Transcript Developing and Applying Scenarios: A summary from the Third

Climate Hazards
&
Risk Assessment
AIACC Kickoff Meeting Nairobi
February 11-14 2002
Roger N. Jones
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
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
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
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
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
Uncertainty
Uncertainty and probability can be
expressed in two ways:
1. Return period / frequency-based
2. Single event
Atmospheric Research
Return period / frequency-based
probability
Recurrent event
Where a continuous variable reaches a critical level, or
threshold.
Eg. Extreme temperature (max & min), Extreme rainfall,
THI >72, >78, 1 in 100 year flood
Discrete event
An event caused by a combination of variables (an
extreme weather event)
Eg. tropical cyclone/hurricane/typhoon, ENSO event
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. That it will occur
•
IPCC (2001) suggests that climate change is occurring with
a confidence of 66% to 95%
2. What form will climate change 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
Atmospheric Research
Uncertainty explosion
global climate
sensitivity

emission
scenarios

regional
variability

range of
possible impacts
Atmospheric Research
CO2 emissions and concentrations
Atmospheric Research
Simulated global warming: A2
Global warming
Atmospheric Research
Mean sea level in the 20th century
Church et al. (2001)
Atmospheric Research
Sea level rise projections for one emission scenario
(IS92a)
Church et al. (2001)
Atmospheric Research
SRES sea level rise to 2100
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
Complex system undergoing change
Vulnerable state
•M3
•M1
•M4
•M2
Pre-adapted state
Atmospheric Research
Probabilistic structure of climate
uncertainties
Variable(s)
Critical threshold
Critical threshold
Time
Atmospheric Research
Linking key climatic variables to impacts
Climate
variable
Impacted
activity
Performance
criteria
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
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
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
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
Potential evaporation change (%)
Probabilities of flow changes
climate view
15
-40
-30
-20
Cumulative
Probability (%)
-10
<100
0
10
<95
<90
5
10
<80
<70
0
20
<60
<50
-5
-10
-5
0
5
Rainfall change (%)
10
10
Dam inflow
change (%)
Atmospheric Research
Probabilities of flow changes impacts view
Range of possible outcomes
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
Characterising risk
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?
Agree or disagree?
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
Characterising the risk of global
warming
5.8ºC
Least likely
Scenario 2
Scenario 6
Risks to Large Negative
Net
Higher
Many Increase for most Negative
regions
in all
metrics
Scenario 1
Scenario 5
Scenario 3
Scenario 4
1.4ºC
Markets
+ and -
Most likely
0ºC
Warming | Risk
Negative
for some
Risks to
Some Increase regions
I
I
II
III
IV
V
II
III
Most
people
worse
off
Very
low
IV
V
Risks to unique and threatened systems
Risks from extreme climate events
Distribution of impacts
Aggregate impacts
Risks from large-scale discontinuities
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