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Coastal Implications and Adaptation to Sea-Level Rise and Climate Change
Eminent Speaker Tour
Robert J. Nicholls Faculty of Engineering and Environment, University
of Southampton, United Kingdom
Hosted by the Civil College and the National Committee on Coastal and Ocean Engineering
Engineers Australia Melbourne
Melbourne VIC 3000 4 July 2016
Plan
• The Coastal Zone • Sea-Level Rise • Climate Mitigation • Adaptation • Concluding Thoughts
The Coastal Zone
Coastal Trends Rising local and global risks
• Population – Growing coastal population (double global trends) – Urbanising coastal zone (new residents are urban) – Increasing tourism, recreation and retirement
• Subsiding, densely-populated deltas, especially in urban areas
• Globalisation of trade and international shipping routes • Increasingly costly coastal disasters • Climate change and sea-level rise • A reactive approach to adaptation • Degrading coastal habitats and declining ecosystem
services
Sea-Level Rise
Sea levels over the last 500,000 years
From Grant et al., 2014 doi:10.1038/ncomms6076
Map by Emanuel Soeding, Christian-Albrechts University, using U.S. National Oceanic & Atmospheric Administration Etopo2v1 elevation data.
South-east USA Continental Shelf
< 1mm/year
6mm/year
> 20mm/year
Based on data from Fleming et al. 1998, Fleming 2000, & Milne et al. 2005
Human Drivers of Climate Change
Global Sea-Level Rise: 1700 to 2100 IPCC AR5 Report 2013
Source: Figure 13.27 -- Chapter 13 IPCC AR5 WG1 Report. Compiled paleo-sea-level data from geological evidence to 1880, tide gauge data from 1880 to present, altimeter data since 1993 to present, and central estimates and likely ranges for projections from present to 2100 based on RCP2.6 (blue) and RCP8.5 (red) emission scenarios.
Global Sea-Level Rise: 1700 to 2100 IPCC AR5 Report 2013
Source: Figure 13.27 -- Chapter 13 IPCC AR5 WG1 Report. Compiled paleo-sea-level data from geological evidence to 1880, tide gauge data from 1880 to present, altimeter data since 1993 to present, and central estimates and likely ranges for projections from present to 2100 based on RCP2.6 (blue) and RCP8.5 (red) emission scenarios.
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Subsiding Coastal Cities population > 1 million in 2005,
including maximum observed subsidence during 20th Century
Source: Nicholls, 2014
Flooding and Storm Damage in New Orleans – post-Katrina (2005)
Extreme sea levels versus return and method
GUM – Gumbel GEV – Generalized extreme value distribution GPD – Generalized Pareto distribution SSJPM – Spatially Revised Joint Probability Method Source: Thomas Wahl et al
Cumulative tracks of all tropical cyclones during the period 1985–2005.
Tropical cyclone tracks
What’s at stake? Coastal Cities with more than one million people in 2005
(Nicholls et al., 2008; Hansen et al., 2011)
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5,000
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AFRICA
ASIA
AUSTRALASIA
EUROPE N. A
MERICA
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popu
latio
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00s)
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1,200,0001,400,000
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AFRICA
ASIA
AUSTRALASIA
EUROPE N. A
MERICA
S. AMERIC
A
Expo
sed
asse
sts
(US$
mn (a) Population exposure (b) Asset exposure
Climate Mitigation and Sea-Level Rise
First IPCC Sea-level rise scenarios Source: Warrick and Oerlemans (1990)
66 cm rise
41 cm rise
0
1
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2000 2010 2020 2030 2040 2050 2060 2070 2080 2090 2100Time
Tem
peat
ure
rise
abov
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e-in
dust
iral (
deg
C)
RCP2.6 global mean surface temperature
RCP4.5 global mean surface temperature
RCP8.5 global mean surface temperature
Global Temperature Rise Model: HadGEM2-ES
Data from: Hinkel et al. 2014
Sea-level rise (Maldives) Model: HadGEM2-ES, including regional (patterned) sea-level rise
Data from: Hinkel et al. 2014
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0.2
0.4
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2000 2010 2020 2030 2040 2050 2060 2070 2080 2090 2100
Glo
bal m
ean
sea-
leve
l ris
e w
rt 1
985-
2005
(m)
Time
RCP2.6 (5th percentile ice sheet melting)
RCP2.6 (50th percentile ice sheet melting)
RCP2.6 (95th percentile ice sheet melting)
RCP4.5 (5th percentile ice sheet melting)
RCP4.5 (50th percentile ice sheet melting)
RCP4.5 (95th percentile ice sheet melting)
RCP8.5 (5th percentile ice sheet melting)
RCP8.5 (50th percentile ice sheet melting)
RCP8.5 (95th percentile ice sheet melting)
Temperature and sea level Model: HadGEM2-ES, including regional (patterned) sea-level rise
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0 1 2 3 4 5 6
Glo
bal m
ean
sea-
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rt 1
985-
2005
(m)
Temperature rise with respect to pre-industrial (deg C)
RCP2.6 (5th percentile ice sheet melting)
RCP2.6 (50th percentile ice sheet melting)
RCP2.6 (95th percentile ice sheet melting)
RCP4.5 (5th percentile ice sheet melting)
RCP4.5 (50th percentile ice sheet melting)
RCP4.5 (95th percentile ice sheet melting)
RCP8.5 (5th percentile ice sheet melting)
RCP8.5 (50th percentile ice sheet melting)
RCP8.5 (95th percentile ice sheet melting)
