Download Atmospheric Research - Global Change System for Analysis

Representing Uncertainties
&
Selecting Scenarios
AIACC Training Workshop on Development and
Application of Integrated Scenarios in Climate Change
Impacts, Adaptation and Vulnerability Assessments
Tyndall Centre, UEA, Norwich UK
April 15-24 2002
Roger N. Jones
Atmospheric Research
Coverage
• Sources of uncertainties
• Implications of each for I, A & V
• How to address each type of
uncertainty
• Risk assessment framework
• Criteria for selecting scenarios
Atmospheric Research
IPCC 1994
1
DEFINE PROBLEM
2
SELECT METHOD
3
TEST METHOD/SENSITIVITY
4
SELECT SCENARIOS
5
ASSESS BIOPHYSICAL IMPACTS
ASSESS SOCIOECONOMIC IMPACTS
6
ASSESS AUTONOMOUS ADJUSTMENTS
7
EVALUATE ADAPTATION STRATEGIES
Atmospheric Research
Uncertainty explosion
Emission scenarios
Global climate sensitivity
Regional changes
Climate variability
Biophysical impacts
Socio-economic impacts
Atmospheric Research
Likelihood
Probability can be expressed in two
ways:
1. Return period / frequency-based
(Climate variability)
2. Single event
(Mean climate change, one-off events)
Atmospheric Research
Return period / frequency-based
probability
Recurrent or simple event
Where a continuous variable reaches a critical level, or
threshold.
Eg. Extreme temperature (max & min), Extreme rainfall,
heat stress, 1 in 100 year flood
Discrete or complex event
An event caused by a combination of variables (an
extreme weather event)
Eg. tropical cyclone/hurricane/typhoon, ENSO event
Atmospheric Research
Hot cows and heat stress
THI between 72 and 78
THI between 79 and 88
mild stress
moderate stress
THI between 89 and 98
THI above 98
severe stress
DEAD COWS!
Atmospheric Research
Frequency of exceeding
heat index threshold
90.0
THI Units
80.0
THI78
THI72
70.0
60.0
50.0
1/10/98
31/10/98
30/11/98
30/12/98
29/01/99
28/02/99
30/03/99
Date
Atmospheric Research
Frequency-based probability
distributions
Atmospheric Research
Single-event probability
Singular or unique event
An event likely to occur once only. Probability refers to
the chance of an event occurring, or to a particular
state of that event when it occurs.
Eg. Climate change, collapse of the West Antarctic Ice
Sheet, hell freezing over
Atmospheric Research
What is the probability of climate
change?
1. Will climate change happen?
•
IPCC (2001) suggests that climate change is occurring with
a confidence of 66% to 90%
2. What form will it take?
Uncertainties are due to:
• future rates of greenhouse gas emissions
• sensitivity of global climate to greenhouse gases
• regional variations in climate
• decadal-scale variability
• changes to short-term variability
Atmospheric Research
Range of uncertainty
M1
UNQUANTIFIABLE
UNCERTAINTY
M2
M3
M4
QUANTIFIABLE RANGE OF UNCERTAINTY
UNQUANTIFIABLE
UNCERTAINTY
TOTAL RANGE OF UNCERTAINTY
Atmospheric Research
CO2 emissions and concentrations
Atmospheric Research
Simulated global warming: A2
Atmospheric Research
Global warming
Atmospheric Research
Risk exercise - estimating joint
probabilities
• Take a gold coin (preferably 1 pound coin)
• Heads represents low end (1.4°C), tails
represents high end (5.8°C)
• Flip coin 7 times and record the number of
heads and tails
• Which outcome is most likely?
Atmospheric Research
What is a hazard?
Atmospheric Research
Typology of extreme climate events
Description
Variable
Measure
Exceeding critical
level on a continuous
scale
Extreme rainfall
Temperature
Frequency
Return period
Sequence
Duration
Complex Weather events
events
combining multiple
variables and/or
resulting in multiple
impacts
Tropical cyclones
ENSO events
Drought
Frequency 
magnitude
Severity of
impacts
Singular
events
Cessation of deep- Probability 
ocean circulation
magnitude of
Ice sheet collapse impact
Type
Simple
events
A possible future
climatic state with
potentially extreme
outcomes
Atmospheric Research
Current climate
Vulnerability
(flood)
Coping
range
Vulnerability
(drought)
Atmospheric Research
Future climate - no adaptation
Vulnerability
(flood)
Coping
range
Vulnerability
(drought)
Atmospheric Research
Future climate with adaptation
Vulnerability
(flood)
Coping
range
Adaptation
Planning horizon
Vulnerability
(drought)
Policy Horizon
Atmospheric Research
Linking key climatic variables to impacts
