Download Australia`s Energy Sector – Drivers for Change

WATER TRANSFORMED:
SUSTAINABLE WATER SOLUTIONS FOR
CLIMATE CHANGE ADAPTATION
MODULE A
ADAPTING TO CLIMATE CHANGE
This online textbook provides free access to a comprehensive education and training package that
brings together the knowledge of how countries, specifically Australia, can adapt to climate change. This
resource has been developed formally as part of the Federal Government’s Department of Climate
Change’s Climate Change Adaptation Professional Skills program.
CHAPTER 1: UNDERSTANDING THE RISKS AND
ADAPTING TO CLIMATE CHANGE
LECTURE 1.4: ADAPTING TO SEA-LEVEL RISES – COASTS AND
THE BUILT ENVIRONMENT
The Natural Edge Project (‘TNEP’), 2009
Copyright in this material (Work) is owned by The Natural Edge Project, hosted by Griffith University and the Australian
National University.
The material contained in this document is released under a Creative Commons Attribution 3.0 License. According to the
License, this document may be copied, distributed, transmitted and adapted by others, providing the work is properly
attributed as: ‘Smith, M., Hargroves, K., Stasinopoulos, P., Desha, C., Reeves, A. and Hargroves, S. (2009) Water
Transformed: Sustainable Water Solutions for Climate Change Adaptation, The Natural Edge Project (TNEP), Australia.’
Document is available electronically at http://www.naturaledgeproject.net/Sustainable_Water_Solutions_Portfolio.aspx.
Acknowledgements
The Work was produced by The Natural Edge Project funded by the Australian Government Department of Climate
Change under the Climate Change Adaptation Skills for Professionals Program, with in-kind hosting provided by Griffith
University and the Australian National University. The development of this publication has been supported by the
contribution of non-salary on-costs and administrative support by the Science, Engineering, Environment and Technology
Division (SEET) of Griffith University, under the supervision of Professor Brendan Gleeson, and both the Fenner School of
Environment and Society and Engineering Department at the Australian National University, under the supervision of
Professor Stephen Dovers.
Project Leader: Mr Karlson ‘Charlie’ Hargroves, TNEP Director
Principle Researchers: Mr Michael Smith, TNEP Research Coordinator and Mr Peter Stasinopoulos, TNEP Technical
Specialist
TNEP Researchers: Ms Cheryl Desha, TNEP Education Coordinator and Miss Angie Reeves, TNEP Research Officer.
Copy Editor: Mrs Stacey Hargroves, TNEP Professional Editor.
Peer Review
Principal reviewers for the overall work were: Dr Graeme Pearman – Graeme is one of Ausralia’s leading climate scientists.
Formerly Chief of Atmospheric Research and CSIRO Climate Director, 1992–2002, he is the author or co-author of over
150 peer reviewed journal papers on climate change. Now he is based at Monash University as a sustainability/climate
change consultant and advisor.
Dr Deborah Abbs– CSIRO Atmospheric and Marine Research Division. Deborah is author or co-author of over 150 papers
and reports on aspects of climate change adaptation.
Alex Fearnside – Alex is sustainability team leader at Melbourne City Council. Melbourne City Council is currently
developing a comprehensive climate change adaptation plan with a strong focus on adapting to sea-level rises.
Disclaimer
While reasonable efforts have been made to ensure that the contents of this publication are factually correct, the parties
involved in the development of this document do not accept responsibility for the accuracy or completeness of the contents.
Information, recommendations and opinions expressed herein are not intended to address the specific circumstances of
any particular individual or entity and should not be relied upon for personal, legal, financial or other decisions. The user
must make its own assessment of the suitability for its use of the information or material contained herein. To the extent
permitted by law, the parties involved in the development of this document exclude all liability to any other party for
expenses, losses, damages and costs (whether losses were foreseen, foreseeable, known or otherwise) arising directly or
indirectly from using this document.
This document is produced for general information only and does not represent a statement of the policy of the
Commonwealth of Australia. The Commonwealth of Australia and all persons acting for the Commonwealth preparing this
report accept no liability for the accuracy of or inferences from the material contained in this publication, or for any action as
a result of any person’s or group’s interpretations, deductions, conclusions or actions in relying on this material.
Enquires should be directed to:
Mr Karlson ‘Charlie’ Hargroves
Co-Founder and Director
The Natural Edge Project
[email protected]
www.naturaledgeproject.net
Prepared by The Natural Edge Project 2009
The Natural Edge Project (TNEP) is an independent non-profit Sustainability ThinkTank based in Australia. TNEP operates as a partnership for education, research and
policy development on innovation for sustainable development. TNEP's mission is to
contribute to, and succinctly communicate, leading research, case studies, tools,
policies and strategies for achieving sustainable development across government,
business and civil society. Driven by a team of early career Australians, the Project
receives mentoring and support from a range of experts and leading organisations in
Australia and internationally, through a generational exchange model.
Page 2 of 25
Water Transformed: Sustainable Water Solutions
Module A: Adapting to Climate Change
Chapter 1: Understanding the Risks and Adapting to Climate Change.
Lecture 1.1: Risks and Vulnerabilities from Climate Change in Australia
Lecture 1.2: Reducing Risks to the Built Environment – from Cyclones and Hailstorms
Lecture 1.3: Reducing Risks to the Built Environment & Infrastructure – from Bushfires
Lecture 1.4: Adapting to Sea-level Rises - Coasts and the Built Environment
Module B: Adapting to Changes in Water Availability - Industry & Commercial
Chapter 2: Getting Started: The Fundamentals of Monitoring/Measuring Water Usage & Identifying Water
Efficiency, Recycling & Water Collection/Storage Opportunities.
Lecture 2.1:The Business case for Water Saving Initiatives and Addressing Organisational Barriers to Change.
(Obtaining & Improving Management Commitment)
Lecture 2.2: Getting Started: Benchmarking, Water Audits, Metering and Monitoring
Lecture 2.3: Identifying & Implementing Water Efficiency & Recycling Opportunities in the Agricultural Sector
Lecture 2.4: Identifying & Implementing Water Efficiency & Recycling Opportunities in the Built Environment
Sector
Chapter 3: Identifying & Implementing Water Efficiency & Recycling Opportunities - by Sector.
Lecture 3.1: The Manufacturing Sector
Lecture 3.2: Food Processing & Beverage Sector
Lecture 3.3: The Mining Sector
Chapter 4: Identifying and Implementing Water Efficiency & Recycling Opportunities by Sector
Lecture 4.1: Tourism, Hotel & Hospitality
Lecture 4.2: Health Sector – Water Savings in Hospitals
Lecture 4.3: Education Sector - Water Savings in Universities
Module C: Best Practice Integrated Urban and Coastal Water Resource Management
Chapter 5: Integrated Water Resource Management – A Whole Systems Approach
Lecture 5.1: A Whole Systems Approach to Water Supply and Treatment
Lecture 5.2: Holistic Water Planning - Protecting and Generating Potable Supply
Lecture 5.3: Holistic Water Planning – To Protect Potable Supply from Storm Surges and Rising Sea Levels.
Chapter 6: Water Sensitive Design, Recycling and Distributed Supply and Treatment Opportunities
Lecture 6.1: Water Sensitive Urban Design
Lecture 6.2: Urban Stormwater - Recycling Options
Lecture 6.3: Urban Treated and Industrial Water – Recycling and Treatment Options
Lecture 6.4: Micro storage options – Residential and Commercial Options
Chapter 7: Integrated Water Resource Management
Lecture 7.1: Integrated Water Resource Management – In the Built Environment
Lecture 7.2: Onsite Distributed Water Treatment Options – Residential & Commercial
Lecture 7.3: Integrated Water Resource Management – Rural
Prepared by The Natural Edge Project 2009
Page 3 of 25
Water Transformed: Sustainable Water Solutions
Adapting to Climate Change
Lecture 1.4: Adapting to Sea-level Rises – Coasts and the
Built Environment
Educational Aim
Adapting to sea-level rises is one of the greatest climate change related challenges that will face
humanity in the coming centuries. In the short term, even very small increases in sea level will
amplify storm surge damage, and in the longer term anticipated rises in sea level stand to threaten
inundation of coastal development across the world. This lecture will explain how climate change is
causing sea-level rises, and discuss the associated risks (including amplification of storm surges) as
well as providing an overview of the adaptation options (which will be covered in more detail in
Module C). It is important also for built environment professionals and planners to realise that the
scientific understanding of sea-level rises induced by climate change is evolving rapidly. This lecture
summarises some of the most important recent developments that will affect the likely scale and rate
of sea-level rises, so as to help better inform planning decision making processes. Practitioners in
the field should continue to stay up-to-date with the climate science which relates to sea-level rises.
Learning Points
1. Global warming, caused by rising levels of greenhouse gas emissions, is causing sea levels
globally to rise, through a combination of thermal expansion of the oceans, and the melting of
glaciers, ice caps, and large ice sheets into the oceans. The average temperature of the global
ocean at depths of up to 3000 m has been increasing since 1961,1 and this additional heat
provides the water molecules with more energy to vibrate, so the volume taken up by the
molecules increases, leading to rising sea levels. This is known as thermal expansion. Thermal
expansion results from the ocean absorbing the heat that has been added to the atmosphere,2
and it is estimated that the world’s oceans have been absorbing more than 80 per cent of this
heat.3 Widespread melting of glaciers, ice caps and ice sheets have also contributed to sea-level
rise. The melting of the Greenland and Antarctic ice sheets, for example, have very likely
contributed to the sea-level rise between 1993 and 2003.4
2. The IPCC has found that ‘The global sea-level rose at an average of 1.8 mm/year from 1961 to
2003, and the rate of increase was faster (about 3.1 mm/year) from 1993 to 2003.’5 It is
anticipated that the global average sea level6 will rise at least between 9 and 88 cm between
1990 and 2100, and if it rises 88 cm, the IPCC 4th Assessment warns that coastal flooding could,
1
IPCC (2007), Climate Change 2007: The Physical Science Basis, Contribution of Working Group I to the Fourth Assessment Report of
the Intergovernmental Panel on Climate Change, Cambridge University Press, Cambridge, see ‘Summary for Policymakers’, p5,
www.ipcc.ch/ipccreports/ar4-wg1.htm, accessed 28Octonber 2008
2
Ibid
3
Ibid
4
Ibid.
5
IPCC (2007) Climate Change 2007: Impacts, Adaptation and Vulnerability, Contribution of Working Group II to the Fourth Assessment
Report of the Intergovernmental Panel on Climate Change, Cambridge University Press, Cambridge, see ‘Coastal systems and low-lying
areas’, pp315-356.
