The
review and case studies provide a number of practical lessons on the
application of real options analysis to adaptation. They provide useful
information on the types of adaptation problem types where ROA might be
appropriate, as well as data needs, resource requirements and good
practice.
In summary, ROA is considered most
useful for project based investment analysis, for major irreversible
capital investment, particularly where there is an existing adaptation
deficit (because this involves a trade-off between acting now and
waiting). It also has applications such as the second case study, where
there is an existing maintenance backlog, and in cases where there is
the possibility of receiving new information in the future. In general
it is less useful for new projects that address future climate change,
where benefits arise in the long-term only, especially if these are
highly uncertain, because in such cases it will make more sense to wait.
It
also has the potential to assess flexible versus conventional options,
which is a particularly important component of iterative risk
management. It can also be used to support initial enabling steps to
help secure projects for future development, even if they are not
expected to be cost-efficient on the basis of traditional, static
CBA/CEA appraisal.
The application requires
inputs related to probability or probabilistic assumptions for climate
change and the identification of decision points. It is therefore less
applicable under situations of (deep) uncertainty, where probabilistic
information is low or missing. For such cases, alternative approaches,
such as robust optimisation, may be considered (
see briefing note 3).
It also requires the analysis of quantitative data on costs and
benefits, the latter which have to match to the decision trees and
outcomes: this usually requires a linked modelling system or a large
number of assessments, coupled with some form of sampling (e.g. Monte
Carlo analysis). For this reason, the resources and level of expert
knowledge needed to apply the approach are high. The focus of the
approach on economic costs and benefits makes the application to
nonmarket sectors more challenging.
Given the
high resource requirements, the review also identifies the potential
for more informal application of ROA, e.g. through the use of decision
trees and more qualitative analysis of information and flexibility.