Download Rate of change, how can it be included in emission metrics?

Rate of change, how can it be
included in emission metrics?
Terje Berntsen
CICERO/University of Oslo, Norway
Workshop on common metrics, Bonn, April 2012
Rate of Change and the UNFCCC
ARTICLE 2:
OBJECTIVE
The ultimate objective of this Convention and any related
legal instruments that the Conference of the Parties may
adopt is to achieve, in accordance with the relevant
provisions of the Convention, stabilization of greenhouse
gas concentrations in the atmosphere at a level that would
prevent dangerous anthropogenic interference with the
climate system. Such a level should be achieved within a
time-frame sufficient to allow ecosystems to adapt
naturally to climate change, to ensure that food production
is not threatened and to enable economic development to
proceed in a sustainable manner.
Rate of Change and the UNFCCC
ARTICLE 2:
OBJECTIVE
The ultimate objective of this Convention and any related
legal instruments that the Conference of the Parties may
adopt is to achieve, in accordance with the relevant
provisions of the Convention, stabilization of greenhouse
gas concentrations in the atmosphere at a level that would
prevent dangerous anthropogenic interference with the
climate system. Such a level should be achieved within a
time-frame sufficient to allow ecosystems to adapt
naturally to climate change, to ensure that food production
is not threatened and to enable economic development to
proceed in a sustainable manner.
Point of departure:
Keep to the cost-effective framework
indicated in UNFCCC article 2
• Use global mean temperature as indicator
• Keep the constraint of a long-term
stabilization target (i.e. the 2°C
target)
• Add a constraint on rate of temperature
change
Basic question (all metrics): When are the
constraint(s) binding?  Time horizon
Basic question (all metrics): When are the
constraint(s) binding?  Time horizon
tL
Basic question (all metrics): When are the
constraint(s) binding?  Time horizon
Rate limit
0.02K/yr
tR
Basic question (all metrics): When are the
constraint(s) binding?  Time horizon
Similar
approach as
Manne & Richels
(Nature, 2001)
Numerical examples based on
pulse AGTP (ΔT(t))
8.0
350.0
300.0
AGTP_CO2
AGTP_CH4
6.0
250.0
5.0
200.0
4.0
150.0
3.0
100.0
2.0
50.0
1.0
0.0
0.0
0
10
20
30
40
50
60
70
80
90
100
AGTP_CH4 (1.0E-16 K/kg)
AGTP_CO2 (1.0E-16 K/kg)
7.0
Construction of a rate and level based metric MR&L
Rate term
Level term
tR=2040
tL=2070
Construction of a rate and level
based metric MR&L
Rate term
Level term
Combined and relative to CO2
f = 0.5 for t<tR
and f=0 for t> tR
MR&L for methane
GWP100
Manne & Richels, 2001
MR&L also for BC (Direct effect)
50.0
4000.0
45.0
40.0
M_R&L CH4
3500.0
M_R&L BC
3000.0
2500.0
30.0
25.0
2000.0
20.0
1500.0
15.0
1000.0
GWP100 = 640
10.0
500.0
5.0
0.0
2010
2020
2030
2040
2050
2060
2070
0.0
2080
M_R&L BC
M_R&L CH4
35.0
Summary
• A purely physical metric including both rate
and level based constraint can be
constructed
• Requires additional value judgments
• E.g. weighting factor rate vs. Level
• Rate constraint
• MR&L ≤ GWP100 in the early phase for SLCFs
• Alternatively
• Consider rate of change as a independent
environmental issue
• Regulate SLCFs in a separate basket, could
use MR as metric for this basket