6
It is important to note that local factors will mean that for any specific region sea levels will rise slightly higher or slightly lower than the
average global sea-level rise.
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Water Transformed: Sustainable Water Solutions
‘grow tenfold or more by the 2080s, to affect more than 100 million people/yr’.7 Whilst, the
Intergovernmental Panel on Climate Change (IPCC) 4th Assessment projected a sea-level rise of
between 9 and 88 cm between 1990 and 2100, the assessment also cautioned that due to
significant levels of ice melt in the northern summer of 2007 the estimate of 88 cm could actually
be an under-estimate. Rahmstorf has shown that the observed rate of sea-level rise is tracking at
or near the upper limits of the envelope of IPCC projections.8
3. Given the uncertainties inherent in long term sea-level rise prediction, a risk management
approach – which weighs the probability of certain changes happening against the magnitude of
the impact if they do – is recommended for decision makers to underpin efforts to reduce the
risks of damage from sea-level rises as cost effectively as possible. When assessing risks and
adaptation strategies it is important that decision makers, planners, and local and state
governments look at the short, medium and long term risks from sea level rises.
4. The main risk of damage from sea-level rises in the short term comes through the potential for
sea-level rises to combine with storm surges from extreme weather events, such as cyclones in
the tropics, and large cold fronts in the middle and lower latitudes.9 The IPCC 4th Assessment
found that the greatest hot spots at risk of damage from sea-level rising is North10 and South
East Queensland, where there are risks of cyclones creating storm surges, which at a high tide
can inflict severe damage.11 This coastline has many sandy beaches and dunes, and also
includes Fraser Island, the world’s largest sand island.12 The region’s population is projected to
increase rapidly in the short term, with many estuaries and nearby lowlands having already been
intensively developed,13 and thus, as sea-level rises, the risks of damage and flooding of
buildings and the built environment Far North and South East Queensland from storm surges
and high tides will grow. It is important to note that the frequency of extreme events is already
increasing in many locations.14 There is clear evidence for this already in Fremantle and Sydney
where the frequency of extreme tidal events has changed upward by between 2 and 3 fold due to
sea level rises.15
5. The potential negative risks, in the medium to longer term, from sea-level rise can be divided into
five categories: 1) inundation of low-lying areas, 2) erosion of beaches and bluffs, 3) salt
intrusion into aquifers and surface waters, 4) higher water tables, and 5) increased flooding and
storm surge damage.16 The potential magnitude of impact in these five areas needs to be
assessed on a case by case basis to determine the level of risk to different cities, towns and
communities along the Australian coast. CSIRO’s researchers are working with local
7
IPCC (2007) Climate Change 2007: Impacts, Adaptation and Vulnerability, Contribution of Working Group II to the Fourth Assessment
Report of the Intergovernmental Panel on Climate Change, Cambridge University Press, Cambridge, see ‘Coastal systems and low-lying
areas’, pp315-356.
8
Rahmstorf, S. et al (2007) ‘Recent climate observations compared to projection’,.Science, vol 316, p709.
9
Sea Level Rise website – Sea Level Impacts: Sea Level at http://www.cmar.csiro.au/sealevel/sl_impacts_sea_level.html. Accessed 22
November 2008.
10
McInnes, K.L., Walsh, K.J.E., Hubbert G.D. and Beer, T. (2003) ‘Impact of sea-level rise and storm surges on a coastal community’,
Natural Hazards, vol 30, no. 2, pp187-207, www.springerlink.com/content/r5046155pq222137/fulltext.pdf?page=1, accessed 1 December
2008.
11
Harper, B. (1999) Storm tide threat in Queensland: history, prediction and relative risks, Queensland Department of Environment and
Heritage.
12
Ibid
13
Ibid
14
Sea Level Rise website – Sea Level Impacts: Sea Level at http://www.cmar.csiro.au/sealevel/sl_impacts_sea_level.html. Accessed 22
November 2008.
15
Church et el (2006) Sea-level rise around the Australian coastline and the changing frequency of extremes levels. Aust. Met Mag. 55,
253-260.
16
Nicholls, R. J., and Leatherman, S.P. (1994) ‘Global sea-level rise’, in Strzepek, K. and Smith, J.B. (eds) As Climate Changes:
Potential Impacts and Implications, Cambridge University Press, Cambridge.
Prepared by The Natural Edge Project 2009
Page 5 of 25
Water Transformed: Sustainable Water Solutions
governments to help understand the nature of these risks. CSIRO’s scientists such as
Drs Debbie Abbs17 and Katherine McInnes18 have published many studies which have mapped
likely sea-level rises and impacts of storm surges for Australia’s major coastal cities and coastal
developments.
6. Over the next one hundred years many Australians will be at risk from sea level rises. The IPCC
warns that that 1 cm rise in sea level erodes beaches about 1 m horizontally.19 Therefore, even
the lower end of the IPCC predictions, 9 cm is likely to result in as much as 9 m of eroded beach
and coastline. Hence by the year 2100, significant coastal erosion is anticipated and sandy
beaches could have receded by up to 88 m.20 Eighty per cent of Australian’s population lives in
the coastal zone. Longer term, if the global sea level rise is not stopped in coming centuries,
about 711,000 Australian household addresses will be threatened, which are located within 3 km
of the coast and less than 6 m above sea level.21
7. When assessing risk, one key factor to take into account, when determining the potential
magnitude of the damage is whether or not insurance is available. Sea level rises will pose a
significant risk to many Australians over the coming decades because currently most insurance
companies are not willing to provide insurance for damages from storm surges. Karl Sullivan
from Insurance Council of Australia recently stated that
“There is very limited cover available for this particularly inundation risk and it is one of many
different flooding risks that you can have. It is viewed as an extreme risk for a large number
of Australians and consequently there's not a huge appetite to insure that risk because we
don't understand how far and how expensive that could be. The first thing that needs to
happen there is mapping that risk right across Australia and making policy decisions in a
planning sense about avoiding the risk into the future.”22
8. The next step in a risk assessment approach is to identify the best way to reduce risks in this
case from sea level rises. The best and most cost effective adaptation measures for sea level
rises are related to urban planning or infrastructure. Since these decisions have very long time
horizon, it is vital that planning decisions made today take likely sea level rises into account. This
is why the Victorian Government Coastal Strategy (2008) requires local government to
incorporate sea-level rises of no less than 0.8 m by 2100 into all planning decisions and bans
any further canal residential development. Local government must assume sea-level rises of 80
cm by 2100 when considering any new developments for approval. The strategy also urges local
government councils to consider other climate change effects, including storm surges, erosion
and landslides, when approving developments.23 Similar new coastal strategies should be
adopted by all state and local governments in Australia, not just because it is the wisest course
of action, but also because it will help governments avoid legal liability for any damages from
CSIRO Atmospheric and Marine Research (undated) ‘Scientist Dr Debbi Abb’s publications’, www.dar.csiro.au/profile/abbs.html,
accessed 1 December 2008.
18
CSIRO Atmospheric and Marine Research (undated) ‘Scientist Dr Katherine McInnes’s publications’,
www.dar.csiro.au/profile/mcinnes.html, accessed 1 December 2008.
19
IPCC (1990) Strategies for Adaption to Sea-Level Rise. Intergovernmental Panel on Climate Change, Response Strategies Working
Group, http://yosemite.epa.gov/oar/GlobalWarming.nsf/UniqueKeyLookup/RAMR5EHLSJ/$File/adaption.pdf accessed 1 December 2008
20
See Department of Climate Change (undated) Factsheet – Potential Impacts and Costs at
http://www.climatechange.gov.au/impacts/publications/pubs/fs-national.pdf accessed 11 March 2009
21
Coleman, T. (2002) The Impact of Climate Change on Insurance against Catastrophes, Insurance Australia Group, Melbourne,
Australia.
22
Sullivan, K (2009) SBS Insight Transcript: Danger Zone. SBS Insight at http://news.sbs.com.au/insight/episode/index/id/54#transcript
accessed 11 March 2009
23
See Victorian Government’s 2008 Coastal Strategy – Planning for Climate Change at
http://www.vcc.vic.gov.au/2008vcs/part2.1climatechange.htm accessed 11 March 2009
17
Prepared by The Natural Edge Project 2009
Page 6 of 25
Water Transformed: Sustainable Water Solutions
rising sea-level rises. With the likely prospect of increasing extreme weather events being
exacerbated by sea level rises, legal experts argue local government is at increasing risk of
incurring liability if they ‘unreasonably fail to take into account the likely effects of climate
change’.24
9. A sound risk management approach to sea level rises also needs to factor in the risk that the
IPCC 4th Assessment predictions for sea level rises may be too conservative. There is concern
that sea levels may rise more quickly and higher than originally expected and even could exceed
1 m by 2100. NASA Scientist, Dr James Hansen, argues that the slow melting of ice sheets used
for the current IPCC Sea-level Rise estimation is does not match up well with the historic climate
change record. Hansen points out that the geological record suggests that when temperatures
increased to 2-3 degrees above today’s level 3.5 million years ago, sea levels rose not by 59 cm
but by 25 m.25
10. Also, there is concern that the IPCC’s latest predictions on the speed of sea level rises may also
be too conservative. The IPCC 4th Assessment predicted that significant melting of the
Greenland and West Antarctica ice sheets would not happen for over 100 years.26 However,
scientific evidence in late 2008, a year after the publication of the IPCC 4th Assessment report,
shows that sea levels could rise faster than scientists had previously predicted,27 due to a
number of environmental side effects feeding back on the overall system and accelerating the
trend known as “positive feedbacks”.28 Hence, there is a need for decision makers, planners and
government officials involved in planning to monitor these ‘feedbacks’ over time to reassess
potential sea-level rises and factor this information into planning and development decisions and
risk assessment.
11. These “positive” feedbacks could lead to sea-level rises higher than 1 m by 2100 and include:
-
The melting of the North Arctic Sea ice, which is particularly dangerous as the ice has a high
‘albedo’ effect, meaning that it reflects light well, and when it is melted it is replaced by water,
with a lower albedo, which absorbs much more heat, hence accelerating the ocean’s
warming even further.
-
Rapid melting of the North Arctic Sea ice and a reduction in albedo will result in more rapid
warming of the permafrost and other substrates in the northern hemisphere. This, in turn, will
increase the rate of release of methane29 from peat deposits, wetlands and thawing
permafrost.30 With increasing temperatures methane is released from a range of storages in
the environment, hence increasing the global greenhouse gas emissions levels.
