Download Report on Climate Change and Greenhouse Gas Emissions in Victoria

Report on Climate Change
and Greenhouse Gas Emissions
in Victoria
As required under Section 17 of the Climate Change Act 2010
Published by the Victorian Government Department of Sustainability and Environment
Melbourne, March 2012
© The State of Victoria Department of Sustainability and Environment 2012
This publication is copyright. No part may be reproduced by any process except in
accordance with the provisions of the Copyright Act 1968.
Authorised by the Victorian Government, 8 Nicholson Street, East Melbourne
Print managed by Finsbury Green
Printed on recycled paper
ISBN 978 1 74287 382 4 (print)
ISBN 978 1 74287 383 1 (online)
For more information contact the DSE Customer Service Centre 136 186
Disclaimer
This publication may be of assistance to you but the State of Victoria and its
employees do not guarantee that the publication is without flaw of any kind or is
wholly appropriate for your particular purposes and therefore disclaims all liability
for any error, loss or other consequence which may arise from you relying on any
information in this publication.
Accessibility
If you would like to receive this publication in an accessible format, such as large print
or audio, please telephone 136 186, or email [email protected]
Deaf, hearing impaired or speech impaired? Call us via the National Relay Service
on 133 677 or visit www.relayservice.com.au
This document is also available in PDF format on the internet at
www.climatechange.vic.gov.au
Report on Climate Change and
Greenhouse Gas Emissions in Victoria
As required under Section 17 of the Climate Change Act 2010
Contents
1Introduction
1
2
Victoria’s greenhouse gas emissions
2
2.1 Greenhouse gases covered in the report
2
2.2 Sources and sinks of greenhouse gas emissions
3
2.3 Victoria’s greenhouse gas emissions profile
5
2.4 Victoria’s greenhouse gas emissions by sector
6
2.5 Greenhouse gas emissions indicators
11
2.6 Measuring the amount of carbon stored in Victoria’s public land
12
3
Progress against Victoria’s emissions reduction target
16
4
Victoria’s changing climate
17
4.1 Observed trends in climate in Victoria
17
4.2 Recent observed weather events
19
4.3 Current climate science
21
4.4 Global climate modelling
22
4.5 Estimates of Victoria’s future climate
23
5References
24
1 Introduction
Victorian weather and climate can change due to a wide range of natural and human factors.
Day-to-day changes in the weather are the result of relatively random atmospheric fluctuations.
Climate variations that occur from year-to-year are largely linked to large-scale ocean-atmosphere
processes affecting the three oceans surrounding Australia, such as El Niño in the Pacific Ocean.
Longer term changes, are linked to a range of factors including decadal to multi-decadal
fluctuations in the Pacific Ocean and, over much longer time scales, changes in the earth’s orbit.
In addition to these natural processes, factors such as greenhouse gases, aerosols, stratospheric
ozone depletion and land-use change also affect weather and climate.
The Climate Change Act 2010 (the Act) recognises that Victoria’s climate is changing. The Act
prescribes a biennial report on climate change and greenhouse gas emissions in Victoria, which
includes: Victoria’s greenhouse gas emissions; the science and data relevant to climate change
in Victoria; and the extent to which the amount of Victoria’s greenhouse gas emissions has
been reduced in relation to the amount of Victoria’s greenhouse gas emissions for the year 2000.
This is the first of those reports.
The remainder of this report is divided into three sections: Section 2 of this report presents
an overview of the most recent estimates for Victoria’s greenhouse gas emissions profile, also
presented by sector, together with emission trends and comparative information for the past
decade. It also provides additional detail on stored carbon in Victoria’s public forests, parks
and reserves.
Section 3 notes progress against the greenhouse gas emissions reduction target established
by the Act.
Finally, Section 4 provides a synthesis of current scientific observations of changes to Victoria’s
climate and the impacts of those changes. The Victorian Government commissioned scientific
experts to help inform this section of the report.
1
2 Victoria’s greenhouse gas emissions
This section provides an overview of the latest available estimates of greenhouse gas emissions
for Victoria, together with emission trends and comparative information for the years 2000
to 2009. Under the Act, the year 2000 is used as the comparative baseline for measuring
greenhouse gas emissions against the 20 per cent reduction target.
Data from Australia’s National Greenhouse Accounts (2011) published by the Department of
Climate Change and Energy Efficiency (DCCEE) has been used to prepare this information.
