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Applying risk analytic techniques to the integrated assessment of climate policy benefits
Roger JonesCSIRO Marine and Atmospheric Research
Gary YoheDepartment of Economics, Wesleyan University
Acknowledgements Ben Preston CSIRO
GLOBAL FORUM ON SUSTAINABLE DEVELOPMENTON THE
ECONOMIC BENEFIT OF CLIMATE CHANGE POLICIESParis 6-7 July 2006
Incr
easi
ng c
ost o
f mitig
atio
nPrecautionary (risk averse) towards economy
Fast rate of time preference
Increasing likelihood of DAI
Precautionary (risk averse) tow
ards environment
Slow rate of tim
e preferenceIn
crea
sing
cos
t of m
itigat
ion
Precautionary (risk averse) towards economyFast rate of time preference
Incr
easi
ng c
ost o
f mitig
atio
nPrecautionary (risk averse) towards economy
Fast rate of time preference
Increasing likelihood of DAI
Precautionary (risk averse) tow
ards environment
Slow rate of tim
e preference
Increasing likelihood of DAI
Precautionary (risk averse) tow
ards environment
Slow rate of tim
e preference
Two extremes of perceived risk
Climate-related risks
Policy-related risks
Integrated Assessment Modelling
(Cost Benefit Analysis)
Policy impasse
Fear No.1 of the highly averse to economic risksType I ErrorFalse Positive – we act on greenhouse but it turns out wrongFavoured policy mix – wait and see, R&D to narrow uncertainty to predictive range, eschews targets and central controls not based on cost signals, favours market-driven tech solutions on supply
Fear No.1 of the highly averse to environmental risksType II ErrorFalse Negative – we don’t act fast enough and end up with DAIFavoured policy mix – set early targets and learn by doing, GHG trade/permit system, social and technological solutions on supply and demand, precautionary approach to DAI
Conventional economic paradigms
Conventional cost-benefit approaches dominate “economically rational” framing of climate issuesThese perceptions are held more strongly in political and business communities as opposed to the research community
• Actors who are risk averse to the short-term costs of mitigating climate change want solid estimates of the benefits of avoiding damage before they will act
• This drives climate modelling and impact assessment into a predictive framework; ill-suited to managing large uncertainties
Adding risk into integrated assessment
Incr
easi
ng c
ost o
f mitig
atio
nPrecautionary (risk averse) towards economy
Fast rate of time preference
Increasing likelihood of DAI
Precautionary (risk averse) towards environment
Slow
rate of time preference
Integrated Assessment Modelling
(Risk-weighted damages, costs & benefits)Incr
easi
ng c
ost o
f mitig
atio
nPrecautionary (risk averse) towards economy
Fast rate of time preference In
crea
sing
cos
t of m
itigat
ion
Precautionary (risk averse) towards economyFast rate of time preference
Increasing likelihood of DAI
Precautionary (risk averse) towards environment
Slow
rate of time preference
Increasing likelihood of DAI
Precautionary (risk averse) towards environment
Slow
rate of time preference
Integrated Assessment Modelling
(Risk-weighted damages, costs & benefits)
Strategy I•Wait and see on everything•Reduce uncertainty through experience•Reactive adaptation (min loss/max benefits)•Modest mitigation – known low cost options
Strategy II•Wait and see on climate and impacts•Research economic, tech uncertainty•Reactive adaptation (min loss/max benefits)•Efforts to reduce mitigation costs
Strategy III•Act early to stabilise•Research climate & impact uncertainty•Anticipatory adaptation•Strong mitigation – develop low cost options
Strategy IV•Act on everything•Research everything•Anticipatory adaptation and cost reduction•Anticipatory mitigation and cost reduction