24
England, P (2007) Climate Change:What Are Local Governments Liable for? Griffith University Urban Research Program Issues Paper
6 http://www.griffith.edu.au/__data/assets/pdf_file/0011/48566/urp-ip06-england-2007.pdf accessed 11 March 2009
25
Hansen et al (2007) Climate Change and trace gases. Philosophical Transactions of the Royal Society
365, 1925-54.
26
IPCC (2001) Climate Change 2001: Synthesis Report, Contributions of Working Groups I, II, and III to the Third Assessment Report of
the Intergovernmental Panel on Climate Change, Cambridge University Press, Cambridge.
27
Pittock, B. (2006) ‘Are Scientists Underestimating Climate Change?’, EOS, vol 87, no 34, pp340-341.
28
Pearman, G. et al (2007) Evidence of Accelerated Climate Change, Prepared by the Climate Adaptation Science and Policy Initiative,
The University of Melbourne for the Climate Institute.
29
Wickland, K.P., Striegl, R.G., Neff, J.C. and Sachs. T. (2006) ‘Effects of Permafrost Melting on CO 2 and CH4 Exchange of Poorly
Drained Black Spruce Lowland’, Journal of Geophysical Research, vol 111, no. G02011.
30
Walter, K. M., Zimov S. A., et al. (2006) Melting Lakes in Siberia Emit Greenhouse Gas, Nature 443: 71 – 75..
Prepared by The Natural Edge Project 2009
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Water Transformed: Sustainable Water Solutions
-
A study published in January 200931 argued that most of the Antarctic continent was
warming, up half a degree over the past half-century, and that ice shelves which hold the
large Antarctic glaciers from the sea are weakening.
-
The weakening of the natural land carbon sinks, reducing the amount of greenhouse gas that
can be absorbed, sometimes to the point that greenhouse gases are released.32 This is due
mainly to deforestation and loss of vegetation combined with agricultural practices affecting
the ability of soil to absorb carbon dioxide.
-
Ocean acidification is happening faster than predicted, spelling disaster for coral reefs and
resulting in the ocean diminishing as a carbon sink — it will absorb less carbon dioxide,
leaving more in the atmosphere to trap heat. The weakening of the natural ocean carbon
sinks reducing the amount of greenhouse gas that can be absorbed.33 As the temperature of
the oceans increase, its ability to absorb carbon dioxide decreases.
12. The following three possible coastal adaptation response options are recommended by the IPCC
to reduce the risks of damage from sea level rises (discussed in the Brief Background
Information):34
-
Protect: Protect the land and cities from the sea so that existing land occupation can be
maintained by constructing hard structures (such as seawalls) and using soft measures (such
as beach nourishment).
-
Accommodate: The land is still occupied but some modifications are made (such as elevating
buildings on piles such as using the old Queenslander house design and growing flood- or
salt-tolerant crops).
-
Retreat: The coastal region is abandoned.35
Brief Background Reading
Climate Change and Sea-level Rises
Current Intergovernmental Panel on Climate Change (IPCC) 4th Assessment projections are for a
sea-level rise of between 9 and 88 cm between 1990 and 2100 but the 4th Assessment final
Synthesis Report has stated that larger values for the upper bound cannot be excluded. As seen in
Figure 1.4.1, at the global scale, ocean temperatures and sea level will continue their rising trends. 36
Observations since 1961 show that the average temperature of the global ocean has increased at
31
Steig, E. et al (2009) Warming of the Antarctic ice-sheet surface since the 1957 International Geophysical Year. Nature 457, 459-462
(22 January 2009) | doi:10.1038/nature07669;
32
Cox, P., Betts, R., Jones, C., Spall, S. and Totterdell, I. (2000) ‘Acceleration of Global Warming Due to Carbon-Cycle Feedbacks in a
Coupled Climate Model’, Nature, vol 408, pp184–187.
33
Le Quere, C. et al (2007) ‘Saturation of the Southern Ocean CO2 Sink Due to Recent Climate Change’, Science, vol 316, Issue 5832,
p1735.
34
IPCC (2001) Climate Change 2001: Impacts, Adaptation, and Vulnerability, Contribution of Working Group II to the Third Assessment
Report of the Intergovernmental Panel on Climate Change, Cambridge University Press, Cambridge, see ‘Coastal Zones and Marine
Ecosystems’, pp 343-379, www.ipcc.ch/ipccreports/tar/wg2/index.htm, accessed 20 November 2008.
35
Ibid
36
Church, J.A., White, N.J., Coleman, R., Lambeck, K. and Mitrovica, J.X. (2004) ‘Estimates of regional distribution of Sea-Level rise over
the 1950-2000 period’, Journal of Climate, vol 17, pp2609-2625; Church, J. A. and White, N.J. (2006) ‘A 20th century acceleration in global
sea-level rise’, Geophysical Research Letters, vol 33.
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Water Transformed: Sustainable Water Solutions
depths of at least 3000 m, and that the ocean has been absorbing more than 80 per cent of the heat
added to the climate system.37
Figure 1.4.1 Projected sea-level rise for the 21st Century
Source: CSIRO38
Such warming causes seawater to expand, contributing to sea-level rise. As Table 1.4.1 shows,
climate change causes sea-level rises due to thermal expansion of the oceans. Thermal expansion
is just one factor causing sea levels to rise. Sea-level rise is also due to the melting of glaciers, ice
caps and large ice sheets into the oceans as shown in Table 1.4.1
Table 1.4.1: Observed rate of sea-level rise and estimated contributions from different sources
Source of sea-level rise
Average annual sea-level rise
(mm/year)
1961–2003
1993–2003
Thermal expansion
0.42 ± 0.12
1.6 ± 0.5
Glaciers and ice caps
0.50 ± 0.18
0.77 ± 0.22
Greenland ice sheet
0.05 ± 0.12
0.21 ± 0.07
Antarctic ice sheet
0.14 ± 0.41
0.21 ± 0.35
Sum of individual climate contributions to sea-level rise
1.1 ± 0.5
2.8 ± 0.7
Observed total sea-level rise
1.8 ± 0.5
3.1 ± 0.7
Difference (Observed minus sum of estimated climate
contributions)
0.7 ± 0.7
0.3 ± 1.0
37
IPCC (2007) Climate Change 2007: Impacts, Adaptation and Vulnerability, Contribution of Working Group II to the Fourth Assessment
Report of the Intergovernmental Panel on Climate Change, Cambridge University Press, Cambridge, see ‘Coastal systems and low-lying
areas ‘, pp315-356.
38
Sea-Level Rise (undated) ‘Sea-Level Impacts: Sea-Level Projections’, www.cmar.csiro.au/sealevel/sl_proj_21st.html, accessed 22
November 2008.
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Water Transformed: Sustainable Water Solutions
Note: Data prior to 1993 are from tide gauges; those from 1993 onwards are from satellite altimetry.
Source: IPCC (2007) 39
The global sea level rose at an average of 1.8 mm/year from 1961 to 2003, and the rate of increase
was faster (about 3.1 mm/year) from 1993 to 2003, as shown in Table 1.4.1.40 It is important to note
that locally sea level rise will be slightly higher or lower than the global average for sea-level rises.
This is because sea-level rise also depends on a number of factors such as where the heat
penetrates the oceans, how this changes circulation patterns and how local geography interacts
which the mean flow.
During the 21st Century, on average, sea levels will continue to rise due to warming from both past
and future greenhouse gas emissions.
Sea levels will respond more slowly than temperatures to changing greenhouse gas
concentrations. Sea levels are currently rising globally at around 3 mm per year and the rise
has been accelerating. According to the IPCC, sea levels are projected to rise by 9-88 cm by
2100, mainly due to expansion of the warmer oceans and melting glaciers on land. However,
because warming only penetrates the oceans very slowly, sea levels will continue to rise
substantially more over several centuries. On past emissions alone, the world has built up a
substantial commitment to sea-level rise.
Sir Nicholas Stern, The Stern Review, 200641
Risks and Costs of Inaction on Sea-level Rises
Many developed locations in Australia are lower than 1m above sea level and are thus vulnerable to
sea-level rises this century. These locations include Broome, Perth and its surroundings, Mandurah
and its surroundings, Busselton, parts of most capital cities and, in particular, the Gold Coast, which
is built on sand and has many canal developments. Approximately 700,000 Australian homes face
flood risks from the combination of rising sea levels and storm surges.42 The IPCC warns that that 1
cm rise in sea level erodes beaches about 1 m horizontally.43 However, depending on the
geomorphology, coastal flooding can be between 50 - 200 times the sea-level rise.44 The coastal
property owners of insured buildings may lose millions of dollars, as whilst the value of coastal
buildings may be protected to some extent by insurance, the land value of properties is not insured
at all. Thus when land gets inundated or severely eroded and their land loses value they will not be
compensated by insurance.45 It is thus in Australia’s interest to mitigate climate change to avoid this
potential future scenario. It is also in the global interest.
39
IPCC (2007) Climate Change 2007: The Physical Science Basis, Contribution of Working Group I to the Fourth Assessment Report of
the Intergovernmental Panel on Climate Change, Cambridge University Press, Cambridge, see ‘Summary for Policymakers’, p5,
www.ipcc.ch/ipccreports/ar4-wg1.htm, accessed 28 Octonber 2008.
40
IPCC (2007) Climate Change 2007: Impacts, Adaptation and Vulnerability, Contribution of Working Group II to the Fourth Assessment
Report of the Intergovernmental Panel on Climate Change, Cambridge University Press, Cambridge, see ‘Coastal systems and low-lying
areas’, pp315-356.
41
Stern, N. (2006) The Stern Review: The Economics of Climate Change, Cambridge Press, Cambridge.
42
. See Department of Climate Change (undated) Factsheet – Potential Impacts and Costs at
http://www.climatechange.gov.au/impacts/publications/pubs/fs-national.pdf
43
IPCC (1990) Strategies for Adaption to Sea-Level Rise. Intergovernmental Panel on Climate Change, Response Strategies Working
Group, http://yosemite.epa.gov/oar/GlobalWarming.nsf/UniqueKeyLookup/RAMR5EHLSJ/$File/adaption.pdf accessed 1 December 2008
44
Your Development (2008) ‘Adaptation to Climate Change – Sea-Level Rises & Flooding’,
http://yourdevelopment.org/factsheet/view/id/62, accessed 28 November 2008.
45
Ibid.