There is typically a two year lag between the Commonwealth Government’s publication of the
National Greenhouse Accounts and the year to which it relates. This is due to the time taken
to acquire and process the wide range of data needed for the compilation of a greenhouse gas
inventory. The greenhouse gas emissions in this section correspond to the inventory year 2009.
Additional estimates of the carbon stored in Victoria’s public land (section 2.6) have been
produced through the use of the FullCAM model, a component of the National Carbon
Accounting Toolbox (NCAT) developed by DCCEE.
2.1 Greenhouse gases covered in the report
The major greenhouse gas emissions covered in this report include:
• carbon dioxide (CO2)
• methane (CH4)
• nitrous oxide (N2O)
• sulphur hexafluoride (SF6)
• others – including hydrofluorocarbons (HFCs) and perfluorocarbons (PFCs)
such as perfluoromethane (CF4).
The impact of each greenhouse gas varies in terms of its effectiveness in trapping solar radiation
and, consequently, its contribution to global warming. The extent of this variation is indicated by
the global warming potential of each gas relative to carbon dioxide (Figure 1).
Greenhouse Gas
Carbon dioxide (CO2)
Methane (CH4)
Nitrous oxide (N2O)
Global Warming Potential
1
21
310
Sulphur hexafluouride (SF6)
23,900
Hydrofluorocarbon-23 (CHF3)
11,700
Perfluoromethane (CF4)
6,500
Figure 1. Global Warming Potential of various greenhouse gases1
2
1 DCCEE 2011
Global Warming Potentials provide a means of combining the emissions of different greenhouse
gases to calculate a total emissions figure expressed in terms of carbon dioxide equivalence
(CO2-e). For example, if emissions of CO2 were 100 tonnes, and emissions of methane were
1 tonne, total CO2-e emissions would be 121 tonnes – that is (100 x 1) + (1 x 21).
2.2 Sources and sinks of greenhouse gas emissions
All greenhouse gas emissions and their removal from the atmosphere presented in this section
relate to human activity. By combining data on the level of emissions with data on their removal,
the level of net greenhouse gas emissions is able to be determined. Where an activity removes
more emissions than it creates, it is described as a net carbon sink.
Sources of greenhouse gas emissions are categorised and presented for the following five
different sectors in this report:
Energy
Emissions from the following six subsectors:
• energy industries – combustion emissions from electricity generation, petroleum refining
and the production and processing of briquettes and natural gas;
• manufacturing industries and construction – emissions from on-site combustion of fossil
fuels by the manufacturing and construction industries (not including emissions from
industrial processes, which are accounted for separately);
• transport 2 – combustion emissions from motor vehicles, rail, civil aviation, shipping and
recreational vehicles;
• fugitive emissions – the unintended release of emissions (such as carbon dioxide and
methane) that may result from exploration, extraction, processing and distribution of oil,
natural gas and coal. Emissions result from leakage, evaporation and storage losses, and
venting and flaring activities;
• other sectors – emissions from on-site combustion of fossil fuels in the residential,
commercial, institutional, agricultural, forestry and fisheries sectors; and
• other – (not elsewhere classified) emissions from lubricants and greases.
Industrial processes
Emissions from:
• aluminium smelting;
• cement and clinker manufacture;
• refrigeration and air conditioning equipment; and
• electrical equipment.
2 Emissions associated with the use of electricity by Melbourne’s metropolitan train and tram system are
accounted for within the energy industries subsector.
3
Agriculture
Emissions from:
• livestock (enteric fermentation and the decomposition of animal manure);
• disturbance of agricultural soil by cropping;
• release of nitrous oxide resulting from the application of nitrogenous fertilisers; and
• burning of agricultural residues (e.g. stubble).
Land Use, Land-Use Change and Forestry (LULUCF)
Emissions and sinks from:
• Forest and grassland conversion (land clearing), including from –
– burning and decay of cleared vegetation;
– soil disturbance; and
– the removal of CO2 due to the regrowth of vegetation on previously cleared land.
• Changes in forest and other woody biomass stocks, including from –
– harvesting of timber;
– burning and decay of forest; and
– the removal of CO2 by growing forests, plantations and vegetation establishment.
• Other sources, including from prescribed burning and wildfires.
Waste
Emissions from (predominantly):
• Methane released by landfills and wastewater treatment facilities.