Strategy I•Wait and see on everything•Reduce uncertainty through experience•Reactive adaptation (min loss/max benefits)•Modest mitigation – known low cost options
Strategy II•Wait and see on climate and impacts•Research economic, tech uncertainty•Reactive adaptation (min loss/max benefits)•Efforts to reduce mitigation costs
Strategy III•Act early to stabilise•Research climate & impact uncertainty•Anticipatory adaptation•Strong mitigation – develop low cost options
Strategy IV•Act on everything•Research everything•Anticipatory adaptation and cost reduction•Anticipatory mitigation and cost reduction
Increasing likelihood of DAI
Incr
easi
ng c
ost o
f mitig
atio
n
Precautionary (risk averse) towards economyFast rate of time preference
Precautionary (risk averse) towards environment
Slow rate of tim
e preference
II
I III
IV
Competing views
Increasing likelihood of DAI
Incr
easi
ng c
ost o
f mitig
atio
n
Precautionary (risk averse) towards economyFast rate of time preference
Precautionary (risk averse) towards environment
Slow rate of tim
e preference
II
I III
IV
Competing views
Integrated approaches to risk
Almost certain
Highly likely
Least likely
Low probability, extreme outcomes
Damage to the most sensitive, many benefits
Increased damage to
many systems, fewer benefits
Considerable damage to most
systems
Moderately likely
Probability Consequence
Core benefits of adaptation and mitigation
Probability – the likelihood of reaching or exceeding a given level of global warmingConsequence – the effect of reaching or exceeding a given level of global warming
Risk = Probability × Consequence
Vulnerable to current climate
Happening now
Almost certain
Highly likely
Least likely
Low probability, extreme outcomes
Damage to the most sensitive, many benefits
Increased damage to
many systems, fewer benefits
Considerable damage to most
systems
Moderately likely
Probability Consequence
Core benefits of adaptation and mitigation
Probability – the likelihood of reaching or exceeding a given level of global warmingConsequence – the effect of reaching or exceeding a given level of global warming
Risk = Probability × Consequence
Vulnerable to current climate
Happening now
Adaptation and mitigation
Adaptation increases the coping range through biological and social means
Mitigation reduces the magnitude and frequency of greenhouse-related climate hazards
At the policy scale they are complementary, not inter-changeable.
They also reduce different areas of climate uncertainty
Global mean warming probabilities 2100
0
10
20
30
40
50
60
70
80
90
100
0 1 2 3 4 5 6 7 8 9 10
Global Mean Temperature Change (°C)
Dec
reas
e in
GD
P (%
)
A1FI A1B A1T
Incremental damages
0
0.5
1
1.5
2
2.5
3
3.5
4
1990 2010 2030 2050 2070 2090Year
Glo
bal M
ean
Tem
pera
ture
Incr
ease
(°
C)
Assessing market damages
Testing cost curve sensitivity
0
10
20
30
40
50
60
70
80
90
100
0 1 2 3 4 5 6 7 8 9 10
Global Mean Temperature Change (°C)
Dec
reas
e in
GD
P (%
)
Linear Quadratic Cubic Step function
Risk under different emissions limits – market
0
10
20
30
40
50
60
70
80
90
100
0 1 2 3 4 5 6 7 8 9 10
Global Mean Temperature Change (°C)
Dec
reas
e in
GD
P (%
)
0
10
20
30
40
50
60
70
80
90
100
Prob
abilit
y of
exc
eedi
ng
tem
pera
ture
(%)
Linear Quadratic Cubic Step function A1FI A1B A1T
Assessing non-market damages
Critical thresholds – coral reefs
0
10
20
30
40
50
60
70
80
90
100
0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0Global Mean Temperature Change (°C)
Area
of c
ritic
al th
resh
old
exce
edan
ce
(%)
CT1: Bleaching
CT2: Sensitive species
CT3: Tolerant species
Critical thresholds – extinction risk
0
10
20
30
40
50
60
70
80
90
100