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Globally, tens to hundreds of millions more people will be flooded each year under the business-asusual greenhouse gas emission scenario.46 According to IPCC 4th Assessment, coastal flooding
could grow tenfold by the 2100, due to sea-level rise alone. Figure 1.4.2 shows the consequences
and total costs of a rise in sea level for developing and developed countries, and globally. For
coastal cities and towns the potential magnitude of negative impact from these risks can be very
high. A 1 m sea-level rise this century would leave 2.2 million square km of land under water, forcing
145 million people to migrate, mostly in Asia, and costing the global economy US$944 billion.47
Figure 1.4.2 Causes, Consequences and Total Costs of an Assumed Sea-level Rise
Source: Tol, R.S. (2007)48
Sea-level rise will directly impact on millions of people over the next century, 49 but this is likely to be
overshadowed, particularly in the shorter term, by the impacts of extreme weather events that are
46
UNEP (2007) Global outlook for Ice & Snow Estimates of people flooded in coastal areas in the 2080s as a result of sea-level rise and
for given socio-economic scenarios and protection responses, UNEP/GRID-Arendal Maps and Graphics Library,
http://maps.grida.no/go/graphic/estimates-of-people-flooded-in-coastal-areas-in-the-2080s-as-a-result-of-sea-level-rise-and-for-givensocio-economic-scenarios-and-protection-responses, accessed 1 December 2008.
47
Siddall, M. and Kaplan, M. (2008) ‘Climate science: A tale of two ice sheets’, Nature GeoScience, pp570 – 572,
www.nature.com/ngeo/journal/v1/n9/index.html, accessed 5 December 2008.
48
Tol, R.S. (2007), ‘The Double Trade-off between Adaptation and Mitigation for Sea-Level Rise: An Application of FUND’, Mitigation and
Adaptation Strategies for Global Change, vol 12, pp741-753, cited in IPCC (2007) Climate Change 2007: Impacts, Adaptation and
Vulnerability, Contribution of Working Group II to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change,
Cambridge University Press, Cambridge, see ‘Coastal systems and low-lying areas’, pp315-356.
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exacerbated by sea-level rise.50 That is, even if the climate conditions that lead to weather events
(such as cyclones and storm surges) remain unchanged in terms of intensity and frequency, the
higher sea level will make the impacts more intense and more frequently reach ‘extreme’ levels. The
frequency of extreme events is already increasing in many locations and, depending on local
conditions, 100-year events could occur as frequently as every few years by 2100.51
Coastal erosion or flood risk will affect at least 158,000 people by 2020 in Europe, while 50 per cent
of Europe’s remaining coastal wetlands most likely will disappear under rising sea levels. 52 In 2004,
about a fifth of the European Union’s coastline suffered serious erosion. Between 1986 and 2001,
expenditure on coastline protection in Europe has risen over 30 per cent to an estimated US$4
billion in 2001.53
Sea-level Rises Combine with Storm Surges
Sea-level rise will cause damage and disruption over the coming centuries. But perhaps more
importantly in the short term, the main threat of damage from sea-level rises comes through the
potential for it to combine with storm surges from extreme weather events, such as cyclones in the
tropics, and large cold fronts in the middle and lower latitudes.
Storm surges occurring on higher mean sea levels will lead to inundation and enable waves to push
further inland, increasing damage and erosion of the built environment and natural coastline. CSIRO
has found that extreme sea-level events that currently occur once every 100 years could occur as
frequently as once every few years by 2100. 54 Along the east coast of the United States and
Canada, sea-level rise over the last century has reduced the period between extreme sea-level
events, leading to greater and more rapid damage to fixed structures, compared to the same events
a century ago.55
Figure 1.4.3 Effect of a small average sea-level rise on sea-level extremes
Sea-Level Rise (undated) ‘Sea-Level Impacts: Sea Level’, www.cmar.csiro.au/sealevel/sl_impacts_sea_level.html, accessed 22
November 2008.
50
ibid
51
Ibid.
52
Eurosion (2004) Living with Coastal Erosion in Europe: Sediment and Space for Sustainability. Part-1 Major Findings and Policy
Recommendations of the EUROSION Project, Guidelines for implementing local information systems dedicated to coastal erosion
management, Directorate General Environment, European Commission.
53
Ibid
54
Sea-Level Rise (undated) ‘Sea-Level Impacts: Extreme Impacts’, www.cmar.csiro.au/sealevel/sl_impacts_extreme.html, accessed 22
November 2008.
55
Zhang, K.Q., Douglas, B.C. and Leatherman, S.P. (2000) ‘Twentieth-century storm activity along the US east coast’, Journal of Climate,
vol 13, pp1748-1761; Forbes, D.L., Parkes, G.S., Manson, G.K. and Ketch, L.A. (2004) ‘Storms and shoreline erosion in the southern Gulf
of St. Lawrence’, Marine Geology, vol 210, pp169-204.
49
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Source: CSIRO56
The IPCC 4th Assessment found that the greatest hot spots at risk of damage from sea-level rising is
north57 and south east Queensland, where there are risks of cyclones creating storm surges, which
at a high tide can inflict severe damage.58 As the IPCC stated, ‘Between 2001 and 2021, the
Sunshine Coast population is projected to grow from 277,987 to 479,806,59 and the Wide BayBurnett population is projected to grow from 236,500 to 333,900.60 Sandy beaches and dunes are
key biophysical characteristics of this coastline, including Fraser Island which is the largest sand
island in the world. These natural features and the human populations they attract are vulnerable to
sea-level rise, flooding, storm surges and tropical cyclones. Many estuaries and adjacent lowlands
have been intensively developed, some as high-value canal estates.’61
Thus a rise in sea level of even a few mm per year, although not threatening spectacular inundation
of the coastline, is still extremely important as it can enhance the reach and power of storm surges,
as Bird,62 Warrick et al,63 and Nicholls and Leatherman64 emphasise. (Figure 1.4.4)
Figure 1.4.4 Storm Surges Diagram
Source: McInnes, K. L. et al (2006)65
Sea-level Rise Impacts on Waste Water and Storm Water systems
Urban water supply and urban stormwater and wastewater treatment systems are also vulnerable to
sea-level rises. Protecting these systems and the potable fresh water supplies from saltwater
Sea-Level Rise (undated) ‘Sea-Level Impacts: Extreme Impacts’, www.cmar.csiro.au/sealevel/sl_impacts_extreme.html, accessed 22
November 2008
57
McInnes, K.L., Walsh, K.J.E., Hubbert G.D. and Beer, T. (2003) ‘Impact of sea-level rise and storm surges on a coastal community’,
Natural Hazards, vol 30, no. 2, pp187-207, www.springerlink.com/content/r5046155pq222137/fulltext.pdf?page=1, accessed 1 December
2008.
58
Harper, B. (1999) Storm tide threat in Queensland: history, prediction and relative risks, Queensland Department of Environment and
Heritage.
59
Queensland Department of Local Government and Planning (2003) Queensland’s Future Population, Queensland Department of Local
Government and Planning (Medium Series), www.lgp.qld.gov.au/?id=1216, accessed 1 December 2008.
60
ABS (2003) Population Projections Australia 2004-2101, Report 3222.0, Australian Bureau of Statistics, Canberra; ABS (2003)
Queensland Government Population Projections, Report 3218.0, Australian Bureau of Statistics, Canberra,
www.abs.gov.au/AUSSTATS/[email protected]/DetailsPage/3218.02004-05?OpenDocument, accessed 1 December 2008.
61
IPCC (2007) Climate Change 2007: Impacts, Adaptation and Vulnerability, Contribution of Working Group II to the Fourth Assessment
Report of the Intergovernmental Panel on Climate Change, Cambridge University Press, Cambridge, see ‘Australia and New Zealand’,
pp507-540,, www.ipcc.ch/pdf/assessment-report/ar4/wg2/ar4-wg2-chapter11.pdf, accessed 1 December 2008.
62
Bird, E.C. (2003) Submerging Coasts, John Wiley and Sons.
63
Warrick, R.A., Barrow, E. M. and Wigley, T.M.L. (Eds.) (1993) Climate and sea-level change: observations, projections, and implications,
Cambridge University Press, Cambridge.
64
Nicholls, R.J.,and S. P. Leatherman (1994) ‘Global sea-level rise’, in Strzepek, K. and Smith, J.B. (eds) As Climate Changes: Potential
Impacts and Implications, Cambridge University Press, Cambridge.
65
McInnes, K.L., Macadam, I., Hubbert, G.D., Abbs, D.J. and Bathols, J. M. (2006) ‘Assessing the impact of climate change on storm
surges’, Third International Conference on Climate Impacts Assessment (TICCIA), Cairns, Qld.
56
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intrusion is one of the most challenging issues relating to climate change.66 Sea-level rises and
storm surges risk leading to an increased level of poor stormwater drainage performance caused by
seawater levels backing up drainage systems. Urban coastal sewerage systems depend on gravity
to help treated sewerage flow, usually out to sea. Sea-level rises and storm surges threaten to
prevent this from happening. This inundation would render gravity drainage systems useless and
require modifications to prevent seawater from backing up into the system.
Sea-level Rises – Is there a Potential for a > 1 m Sea-level Rise by 2100-2200?
Governments and planners across the world are now becoming increasingly aware of the
requirement to consider the risks of sea-level rise in the development of policy and planning,
considering options in the event of a rise of up to 1 m by 2100. Many approaches to this challenge
emphasise strategies to ensure that future development occurs further inland, and at least 1 m
above sea level. But is 1 m sufficient? What if the global average sea-level rise ends up being
greater than 1 m over the next one hundred years? Also, since there is a long delay built into sealevel rises, due to the thermal expansion effect, even with strong climate change mitigation in the
early decades of the 21st Century, sea levels may continue to rise well into the next century. 67
Investors in real estate, or other forms of development, need the security of knowing that the site,
which they are investing in, will be safe from sea-level rises for at least 50-100 years to ensure land
resale values are at least maintained.68
Whilst it is true to say that the highest probability is that sea levels will rise between 18 cm and 1 m
by 2100, it is possible that it could be higher than this. Should the Greenland ice sheet and the
Western Antarctic Ice Shelves melt, this would result in up to a 7 m,69 and 5-6 m global sea-level rise
respectively, significantly greater than the 1 m predicted. One of the reasons why there is such
uncertainty about the loss of polar ice sheets is that climate scientists have never witnessed their
disappearance. Thus, scientists, led by Anders Carlson,70 have investigated the melting of polar ice
sheets using geological evidence from the end of the last ice age, to better understand the
phenomenon of ice sheets melting. Around 20,000 years ago, when the last ice age was at its peak,
the Laurentide ice sheet covered much of North America. This ice sheet was the most recent large
Northern Hemisphere ice sheet to completely disappear. The researchers used geological evidence
and computer modelling to reconstruct the demise of the Laurentide ice sheet. Computer simulations
based on the geological data showed that that the first ice melt, from around 9,000 years ago, led to
sea-level rises of 7 m at a rate of around 1.3 m per hundred years.71 The scientists involved in this
study argue that there are strong parallels with this ice sheet and the Greenland ice sheet today.