4
2.3 Victoria’s greenhouse gas emissions profile
As shown in Figure 2, carbon dioxide (CO2) is the most significant greenhouse gas. In 2009 it
contributed around 83% of Victoria’s total net emissions.
Gas
2009 emissions
(million tonnes)
(million tonnes)
CO2-equivalent
2009 emissions (%)
CO2
101.54
101.54
83
CH4
0.70
14.64
12
N 20
0.01
4.28
4
Others
–
1.67
1
Total CO2-e
_
122.13
100
Figure 2. Estimates for Victorian emissions of various greenhouse gases3.
Figure 3 presents a summary of Victoria’s net greenhouse gas emissions by sector
in 2000 and 2009.
Emissions source
Year
2000 (MtCO2-e)
2009 (MtCO2-e)
100.18
103.60
65.67
68.45
5.78
5.48
18.41
19.27
Fugitive emissions from oil and natural gas
2.56
2.35
Other (including ‘other sectors’ and ‘lubricants’)
7.77
8.04
Industrial processes
1.99
3.15
15.40
13.16
Land Use, Land-Use Change and Forestry (LULUCF)4
0.33
-0.69
Waste
3.10
2.91
121.00
122.13
Energy
Energy industries
Manufacturing industries and construction
Transport
Agriculture
Total emissions (including LULUCF)
Figure 3. Net greenhouse gas emissions by sector for Victoria: 2000 and 2009 (million tonnes of CO2-e).
Victoria’s net greenhouse gas emissions were 122.13 MtCO2-e in 2009. Between 2000 and 2009,
Victoria’s total net greenhouse gas emissions grew by 0.9% or 1.1 million tonnes CO2-e.
3 Emissions rounded to two decimal places, % rounded to nearest whole number.
4 Because the Kyoto Protocol accounting rules for LULUCF activities differ between the 1990 base year and the
commitment period (2008-2012), DCCEE cannot provide a consistent time-series of emissions and removal
for these activities. However, for tracking purposes, a total LULUCF estimate has been compiled for the year
2000 by DCCEE. Figures which exclude LULUCF are specifically noted.
5
2.4 Victoria’s greenhouse gas emissions by sector
The sectoral composition of
Victoria’s greenhouse gas
emissions (excluding those from
land use, land use change and
forestry) for 2009 is shown
in Figure 4. Stationary energy
(emissions from the energy
sector excluding transport
energy) is the largest source
of emissions’ representing
around 69% of Victoria’s total
greenhouse gas emissions.
10.7%
2.4%
68.7% Stationary Energy
15.7% Transport Energy
2.6% Industrial Process
10.7% Agriculture
2.4% Waste
2.6%
15.7%
2.4%
10.7%
2.6%
15.7%
68.7% Stationary Energy
15.7% Transport Energy
2.6% Industrial Process
10.7% Agriculture
2.4% Waste
68.7%
Figure 4. Victoria’s greenhouse gas emissions by sector for 2009.
Energy
The energy sector was responsible for around 85% (or 103.6 million tonnes of CO2-e)
of Victoria’s net greenhouse gas emissions in 2009.
Energy industries
68.7%
Carbon dioxide equivalent (million tonnes)
In 2009, greenhouse gas emissions from energy industries contributed 56% (68.45 million
tonnes of CO2-e) of Victoria’s net greenhouse gas emissions. Between 2000 and 2009,
emissions from this subsector increased by around 4% (Figure 5).
80
70
60
50
40
30
20
10
0
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
Year
Figure 5. Trends in Victoria’s energy industries emissions (2000 to 2009).
Electricity generation was responsible for 95.3% of this subsector’s emissions in 2009,
contributing 65.23 million tonnes of CO2-e or 53% of total net Victorian emissions. Between
2000 and 2009 emissions from electricity generation increased by around 4% or 2.6 million
tonnes of CO2-e. Compared to 2008, emissions from the electricity sector in 2009 increased
by around 3%.
6
Manufacturing industries and construction
The manufacturing industries subsector includes manufacturers of pulp and paper, metal
products, food and beverages, tobacco and chemicals. Emissions reported for this subsector
do not include emissions attributable to consumption of electricity from the grid, emissions
from fugitive sources, or emissions resulting from specific industrial processes, but may include
emissions from on-site electricity generation.
Carbon dioxide equivalent (million tonnes)
Between 2000 and 2009 energy-related emissions from manufacturing industries and
construction declined by approximately 5% or 0.3 million tonnes of CO2-e (Figure 6).
