Lisø PhD Dissertation Manuscript - NTNU

766 Nordvik and Lisø
The topic of this paper has not been much studied
using tools from economic theory. Central issues for
us are to survey the possible impacts of climate change
on the building stock and the behaviour of building
owners. Hence, as the title indicates, the paper is a
primer on the building economics of climate change
rather than providing final empirical answers. Furthermore,
we have focused on the microeconomics of
impact on and adaptation of single buildings. Aggregation
will be treated at a later stage. At the outset, we will
stress that even though the paper is purely theoretical, it
has an empirical ambition.
Analysing the building economics of climate
change
Climate vulnerability in general
While few studies have focused on the possible impacts
of climate change on the built environment in Norway,
impact studies in other countries show how vulnerable
society becomes in the face of major climatic events and
severe weather conditions. A British study (Graves and
Phillipson, 2000) shows that an increase in wind speeds
of 6% is likely to cause damage to 1 million buildings at
a cost of £1–2 billion. The study also addressed the
major impacts of increased driving rain quantities on
the suitability of different types of building enclosures,
and the likely increase of maintenance costs due to more
extreme weather in parts of England. Dry summers in
the south of England could lead to a 50–100% increase
in subsidence claims in vulnerable areas.
A study published by the Building Research Association
of New Zealand highlights climate change impacts
on building performance (Camilleri et al., 2001). The
study concludes that the future performance of buildings
in New Zealand may be significantly altered with
regard to coastal and inland flooding, overheating, and
wind damage and flooding associated with tropical
cyclones.
Climate vulnerability in a Norwegian context
Norway can be considered a highly exposed country
due to its extreme weather conditions (O’Brien et al.,
2003). The country’s long coastline and steep topography
make it particularly prone to extreme events like
coastal storms, avalanches and landslides. In addition,
Norway may be exposed to changes in autumn rainfall,
and to an increase in the frequency and intensity of
storms due to global warming. While the full range of
impacts resulting from these changes remains uncertain,
it is becoming clear that adaptation to climate
change is necessary and inevitable. Adaptation to the
prevailing climatic conditions has always been crucial
for the viability of Norwegian society, but future climate
changes may expose Norway to new challenges (Lisø
et al., 2003a).
Future building materials, structures and building
enclosures will likely need to withstand even greater
climatic impact in parts of Norway than they do today.
When designing building enclosures to resist wind
actions, extremes are much more important than mean
wind velocity values. For rendered walls, the duration of
rainy periods might be of greater importance than the
maximum intensity of precipitation that occurs in the
form of lashing rain. For board-clad walls, the intensity
of driving rain may be the most important. The total
number of freezing and thawing cycles is significant
when the whole-life performance of masonry constructions
is to be determined. For polymer materials, the
sum of ultraviolet radiation may determine the lifetime
of the products, rather than the yearly averages in temperature.
Many parts of buildings’ external enclosures
are likely to be subject to faster degradation in parts of
the country where there is increased ultraviolet radiation
(Lisø et al., 2003b). The prospect of an even
harsher climate in parts of the country means that we
must pay more attention to the design, construction and
geographical location of the built environment, and be
more cognisant of the climatic-related impacts that
buildings will have to endure.
Buildings and potential impacts of climate
change
Several sources of uncertainty exist related to both
scenarios for global climate change, and to the effects of
global warming on regional-level climate. The regional
scenarios, therefore, should not be considered as forecasts
in an absolute sense, but they do offer insights into
likely range and nature of future weather scenarios (Lisø
et al., 2003a). The climatic impact that a single building
is exposed to over a limited period of time can be
described as a stochastic process. The less than perfectly
known regional climate development under global
warming can consequently be described as a stochastic
process that selects among climate generated processes,
or climate change scenarios. The perceived characteristics
of this climate-generating process can change over
time, i.e. the different actors in the construction industry
and in the real estate market are assumed to be able
to learn.
Scenarios for future climate change at the very
local level are highly uncertain. However, buildings
are located and they are affected by weather related
strains. Owners will consequently have to adapt to the
expected climatic environment at the very place where
the building is located.