Thus Carlson, lead author of the study, concludes that, ‘For planning purposes, we should see the
IPCC projections as conservative. We think this is a very low estimate of what the Greenland ice
66
IPCC (2007) Climate Change 2007: Impacts, Adaptation and Vulnerability, Contribution of Working Group II to the Fourth Assessment
Report of the Inter-governmental Panel on Climate Change, Cambridge University Press, Cambridge, see ‘Coastal systems and low-lying
areas’, pp315-356.
67
Wigley, T. (2005) ‘The Climate Change Commitment’, Science, vol 307, no. 5716, pp1766 – 1769.
68
This is exacerbated by the fact that locally changes might be more or less than the global average. The kind of work that CSIRO
researchers like Deborah Abbs and Kathy McInnes are doing is to try to make these projections of change more realistic at the regional to
local level.
69
IPCC (2001) Climate Change 2001: The Scientific Basis, Contribution of Working Group I to the Third Assessment Report of the
Intergovernmental Panel on Climate Change, Cambridge University Press, Cambridge,
www.grida.no/publications/other/ipcc_tar/?src=/climate/ipcc_tar/wg1/412.htm, accessed 1 December 2008.
70
Carlson, A. (2008) ‘Rapid Early Holocene Deglaciation of the Laurentide ice Sheet’, Nature Geoscience, vol 1, pp620-624,
www.nature.com/ngeo/journal/v1/n9/abs/ngeo285.html, accessed 5 December 2008.
71
Brahic, C. (2008) ‘Sea-level rises could far exceed IPCC estimates’, New Scientist, www.newscientist.com/article/dn14634-sea-levelrises-could-far-exceed-ipcc-estimates.html, accessed 5 December 2008.
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sheet will contribute to sea level.’72 This has implications for governments and planning authorities
currently grappling with what level of sea rise they should build into their long term planning. It is
important therefore for urban planners and government officials, and those working in the built
environment, to understand the most recent developments in climate change which will affect the
scale and rate of sea-level rises. We consider these recent developments next.
Understanding the Latest Climate Science and the Risks of > 1 m Sea-level Rises by 2100
The concern over the conservative estimate of the IPCC arises because of the complexity of the
climate system, and in particular, how a range of associated environmental changes and impacts will
affect the rate of melting. The following environmental changes and impacts stand to have direct
effects on the scale and rate of sea-level rise.
The Melting of Polar Sea Ice and Implications for Greenland Ice Melt and Sea-level Rise
The first important trend to consider is the rate of thawing of Arctic sea-ice into water. This is
particularly important as ice floating in water reflects a much higher percentage of incoming sunlight
back into the atmosphere than water, down from around 80 per cent to 10 per cent. This is known as
the ‘albedo’ effect, where the replacement of highly reflective sea ice with darker open water greatly
increases heat absorbed from sunlight.73 Greater absorption of the Sun’s heat leads to an increase
in water temperatures, resulting in further thermal expansion, faster melting of remaining sea ice,
and local increases in air temperature that increases melting of land based ice in the area. NASA
climate change expert Dr James Hanson asks the question: ‘Could the Greenland ice sheet survive
if the Arctic were ice-free in summer and fall? It has been argued that not only is the ice-sheet
survival unlikely (under this circumstance), but its disintegration would… proceed rapidly. Thus an
ice-free Arctic Ocean, because it may hasten melting of Greenland, may have implications for global
sea level, as well as the regional environment, making Arctic climate change centrally relevant….’74
If you had asked most climate scientists at the start of 2007 when they thought the Arctic would be
free of sea ice in summer, most would have said by 2100 or perhaps 2070 at the earliest. Now
respected climate scientists say that the summer arctic ocean could be ice free by as early as 20132030.75 The reason for this significantly revised estimation is the September 2007 sea ice levels,
which were the lowest ever recorded, beating the old record set in September 2005 by 23 per cent –
i.e. additional melting the size of the USA’s states of Texas and California combined.76 Between
1997 and 2002, the ice thickness in the Arctic decreased 35 per cent and the volume by 33 per
cent.77 The decrease in both extent and thickness suggests that the summer sea-ice has lost more
than 80 per cent of its volume in 40 years. Arctic sea-ice now is unusually thin, making it more likely
Sample, I. (2008) ‘Global warming: Sea-level rises may accelerate due to melting ice sheet:By the end of the century sea levels may be
rising three times as fast as they are at present, as a result of rapid melting of the Greenland ice sheet’, The Guardian, London, UK,
www.commondreams.org/headline/2008/09/01-4, accessed 5 December 2008.
73
Brown, L.R. (2008) Plan B 3.0 Mobilizing to Save Civilization, W.W. Norton, Chapter 3: Rising Temperatures and Rising Seas, p64,
www.earth-policy.org/Books/PB3/Contents.htm, accessed 1 December 2008.
74
Hansen, J. and Sato, M. et al (2007) ‘Dangerous human-made interference with climate: a GISS modelE study’,
Atmospheric Chemistry and Physics, vol 7, pp2287–2312.
75
Adam, D. (2007) ‘Ice-Free Arctic Could be Here in 23 Years’, Guardian (London), 5 September 2007 in Brown, L (2007) Plan B 3.0,
W.W. Norton, p5.
76
Serreze, M., Luthcke, S.B. and Konrad, S. (2007) Arctic Sea Ice Melt and Shrinking Polar Ice Sheets: Are Observed Changes
Exceeding Expectations? An address to the American Meteorological Society's Environmental Science Seminar Series,
www.ametsoc.org/atmospolicy/ESSSSummaryPrint11262007.html, accessed 10 April 2008.
77
Maslowski, W. (2006) Causes of changes in Arctic sea ice, AMS ESSS Seminar, 3 May 2006.
72
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to melt in future summers. Combining the shrinking sea-ice area with the thinness of the remaining
ice, it has been estimated that the overall volume of ice has fallen by half since 2004.78
Figure 1.4.5: Actual Arctic Summer Sea Ice Loss Compared to IPCC Models
Source: Dr Asgeir Sorteber (2007079
Following the extraordinarily hot Arctic summers of 2007 and 2008,80 many climate scientists have
warned that we are approaching a tipping point of great significance. Hansen,81 for example, has
said that the today’s level of CO2 in the atmosphere is enough to cause Arctic sea-ice cover and
massive ice sheets such as on Greenland to eventually melt away leading to greater sea level 82
rises. Many other scientists agree.83
Implications from Recent North Arctic Sea Ice Melt on Rates of Greenland and West Antarctic Ice
Melt
The rapid melting of sea ice in the Arctic in 2007 led to the absorption of enough heat by the ocean
to affect the melting of land ice in Greenland. Eric Rignot, a lead author of a paper showing a
doubling of loss from the Greenland ice sheet over the last decade,84 has stated that, ‘These results
absolutely floored us… The glaciers are sending us a signal. Greenland is probably going to
Borenstein, S. (2007) ‘Arctic sea ice gone in summer within five years?’, Associated Press, 12 December 2007,
http://news.nationalgeographic.com/news/2007/12/071212-AP-arctic-melt.html, accessed 1 December 2008.
79
Sorteberg, A. (2007) Actual Arctic Summer Sea Ice Loss Compared to IPCC Models, Bjeknes Centre for Climate Research and
University Center at Svalbard, Norway, www.carbonequity.info/images/seaice07.jpg, accessed 1 December 2008.
80
Rice, D. (2008) ‘Arctic sea ice melts to 2nd-lowest level on record’, USA Today, www.usatoday.com/weather/climate/2008-08-27-arcticsea-ice_N.htm, accessed 8 December 2008.
81
Hansen, J. and Sato, M. et al (2007) ‘Climate change and trace gases’, Philosophical Transactions Royal Society, vol 365, pp19251954.
82
Hansen, J. (2007) ‘Huge sea-level rises are coming — unless we act now’, New Scientist, 28 July 2007.
83
Borenstein, S. (2007) ‘Arctic sea ice gone in summer within five years?’, Associated Press, 12 December 2007,
http://news.nationalgeographic.com/news/2007/12/071212-AP-arctic-melt.html, accessed 1 December 2008; Rice, D. (2008) ‘Arctic sea
ice melts to 2nd-lowest level on record’, USA Today, www.usatoday.com/weather/climate/2008-08-27-arctic-sea-ice_N.htm, accessed 1
December 2008; Connor, S. (2007) ‘Scientists warn Arctic sea ice is melting at its fastest rate since records began’, The Independent, 15
August 2007; McCarthy, M. (2007) ‘Arctic sea ice melts to its lowest level ever’, The Independent, 22 September 2007; Connor, S. and
McCarthy, M. (2006) ‘Our worst fears are exceeded by reality’, The Independent, 29 December 2006; Flannery, T. (2006) ‘Climate’s Last
Chance’, The Age, 28 October 2006,,www.theage.com.au/news/opinion/climates-last-chance/2006/10/27/1161749313108.html, accessed
1 December 2008.
84
Rignot, E. and Kanagaratnam, P. (2006) ‘Changes in the Velocity Structure of the Greenland Ice Sheet’, Science, vol 311, p5763.
78
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contribute more and faster to sea-level rise than predicted by current models.’85 Air temperatures on
the Greenland ice sheet have increased by 4°C since 1991, and the increasing trend in the total area
of bare ice subject to at least one day’s melting per year is unmistakeable at 13 per cent per year. 86
A 2006 study found that the Greenland ice cap ‘may be melting three times faster than indicated by
previous measurements’ and that, ‘the mass loss is increasing with time.’87
The edges of the ice-sheet are melting up to ten times more rapidly than earlier research had
indicated, and the ice sheet height is falling by up to 10 m a year.88 In addition to these surface
processes, there are suggestions of a potential dynamical response (sliding of the outlet glaciers
over the bedrock) of the Greenland and Antarctic ice sheets. In Greenland, there was a significant
increase in the flow rate of many of the outlet glaciers during the early 21st Century. One potential
reason for this is increasing surface melt making its way to the base of the glaciers, lubricating their
flow over the bed rock, consistent with increased glacier flow rates. Another effect which may be
becoming more important is that, as the ice shelves around Antarctica and Greenland melt or break
up they allow the glaciers behind them to flow faster, leading to increased flow into the ocean.