7.0
6.0
5.0
4.0
3.0
2.0
1.0
0.0
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
Year
Figure 6. Trends in energy-related emissions from Victorian manufacturing and construction
(2000 to 2009).
Transport
Carbon dioxide equivalent (million tonnes)
Transport was the second largest contributor to Victoria’s net greenhouse gas emissions in 2009
with emissions of 19.3 million tonnes of CO2-e. Emissions from this subsector grew by 4.7%
between 2000 and 2009 (Figure 7).
25
20
15
10
5
0
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
Year
Figure 7. Trends in Victoria’s transport emissions (2000 to 2009).
7
Road transportation is responsible for most of the emissions from the transport subsector.
Emissions associated with the use of electricity by Melbourne’s metropolitan train and tram
system is accounted for within the energy industries subsector.
Fugitive emissions
Carbon dioxide equivalent (million tonnes)
Fugitive emissions contributed to 1.9% of Victoria’s total net emissions in 2009. Emissions from
this subsector fell by 8% or 0.2 million tonnes of CO2-e compared with 2000 (Figure 8).
3.0
2.5
2.0
1.5
1.0
0.5
0.0
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
Year
Figure 8. Trends in Victoria’s fugitive emissions from oil and natural gas (2000 to 2009).
Other
As noted earlier, other sources of energy emissions include lubricants and the on-site combustion
of fossil fuels in the residential, commercial, institutional, agricultural, forestry and fisheries
sectors. It does not include emissions attributable to electricity consumption in these sectors.
8
Industrial processes
Carbon dioxide equivalent (million tonnes)
Emissions from industrial processes increased by 58% from 1.98 to 3.15 million tonnes of
CO2-e between 2000 and 2009 (Figure 9). This increase is principally attributable to a higher
consumption of halocarbons and sulphur hexafluoride, used in refrigeration and the
electricity network.
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0.0
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
Year
Figure 9. Trends in Victoria’s emissions from industrial processes (2000 to 2009).
Agriculture
Carbon dioxide equivalent (million tonnes)
The agricultural sector contributed around 11% of Victoria’s total net emissions (including
LULUCF) in 2009. Between 2000 and 2009, emissions from this sector decreased by 14.6%
or 2.24 million tonnes of CO2-e (Figure 10).
18
16
14
12
10
8
6
4
2
0
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
Year
Figure 10. Trends in Victoria’s agricultural emissions (2000 to 2009).
9
Methane from enteric fermentation by ruminant livestock was responsible for most of the
emissions from this sector and contributed to around 71% of the total agricultural emissions.
Compared to 2008, emissions from this sector in 2009 reduced by 0.53 million tonnes of CO2-e.
A reduction in the number of livestock contributed to this fall.
Land Use, Land-Use Change and Forestry (LULUCF)5
The Land Use, Land-Use Change and Forestry subsector acted as a sink for carbon dioxide for
Victoria in 2009. In that year, emissions from land clearing were 5.99 million tonnes of CO2-e,
while removals of CO2 by afforestation (the establishment of a forest or trees in an area where
there was no forest previously) and reforestation were 6.68 million tonnes of CO2-e. This
resulted in the net removal of 0.69 million tonnes of CO2-e.
This sector has moved from being a net source of emissions in 2000 to a net sink in 2009,
from 0.33 million tonnes of CO2-e to minus 0.69 million tonnes of CO2-e (Figure 11).
Carbon dioxide equivalent (million tonnes)
It is important to note that this data has been compiled according to Kyoto Protocol accounting
rules. Under these rules, only net emissions associated with afforestation and reforestation of
new forest plantings since 1990 are taken into account.
0.4
0.2
0.0
-0.2
-0.4
-0.6
-0.8
2009
2000
Year
Figure 11. Emissions from Land Use, Land-Use Change and Forestry sector in Victoria for 2000 and 20096.
5 Land carbon has been dealt with outside of this section, see Section 2.6.
6 Negative value means that the sector was a net carbon sink.
10
Waste
Carbon dioxide equivalent (million tonnes)
The waste sector was responsible for 2.4% of Victoria’s net emissions in 2009 – with emissions
from landfills responsible for around 75% and wastewater treatment 25%. Between 2000 and
2009, emissions from this sector declined by 6% (Figure 12). This decrease is mostly due to the
increased capture of methane at waste facilities.
