Embed Size (px)
Citation preview
Impacts of Global Sea-Level Rise:
The AVOID Analysis
Robert Nicholls and Sally Brown
School of Civil Engineering and the Environment and the Tyndall Centre for Climate Change Research
University of SouthamptonSouthampton SO17 1BJ UK
Earth Systems Science 2010
Plan
• Introduction• Methods• Results• Conclusions
Global sea-level rise(IPCC, 2007, AR4 WG1)
DIVA(Dynamic Interactive Vulnerability Assessment)
Input Parameters
• A1B socio-economic scenarios• Unmitigated vs. mitigated sea-
level rise scenarios• No protection versus quazi-
optimum protection scenarios
Sea-level rise scenarios
Emissions Scenario Families Range SRES A1B 1. SRES A1B –
unmitigated 37 to 59 cm by 2100
2016.R2.High 2. 2016.R mitigation scenarios
23 to 40 cm by 2100 2016.R4.Low 2016.R5.Low 2030.R2.High 3. 2030.R mitigation
scenarios 27 to 46 cm by 2100
2030.R5.Low
A1B.2016 SLR scenario family
0
0.1
0.2
0.3
0.4
0.5
2000 2020 2040 2060 2080 2100
Time (years)
Glo
bal
-mea
n s
ea-l
evel
ris
e (m
)
A1B.2016:R2.high 10th
A1B.2016:R2.high 50th
A1B.2016:R2.high 90th
A1B.2016:R4.low 10th
A1B.2016:R4.low 50th
A1B.2016:R4.low 90th
A1B.2016:R5.low 10th
A1B.2016:R5.low 50th
A1B.2016:R5.low 90th
A1B.2030 SLR scenario family
0
0.1
0.2
0.3
0.4
0.5
2000 2020 2040 2060 2080 2100
Time (years)
Glo
bal
-mea
n s
ea-l
evel
ris
e (m
)
A1B.2030:R2.high 10th
A1B.2030:R2.high 50th
A1B.2030:R2.high 90th
A1B.2030:R5.low 10th
A1B.2030:R5.low 50th
A1B.2030:R5.low 90th
Output Parameters
• Wetland Area (Natural Systems)• Floods (Human Systems)• Dike Costs (Adaptation)
Saltmarsh losses2080s
0.0%
10.0%
20.0%
30.0%
40.0%
50.0%
Nomitigation
2016.R 2030.R
Sa
ltm
ars
h l
os
s
10th percentile
50th percentile
90th percentile
Mangrove loss2080s
0.0%
10.0%
20.0%
30.0%
40.0%
50.0%
No mitigation 2016 R 2030 R
Ma
ng
rov
e l
os
s
90th percentile
50th percentile
10th percentile
Coastal Flooding
• Exposure– flood plain population
(1 in 1000 year flood plain)
• Risk– expected annual frequency (or
damage)Exposure x Probability(considers adaptation strategies)
Coastal flood plain population
0
50
100
150
200
250
300
No
miti
gatio
n
2016
.R
2030
.R
No
miti
gatio
n
2016
.R
2030
.R
No
miti
gatio
n
2016
.R
2030
.R
2020s 2050s 2080s
Mill
ion
s o
f p
eop
le
10th percentile
50th percentile
90th percentile
People flooded and no adaptation
change in expected annual frequency
0.0%
1000.0%
2000.0%
3000.0%
4000.0%
5000.0%
No mitig
ation
205
0
2016
R 2
050
2030
R 2
050
No mitig
ation
210
0
2016
R 2
100
2030
R 2
100
Flo
od
ing
in
cre
as
e
10th percentile
50th percentile
90th percentile
0
1000
2000
3000
4000
2000 2050 2100
Pe
op
le f
loo
de
d p
er
ye
ar
(00
0s
)
No mitigation 10thpercentile
No mitigation 90thpercentile
No mitigation 50thpercentile
2016 R 10th percentile
2016 R 50th percentile
2016 R 90th percentile
2030 R 10th percentile
2030 R 50th percentile
2030 R 90th percentile
People flooded and adaptation
change in expected annual frequency
Protection costsin 2050s to 2080s (1995 dollars)
0
5000
10000
A1B
201
6.R
203
0.R
A1B
201
6.R
203
0.R
2050s 2080s
Co
st (
US
do
llars
/yea
r) (
bill
ion
s)
10th percentile
50th percentile
90th percentile
Results -- Summary• Emission reductions will slightly reduce the global losses of
saltmarsh and mangrove after the 2050s -- 4 to 7% of the global stock ‘saved’ by the 2080s;
• The size of the coastal flood plain population is insensitive to emission reductions;
• Emission reductions will reduce the global number of people experiencing flooding by 2050, and the benefits are substantial by 2100, assuming no adaptation;
• However, flood impacts still increase by 10 to 20 times under mitigated scenarios and the reductions in flood impacts represent delayed (to the 22nd Century) rather than avoided damages;
• Assuming quazi-optimum adaptation greatly reduces the benefits of emissions reduction identified above.
Conclusions• For coasts, emission reductions mainly delay
rather than avoid 21st Century impacts;• This reflects the ‘commitment to sea-level rise’;• Need more information about mitigation and
large sea-level rise and storms; • Collectively, this supports the IPCC AR4
conclusion:“the most appropriate response to sea-level rise for coastal areas is a combination of adaptation to deal with the inevitable rise, and mitigation to limit the long-term rise to a manageable level.”
Impacts of Global Sea-Level Rise:
The AVOID Analysis
Robert Nicholls and Sally Brown
School of Civil Engineering and the Environment and the Tyndall Centre for Climate Change Research
University of SouthamptonSouthampton SO17 1BJ UK
Earth Systems Science 2010