Implications from the Release of Methane from Peat Deposits, Wetlands and Thawing Permafrost
The rate of global temperature and sea-level rise will also be amplified by the potential release of
billions of tons of methane from peat deposits, wetlands and thawing permafrost.89 Methane is a
greenhouse gas with a global warming effect that is 25 times more potent than carbon dioxide. 90
Models suggest that up to 90 per cent of the upper layer of permafrost will thaw by 2100, 91 and this,
together with the wetland and permafrost soil stores, comprise more than double the total cumulative
emissions from fossil fuel burning so far.92 As the Stern Review recognises, permafrost melting is
now another escalating issue to consider with global warming and predictions of rates of Greenland
ice sheet melting and sea-level rises.93
Implications of the Weakening of the Planet’s ‘Carbon Sinks’
Global temperature increases and sea-level rises will also be amplified by the weakening of the
ocean and land ‘carbon sinks’ to absorb greenhouse gas emissions. Scientists are warning that
levels of carbon dioxide in the atmosphere have grown 35 per cent more quickly than expected since
2000 partly because of a ‘weakening’ of natural carbon sinks.94 Over the last 200 years, the oceans
have absorbed nearly half the carbon dioxide produced by human activities.95 However, as
emissions and ocean temperatures have gradually increased, the buffering capacity of the oceans
New Scientist (2006) ‘Greenland’s water loss has doubled in a decade’, New Scientist, 25 February 2006.
Steffen, W. and Huff, R. et al (2007) ‘Arctic warming, Greenland melt and moulins’, Eos Trans, AGU 88(52) Fall Meet. Suppl., Abstract
C21C-07 88(52)
87
Young, K. (2006) ‘Greenland ice cap may be melting at triple speed’, New Scientist, 10 August 2006.
88
Shukman, D. (2007) ‘Greenland ice-melt ‘speeding up’, BBC News, 28 July 2007, http://news.bbc.co.uk/2/hi/europe/3922579.stm,
accessed 28 November 2008.
89
ACIA (2004) Impacts of a warming Arctic, Arctic Monitoring and Assessment Programme, Cambridge University Press, Cambridge.
90
IPCC (2007) Climate Change 2007: The Physical Science Basis, Contribution of Working Group I to the Fourth Assessment Report of
the Intergovernmental Panel on Climate Change, Cambridge University Press, Cambridge, see ‘Summary for Policymakers’, p33; Zimov,
S.A. et al (2006) ‘Permafrost and the Global Carbon Budget’,Science, vol 312, no.3780, pp 1612-13.
91
Lawrence, D.M., and Slater, A.G. (2005) ‘A projection of severe near-surface permafrost degradation during the 21st century’,
Geophysical Research Letters, vol 32, pL24401. Based on the IPCC’s A2 Scenario, cited in Stern, N. (2007) The Stern Review,
Cambridge University Press, Cambridge.
92
Stern, N. (2007) The Stern Review, Cambridge University Press, Cambridge.
93
Walter, K.M. and Zimov S.A. et al (2006) ‘Melting Lakes in Siberia Emit Greenhouse Gas’, Nature, vol 443, pp71–75,
www.nature.com/news/2006/060904/full/060904-10.html, accessed 13 February 2008.
94
Raupach, M. et al. (2007) ‘Global and regional drivers of accelerating CO2 emissions’, PNAS, 22 May 2007,
www.pnas.org/cgi/content/abstract/0700609104v1, accessed 13 February 2008; British Antarctic Survey (2007) ‘Unexpected Increase in
Atmospheric CO2’, Press Release, 23 October 2007, www.antarctica.ac.uk/press/press_releases/press_release.php?id=328, acessed 10
April 2008.
95
Kuylenstierna, J. and Panwar, T. (ed) (2007) Global Environment Outlook (GEO4): Environment for Development 4, United Nations
Environment Program, Chapter 2: Atmosphere, p65.
85
86
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have decreased, resulting in ocean acidification, changes to biological processes, increased
temperatures and a reduced ability to absorb more carbon dioxide.96 This is also reflected in land
ecosystems through reduced plant growth and the drying and burning of forests (releasing more
carbon dioxide).97
To conclude, the latest science concerning these ‘positive feedbacks’ is leading many climate
experts to review their estimates of the potential speed and scale of sea-level rises for this century
and beyond. Dr Graeme Pearman, former head of CSIRO’s Atmospheric and Marine Research
Division, summed up the situation well in a report98 in 2007, stating that,
A recent review of climate observations compared to projections suggests that the IPCC
projections may have underestimated sea-level rise. The observed sea-level rise for 1993 to
2006 shows a linear trend of 3.3 +/- 0.4 mm/year, which is higher than the IPCC projected
best estimate of 2mm/year.99 Rahmstorf100 estimates a sea-level rise of 0.5 to 1.4 m by 2100,
which is much higher than the range of projections in the IPCC Fourth Assessment Report. In
its 2007 assessment, the IPCC assumed a negligible contribution to 2100 sea-level change
from the loss of Greenland and West Antarctic ice. More recent work suggests that this
conclusion is likely to be incorrect. Projected warming of 2-3 degrees Celsius would result in
increased melt-water during lengthened melt seasons. Multiple positive feedbacks would
have a significant impact on accelerated loss of ice sheets. The consequences ‘could yield
sea-level rise of several metres per century with eventual rise of tens of metres, enough to
transform global coastlines’.101
Climate Change Adaptation Strategies to Address Risks from Sea-level Rises, Storm Surges
and Flooding
Increasingly national,102 state103 and local governments104 are undertaking the development of
serious climate change adaptation strategies to address the risks of sea-level rises. The choice of
96
Royal Society (2005) Ocean Acidification due to increasing atmospheric carbon dioxide, Policy Document 12/05, The Royal Society,
London, www.royalsoc.ac.uk/displaypagedoc.asp?id=13539, accessed 8 December 2008, cited in UNEP (2007) GEO4, UNEP, Chapter 4
‘Water’, p128; Homer-Dixon, T. (2007) ‘A Swiftly Melting Planet’, Op-Ed Contributor, New York Times, 4 October 2007,
www.nytimes.com/2007/10/04/opinion/04homer-dixon.html, accessed 10 April 2008; Cox, P., Betts, R., Jones, C., Spall, S. and Totterdell,
I. (2000) ‘Acceleration of Global Warming Due to Carbon-Cycle Feedbacks in a Coupled Climate Model’, Nature, vol 408, pp184–187;
Jones, C.D. and Cox, P. et al (2003) ‘Strong carbon cycle feedbacks in a climate model with interactive CO2 and sulphate aerosols’,
Geophysical Research Letters, vol 30, no. 9, p1479.
97
IPCC (2001) Climate Change 2001: Synthesis Report, Contributions of Working Groups I, II and III to the 3rd Assessment Report of the
Intergovernmental Panel on Climate Change, Cambridge University Press, Cambridge.
98
Pearman, G. (2008) Evidence of Accelerated Climate Change, Prepared by the Climate Adaptation Science and Policy Initiative, The
University of Melbourne for the Climate Institute, www.climateinstitute.org.au/images/stories/CI056_EACC_Report_v1.pdf, accessed 8
December 2008.
99
Rahmstorf, S., Cazenave, A., Church, J., Hansen, J., Keeling, R., Parker, D. and Somerville, R. (2007) ‘Recent
Climate Observations Compared to Projections’, Science, vol 316.
100
Rahmstorf, S. (2007) ‘A Semi-Empirical Approach to Projecting Future Sea-Level Rise’, Science, vol 315.
101
Hansen, J., Sato, M., Kharecha, P., Russell, G., Lea, D. and Siddal, M. (2007) ‘Climate Change and Trace Gases’,
Philosophical Transactions of the Royal Society A, vol 365.
102
Australian Federal Government’s Department of Climate Change (2006) ‘Assessing and Mapping Australia's Coastal Vulnerability to
Climate Change’, Expert Technical Workshop, Australian Government,,www.climatechange.gov.au/impacts/publications/pubs/coastalworkshop.pdf, accessed 4 December 2008.
103
State Government of Victoria (undated) ‘Future Coasts’, www.climatechange.vic.gov.au/greenhouse/wcmn302.nsf/childdocs/D7563C7AA2711C29CA2575000019D233?open, accessed 4 December 2008.
104
Betts, H. (2001) The incorporation of climate change in flood plain planning at the Gold Coast City Council, Gold Coast City Council;
Preston, B.L., Smith, T., Brooke, C., Gorddard, R., Measham, T., Withycombe, G., McInnes, K., Abbs, D., Beveridge, B. and Morrison, C.
(2008) Mapping Climate Change Vulnerability in the Sydney Coastal Councils Group, Sydney Coastal Councils Group (SCCG),
www.csiro.au/files/files/pk2x.pdf, accessed 8 December 2008; Maunsell Consulting (2008) Towards a City of Melbourne Climate Change
Adaptation Strategy A Risk Assessment and Action Plan Discussion Paper Responding with Resilience, Melbourne City Council,
www.melbourne.vic.gov.au/rsrc/PDFs/EnvironmentalSustainability/CLIMATE_CHANGE_ADAPTATION_STRATEGY_DRAFT.PDF,
accessed 8 December 2008
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the best mix of measures to adapt to sea-level rises depends on many variables, such as the
geography, economic, political and environment of the particular part of the coastline. Although such
measures could be implemented on a case by case basis there are general patterns. In 1990, the
IPCC published a comprehensive guide to governments on the three possible coastal adaptation
response options:105

Protect: which aims to protect the land from the sea so that existing land uses can continue, by
constructing hard structures (e.g. seawalls) as well as using soft measures (e.g. beach
nourishment).

Accommodate: which implies that people continue to occupy the land but make some
adjustments (e.g., elevating buildings on piles, growing flood- or salt-tolerant crops).

Retreat: which involves no attempt to protect the land from the sea; in an extreme case, the
coastal area is abandoned.
