coastal implications and adaptation to sea-level rise and ... · coastal implications and...

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)

0

5,000

10,000

15,000

20,000

25,000

30,000

AFRICA

ASIA

AUSTRALASIA

EUROPE N. A

MERICA

S. AMERIC

A

Expo

sed

popu

latio

n (0

00s)

0

200,000400,000

600,000800,000

1,000,000

1,200,0001,400,000

1,600,000

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

2

3

4

5

6

7

2000 2010 2020 2030 2040 2050 2060 2070 2080 2090 2100Time

Tem

peat

ure

rise

abov

e pr

e-in

dust

iral (

deg

C)

RCP2.6 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

0

0.2

0.4

0.6

0.8

1

1.2

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)









Temperature and sea level Model: HadGEM2-ES, including regional (patterned) sea-level rise

0

0.2

0.4

0.6

0.8

1

1.2

0 1 2 3 4 5 6

Glo

bal m

ean

sea-

leve

l ris

e w

rt 1

985-

2005

(m)

Temperature rise with respect to pre-industrial (deg C)










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)

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