Chapter 5 Climate change adaptation in Australia
Introduction
5.1
In chapter two, the Committee noted that some climate change has already
occurred, and that, regardless of the extent and timing of mitigation efforts,
climate change will continue to occur for some time.
5.2
This chapter focuses on an aspect of the climate change debate that will
become increasingly important as the climate change already in train starts to
take hold: how to adapt to the effects of climate change.
5.3
During the inquiry, the Committee heard evidence about two mechanisms
for adapting to climate change. One is the more energy efficient design of
buildings, and the other is the moderating effect revegetation can have on climate
change at a local level.
Energy efficiency in buildings
5.4
The energy used in new and existing buildings forms a significant
part of the total energy use in Australia. According to the Australian Bureau
of Statistics’ Year Book Australia 2008 Australian households alone
account for about 11 percent of total energy use in Australia.[1]
Improving energy efficiency in new and existing buildings will thus form an
integral part of Australia’s response to climate change.
Energy efficiency in new buildings
5.5
In warmer regions of Australia, a mixture of standardised regulation and
an ill-informed consensus as to what constitutes an energy efficient house is
driving climatically inappropriate design.
5.6
Currently all construction in the states and territories is regulated by
the Building Code of Australia (the BCA). The BCA is administered by the
Australian Building Codes Board on behalf of the Australian Government and
state and territory governments. The BCA governs a range of factors relating to
structure, fire safety, access, equipment, health and sustainability.
5.7
One of the objectives of the BCA is to reduce greenhouse gas emissions
by ensuring the efficient use of energy in newly constructed buildings. This is
achieved through a verification process where all proposed designs for new
buildings must achieve an ‘efficiency star rating’ or equivalent level of
efficiency.
5.8
This efficiency star rating takes into account design features
such as geographical location, energy source, heating and cooling, and
placement of windows. These factors are then used to model the energy
efficiency of the building either through a computer programme or an equivalent
modelling method.[2]
5.9
During the inquiry the Committee was informed that the nation-wide
character of the BCA, far from encouraging efficient design, may in fact be
driving inefficient design in some regions of Australia.
5.10
Mr Ross Conolly, from the Darwin Chapter of the Institute of Architects, had the following to say about the effect of BCA regulations on energy efficient
design in Darwin:
The typical thrust has been to use computer based modelling
to assess the energy efficiency of, particularly, domestic dwellings. [The
modelling] is often based on the effect of sealing small windows, minimisation
of heat loss and gain, which can be very good if you live in Melbourne or
wherever, but in Darwin you want to get rid of the heat.[3]
5.11
In regards to housing design in Darwin, Mr Connolly advocated housing
that is elevated, long and thin with through-ventilation. Mr Connolly stated that this form of housing, whilst significantly more energy efficient than the
housing designs mandated by the BCA, is discouraged by the current energy
efficiency rating system:
…[in a house that is elevated, long and thin with
through-ventilation], I can say that there might be 20 days a year where the
conditions are so humid and hot that you flick on a room air-conditioner which
might sit in the wall. When you put the house on the ground, make it out of
heavy weight construction, let the sun bear on the walls and heat up the walls
through the day, put in small sliding windows instead of big louvres, you might
find that it becomes 200 days a year that you feel that you need to have the
air-conditioner on in the building.
While the [BCA] computer models will assess the amount of
insulation and the amount of sealing against energy infiltration there is no
doubt that, if you are using an air-conditioner for 200 days of the year, you
are using a great deal more energy than if you are using it for 20 days a year.[4]
5.12
Mr Gregory McNamara, another Darwin architect, supported this view:
The current direction of regulation is counterproductive and
is leading us to an energy-reliant scenario.[5]
5.13
The Committee heard further evidence that, in some areas of Australia, inefficient housing design is also being driven by ill-informed demand. People
moving to warmer parts of Australia from the southern states have a
pre-existing notion of good housing design. Namely, there is a wide expectation
of a ground level brick veneer design with small sealed windows and
air-conditioning, which may be appropriate in more temperate regions but is not
suitable for a tropical climate. The housing market then responds to this
demand leading to the proliferation of energy-inefficient housing designs.[6]
5.14
This issue is exacerbated by the low costs of this housing design and
the short term interests of the developers who are contracted to build these
houses. Mr McNamara stated that:
The real concern is that these sealed houses are cheaper and
faster to build and the mass building market will take on this narrow view of
energy efficiency with great vigour…[7]
5.15
Ensuring energy-efficiency in the design phase of new buildings
throughout all regions of Australia would aid in reducing the amount of energy
used by buildings and their occupants in Australia.