Figure 1.4.6 Evolution of Coastal Adaption Strategies
Source: IPCC (1990)106
In Figure 1.4.7, the IPCC extends this framework as it is relevant to the protection of island states
that are threatened by rising sea levels. The 1990 IPCC report on Strategies for Adaptation to Sea
Level Rise outlines in detail each of the options engineers and government planners need to
consider.107 Other useful resources to guide decision makers, engineers and planners here include:
-
The publications pages of CSIRO scientists such as Drs Debbie Abbs108 and Katherine
McInnes.109 These pages list many studies which have mapped likely sea-level rises and impacts
of storm surges for Australia’s major coastal cities and coastal developments. For instance, they
found that in Gippsland, Victoria, by 2070, climate change would increase 1-in-100 year storm
105
IPCC (1990) Strategies for Adaption to Sea-Level Rise, Intergovernmental Panel on Climate Change, Response Strategies Working
Group, http://yosemite.epa.gov/oar/GlobalWarming.nsf/UniqueKeyLookup/RAMR5EHLSJ/$File/adaption.pdf, accessed 1 December 2008.
106
IPCC (1990) Strategies for Adaption to Sea-Level Rise, Intergovernmental Panel on Climate Change, Response Strategies Working
Group, http://yosemite.epa.gov/oar/GlobalWarming.nsf/UniqueKeyLookup/RAMR5EHLSJ/$File/adaption.pdf, accessed 1 December 2008.
107
IPCC (1990) Strategies for Adaption to Sea-Level Rise, Intergovernmental Panel on Climate Change, Response Strategies Working
Group, http://yosemite.epa.gov/oar/GlobalWarming.nsf/UniqueKeyLookup/RAMR5EHLSJ/$File/adaption.pdf, accessed 1 December 2008
108
CSIRO Atmospheric and Marine Research (undated) ‘Scientist Dr Debbi Abb’s publications’, www.dar.csiro.au/profile/abbs.html,
accessed 1 December 2008.
109
CSIRO Atmospheric and Marine Research (undated) ‘Scientist Dr Katherine McInnes’s publications’,
www.dar.csiro.au/profile/mcinnes.html, accessed 1 December 2008.
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surge heights by 38-46%.110 Their modelling indicated that most of this height increase was due
to sea-level rise.111
-
There have been a range of recent conferences which have brought together expertise in this
area and experience to-date in making these choices to plan to adapt to sea-level rises.112
-
There are also studies and economic modelling which seeks to work out the relative cost benefits
of the different options, such as retreat versus protection, which can help guide processes to
make these decisions.113
-
Finally, the Australian Government and CSIRO’s ‘Your Development Portal’ provides a list of
questions to ask to help guide adaptation to sea-level rises for specific future developments.114
Figure 1.4.7 Responses to sea-level rise
Source: IPCC (2001)115
We now overview the general strategies to adapting to sea-level rises briefly. A more detailed
discussion of these options will be covered in Module C.
Protection of Coastal Cities and Towns from Sea-level Rises and Storm Surges
While it will not be economically viable to protect all of the world’s coastlines from sea-level rises and
the amplified storm surges, studies show that it is viable to protect highly populated areas, where
110
McInnes et al (2005) Climate Change in Eastern Victoria. Stage 2 Report: The effect of climate change on storm surges. Report to
Gippsland Coastal Board, 37 pp,.
111
CSIRO (2007) Climate Change in Australia - Technical Report 2007.CSIRO.
112
IPWEA (2008) ‘Conference Proceedings from National Conference on Climate Change Responding to Sea-Level Rise, Coffs Harbour,
NSW 3 - 5 August 2008’ www.ipwea.org.au/Content/NavigationMenu/SIGS/ClimateChange/ConferencePapers/default.htm, accessed 1
December 2008.
113
Fankhauser, S. (1995) ‘Protection versus retreat: the economic costs of sea-level rise’, Environment and Planning , vol 27, no. 2,
pp299 – 319, www.uea.ac.uk/env/cserge/pub/wp/gec/gec_1994_02.pdf, accessed 1 December 2008.
114
Your Development (2008) ‘Adaptation to Climate Change – Sea-Level Rises & Flooding’,
http://yourdevelopment.org/factsheet/view/id/62, accessed 28 November 2008.
115
IPCC (2001) IPCC Special Report on the Regional Impacts of Climate Change: An Assessment of Vulnerability, IPCC,
www.grida.no/publications/other/ipcc_sr/, accessed 28 November 2008.
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large proportions of national populations are concentrated,116 even if faced with sea-level rises in the
order of 1-2 m.117 There is a wealth of studies going back twenty years118 investigating sea-level
rises up to 1 m which shows that the costs of protecting highly populated cities - with bulkheads,
dikes, levees and pumping - is economically efficient compared to the potential direct losses and
costs of relocation and retreat.119 Hence even a partial defence against sea-level rise can protect
much of the world’s coastal population over the coming centuries. A number of cites around the
world are gaining important experience in responding to sea-level rises, including:
- Coastal cities such as Tianjin, Shanghai, Tokyo,120 London,121 Osaka, and Bangkok presently
have large areas below sea-level which are dependent on flood defences and pumped drainage
to avoid flooding. Some of these cities have sea protection barriers which are now very famous,
such as the Thames River Barrier. London is particularly vulnerable to storm surges and high
spring tides and the Thames Barrier was built to protect London from these and other potential
flooding scenarios. 122
- In the case of the Netherlands, half of the country is below sea level. The Netherlands has
constructed walls to protect their land and cities from flooding by the sea, nearly two-thirds of
which lies below sea level. The Netherlands government intends to spend up to EU1.5 billion
(US$2.1 billion dollars) per year during the 21st Century on additional safety measures. The
country has already built an elaborate network of dikes, man-made islands and a 1.5 mile stretch
of 62 gates to control the entry and exit of North Sea waters into the country's low-lying southwestern provinces.123
In Australia, local governments like the City of Melbourne are learning from overseas experience to
develop their own climate change adaptation strategies to plan for sea-level rises to protect their built
environment and infrastructure.124
While there is a growing level of experience globally on how to protect coastal cities, towns and
coastlines from rising sea levels and the associated increased risks of storm surges, 125 much of this
experience is in the range or 1-2 m, and will not be sufficient to deal with a future rapid increase in
the range of 5 – 6 m from the potential melting of the remaining massive ice stores as described
previously. This is because most have assumed that, if there are extreme sea-level rises, retreat is
the only option. Certainly, it will not be economically viable to protect every coastal city and town with
Small, C. and Nicholls, R.J. (2003) ‘A Global Analysis of Human Settlement in Coastal Zones’, Journal of Coastal Research, vol 19, no.
3, pp584-599.
117
Tol, R.S. et al(2006), ‘Adaptation to Five Metres of Sea-Level Rise’, Journal of Risk Research, vol 9, no. 5, pp467-482.
118
National Research Council, Committee on Engineering Implications of Changes in Relative Mean Sea-Level (1987) Responding to
Changes in Sea Level: Engineering Implications, National Academy Press, Washington, DC, p148,
http://books.nap.edu/openbook.php?record_id=1006&page=R1, accessed 1 December 2008.
119
National Research Council, Committee on Engineering Implications of Changes in Relative Mean Sea Level (1987) Responding to
Changes in Sea Level: Engineering Implications, National Academy Press, Washington, DC, p148,
http://books.nap.edu/openbook.php?record_id=1006&page=R1, accessed 1 December 2008.
120
Nicholls, R.J. (1995) ‘Coastal Megacities and Climate Change’, Geojournal , vol 37, no. 3, pp369 – 379.
121
Thames Barriers and Learning Centre, London website, www.environmentagency.gov.uk/regions/thames/323150/335688/341764/344671/?version=1&lang=_e, accessed 22 September 2008.
122
Thames Barriers and Learning Centre, London website, www.environmentagency.gov.uk/regions/thames/323150/335688/341764/344671/?version=1&lang=_e, accessed 22 September 2008
123
Building Better Dams (undated) ‘Civil Engineers Learn from Dutch Flood Barrier System’, www.sciencedaily.com/videos/2006/0807building_better_dams.htm, accessed 22 September 2008.
124
Maunsell (2008) Towards a City of Melbourne Climate Change Adaptation Strategy: A Risk Assessment and Action Plan Discussion
Paper Responding with Resilience. City of Melbourne
http://www.melbourne.vic.gov.au/rsrc/PDFs/EnvironmentalSustainability/CLIMATE_CHANGE_ADAPTATION_STRATEGY_DRAFT.PDF
accessed 11 March 2009
125
National Research Council, Committee on Engineering Implications of Changes in Relative Mean Sea Level (1987) Responding to
Changes in Sea Level: Engineering Implications,.National Academy Press, Washington, DC, p148
http://books.nap.edu/openbook.php?record_id=1006&page=R1, accessed 1 December 2008.
116
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a 5 m high sea wall, however a recent global cost benefit analysis study126 shows that, even with 5 m
sea-level rises, it is economically efficient to invest in protecting highly populated major coastal
cities.127 However, this is unlikely to be true for those mega-cities that are built on river deltas which
are already subsiding. Studies show that coastal protection infrastructure like dikes, water gates,
pumping and drainage systems, seawalls and breakwater can lose their stability due to sea-level
rise.128 The reason is that sea-level rise decreases the bearing capacity of the soil foundation.129
Detailed and locally specific studies for the Netherlands,130 Thames Estuary, London131 and the
Rhone delta132 suggest that a range of factors will mean that retreat is the most likely option than
protection. These studies suggest that, under a 5 m sea-level rise scenario, strategic retreat with a
lower level of protection further inland is more likely than further major coastal investment in
protection. This is thought to be due to a range of issues, including:
-
The fact that decisions are made not just on the basis of cost-benefit analysis, as investing in
coastal protection involves opportunity costs. The voting public may overall prefer that money is
spent on other priorities such as health and education, and an organised retreat and relocation
rather than major coastal protection.
-
The risk that inefficiencies in the adaptation process can threaten the success, including
indecision and inertia due to the fact that co-ordination is needed across all levels of government.
-
The potential for the public to lose confidence that coastal protection will work under such a
scenario of abrupt climate change and sea-level rise. Thus, even when cost-benefit analysis
suggests that protection should occur, there are a range of reasons why it may not be wise to do
so.
Accommodation by Coastal Cities and Towns to Sea-level Rises and Storm Surges
A strategy focused on accommodation rather than protection accepts that it is not economically
viable to seek to protect all of the world’s coastlines and includes a number of key options, including:
-
Elevating residential and small commercial buildings on pilings to protect them from sea-level
rises and storm surges. This is already done in regions and countries that are low lying or below
sea level, such as in the Netherlands. Building codes should be adapted to specify minimum
elevations and piling depths in such conditions. In Australia, the traditional “Queenslander
home”, which was raised on pilings, is a good example of effective building design to adapt to the
risks of sea-level rises and storm surges.
