Lisø PhD Dissertation Manuscript - NTNU

change in quality (Mehus et al., 2004). Reviews of the
implementation of performance-based codes in New
Zealand also show that performance-based codes
have advantages if carefully implemented to capture
these advantages (Duncan, 2005). Performance-based
codes may also have the opposite effect by being
more complex and thus more difficult to enforce or
easier to evade.
The material rules of the Planning and Building Act
and the technical requirements of these Regulations
are deemed to be fulfilled if the products employed
are in conformity with established requirements on
products for construction works and methods and
execution are in conformity with Norwegian Standard,
equivalent standard or European technical approval.
However, the building authorities cannot demand
that methods and execution according to Norwegian
Standard, equivalent standard or European technical
approval be used if the requirements for the construction
works are satisfactorily fulfilled in other ways
(e.g. documentation through pre-accepted solutions).
The present general trend in legislation and regulation
away from prescriptive rules to performance-based
codes will increase the need for interaction between
regulatory decision-makers and experts within relevant
fields or disciplines (Rasmussen, 1997). The transition
from a prescriptive to a performance-based code (e.g.
functional criteria) implies that the interpretation of
the codes is delegated to different actors in the
construction industry, and has thus strengthened the
demand for supporting standards and design guidelines.
The NBI Building Research Design Sheets in the
Building Research Series comply with the performance-based
requirements in the building code, and are
an important reference to pre-accepted solutions.
These design sheets could be used as a foundation for
precautionary adaptation measures in the construction
industry, and would be an excellent starting point for
precautionary adaptation measures. However, alterations
of regulatory measures and design guidelines
within the construction industry constitute only a
partial adaptation to climate change. In order to
develop necessary adaptation strategies, larger societal
and cross-disciplinary adjustments are crucial (Lisø
et al., 2003).
Managing risks: principal approaches
Introduction
Klinke and Renn (2001) present an integral risk
concept consisting of a criteria-based risk evaluation
aimed at an analytic-deliberative approach in risk regulation.
Six risk classes, all with names from Greek
mythology, are deduced from eight criteria for evaluating
risks (damage potential, probability of occurrence,
incertitude, ubiquity, persistency, reversibility, delay
Integrated approach to risk management of future climate change impacts
effect, mobilization potential). These characterizations
and classifications of risks provide a well-funded point
of departure for the design of risk policies, management
strategies and measures for risk reduction associated
with potential impacts of climate change on the
built environment. One of these risk classes is used
by Klinke and Renn (2001, p. 165) to classify the
atmospheric greenhouse effect, the risk class ‘Pythia’,
because ‘the extent of changes is still not predictable’.
The Ancient Greeks consulted their oracles in cases
of uncertainty. The sayings of sibyls and oracles were
‘notoriously open to interpretation’: the oracle at
Delphi (commonly known as the Pythia) was no exception.
2 A great danger could threaten, but the probability
of occurrence, the extent of the damage, the
allocation and the cause of the damage remained
uncertain, i.e. both the probability of occurrence and
the extent of damage could be intolerable.
Precautionary strategy
The risk class Pythia demands the application of a precautionary
risk-management strategy, as uncertainty is
attached to both frequency and consequences. In this
paper, this risk class will be used to illustrate a point
of departure for discussions on risk-management strategies
related to climate change and the built environment.
The future risk of adverse impacts of climate
change on buildings is connected with uncertainty.
Thus, the risk potential is characterized by a relatively
high degree of uncertainty concerning both probability
of occurrence and extent of damage. Precaution in this
context means the development of policies on mitigation,
adaptation, monitoring and continuous research,
even if there is no clear evidence of future harmful
impact. Technically, uncertainty concerning the probability
of occurrence and the extent of damage can be
handled as probability distributions over probability
distributions: The probability of a future occurrence
of an event is unknown, but one can hypothesize that
this probability is in itself a stochastic random variable
with a certain distribution. These ideas are discussed by
Nordvik and Lisø (2004).
However, as new knowledge leads to a greater understanding
of global-, regional- and local-level climate
change and associated effects, and thus reduces uncertainty,
other risk-management strategies could be
advantageous. When the main criteria of risk classification,
probability of occurrence and extent of
damage, are relatively well known, a risk-based management
strategy could also be applied. Reducing the
potential for damage through the development of technical
and organizational preventive measures (a riskbased
management strategy), while at the same time
applying the precautionary principle in the design, construction
and geographical localization of buildings, is
likely to increase the robustness of the built
environment.
5