5.16
Mr McNamara concluded that it is imperative for building design
regulations, namely the BCA, to be responsive to the local climate and
conditions of different regions throughout Australia.[8]
5.17
To combat the negative force of market demand, Mr McNamara
advocated educating the public about appropriate design and the long-term
benefits of such design.[9]
5.18
Ms Karen White, from the Northern Territory Branch of the Real Estate
Institute, cited a range of mechanisms that could be implemented to encourage
the uptake of energy efficient design by developers, including rewarding
efficient design with rebates on infrastructure charges and stamp duty or with
the relaxing of other design regulations such as height and volume.[10]
Recommendation 10 |
|
The Committee recommends that the Australian Government direct
the Australian Building Codes Board to review the Building Code of Australia to ensure that it better provides for energy efficiency standards suitable for
varied climate zones.
|
Energy efficiency in existing buildings
5.19
Energy efficiency in buildings is mainly driven through regulating the
design of new constructions. The Committee received evidence that encouraging
energy efficiency in pre-existing buildings should also be a priority.
5.20
Ms White stated that each year there is an increase of only two percent
in Australia’s residential building stock, implying that 98 percent of Australia’s building stock consists of pre-existing buildings. Encouraging energy
efficiency in existing buildings could thus deliver a significant reduction in
household emissions.[11]
5.21
A range of options are available to reduce energy usage in existing
buildings depending on the regional climate:
n increasing insulation
and double glazing windows;
n installation of
energy efficient ventilation systems;
n installation of
energy efficient light bulbs such as fluorescent lamps or LED lighting;
n installation of
energy efficient heating systems such as geothermal and solar heating;
n installation of
energy efficient cooling systems such as evaporative cooling;
n installation of
energy efficient water heating systems such as gas or solar water heaters; and
n upgrading appliances
to modern models with higher energy efficiency.[12]
5.22
There is a range of barriers preventing the uptake of energy efficient
technologies and practices in existing buildings.
5.23
One of the central factors preventing an increase in energy efficiency
in buildings is a lack of the necessary experts to advise on and implement
energy efficiency measures. In turn, a lack of supply of experts increases the
cost of their services, thus increasing the cost of upgrading the energy
efficiency of existing buildings.
5.24
Business operators may lack incentives to invest in increasing the
energy efficiency of existing properties. Operators may be focused on short
term profits whereas the benefits of increased energy efficiency are generally
only realised in the long-term. Thus operators are not likely to choose to
invest significant capital in upgrading their current properties.
5.25
In the rental market, any potential benefits from increased energy
efficiency will be felt by the tenants through lower energy bills, resulting in
little or no benefit to the landlord. Thus, landlords have few incentives to
upgrade the energy efficiency of their existing investments.[13]
Star rating programmes
5.26
The New South Wales Government currently manages the National Australian
Built Environment Rating System (NABERS). This is a voluntary national
initiative through which property owners can reliably assess the energy
efficiency of their properties and seek ways to improve their energy
efficiency.[14]
5.27
Australian Government agencies, in conjunction with NABERS and subject
to the 2006 Energy Efficiency in Government Operations policy, must meet
mandatory energy efficiency targets, and thus reduce the amount of emissions
resulting from Government operations. Part of these efficiencies must be gained
through achieving a specific level of efficiency, denoted by a star rating, in
existing buildings.[15]
5.28
Ms White discussed some of the disadvantages of the star rating system
in warmer parts of the Australia:
We need to be careful that any rules that are put in place
regarding the building sector do not drive the obsolescence of existing
buildings, because that would not be a good environmental outcome. …When you
build a new building it takes at least 30 years to reclaim the annual operating
energy that could be saved, so it really is not the best environmental outcome
to have any policy that drives the knocking down of existing buildings and a
preference for new buildings.[16]
5.29
Rather, Ms White advocated a system where improvements on current energy
ratings should be sought. For example, an improvement of one star during the
reporting period as opposed to having to achieve a mandatory 4.5 star rating. Ms White stated that this form of programme would lessen the dangers of building obsolescence
whilst maintaining the incentive for land holders to increase efficiency.[17]
5.30
Ms White outlined a range of mechanisms available to governments to
reward increased energy efficiency in homes. Ms White advocated a reduction in
council rates or accelerated depreciation for homes with high energy efficiency
and grants to assist in retrofitting of energy efficient technologies.[18]
Land clearing and climate
5.31
The Committee has already discussed the impact changes in land use can
have on carbon sequestration. However, land use change can also impact the
climate more directly. Studies have shown that a reduction in vegetation
across a region may affect temperature and rainfall levels in that region.
