Just as ooding threats need to be factored into coastal community planning initiatives, so too should sea level change. Unfortunately, the “one size ts all” approach does not work.
The level of uncertainty represented in sea level projections is one challenge. Furthermore, universal projections can’t be uniformly applied to all communities because of the many local variables. These variables include subsidence or uplift, and changes in estuarine and shelf hydrodynamics, regional oceanographic circulation patterns, and river ows. Local calculations are needed.
Then add in the local response, where many variables come into play as well. Even if two communities have similar projection numbers, their responses are likely to be widely di erent because of the external factors speci c to their locations that must be considered, such as anticipated local risk, community will, and the type of planning process in which the numbers will be used.
Incorporating sea level change into planning processes involves more than selecting a number. That is why this document advocates the scenario approach.
Using the information provided here, communities can develop a process that incorporates a range of possibilities and factors. With this information various scenarios can be developed, both in terms of projections and responses, to meet the speci c circumstances of a community. Moreover, working through the scenario development process provides the data and information that o cials will need to make communities readily adaptable to changing circumstances.