Transcript Metrics and a stabilization of the global average surface

Chalmers University of Technology
Metrics and stabilization of the global
average surface temperature
UNFCCC workshop on common metrics
Bonn, Germany, 2012-04-03
Daniel J.A. Johansson
Division of Physical Resource Theory, Department of Energy and Environment
Chalmers University of Technology
Gothenburg, Sweden.
Chalmers University of Technology
Outline
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Emissions profiles
Global Cost Potential (GCP)
Global Temperature change Potential (GTP)
Cost-Effective Temperature Potential (CETP)
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Stabilizing below 2ºC cost-effectively
CO2 equivalent emissions
using GWP-100
GWP was not designed
to facilitate the basket
approach in a cost
effective stabilization
regime.
UNEP, 2010, The Emissions Gap Report
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Global Cost Potential (GCP).
• Based on that a climate target should be met at lowest
possible abatement cost.
• Based on optimizing Integrated Assessment Models
(IAMs).
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Optimizing Integrated Assessment
Model
Economy & Energy module
Emissions
Climate module:
Calculates concentrations, radiative forcing
and subsequent temperature response
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Optimizing Integrated Assessment
Model
Objective:
Economy & Energy module
Minimize total NPV abatement costs to stabilize the temperature at 2°C
above the pre-industrial level
Emissions
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•
Cost optimal emissions
profiles
compatible with this target
Climate
module:
Cost Calculates
optimal emissions
prices (taxes) needed
to induce
abatement
concentrations,
radiative
forcing
and subsequent temperature response
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Global Cost Potential (GCP)
• Based on that a climate target should be met at lowest
possible abatement cost.
• Based on optimizing Integrated Assessment Models
(IAMs).
• The metric is the ratio of the cost-optimal price (tax) on
emissions of a gas X to the cost-optimal tax on emissions
of CO2.
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Global Cost Potential (GCP)
2000
2200
2000
Manne & Richels, 2001, An alternative approach to establishing trade-offs among
greenhouse gases, Nature
2100
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GCP - Transparency and numerical models
• Optimizing IAMs are complex and far from
transparent for most climate scientist, policy
advisors and policy makers.
• Include a range of very uncertain parameters and
uncertain structural relationships.
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Global Temperature change Potential (GTP)
GTP for year t
0,06
0,05
Temperature (mK)
100 M ton CO2
0,04
GTP t  
0,03
 T X (t )
 T CO 2 ( t )
0,02
1 M ton CH4
0,01
0
0
50
100
150
200
250
300
350
400
450
500
Time (Year)
GTP initially developed in: Shine K.P., Fuglestvedt J.S., Hailemariam K., Stuber N. , 2005, Alternatives to the Global
Warming Potential for Comparing Climate Impacts of Emissions of Greenhouse Gases, Climatic Change
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Comparison GCP and GTP for CH4
120
Relative valuation of CH4 to CO2
100
80
GCP
GTP
60
40
20
0
2000
2010
2020
2030
2040
2050
2060
2070
2080
2090
2100
Time (year)
Results from runs with the MiMiC model (Azar, Johansson & Persson)
Relationship between GTP and GCP originally formulated in : Shine K.P., Berntsen T.K., Fuglestvedt J.S., Bieltvedt
Skeie R., Stuber N., 2007, Comparing the climate effect of emissions of short- and long-lived climate agents,
Philosophical Transactions of The Royal Society A
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Cost-Effective Temperature Potential
(CETP)
An approximation of GCP.
Includes:
-physical information,
-an estimate of stabilisation year,
-discount rate.
Johansson, 2011, Johansson, 2011, Economics- and physical-based metrics for comparing greenhouse gases, Climatic
Change.
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CETP
The time integrated
discounted temperature
pulse beyond the target
time year.
CETP for year t
0,06
0,05