5.0
4.5
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0.0
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
Year
Figure 12. Trends in emissions from Victorian waste (2000 to 2009).
2.5 Greenhouse gas emissions indicators
Victoria’s per capita emissions
Tonnes of carbon dioxide equivalent per person
Per capita emissions are an estimate of the average greenhouse gas emissions per person,
and are calculated by dividing the net greenhouse gas emissions for Victoria by the number
of residents. In 2009, Victorians emitted 22.2 tonnes of CO2-e per person (Figure 13).
30
25
20
15
10
5
0
2009
2000
Year
Figure 13. Victoria’s per capita greenhouse gas emissions for 2000 and 2009.
11
Victoria’s emissions per Gross State Product (GSP)
Emissions per unit of Gross State Product (GSP) are calculated by dividing a jurisdiction’s net
greenhouse gas emissions by the value of that jurisdiction’s GSP (chain volume measure).
Tonnes of carbon dioxide equivalent
per million $ of GSP (chain volume measure)
Over the period 2000 to 2009, Victoria’s greenhouse gas emissions per $ million GSP declined
from 544 tonnes to 425 tonnes (Figure 14). This reduction reflects a range of factors, including
structural change in the economy.
600
500
400
300
200
100
0
2009
2000
Year
Figure 14. Victoria’s emissions per $ million GSP (chain volume measures) for 2000 and 2009.
2.6 Measuring the amount of carbon stored in Victoria’s public land
Victoria has around 7.5 million hectares of public land, representing a significant carbon stock.
Living vegetation and soil both store carbon, and remove emissions from the atmosphere.
Victoria is the first state to model the amount of carbon stored in public forests, parks and
reserves using the National Carbon Accounting System. The information produced through
this Victorian initiative, and modelled for this report (including Figures 15–18), is more detailed
than what is currently available in the nationally-derived data presented in section 2.3 under
‘Land Use, Land-Use Change and Forestry’. The estimates are different from the nationallyderived estimates, as they deal only with Victorian public land, and have been generated using
different sources of data. This information however can help decision-makers take into account
how bushfires and sustainable timber harvesting impact on levels of carbon stored in Victoria’s
public land.
Forest types vary in their inherent carbon storage capacity, which is then moderated by various
environmental constraints (such as rainfall, soil nutrition, timber harvesting and bushfire events).
Victorian forests have a mean aboveground carbon density of 157 tonnes of carbon per
hectare7, but, as Figure 15 illustrates, carbon values vary widely across the state.
12
7 Grierson et al 1991
Total Carbon on Publicly Managed Land in Victoria 2010
Figure 15. Total carbon on publicly managed land in Victoria 2010. Modelling shows that land carbon
tends to be greater in places of high rainfall. The impact of recent fires is also clearly evident in the
Central Highlands and the Alps, where carbon stocks are relatively low in comparison to unburnt areas.
Victoria’s land carbon profile
Carbon stock on Victorian public land remained relatively stable between 1950 and 2010
(see Figure 16), with any significant variations a result of major bushfire events (in 1983, 2003,
2006–07 and 2009).
The model suggests that Victoria’s average carbon stock on public land (from 1950–2010) is
approximately 717 million tonnes of carbon (2.6 billion tonnes of CO2). It also suggests that
at the end of 2010 (a year after the Black Saturday fires) the carbon store was approximately
680 million tonnes. A return to the long-term average will depend on future bushfire events.
If trends for increased fire risk for Victoria occur8, modelling indicates that the structure,
dominant species and function of some forest ecosystems could alter, changing the state’s
carbon storage capacity.
8 Clarke et al 2011
13
3,000,000,000
1,500,000,000
Black Saturday
2,000,000,000
Great Divide fire
Alpine fire
Ash Wednesday
On-site C mass (tCO2 )
2,500,000,000
1,000,000,000
500,000,000
C mass on-site
0.0
1950
1960
1970
1980
1990
2000
2010
Year
Figure 16. Onsite carbon mass (expressed as tonnes of carbon dioxide) across Victoria’s publicly
managed land from 1950-20109.
Fire and its impact on Victoria’s carbon storages
Fire is a major source of carbon dioxide emissions from Victoria’s public land, with even relatively
small areas able to emit considerable amounts of CO210. Emissions from fire occur from two
processes: the direct combustion as the fire burns, and changed decomposition dynamics after
the fire, largely driven by fire-induced mortality11.
