Slide 1

Mitigation scenarios developed to
inform DEFRA at COP13
Laila Gohar and Jason Lowe
Updated 16-10-08
© Crown copyright Met Office

Tools
• Complex models of climate and the carbon
cycle are used at the Hadley Centre.
• These models are too complex to run a very
large number of simulations, so simpler models
were used here.
• Adjustable parameters in the tried and tested
MAGICC climate model were set so that the
simple model reproduces the results of the
complex models
• In total we have looked at 729 simulations for
each emissions scenario and more than
7million simulated years in total.
© Crown copyright Met Office

The scenarios
• Scenario I: Global GHG emissions peak in 2015 and decline.
Type “a” reduce to 85% below 1990 levels by 2050 and to 90%
below 1990 levels by 2100.
Type “b” reduce to 50% below 1990 levels by 2050 and to 80%
below 1990 levels by 2100.
• Scenario II: Global GHG emissions peak in 2020 and decline.
Type “a” declines to 60% below 1990 levels by 2050 and to 85%
below 1990 levels by 2100.
Type “b” reduce to 30% below 1990 levels by 2050 and to 80%
below 1990 levels by 2100.
• Scenario III: Global GHG emissions peak in 2030 and decline.
Type “a” declines to 30% below 1990 levels by 2050 and to 80%
below 1990 levels by 2100.
Type “b” reaches 5% above 1990 levels by 2050 and to 60% below
1990 levels by 2100.
• Emissions supplied by James Davey (DEFRA)
© Crown copyright Met Office

Assumptions made for Bali
scenarios
• The CO other contribution that is not from fossil fuel or
2
LULUCF was combined with the fossil fuel contribution as
input to MAGICC (MAGICC has no other option apart
from fossil or LULUCF)
• The F gas emissions were represented by HFC-134a
only. The difference between individually representing the
gases and a one gas representation for these emissions
values is less than 2%
• The NO , CO and VOC emissions were set to zero as
x
emissions for these gases were not provided.
• The A1B SRES emissions were used for aerosol. The
aerosol emissions were reduced linearly to zero from the
action years corresponding to the peak GHG emissions
in each scenario (2015, 2020 and 2030).
© Crown copyright Met Office

GWP weighted emissions for
type “a” scenarios
The GWP weighted emissions for type "a" scenarios
70000
60000
) 2 50000
CO
t
M
Peak emissions at 2015 (Ia)
(
s
Peak emissions at 2020 (IIa)
ion 40000
ss
Peak emissions at 2030 (IIIa)
mis
ed e
t 30000
weigh
P
W 20000
G
10000
0
1980
2000
2020
2040
2060
2080
2100
2120
2140
2160
2180
2200
Year
© Crown copyright Met Office

GWP weighted emissions for
type “b” scenarios
The GWP weighted emissions of the type "b" scenarios
70000
60000
) 2 50000
Peak emissions at 2015 (Ib)
CO
t
Peak emissions at 2020 (IIb)
M
(
s
Peak emissions at 2030 (IIIb)
n
o 40000
si
mis
ed e
t 30000
weigh
P
W 20000
G
10000
0
1980
2000
2020
2040
2060
2080
2100
2120
2140
2160
2180
2200
Year
© Crown copyright Met Office

The time history of the median
response temperature rise for
type “a” scenarios
The time history of the global mean surface temperature rise estimate from scenarios
Ia, IIa and IIIa
3
Peak emissions 2015 (Ia)
Peak emissions 2020 (IIa)
2.5
Peak emissions 2030 (IIIa)
C)
o (
2
se
i
r
e
r 1.5
atu
er
1
emp
T
0.5
0
1980
2000
2020
2040
2060
2080
2100
2120
2140
2160
2180
2200
Year
© Crown copyright Met Office

The time history of the median
response temperature rise for
type “b” scenarios
The time history of the global mean surface temperature rise estimate from scenarios
Ib, IIb and IIIb
3.5
Peak emissions 2015 (Ib)
Peak emissions 2020 (IIb)
3
Peak emissions 2030 (IIIb)
2.5
C)
o (
se
i
r
2
e
r
atu 1.5
er
emp
T
1
0.5
0
1980
2000
2020
2040
2060
2080
2100
2120
2140
2160
2180
2200
Year
© Crown copyright Met Office

The time history of the median
response total CO e for type “a”
2
scenarios
Time history of the total CO2e for scenarios Ia, IIa and IIIa
600
Peak emissions 2015 (Ia)
Peak emissions 2020 (IIa)
550
Peak emissions 2030 (IIIa)
mv)
p 500
(p
s
n
o
ati 450
tr
cen
n
co 400
e 2
CO
350
300
1980
2000
2020
2040
2060
2080
2100
2120
2140
2160
2180
2200
Year
© Crown copyright Met Office

The time history of the median
response total CO e for type “b”
2
scenarios
Time history of the total CO2e for scenarios Ib, IIb and IIIb
650
Peak emissions 2015 (Ib)
Peak emissions 2020 (IIb)
600
Peak emissions 2030 (IIIb)
mv) 550
p
(p
s
n
o 500
ati
tr
450
cen
n
co
e 2 400
CO
350
300
1980
2000
2020
2040
2060
2080
2100
2120
2140
2160
2180
2200
Year
© Crown copyright Met Office