Temperature (mK)
100 M ton CO2
0,04
0,03
CETP t  
Integrate and discount
0,02
1 M ton CH4
0
50
100
 r 
150
200
250
300
350
400
450
500

d
t

  TCO 2 ( )·e
0,01
0
  T X ( )·e
 r 
t
Time (Year)
e-rτ=Discount factor
r-discount rate
τ -time

d
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Simple Carbon Cycle and Climate model ACC2
Climate
Carbon Cycle
Temperature feedback
Atmosphere
Ocean
Uptake
Uptake
CH4 & N2O
SF6 & 29 Halocarbons
Tropos-/Stratospheric O3
Sulfate/Carbonaceous
Aerosols (direct/indirect)
Stratospheric H2O
OH, NOx, CO, VOC
Parameterization (Joos et al., 2001)
Atmospheric Chemistry
Surface Air Temperature Change
Minimizing NPV Land
abatement cost
DOECLIM (Kriegler, 2005)
Total Radiative Forcing
Parameterization
Joos et al. (1996)
IRF 4-Box Model
Emissions of greenhouse gases & related agents
Hooss et al. (2001)
IRF 4-Box Model
Max 2ºC above pre-industrial level
Tanaka et al., 2007, MPI Report;
Tanaka et al., 2009, GRL
Tanaka et al., 2009, Climatic Change
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CH4 metric value in 2°C stabilization scenario
140
GWP5
120
GWP20
CH4 metrics
100
80
GWP100
60
GTP5
40
GTP20
20
GTP100
0
2000
2020
2040
2060
2080
2100
Year
Tanaka K., Berntsen T.K., Fuglestvedt J.S., Johansson D.J.A., O’Neill B., 2012, [working title:]
Evaluation of emission metrics under climate stabilization targets, Ongoing work.
Chalmers University of Technology
CH4 metric value in 2°C stabilization scenario
140
GWP5
120
GWP20
CH4 metrics
100
GWP100
80
GTP5
60
GTP20
40
GTP100
CETP
20
GCP
0
2000
2020
2040
2060
2080
2100
Year D.J.A., O’Neill B., 2012, [working title:]
Tanaka K., Berntsen T.K., Fuglestvedt J.S., Johansson
Evaluation of emission metrics under climate stabilization targets, Ongoing work.
Chalmers University of Technology
CH4 metric value in 2°C stabilization scenario
140
CH4 metrics
GWP5
120
GWP20
100
GWP100
GTP5
80
GTP20
60
GTP100
40
GTPSTB
20
CETP
0
2000
GCP
2020
2040
2060
2080
2100
Year
Tanaka K., Berntsen T.K., Fuglestvedt J.S., Johansson D.J.A., O’Neill B., 2012, [working title:]
Evaluation of emission metrics under climate stabilization targets, Ongoing work.
Chalmers University of Technology
N2O metric value in 2°C stabilization scenario
400
GWP5
GWP20
350
N2O metrics
GWP100
GTP5
300
GTP20
250
GTP100
GTPSTB
200
CETP
GCP
150
2000
2020
2040
2060
2080
2100
Year
Tanaka K., Berntsen T.K., Fuglestvedt J.S., Johansson D.J.A., O’Neill B., 2012, [working title:]
Evaluation of emission metrics under climate stabilization targets, Ongoing work.
Chalmers University of Technology
Importance of discount rate
CH4
Johansson, 2011, Economics- and physical-based metrics for comparing greenhouse gases, Climatic
Change.
Chalmers University of Technology
Importance of discount rate
N2O
Chalmers University of Technology
Conclusion
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GWP was not constructed to facilitate the implementation of cost-effective
climate stabilization regime…
… although it has enabled the implementation of the basket approach.
Using cost effective trade-off ratios (Global Cost Potential - GCP) instead
of GWP could enhance the cost-effectiveness of a stabilization regime…
… but one would then depend on complex and uncertain optimizing
IAMs.
CETP approximate GCP well under a range of assumptions.
Neither GTP, CETP and GCP take into account climate effects in the
short term.
CETP and GCP do to take into account climate effects in the long-term,
beyond stabilization, while GTP does not.
Chalmers University of Technology
THANK YOU!
Questions, comments?
Chalmers University of Technology
Additional cost of meeting the 2°C limit when using
GWP-100 as compared to GCP
• The use of GWP-100 would set a too high price on CH4
(short lived gases) years far from when stabilization occur,
while the opposite hold for years close to when
stabilization occur.
• The cost of of using GWP-100 is very approximately about
5% of Net Present Value (NPV) abatement cost.
Based on: Johansson, Persson & Azar, 2006, The cost using Global Warming Potentials, Climatic Change