Sea levels will continue to rise, even if temperatures stabilise
Sea-Level Rise vs. Emissions: 2000 to 2500
(Source: Figure 13.13 -- Chapter 13 IPCC AR5 WG1 Report)
Climate Mitigation Source: MIT Joint Program on Global Change
Impacts and Adaptation to Sea-Level Rise
The coastal system: Climate drivers
Source: IPCC AR4 WG II
The coastal system: Non-climate drivers
Source: Nicholls et al. 2014Masselink and Gehrels (eds)
Source: Klein et al., 1999; 2000
Elements of an adaptation strategy
Elements of an adaptation
strategy
Information and good science
Education and communication
Responsibility for development
Riskmanagement
plans Linking with other planning
processes
Legislation and enforcement
Support networks
Financing adaptation
Governance controls and/or influences: Delivery of adaptive responses Adaptive capacity Distribution of costs and benefits Source: Emma Tompkins
Shoreline Management Plans (SMPs) For coastal erosion and flood management of England and Wales
Recognise three mesoscale epochs Epoch 1: 0 to 20 yrs Epoch 2: 20 to 50 yrs Epoch 3: 50 to 100 yrs
22 SMPs 2000 management units Four policy choices per Epoch (1) Advance the line (2) Hold the line (3) Managed Realignment (4) Limited Intervention
Building with Nature, Sand Motor, Holland Coast
Photo courtesy of Bas Jonkman, TUD
Dubai – Land Claim
.
Coastal Cities More than one million people in 2005
Coastal Cities and Sea-Level Rise (Hallegatte et al., 2013; Nature Climate Change)
• Failing to adapt (protect) is not a viable option in coastal cities: damages could reach $1 trillion per year
• Indicative annualized adaptation (protection) costs are about $350 million per year per city, or approximately $50 billion per year for the 136-city sample.
• These are of the same order of magnitude as residual losses with adaptation.
• Managing coastal flood risk requires doing more than maintaining today’s standard of protection (and current probability of flooding).
• While improving standards of protection could maintain or reduce risk levels (expected annual damages) and decrease the number of floods, the magnitude of losses when floods do occur will still increase. So expect bigger disasters!
City Adaptation Responses some combination of:
• Upgraded protection; • Managing subsidence (in susceptible cities); • Land use planning to reduce vulnerability, including
– focusing new development away from the floodplain, – preserving space for future flood defence infrastructure development;
• Flood proofing/resilience of new buildings • Selective relocation away from existing city areas; and • Flood warning and evacuation.
RESILIENT CITIES!! RESILIENT COASTS!!
What are the limits to protection? (Nicholls et al., 2015)
Three types of limit might exist?
Physical/engineering limits Economic/financial limits Socio-political limits
If you cannot protect you will use other adaptation methods – essentially retreat and maybe (forced) migration
Thames Estuary 2100 Project Thames Barrier
Source: Tim Reeder, Environment Agency
Time2007 2050 2100
• more people/property
• climate change
• ageing FD
UnacceptableTolerable
As low as reasonably possible
Managing Flood Risk through the Century
Source: Tim Reeder, Environment Agency
1m 0m 4m 3m 2m Max water level rise:
New barrier, retain Thames Barrier, raise defences
Raise Defences
New barrier, raise defences
New barrage
Existing system
Improve Thames Barrier and raise d/s defences
Over-rotate Thames Barrier and restore interim defences
Flood storage, improve Thames Barrier, raise u/s & d/s defences
Flood storage, over rotate Thames Barrier, raise u/s & d/s defences
Flood storage, restore interim defences
Previous Extreme Defra and upper part of new TE2100 likely range
Top of new H++ range
TE2100 developed optionsSource: Tim Reeder, Environment Agency
The Maldives: the Lowest Country
Malé
Source: Laurens Speelman (PhD thesis).
Migration Trends
Hulhumalé: Island Creation
Malé Adaptation pathways
Hulhumalé Adaptation pathways
Potential third island Adaptation pathways
Island Raising: A Long-Term Future for the Maldives?
Concluding Remarks • Sea level has shaped the world’s coast through time • Human-induced sea-level rise has a major impact potential over the
21st Century (and beyond) • Planning for these issues would seem prudent taking account of:
– The multiple drivers of change and societal development aspirations – High levels of uncertainty – Requires a system perspective
• The most appropriate response will be a combination of climate mitigation and adaptation
• Mitigation has the goal of minimising the high-end changes • Adaptation is required for the “residual” committed sea-level rise • Adaptation is a process which remains under appreciated • These issues require considerably more research coupled to policy
formulation (learning by doing) • Issues of equity and finance will be significant
Coastal Implications and Adaptation to Sea-Level Rise and Climate Change
Eminent Speaker Tour
Robert J. Nicholls Faculty of Engineering and Environment, University
of Southampton, United Kingdom
Hosted by the Civil College and the National Committee on Coastal and Ocean Engineering
Engineers Australia Melbourne
Melbourne VIC 3000 4 July 2016
Observed coastal impacts Summary of detection and attribution of climate change
in IPCC AR5 Report
Source Figure 5.5 in Wong et al. (2015)