5.32
The impacts of land clearing on climate can be divided into two
categories: biogeochemical and biogeophysical.[19]
5.33
Biogeochemical refers to the transfer between living things and the
physical environment.[20] A good example is the
‘water cycle’, which describes the continuous rotation of water between the
atmosphere, the land and living things.
5.34
The biogeochemical effect of land clearing is already recognised in
climate science through the concept of carbon sequestration: as vegetation is
cleared, less carbon dioxide is removed from the atmosphere.[21]
5.35
Biogeophysical refers to the effect of living things on the physical
environment. A common example is the use of plants to prevent erosion.[22]
5.36
Biophysical effects on the environment are starting to be considered
very seriously as part of the climate change debate. There are four principal
biophysical effects of concern to climate scientists:
n a reduction in leaf
cover means that less moisture is transmitted to the atmosphere through the
process of transpiration resulting in less convective build up;
n as land cover is
altered, so are the reflective properties of that area, which means that land
clearing changes the ratio of solar radiation absorbed and reflected by a
particular region;
n the conversion of
woody vegetation to low lying crops and pastures decreases aerodynamic drag in
the atmosphere which in turn increases the strength of surface winds; and
n changing the
structure of vegetation affects the water runoff patterns across the altered
region thus affecting the balance between runoff, evaporation, and surface and
sub-soil moisture.[23]
5.37
Studies by Feddema et al, and, in Australia, McAlpine et al, show that
land clearing is affecting temperature and rainfall on a regional scale and may
even be influencing global weather patterns. [24]
5.38
The evidence indicates that whether a reduction in vegetation will
result in a cooling or warming effect depends on the latitude and geographical
nature of the region. For example, snow generally reflects more solar radiation
than alpine vegetation. A reduction in vegetation in a region with snow cover
may result in a larger amount of solar radiation being reflected, which in turn
may cause a cooling effect. However in other areas, with different geographical
attributes, land clearing may force a warming effect.[25]
Effect of land clearing on temperature and rainfall
5.39
The Australian landscape has undergone a significant amount of land
clearing since European settlement. Land clearing in Australia has primarily
taken the form of converting native vegetation to pastures and cropland.
5.40
In 2007, researchers from the University of Queensland, Queensland
Government, the University of Colorado and the CSIRO completed a study
concluding that the clearing of native vegetation has resulted in significant
changes in regional climate in Western Australia and eastern Australia.
5.41
The study compared two simulations of the Australian climate for the
period 1949-2003. One simulation recreated the climate for this period with
pre-European land cover characteristics whilst the other simulation reproduced
the climate over this period with modern day land cover characteristics.
5.42
To accurately carry out these simulations, the study used satellite
imagery data on leaf area to build a map, with a resolution of eight
kilometres, of vegetation in modern-day Australia, reflecting the significant
land clearing that has taken place. The map was then used to extrapolate Australia’s pre-European vegetation characteristics where no land clearing had taken place.
These two different sets of information were then used to run two climate
simulations.[26]
5.43
The simulation showed that modern day land clearing produced
significantly higher temperatures than the simulation with no land clearing.
These temperature differences showed a correspondence with areas where major
clearing of native vegetation had taken place, such as eastern and southwest Western Australia.[27]
5.44
The study further indicated that, in the scenario accounting for
modern-day land clearing, the mean summer rainfall in eastern Australia and southwest Western Australia was lower by four to 12 percent and four to eight percent respectively compared to the non-cleared scenario.[28]
5.45
In other words, the study inferred that land clearing increased the severity
of drought. In particular, the study concluded that temperatures during the
2002–2003 El Nino event were 0.75-2.0 degrees Celsius higher than they would
have been if the land had not been cleared. [29]
5.46
Similar climate modelling studies provide additional evidence for the
effect of land clearing on temperatures and rainfall:
n Two separate studies
from 1989 and 1992 both modelled climate in the Amazon with and without land
clearing. The studies found that where forest had been converted to pasture,
there was an increase in temperature and decrease in rainfall. Further, the
1992 study found that the length of the dry season increased in areas where
deforestation had taken place.[30]
n A 2002 climate
modelling exercise established that changes to the land surface in the Amazon
directly affects the circulation patterns of clouds and thus changes the level
of rainfall in the Amazon.[31]
n A 2003 study of the Tocantins River in the Amazon demonstrated that deforestation has increased runoff from
precipitation in the region, thus altering river flows and soil moisture in the
region.[32]
n Finally, a global climate
modelling study from 2000 demonstrated that land clearing affects temperature
differently depending on the latitude and geographical nature of the region.