0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0
Global Mean Temperature Change (°C)
Spec
ies
unde
r Ext
inct
ion
Ris
k (%
)
Critical thresholds – thermohaline circulationy = 9.9747x - 2.9767
R2 = 0.6055
0
10
20
30
40
50
60
0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0
Global Mean Temperature Change (oC)
% R
educ
tion
in A
tlant
ic O
vert
urni
ng
Raper et al. (2001)IPCC (2001)Zickfield et al. (2004)Voss and Milkalajewicz (2001)Boar et al. (2000)Schmittner et al. (2005)Dai et al. (2005)Washington et al. (2000)Bleck and Sun (2004)Kamenkovich et al. (2003)Gent (2001)Wood et al. (1999)Sun and Bleck (2001)Hu et al. (2004)
Critical thresholds – Greenland ice-sheet
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0.0 0.5 1.0 1.5 2.0 2.5 3.0
Global Mean Temperature Change
Cum
ulat
ive
Prob
abili
ty o
f Col
laps
e
Hansen (2005)Huybrechts et al. (1991)Greve (2000)Huybrechts and De Wolde (1999)
Critical thresholds – all
0
10
20
30
40
50
60
70
80
90
100
0 1 2 3 4 5 6 7 8 9 10Global Mean Temperature Change (°C)
Prop
ortio
n of
loss
(%)
Irr
ever
sibl
e G
reen
land
ice-
mel
t (%
)
Species Extinction Coral Reefs THC Greenland
Risk under different emissions limits – non-market
0
10
20
30
40
50
60
70
80
90
100
0 1 2 3 4 5 6 7 8 9 10Global Mean Temperature Change (°C)
Prop
ortio
n of
loss
(%)
Gre
enla
nd ic
e-m
elt (
%)
0
10
20
30
40
50
60
70
80
90
100
Prob
abilit
y of
exc
eedi
ng
tem
pera
ture
(%)
Species Extinction Coral Reefs THC GreenlandA1FI A1B A1T
Testing a Kyoto-like mitigation
0
1
2
3
4
1990 2010 2030 2050 2070 2090Year
Mea
n G
loba
l War
min
g (°
C)
Mitigated warmingRemaining warming
Changed temp risk with Kyoto-like mitigation
0
10
20
30
40
50
60
70
80
90
100
0 1 2 3 4 5 6 7 8 9 10
Global Mean Temperature Change (°C)
Dec
reas
e in
GD
P (%
)
A1FI A1B A1T A1FI (KP-like) A1B (KP-like) A1T (KP-like)
Risk-weighted damages – non-monetary
Species Coral Reefs THC slow-down
Green-land ice sheet
Scenario upper limit
(% damage) Chance of loss (%)
A1FI 54.6 97.3 36.1 99.3 A1B 31.2 94.5 27.2 98.3 A1T 25.1 92.3 24.3 96.7
Risk-weighted damages – monetary
Linear Squared Cubic Step change Scenario
upper limit (% decrease in GDP) A1FI 3.9 5.1 5.5 9.4 A1B 3.0 3.1 3.2 4.3 A1T 2.4 2.6 2.6 3.2 (NPV $Trillion 1990) A1FI 68.3 53.1 74.2 131.6 A1B 49.2 35.1 46.2 57.1 A1T 43.6 30.1 38.8 44.8
Risk-weighted benefits – non-monetary
Species Coral Reefs THC slow-down
Green-land ice sheet
Scenario upper limit
(% damage) Chance of loss (%)
A1FI -3.0 -0.4 -1.3 -0.4 A1B -3.3 -0.8 -1.4 -1.1 A1T -2.8 -0.9 -1.3 -2.0
Risk-weighted benefits – monetary
Linear Squared Cubic Step change Scenario
upper limit (% decrease in GDP) A1FI -0.1 -0.3 -0.4 -0.7 A1B -0.1 -0.2 -0.3 -0.5 A1T -0.1 -0.2 -0.2 -0.4 (NPV $Trillion 1990) A1FI -2.8 -2.7 -4.2 -11.6 A1B -2.7 -2.3 -3.5 -5.6 A1T -2.7 -2.3 -3.5 -5.6
Damages and benefits
Damages build from bottom upBenefits of mitigation come from top down (highest temperatures, worst plausible risks developed from a comprehensive set of reference scenarios)Benefits of adaptation work from bottom-up, reducing damagesKnowledge of costs and benefits of adaptation remains poorIt is possible to assess near to mid-term adaptation needs (adapting to the inevitable) by using risk analysis based on changes already committed to
Conclusion
Risk can be used to compare policy and climate risksFrameworks for assessing the benefits of climate policy within probabilistic “risk” frameworks provide insights into where policy benefits may lieBenefits could be expressed in familiar terms (e.g. cost effectiveness) but expanded to include monetary and non-monetary benefits of risk managementNew knowledge and actions will both alter risk profile –learn by research, learn by doing