Climate
variable
Impacted
activity
Performance
criteria
Atmospheric Research
2
2
2
1
1
2
2
1
3
2
1
1
2
2
3
2
1
1
2
1
3
3
3
3
2
2
1
1
1
1
1
1
2
1
3
1
1
2
2
2
1
2
1
1
2
2
1
3
3
3
3
3
3
3
1
2
1
3
2
1
2
2
1
3
3
1
2
2
2
2
2
1
3
1
1
1
1
2
1
1
1
1
3
3
2
1
3
1
1 1
3
8 24 23 29 28 11 18 13 17 14 24 27 20 27
2
Health
2
3
1
2
1
Industry, coal & power
2
3
3
2
2
3
Air quality
3
2
3
3
Waste
1
2
1
2
Dryland/irrigation salinity
Harbour
Coastal water supply
Beach
2
2
2
1
1
1
2
2
3
2
1
1
1
2
Marine (esp. fisheries)
Horses
1
1
2
1
2
1
Urban infrastructure
2
2
1
Forest & biodiversity
2
1
2
2
2
River management
2
2
3
3
2
2
2
2
1
Wine
1
2
3
3
1
2
2
2
Cropping
2
1
2
2
2
2
2
2
Inland water supply
1
3
Grazing
Rainfall - average
Rainfall - extreme
Rainfall - variability
Drought
Temperature - average
Temperature - max
Temperature - min
CO2
Cloud
Pressure
Humidity
Wind
Evaporation
Soil moisture
Stream flow
Flood
Watertable
Water salinity
Irrigation
Sea level
Storm surge
Waves
Lightning
Hail
Fire
Dairy
Poultry
Cross impacts analysis
2
2
1
1
3
1
1
2
1
1
1
2
1
2
1
1
1
2
1
2
1
3
3
1
2
2
1
1
2
3
2
2
1
1
1
2
1 2
1 2
30 9 14 18 16
21
30
23
28
20
24
16
11
3
1
10
16
10
20
17
29
12
17
13
12
7
8
3
7
12
Atmospheric Research
Cross impacts analysis
Climate and related variables
(forcing)
Activities
(sensitivity)
High
Rainfall - extreme
Flood
Drought
Temperature - max
Rainfall - variability
Rainfall - average
Temperature - average
Soil moisture
Urban infrastructure
Cropping
Wine
River management
Forest & biodiversity
Inland water supply
Dairy
Grazing
Dryland/irrigation salinity
Moderate
Stream flow
Water salinity
Temperature - min
Wind
Irrigation
Watertable
Sea level
Fire
CO2
Humidity
Evaporation
Industry, coal & power
Marine (esp. fisheries)
Coastal water supply
Health
Harbour
Waste
Beach
Horses
Low
Waves
Storm surge
Hail
Cloud
Lightning
Pressure
Air quality
Poultry
Atmospheric Research
Characterising vulnerability
Presentations in this workshop suggest two
ways of characterising vulnerability:
1. In response to a fixed climate hazard e.g.
temperature, peak wind speed
2. As a measure where the degree of harm
cannot be tolerated, and that can be linked to
a given climatic condition (threshold
approach)
Atmospheric Research
Thresholds
A non-linear change in a measure or
system, signalling a physical or
behavioural change
Climate related thresholds are used to
mark a level of hazard
Atmospheric Research
Thresholds
Biophysical
Behavioural
•
•
•
•
•
•
•
•
•
•
Tropical cyclone
Coral bleaching
ENSO event
Island formation
Island removal
Legal/regulatory
Profit/loss
Cultural
Agricultural
Critical
Atmospheric Research
Thresholds
• Link socio-economic criteria with
biophysical criteria through a value
judgement
• Provide a fixed point against which to
measure climate uncertainty
• Directly link a particular impact to climatic
variables
• Introduce criteria as defined by stakeholders
into an impact assessment
Atmospheric Research
Critical thresholds
A level considered to represent an
unacceptable degree of harm
This is a value judgement and may be
decided by stakeholders, be a legal
requirement, a safety requirement, a
management threshold etc
Atmospheric Research
Metrics for measuring costs
•
•
•
•
•
Monetary losses (gains)
Loss of life
Change in quality of life
Species and habitat loss
Distributional equity
Atmospheric Research
Planning horizons
2000
Election cycles/profit & loss
Agriculture (whole farm planning)
Plant breeding (new crops)
2020
2040
Forest lease agreements
Pulp plantations
Generational succession
New irrigation projects
Coastal/tourism infrastructure
Tree crops
National parks
Airport design life
2060
Large dams
Major urban infrastructure
2080
Intergenerational equity
2100
Long-term biodiversity
Bridge design life
Atmospheric Research
Probabilistic structure of climate
uncertainties
Variable(s)
Critical threshold
Critical threshold
Time
Atmospheric Research
What is a risk?
Atmospheric Research
What is a risk?
Two uses
1. In general language
2. A specific operational meaning
Atmospheric Research
Characterising risk
UNEP definition
risk = hazard + vulnerability
vulnerability = exposure + susceptibility to loss
risk = f(hazard,likelihood)
Atmospheric Research
Placing thresholds within scenario
uncertainty
A
B
global climate
sensitivity

