International assessments of the vulnerability.pdf - Climate ...

International assessments of the vulnerability of the coastal zone to climate change, including an Australian perspective
The IPCC report indicated that rates of sea-level rise will be variable at the regional
and local scales. The details of this variation are largely unknown; global climate
models do enable some aspects of regional variation in sea-level to be modelled, but
regional projections are not yet available and local projections are largely impossible.
Evaluation of effects on several nations indicates that the likely impacts of sea-level
rise can vary from country to country and from one geomorphic setting to another
(Biljsma et al., 1996). Certain geomorphic settings are more vulnerable than others,
for example, deltas, small islands and most particularly low-lying coral atolls are
especially vulnerable. Coastal wetlands appear to be threatened with loss or
significant change in most locations as their present location is intimately linked with
present sea level, although their ability to respond dynamically to such changes by
sedimentation and biomass production needs to be carefully considered (French et al.,
1995). Urbanised sandy coasts may also be vulnerable if development is concentrated
too close to the shoreline, primarily due to the large costs of maintaining a sandy
beach for both recreation and protective purposes (Nicholls and Lowe, 2004). These
costs are often highly uncertain.
The concept of vulnerability embraces: (1) the physical and socio-economic
susceptibility to global climate change and (2) the ability to cope with these
consequences (i.e. susceptible countries or areas may not be vulnerable). The IPCC
developed a Common Methodology (CM) to provide a better understanding of
societal vulnerability to climate changes, particularly sea-level rise (IPCC CZMS,
1992; IPCC, 1994). This CM procedure is examined in section 4.1.1.
3.2.2 What IPCC says about Australia
Although sea-level projections imply minor differences in the extreme estimates, the
broad range of expected average sea-level rise by the year 2100 is in the range 0.1-0.9
m, with a mean of 0.5 m (IPCC, 2001b; NCCOE, 2004). For the majority of the
Australian coast, it appears appropriate to adopt this projected sea-level rise. Several
coupled atmosphere-ocean Global Climate Models (including the CSIRO model)
suggest Australia will experience a slightly lower value than the global average. This
increase in sea level is less than the current vertical range over which the tide varies
around most of the Australian coast. It is also less than the height reached by the sea
during the Holocene highstand around 6000 years ago around many parts of the
Australian coast. These two comparisons serve to emphasise the challenges ahead in
discriminating between the impact of sea-level change from the natural variability that
already exists, and that which is likely to be experienced. For example, it has not
been possible to establish the elevation of sea level 6000 years ago in many of those
parts of Australia that have a large tidal range because many of the proxy indicators of
sea level do not permit a clear discrimination of different tidal levels.
IPCC has also carried out several studies in individual developing countries, such as
Mongolia, India, Kenya, China, Senegal, Brazil, Ukraine, Uganda, Mexico, Baltic
States, the Caribbean Islands, Thailand, Sierra Leone and South Pacific (Tuvalu). No
IPCC country study of this type has been undertaken in Australia; the greater
availability of detailed population and economic data, and sophisticated topographic,
remote sensing and other datasets, suggest that Australia has the capacity as a
provider rather than a recipient of these types of assessments.
Australian Greenhouse Office, Department of the Environment and Heritage, 2006
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