18.104.22.168. Vulnerability Assessments and Case Studies
In Australia, vulnerability assessments were carried out for Cocos (Keeling)
Island (an Australian Territory), Geographe Bay in Western Australia, and Kiribati
in response to the first version of the IPCC Common Methodology (IPCC, 1991).
This led to recommendations for changes to the Common Methodology (McLean and
Meanwhile, a major vulnerability study was carried out by the Port of Melbourne
Authority (1992) on the impact of projected greenhouse changes on the 3,000
km of the Victorian coast. Quantitative assessment was carried out for selected
beaches for 0.3- and 0.5-m rises in mean sea level, without considering other
changes. The largest recession rates were indicated for beaches west of Cape
Otway, due to the relatively fine sand and more severe wave conditions. Shoreline
recession rates also were significant in parts of Port Phillip Bay and the Gippsland
Lakes, due to generally narrower beaches. Detailed assessments identified beaches,
barriers, estuaries, mudflats, swamps, and sedimentary cliffs that are particularly
A series of nine case studies initiated by the Australian Department of the
Environment, Sport and Territories (DEST) on coastal vulnerability to climate
change and sea-level rise was undertaken during 1994 and 1995 (Waterman, 1996).
Impacts considered included sea-level rise, temperature and rainfall variation,
changes in storm intensity and frequency, and saltwater intrusion into surface
and groundwater supplies. Case studies were undertaken for Mackay, Queensland;
Batemans Bay, New South Wales; Gippsland Lakes and Port Phillip Bay, Victoria;
South Arm, Hobart, Tasmania; Northern Spencer Gulf, South Australia; Perth,
Western Australia; and the Darwin and Alligator Rivers regions in the Northern
Territory. Emphasis in the studies was placed on the wider socioeconomic, environmental,
aesthetic, and cultural aspects, as well as strategies for integration of vulnerability
assessment into coastal management and planning processes. The main aim in most
of the studies, however, was to test the methodology rather than to produce
definitive assessments of the vulnerability in the regions.
The studies found that vulnerability to climate change is difficult to determine
in the context of the inherent variability of natural systems and the impacts
of development on the coastal zone. In addition, the effects of change are poorly
understood, and the implications for coastal management are not well appreciated
by the wider community. The researchers concluded that community consultation,
along with serious attempts to address the complex jurisdictional issues concerning
coastal management, was essential.
Several of the studies, such as those for Port Phillip Bay and Hobart, noted
the high degree of variability in potential impacts, even over distances of
a few kilometers. The basis for identifying vulnerable areas was a geomorphological
study that identified the main coastal landforms. At the broadest scale of generalization,
the whole coast of Australia has been categorized by Chappell et al. (1996)
according to several overlapping geomorphological and greenhouse hazard criteria,
partly based on the work of Bird (1988, 1993) and Thom (1984). High wave energy
coasts in the southern parts of the west and east of the continent are vulnerable
to shifts in wave direction and energy, especially on beach coasts. Across most
of northern Australia, rising sea level and changes in tropical cyclone activity
are the greatest threats, whereas the Great Barrier Reef may benefit in some
respects from moderate sea-level rises.
Severe limitations applied in quantitatively assessing likely impacts in the
DEST case studies because of the wide range of uncertainty in the scenarios
for sea-level rise, temperature and rainfall changes, and changes in storm intensity
and frequency. Moreover, even in well-studied areas-such as the Alligator Rivers
region in the Northern Territory, where rapid changes (such as saltwater intrusion
into the Kakadu freshwater flood plains) (Knighton et al., 1991; Woodroffe and
Mulrennan, 1993) have occurred in historical times-processes of natural change
are not well understood. Nevertheless, it is clear that Kakadu National Park,
which is a World Heritage Area and major tourist attraction as well as Aboriginal
hunting and fishing grounds, would be almost totally transformed into mangrove
forest by a sustained 1-m rise in mean sea level.
In several of the areas studied, towns such as Port Augusta, Port Pirie, Lakes
Entrance, and Mackay have experienced partial flooding from the sea due to extreme
events in the recent past, so they are very vulnerable to effects of sea-level
rise. This was highlighted for Mackay by Smith and Greenaway (1994), who note
a high sensitivity of flood damage to any change in the climatology of storm
Potential vulnerability to health effects, particularly due to increases in
standing water (see Section 22.214.171.124), also were noted.
The study of the Perth metropolitan coastline noted the natural "breakwater
effect" of the offshore reef system and concluded that "climate change, natural
or greenhouse-induced, appears to be more important to future changes ... than
projected rises in mean-sea level." Saltwater penetration into the coastal aquifer
also is an issue in the Perth region, as it is in some other coastal aquifers
(Ghassemi et al., 1991).
Small, low-lying coastal and island communities are particularly vulnerable
to sea-level rise and changes in climatic forcing of extreme events. These communities
include several of the Torres Strait islands (Mulrennan, 1992), the Australian
territory of Cocos (Keeling) Islands, and several Aboriginal coastal communities
across northern Australia. Unlike cities such as Darwin, these small communities
usually do not abide by strict building codes or have evacuation procedures.
Development of such codes and procedures therefore is necessary for effective
The DEST project (Waterman, 1996) identified a number of issues concerning
how policy and management decisions are made about the effects of climate change
and sea-level rise by authorities and groups in coastal areas. Common methodological
elements that should form part of a region-specific approach to vulnerability
assessment were identified. Specific recommendations included capacity-building
at governmental and community levels, including awareness raising; the development
of a better appreciation of insurance, legal, and land-use planning implications,
including professional and public liability; the development of a guide to best
practice in integrated coastal zone management; and the development of benchmarks,
monitoring programs, and databases for coastal zones.
In New Zealand, there has been no comprehensive national assessment of coastal
vulnerability to climate and sea-level changes. Nonetheless, under the Resource
Management Act (RMA) of 1991, local authorities are obligated to ensure the
"avoidance or mitigation of natural hazards," including coastal flood and erosion
hazards. Subsequent legal rulings have confirmed that future sea-level rise
should be taken into account in coastal hazard analyses in connection with resource
consent (permit) procedures as specified under the RMA. Furthermore, the New
Zealand Coastal Policy Statement (Department of Conservation, 1994), which contains
policies aimed at achieving the single purpose of the RMA (the "sustainable
management of natural and physical resources"), includes specific reference
to the possibility of a "rise in sea level" and its impacts on the subdivision,
use, and development of the coast.
As a consequence of this policy framework, numerous coastal hazard studies
have been commissioned by local authorities and developers in New Zealand for
planning, policy development, and environmental impact assessment purposes.
On the whole, these analyses-mostly in the form of unpublished consultants'
reports-suggest that a considerable portion of the existing built environment
of the New Zealand coast would be endangered by a future rise in sea level of
the order of 0.5-1 m, especially along sandy beach and dune coasts. Where development
pressures are high, such as in the Bay of Plenty, the potential increase in
vulnerability is large unless adaptive measures are taken.