emission
scenarios

regional
variability

range of
possible impacts
Atmospheric Research
Impact thresholds
4.0
Global Warming (°C)
3.5
3.0
2.5
2.0
Threshold A
1.5
1.0
0.5
Threshold B
0.0
1990 2000 2010 2020 2030 2040 2050 2060 2070 2080 2090 2100
Year
Atmospheric Research
Probabilistic structure of climate
uncertainties
Variable(s)
Critical threshold
Critical threshold
Time
Atmospheric Research
Production effects
THI between 72 and 78
mild stress
no stress
THI between 79 and 88
moderate stress
mild stress
Atmospheric Research
Coral bleaching
• Caused by SST above a threshold
• Expels xosanthellae algae
• Severity related to days above
bleaching threshold
• Corals may recover or die
Atmospheric Research
Macquarie River Catchment
Macquarie
Marshes
Major Areas of
Abstraction
Burrendong Dam
Macquarie R
Contributing
Area

Area ~ 75,000 km2

P = 1000 to <400 mm.

Major dams: Burrendong and
Windamere

Water demands: irrigation
agriculture; Macquarie
Marshes; town supply

Most flow from upper
catchment runoff

Most demand in the lower
catchment
Windamere Dam
Atmospheric Research
Ranges of seasonal rainfall change
for the MDB
Summer
Winter
-40
-20
0
20
Rainfall Change (%)
40
2030
2070
Autumn
Spring
-40
-20
0
20
Rainfall Change (%)
40
Atmospheric Research
P and Ep changes for Macquarie
catchment
Change for 1ºC global warming (%)
16.0
8.0
0.0
-8.0
-16.0
J
F
M
A
M
J
Evaporation (Ep)
J
A
S
O
N
D
Rainfall (P)
In change per degree global warming
Atmospheric Research
Changes to MAF for 9 models in 2030 (%)
Based on IPCC 1996
Low
Mid
0
0
-8
-8
High
0
-10
-16
-16
-20
-24
-30
B1 at 1.7°C
0.55°C
A1 at 2.5°C
0.91°C
A1T at 4.2°C
1.27°C
Atmospheric Research
Climate change – flow relationship
flow = a  ( atan (Ep / P ) – b
Standard error < 2%
Atmospheric Research
Sampling strategy
• The range of global warming in 2030 was 0.55–
1.27°C with a uniform distribution. The range of
change in 2070 was 1.16–3.02°C.
• Changes in P were taken from the full range of
change for each quarter from the sample of nine
climate models.
• Changes in P for each quarter were assumed to be
independent of each other
• The difference between samples in any consecutive
quarter could not exceed the largest difference
observed in the sample of nine climate models.
• Ep was partially dependent on P (dEp = 5.75 –
0.53dP, standard error = 2.00, randomly sampled
using a Gaussian distribution)
Atmospheric Research
Potential evaporation change (%)
Changes to Burrendong Dam storage
2030
Cumulative
Probability (%)
15
-40
-30
-10
-20
<100
0
10
<95
5
10
<90
<80
<70
0
20
<60
-5
<50
-10
-5
0
5
10
Rainfall change (%)
Atmospheric Research
Potential evaporation change (%)
Changes to bulk allocations for
irrigation 2030
15
-30
-20
-10
Cumulative
Probability (%)
<100
10
<95
0
<90
5
<80
10
<70
0
<60
-5
<50
-10
-5
0
5
10
Rainfall change (%)
Atmospheric Research
Potential evaporation change (%)
Changes to Macquarie Marsh
inflows 2030
15
-40
-30
-20
-10
Cumulative
Probability (%)
<100
10
<95
0
<90
5
10
<80
<70
0
20
-5
<60
<50
-10
-5
0
5
10
Rainfall change (%)
Atmospheric Research
Probabilities of flow changes impacts view
Range of possible outcomes
Atmospheric Research
Critical thresholds
Macquarie River Catchment
Irrigation
5 consecutive years below 50% allocation of
water right
Wetlands
10 consecutive years below bird breeding
events
Atmospheric Research
Irrigation allocations and wetland inflows
- historical climate and 1996 rules
100
Flow (Gl x 10)
80
1,000,000
60
40
100,000
20
10,000
1890
Irrigation allocation (%)
10,000,000
0
1910
1930
1950
1970
1990
Year
Allocations
Marshes
Atmospheric Research
Threshold exceedance as a function
of change in flow (irrigation)
Sequences below
threshold (years)
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
Percent of total years
below threshold
+5%
Change in mean average allocation
0
-10%
-15%
-30%
-40%
1
1
-45%
1
1
1
1
0
1
1
2
6
12
1
2
2
4
5
7
38
50
2
1
5
10
1
4
13
2
1
6
11
22
23
34
1
4
1
6
4
1
5
1
2
4
58
64
Atmospheric Research