The study suggested that deforestation in high latitude alpine regions results
in a cooling effect.[33]
5.47
Dr McAlpine, a researcher from the 2007 study on land clearing in Australia, advised the Committee that:
…when we start getting the interaction
of a drier climate from increased concentrations of carbon dioxide in the
atmosphere and we move into a more drought-prone climate, the land surface is
going to dry, the vegetation is going to become more stressed, and our ability
to keep the remaining vegetation in the landscape is going to become more
difficult. Potentially we are going to see a stronger feedback of the land
surface on climate, which could actually make our climate change impacts even
worse than what is predicted...[34]
5.48
Dr McAlpine further commented on the interconnectedness of the impacts
of land clearing across separate regions:
When we change the land use and clear the vegetation, we
essentially change the radiative force that is coming off the land surface and
also the surface hydrology and the transpiration rates, which then has an
impact on the atmosphere—the ability of that atmosphere to produce convective
rainfall, which also affects circulation patterns beyond the area where the
clearing occurred.[35]
5.49
This proposal is again supported by studies from abroad. A 2004
modelling exercise indicated that land clearing in the Amazonia and Central Africa severely reduces rainfall in the U.S. Midwest during summer and reduces rain
fall on the Californian coast in winter.[36] A similar study found
that land clearing in Australia and Africa may affect the Asian monsoon season.[37]
5.50
In regard to land clearing’s importance as a driver of climate change Dr McAlpine concluded:
I am confident that I can say that
[land clearing] is part of the problem and that climate change is a
multidimensional process.[38]
5.51
A key question is the magnitude of land clearing’s effect on climate
change. Some studies conclude that whilst the effect of land clearing is
perceptible on a regional scale, its overall impact on global average
temperatures is minor.[39] However, others argue
that the spatial scale of land clearing at a global level is comparable to the
size of the oceanic drivers that influence the El Niño.[40]
In Dr McAlpine’s view:
… when we come to Australia … I would say that [land
clearing] is getting up there to being equal with carbon dioxide in terms of
some of its effects. I think it is the interaction between the two. As one
changes, it is going to accelerate the feedback of the other ones.[41]
5.52
If Dr McAlpine is correct, then the restoration of cleared vegetation
could significantly ameliorate the regional effects on temperature and rainfall
of global heating. Dr McAlpine was of the view that the restoration of
vegetation in certain regions may lead to higher rainfall and lower
temperatures.[42]
5.53
The 2007 Australian climate modelling study, of which Dr McAlpine took part, also recommends that protecting and restoring Australia’s vegetation
should be a priority in mitigating the effects of climate change.[43]
5.54
It is the view of the Committee that Dr McAlpine may have identified a way
of limiting the effects of global heating in certain regions. This is an area
that requires further investigation and is too valuable a possibility to be
passed up.
Recommendation 11 |
|
The Committee recommends that the Australian Government
investigate using revegetation as an adaptation mechanism to reduce temperature
and increase rainfall in applicable parts of Australia.
|
5.55
This chapter has examined two adaptation strategies for Australia to
manage climate change. The Committee has not set out to undertake a thorough
review of adaptation strategies, and has limited itself to reporting on those
strategies that were presented to it during the course of the inquiry.
5.56
As climate change becomes more noticeable, adaptation strategies are likely
to become more important for Australia. We need to begin the process of identifying
and developing adaptation strategies now.
Recommendation 12 |
|
The Committee recommends that the Australian Government
conduct an inquiry into adaptation strategies for climate change. This
inquiry should include consideration of projected sea-level rise due to
climate change and its impact upon Australian coastal communities and
neighbouring countries.
|
Kelvin Thomson MP
Chair