-
Storm warning, evacuation and preparedness plans could be instituted to protect communities
from extreme events and the amplified storm surges that will be a result of higher sea levels.
Tol, R.S. et al (2006) ‘Adaptation to Five Metres of Sea-Level Rise’, Journal of Risk Research, vol 9, no. 5, pp467-482,
www.fnu.zmaw.de/fileadmin/fnu-files/publication/working-papers/waisglobalwp.pdf, accessed 1 December 2008.
127
Tol, R.S. et al (2006) ‘Adaptation to Five Metres of Sea-Level Rise’, Journal of Risk Research, vol 9, no. 5, pp467-482,
www.fnu.zmaw.de/fileadmin/fnu-files/publication/working-papers/waisglobalwp.pdf, accessed 1 December 2008.
128
Nicholls, R.J. and Mimura, N. (1998) ‘Regional issues raised by sea-level rise and their policy implications’, Climate Research, vol 11,
no. 1, pp5-18.
129
Shaw, J., Taylor, R., Solomon, S., Christian, H. and Forbes, D. (1998) ‘Potential impacts of global sea-level rise on Canadian coasts’,
The Canadian Geographer, vol 42, pp365-379.
130
Olsthoorn, X., van der Werff, P., Bouwer, L.M. and Huitema, D. (2005) Neo-Atlantis: Dutch Responses to Five Metre Sea-Level Rise,
No FNU-75, Working Papers from Research unit Sustainability and Global Change, Hamburg University, www.fnu.zmaw.de/fileadmin/fnufiles/publication/working-papers/waishollandwp.pdf, accessed 1 December 2008.
131
Lonsdale, K., Downing, T.E., Nicholls, R.J., Vafeidis, A.T., Parker, D., Dawson, R.J. and Hall, J.W. (2008) ‘Results from a dialogue on
responses to an extreme sea-level rise scenario in the Thames Region, England’, Climatic Change.
132
Poumadère, M., Mays, C., Pfeifle, G. with Vafeidis, A.T. (2008) ‘Worst Case Scenario and Stakeholder Group Decision: A 5-6 Metre
Sea-Level Rise in the Rhone Delta, France’, Climatic Change, www.uni-hamburg.de/Wiss/FB/15/Sustainability/annex9.pdf, accessed 1
December 2008.
126
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-
Where sea-level rises harms agricultural lands and traditional crops, salt tolerant crops could be
used to adapt and accommodate. Long term larger changes to coastal agriculture may be
required such as a shifting from agricultural lands to aquaculture farming.
Retreating from Sea-level Rises and Storm Surges
The lowest risk adaptation strategy is that of retreat. Retreating from low lying areas may prove to be
the most cost effective way to adapt to rising sea levels. To facilitate such a retreat, coastal zone
development plans should be adjusted to discourage development of coastal areas likely to be
vulnerable to sea-level rise.133 Such a strategy may restrict future development to areas that are now
less than 2-3 m above sea-level over the next 100 years. Government can ensure this happens by
limiting development on low lying lands through land acquisition and applying land use restrictions,
prohibiting reconstruction of property damaged by storms, and reductions of subsidies and
incentives for development in vulnerable areas.
Many nations, including Australia, already require new buildings be set back from the sea. These
regulations should be updated to require the consideration of the future impacts from a rising sea
level. Increasingly government planners and local government councils are doing this. Byron Bay
Council, in New South Wales, for example, has incorporated a requirement for all future
development to consider the location in respect to sea-level in order to receive approvals. The
Victorian Government through their Victorian Coastal Strategy (2008) now requires local government
to incorporate sea-level rises of no less than 0.8 m by 2100 into all planning decisions and bans any
further canal residential development. Local government must assume sea-level rises of 80 cm by
2100 when considering any new developments for approval. The strategy also urges local
government councils to consider other climate change impacts, including storm surges, erosion and
landslides, when reviewing development applications.134 Similar new coastal strategies should be
adopted by all state and local governments because it will reduce the risk of legal liability for any
damages from rising sea-level rises. Local government is at increasing risk of incurring liability if they
‘unreasonably fail to take into account the likely effects of climate change’.135
As outlined above, another driver for change will be as Australian citizens realise how difficult it is to
gain storm surge insurance in Australia. Currently few Australians are aware that the insurance
industry sees storm surges as a high risk area and hence is rarely offering insurance to cover it. For
all these reasons we recommend that state and local government follow the lead of the Victorian
Government136 and councils like the Melbourne City Council137 which are developing clear planning
criteria to address the risks of sea-level rises this century.
Fankhauser, S. et al (1999) ‘Weathering Climate Change: Some Simple Rules to Guide Adaptation Decisions’, Ecological Economics,
vol 30, pp67-78, www.fnu.zmaw.de/fileadmin/fnu-files/publication/tol/ececadaptation.pdf, accessed 1 December 2008.
134
See Victorian Government’s 2008 Coastal Strategy – Planning for Climate Change at
http://www.vcc.vic.gov.au/2008vcs/part2.1climatechange.htm accessed 11 March 2009
135
England, P (2007) Climate Change:What Are Local Governments Liable for? Griffith University Urban Research Program Issues Paper
6 http://www.griffith.edu.au/__data/assets/pdf_file/0011/48566/urp-ip06-england-2007.pdf
136
See Victorian Government’s 2008 Coastal Strategy – Planning for Climate Change at
http://www.vcc.vic.gov.au/2008vcs/part2.1climatechange.htm accessed 11 March 2009
137
Maunsell (2008) Towards a City of Melbourne Climate Change Adaptation Strategy: A Risk Assessment and Action Plan Discussion
Paper Responding with Resilience. City of Melbourne
http://www.melbourne.vic.gov.au/rsrc/PDFs/EnvironmentalSustainability/CLIMATE_CHANGE_ADAPTATION_STRATEGY_DRAFT.PDF
accessed 11 March 2009
133
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Key References
Assessing Vulnerability to Sea-level Rises – Australia
CSIRO Atmospheric and Marine Research (undated) ‘Scientist Dr Debbi Abbs publications’,
www.dar.csiro.au/profile/abbs.html, accessed 1 December 2008.
CSIRO Atmospheric and Marine Research (undated) ‘Scientist Dr Katherine McInnes publications’,
www.dar.csiro.au/profile/mcinnes.html, accessed 1 December 2008.
Church, J., Hunter, J., McInnes, K. and White, N.J. (2004) ‘Sea-level rise and the frequency of
extreme event around the Australian coastline’, Coast to Coast '04: Australia's National Coastal
Conference, Hobart, Tasmania, www.bom.gov.au/amm/200604/church.pdf, accessed 1 December
2008.
IPCC CZMS (1992) ‘A common methodology for assessing vulnerability to sea-level rise, 2nd
revision’, in IPCC, Global Climate Change and the Rising Challenge of the Sea, Report of the
Coastal Zone Management Subgroup, Response Strategies Working Group of the
Intergovernmental Panel on Climate Change, Ministry of Transport, Public Works and Water
Management, The Hague.
Strategies to Adapt to Sea-level Rises, Storm Surges and Flooding
IPCC (1990) Strategies for Adaption to Sea-level Rise. Intergovernmental Panel on Climate Change,
Response
Strategies
Working
Group,
http://yosemite.epa.gov/oar/GlobalWarming.nsf/UniqueKeyLookup/RAMR5EHLSJ/$File/adaption.pdf
accessed 1 December 2008
IPWEA (2008) ‘Conference Proceedings from National Conference on Climate Change Responding
to
Sea-level
Rise,
Coffs
Harbour,
NSW
3
5
August
2008’,
www.ipwea.org.au/Content/NavigationMenu/SIGS/ClimateChange/ConferencePapers/default.htm,
accessed 1 December 2008
Commission on Engineering and Technical Systems (CETS) (1987) Responding to Changes in Sea
Level: Engineering Implications, CETS, USA National Academies Press,
http://books.nap.edu/openbook.php?record_id=1006&page=R1, accessed 1 December 2008.
NCCOE (2004) Guidelines for responding to the effects of climate change in coastal and ocean
engineering, The National Committee on Coastal and Ocean Engineering, Engineers Australia,
www.engineersaustralia.org.au/shadomx/apps/fms/fmsdownload.cfm?file_uuid=38749952-E3C67552-7D61-76F72E15A317&siteName=ieaust, accessed 1 December 2008.
Institution of Mechanical Engineers (UK) (2008) Climate Change: Adapting to the Inevitable.
Institution of Mechanical Engineers (UK) Available at
http://www.imeche.org/NR/rdonlyres/D72D38FF-FECF-480F-BBDB6720130C1AAF/0/Adaptation_Report.PDF accessed 11 March 2009
Best Practice Adaptation Case Studies – Government Planning Policy Addressing Risks of
Sea-Level Rises.
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See Victorian Government’s 2008 Coastal Strategy – Planning for Climate Change at
http://www.vcc.vic.gov.au/2008vcs/part2.1climatechange.htm accessed 11 March 2009
Maunsell (2008) Towards a City of Melbourne Climate Change Adaptation Strategy: A Risk
Assessment and Action Plan Discussion Paper Responding with Resilience. City of Melbourne
http://www.melbourne.vic.gov.au/rsrc/PDFs/EnvironmentalSustainability/CLIMATE_CHANGE_ADAP
TATION_STRATEGY_DRAFT.PDF accessed 11 March 2009
Best Practice Adaptation Case Studies in Protection Strategies –
Thames Barriers and Learning Centre, London website,
www.environmentagency.gov.uk/regions/thames/323150/335688/341764/344671/?version=1&lang=
_e, accessed 22 September 2008.
Science Daily (2006) Building Better Dams: Civil Engineers Learn from Dutch Flood Barrier System’,
Science Daily, 1 August 2006, www.sciencedaily.com/videos/2006/0807-building_better_dams.htm,
accessed 22 September 2008.
Other Useful Links
Your Development (2008) ‘Adaptation to Climate Change - Sea-level rise & flooding’,
http://yourdevelopment.org/factsheet/view/id/62 Accessed 17 September 2008, accessed 1
December 2008.
USA EPA (undated) ‘Sea-level Rising’,
http://yosemite.epa.gov/oar/GlobalWarming.nsf/content/ResourceCenterPublicationsSeaLevelRiseIn
dex.html, accessed 1 December 2008.
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