to the UNFCCC initiated
  process)
• to present new attribution calculations with
  non-linear carbon cycle and climate models using
  non-linear attribution methodologies and updated
  historical emissions datasets
• to investigate the effect of a range of
  scientific, methodological and policy-related
  choices on the attribution, but not the full
  range by all uncertainties.

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Policy choices

• Policy choices refer to parameters of which the
  values can not be based on objective scientific
  arguments alone. For example, 100 year time
  horizon of GWPs. The choices have to be made
  largely within the policy context.
• Policy choices analysed here
• Indicator
• Timeframes
• Emission scenarios
• Mixture of Greenhouse gases
• Attribution method

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Scientific uncertainties

• Choice of the dataset on historical emissions
• Choice of the representation of the climate
  system (different models)

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Models used
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Model show similar outcomes
Source UNFCCC
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Policy choices

• 1. Indicator
• 2. Timeframes
• 3. Attribution method
• 4. Mixture of greenhouse gases

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1. Indicators
Source Ecofys-ACCC
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1. Indicators
Also discounting most recent emissions Can
be made forward looking, when evaluating at a
date after attributed emissions end. In such case
also a time horizon is required
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1. Indicators
Preliminary
Relative contributions using different indicators
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1. Indicators

• Conclusions
• Two main factors influence results
• Whether a source emitted early versus late
• The share of emissions of short-lived /
  long-lived gases.
• Choosing the right indicator is ultimately a
  policy choice that also depends on the purpose of
  use of the results.
• Temperate increase use evaluation date after the
  attribution end date
• Backward discounting and forward looking
  weighted concentrations or integrated
  temperature
• Not backward discounting GWP-weighted
  cumulative emissions could be an option, which is
  simple and approximately represents the
  integrated impact on temperature.

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2. Timeframe

• Start date emissions 1890, 1950 and 1990
• End date emissions 1990, 2000, 2050 and 2100
• Evaluation date of attribution 2000, 2050, 2100,
  2500

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Start-date
Source RIVM-ACCC

• Choosing a shorter time horizon (e.g. 1950 or
  1990 instead of 1890) reduces the contributions
  of OECD90 countries ('early emitters') to
  temperature increase.

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End-date
Source RIVM-ACCC

• A late end-date increases non-Annex-I
  contributions, because it gives more weight to
  their larger future emissions.
• Impact of emissions scenarios (error bars) can be
  large

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Evaluation-date
Source RIVM-ACCC

• A later evaluation-date raises OECD contributions
  due to (1) their large share in historical CO2
  emissions (long residence time) (2) and their
  small share of methane emissions (short residence
  time)

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3. Attribution methods

• Normalised marginal method - Attributes
  responsibility using total sensitivities
  determined "at the margin".
• Residual (all-but-one) method - Attributes
  responsibility by leaving out the emissions of
  each region in turn.
• Time-sliced - determines the effect of emissions
  from each time as if there were no subsequent
  emissions.

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3. Attribution methods

• The Residual method, although simple to implement
  and explain, can be rejected on scientific
  grounds (not additive).
• The Normalised marginal and Time-sliced methods
  are harder to implement and explain. These
  methods differ in how they treat early vs. late
  emissions.

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3. Attribution methods
Source CSIRO-SCM

• The differences between methods are fairly small
  compared to the effects of many of the other
  choices already considered.

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3. Attribution methods

• Differences between methods are greater
  for later evaluation date (2100)
• In general, the results of the different methods
  vary most for regions with emissions that differ
  most from the average in terms of early versus
  late emissions, i.e. India and EU.

Source CSIRO-SCM
Source CSIRO-SCM
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4. Greenhouse gas mixture

• Which gases are attributed to the regions?
• Fossil CO2
• All anthropogenic CO2
• CO2, CH4, N2O
• Kyoto basket (CO2, CH4, N2O, HFCs, PFCs, SF6)
• Kyoto basket more O3 precursors (NOx, CO and
  VOC)

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4. Greenhouse gas mixture
Source CICERO-SCM

• Two main effects i) Going from fossil fuel CO2
  emissions only to total anthropogenic CO2
  emissions, ii) Inclusion of CH4 and N2O.
• The effect is less pronounced on longer time
  scales (except for the shift from fossil CO2 to
  total CO2).

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Scientific uncertainties

1. Choice of the dataset on historical emissions
2. Choice of the representation of the climate
   system carbon cycle and climate model and
   feedbacks

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1. Historical datasets
Source RIVM-ACCC

• Fossil CO2 emissions small differences in
  relative attribution
• CO2 emissions from land-use changes differences
  in estimates leading to large differences. Data
  sets need to be compared and improved.
• CH4 and N2O Only one dataset is available (EDGAR)

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2. Other scientific uncertainties

• The influence of other climate model parameters
  (e.g. IRFs), based on simulation experiments with
  nine GCMs and climate models is limited
• Including additional non-linearities in
  calculations of methane-concentrations (IPCC-TAR
  atmospheric chemistry model ) has a negligible
  effect on the relative contributions
• ...

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Overall conclusions

• First summary of the work undertaken to date.
• Not a full assessment of the uncertainty range,
  but an evaluation of the influence of different
  policy-related and scientific choices.
• The influence of scientific choices is notable.
  Therefore research is ongoing (see papers 2 and
  3)
• However, the current work suggests, that the
  impact of policy choices, such as time horizon of
  emissions, climate change indicator and
  greenhouse-gas mix is larger than the impact of
  scientific uncertainties
• Impact of uncertainties on the relative
  contributions is smaller than impact of
  uncertainties on the absolute changes in
  temperature.
• Research needs Historical emission datasets

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Backup slides
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Policy choices
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Models are calibrated
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(No Transcript)
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Table 3
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Contribution to radiative forcing
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Aerosol forcing
Source CICERO-SCM

• Inclusion of SO2 emissions reduces the
  contributions from ASIA and REF, but the effect
  disappear when there is a gap between attribution
  end date and evaluation date.
• Again effect is less less pronounced on longer
  time scales

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Policy choices vs. scientific choices
Source RIVM-ACCC

• Policy choices (start-date, indicators) are more
  important than scientific uncertainties
  (attribution method, climate model)

Modelling and assessment of contributions to
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