Vulnerability, Impacts and Adaptation of Coastal Zones to Global Change - Vulnerability of Coastal Ecosystems and Adaptation - page 162

above mean sea level and with a population of about 1,700 people.
The floods associated with extreme weather events, particularly
tropical cyclones, cause the salinization of soils and water resources,
making agriculture and the population's survival very problematic.
Some of the inhabitants of the Carteret Atoll have migrated to other
less vulnerable nearby islands since 1980.
4.6.2. Systems for analyzing institutional and government decisions
When choosing from diverse options for the adaptation of coastal
zones to climate change, it is generally necessary to consider long-
term investment (more than 30 years) options, such as changes in land
planning, the construction of defenses against flooding and
submersion and construction of housing, leisure, tourism and transport
infrastructures. This implies that classical cost-benefit analysis
methods cannot be used because it is not possible to attribute
probabilities to the different socio-economic scenarios that
determine the scenarios for greenhouse gas emissions [LEM 01].
These are the scenarios that allow us to project the impacts and the
vulnerabilities of long-term investments. Nevertheless, cost-benefit
analyses are often used in coastal adaptation strategies. To resolve the
problem of attributing probabilities, it is preferable to use approaches
where the uncertainty is represented by a group of scenarios instead of
a distribution of probabilities. Robust decision-making is a method
characterized by the choice of options considered to be efficient in a
broad range of socio-economic and climate scenarios.
The decision-making systems should moreover be flexible so that
the decisions can be adjusted if new information and knowledge arises
on the climate evolution and on the resulting vulnerabilities of natural
and human coastal systems [HAL 09]. The multiple-criteria decision
analysis enable robustness and flexibility to be included
simultaneously. The application of this type of approach in decision-
making processes is becoming increasingly frequent.
The institutional and governmental framework that supports the
coastal zones' adaptation is a very important issue because it
addresses a particularly dynamic and iterative process where various