Threshold exceedance as a function
of change in flow (bird breeding)
Sequences below
threshold (years)
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
Percent of total years
below threshold
+5%
0
Change in MAF
-10%
-15%
-30%
1
1
1
1
1
1
-40%
1
1
1
1
1
1
2
2
-50%
1
2
2
3
3
1
1
1
1
1
3
2
4
4
1
2
1
7
3
1
2
3
4
7
1
3
4
2
5
2
4
3
2
3
40
45
52
56
63
2
1
2
3
1
1
3
1
1
3
71
79
Atmospheric Research
Risk analysis results
Macquarie 2030
DDR
N or m a l
FD R
-10
-20
-30
C um u la tiv e P rob ability
100
90
80
70
60
50
40
30
20
10
0
20
10
0
-40
C ha nge in sup ply (% )
B u r ren d on g
M a rsh es
Irr ig ation
Atmospheric Research
Risk analysis results
Macquarie 2070
DDR Normal FDR
100
90
Cumulative Probability
80
70
60
50
40
30
20
10
0
40
20
-20
0
-40
-60
-80
Change in supply (%)
Burrendong
Marshes
Irrigation
Atmospheric Research
Bayesian analysis results
Macquarie 2030
100
90
Cumulative Probability
80
70
60
50
40
30
20
10
0
20
10
0
-10
-20
-30
-40
Change in supply (%)
Standard
W&R warming
All
Atmospheric Research
Bayesian analysis results
Macquarie 2070
100
90
Cumulative Probability
80
70
60
50
40
30
20
10
0
40
20
0
-20
-40
-60
-80
Change in supply (%)
Standard
W&R warming
All
Atmospheric Research
Characterising risk as a function of
global warming
The standard “7 step method” of impact
assessment progresses from climate to
impacts to adaptation. This infers that we
must predict the likeliest climate before we
can predict the likeliest impacts.
Can we get around this limitation?
Atmospheric Research
Characterising risk
There is another way.
Impacts = function(Gw)
Impacts = function(Gw,t,p)
p(impacts) = no. of scenarios < threshold = risk
Atmospheric Research
Risk exercise - estimating threshold
exceedance: sea level rise
• Recover coin from greedy presenter
• Heads represents low end (9 cm), tails
represents high end (88cm)
• The group chooses two critical thresholds
• Flip coin 7 times and record the number of
heads and tails
• Which outcome is most likely?
Atmospheric Research
6
5
5
4
3
2
4
3
2
1
1
0
0
0
1
2
3
4
Frequency (%)
5
Probability of threshold
exceedance
6
Global warming (°C)
Global warming (°C)
Characterising the risk of global
warming
0
50
100
Frequency (%)
Increasing likelihood of
global warming
Atmospheric Research
Characterising the risk of global
warming
5
Global warming (°C)
Probability of threshold
exceedance
6
Risks to Large Negative
Net
Higher
Many Increase for most Negative
regions
in all
metrics
4
3
Markets
+ and -
2
1
Negative
for some
Risks to
Some Increase regions
0
0
50
Frequency (%)
Most
people
worse
off
Very
low
IV
V
100
I
I
II
III
IV
V
II
III
Risks to unique and threatened systems
Risks from extreme climate events
Distribution of impacts
Aggregate impacts
Risks from large-scale discontinuities
Atmospheric Research
Long-term planning
Short-term policy response
1. Enhance adaptive capacity so that the
current coping range expands,
reducing present vulnerability.
2. Develop this capacity in such a way
that the longer-term risks to climate
change are also reduced.
Atmospheric Research
Basic principles
• Pay greater attention to recent climate experience. Link
climate, impacts and outcomes to describe the coping range.
• Address adaptation to climate variability and extremes as part
of reducing vulnerability to longer-term climate change.
• Assess risk according to how far climate change, in
conjunction with other drivers of change, may drive activities
beyond their coping range.
• Focus on present and future vulnerability to ground future
adaptation policy development in present-day experience.
• Consider current development policies and proposed future
activities and investments, especially those that may increase
vulnerability.
Atmospheric Research
Foresighting your project
• Visualise how you will present the results
(graph, text, table, animation)
• Rehearse how you will communicate the
uncertainties
• Anticipate questions upon presentation or
review
• How will you engage different stakeholders?
Atmospheric Research