These kinds of emissions are largely a product of bushfires, with relatively less carbon dioxide
emitted from planned burns. Whilst the source of ignition does not determine the scale of
emissions, planned (controlled, patchy, less intense) burns often lead to fires of smaller extent
and potentially less tree mortality12.
Victoria’s ecosystems are largely fire-adapted and inherently fire-prone13, with regrowth quickly
replacing the lost biomass. In the context of carbon storage, fire in Victoria has a significant but
temporary impact on stocks. Carbon released from fire is stable in Victoria if vegetation has time
to regenerate between fires (and provided the vegetation function remains the same). In other
words, the loss of carbon from living, aboveground biomass in fire-adapted environments is a
‘no net loss’ process if a fire regime is ecologically appropriate.
9 The decline shown relates to uncertainty about rates of forest recovery built into the FullCAM model.
10 Schimel & Baker 2002; King et al 2007
11 DeBano et al 1998
12 Abbott & Loneragan 1983; Penman et al 2007
14
13 Adams 1996; Adams & Attiwill 2011
Emissions from fire across the reporting period (1950–2010) were variable, ranging from
just above 10 million tonnes CO2 in the 1990s to nearly 70 million tonnes CO2 in the 2000s
(Figure 17). The decade starting in 2000 is the most fire emission intense decade across the
modelled reporting period (Figure 18), similar to estimates of fire emissions from 1939
(a significant year for bushfires in Victoria, data not shown).
30,000,000
Emissions (tC2)
25,000,000
20,000,000
15,000,000
10,000,000
5,000,000
0
1950
1970
1960
1980
2000
1990
2009
Year
Figure 17. Emissions from fire (tonnes of CO2) across Victoria’s publicly managed land from 1950–2009.
30,000,000
Emissions (tC2)
25,000,000
20,000,000
15,000,000
10,000,000
5,000,000
0
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
Year
Figure 18. Emissions from fire (tonnes of CO2) across Victoria’s publicly managed land from 2000–2009.
15
3 Progress against Victoria’s emissions reduction target
In the year 2000, Victoria’s greenhouse gas emissions were 121 million tonnes of CO2-e.
To meet the target set by the Act of a 20 per cent reduction in emissions from 2000 levels,
Victoria’s annual emissions would need to be 97 million tonnes of CO2-e in 2020.
As noted in Section 2, there is typically a two year lag between the Commonwealth
Government’s publication of the National Greenhouse Gas Accounts and the year to which
they relate. The most recent emissions data measured Victoria’s emissions at 122.13 million
tonnes of CO2-e in 2009 – approximately 25 million tonnes higher than the reduction target.
16
4 Victoria’s changing climate
4.1 Observed trends in climate in Victoria
The weather and climate in Victoria changes on time scales from days to centuries due to a
wide range of factors. Day-to-day fluctuations are a result of relatively random atmospheric
fluctuations. Climate variations that occur from year-to-year are largely linked to large-scale
ocean-atmosphere processes affecting the three oceans surrounding Australia, such as El Niño
in the Pacific Ocean. Longer term changes are linked to a range of factors including decadal
to multi-decadal fluctuations in the Pacific Ocean and, over much longer time scales, changes
in the earth’s orbit. In addition to these natural processes human-induced factors such as
greenhouse gases, aerosols, stratospheric ozone depletion and land-use change also affect
weather and climate.
Since 1910, the Victorian average annual mean temperature has increased by 0.87°C.
Figure 19 depicts trends in Victorian maximum and minimum temperatures from 1910–2010.
Trend in maximum temperature
1910–2010 (˚C/10yrs)
Trend in minimum temperature
1910–2010 (˚C/10yrs)
Figure 19. Trends in Victorian maximum temperatures (left14) and minimum temperatures (right15),
1910–2010 as a change in degrees celsius per decade. Red indicates warming trends and blue indicates
cooling trends.
Increases to Victoria’s maximum temperatures in the century to 2010 (by 0.85°C) are slightly
greater than the Australian average of around 0.75°C. Victorian minimum temperatures have
increased by approximately 0.90°C between 1910–2010. However, during the last decade this
warming has been tempered by the prolonged drought, as reduced cloud cover and soil moisture
produced cooler overnight temperatures. Despite this, Victorian minimum temperatures averaged
over the decade 2000–2010 were at least 0.2°C warmer than any other decade from 1910. The
frequency and severity of very hot temperatures has increased, and the frequency and severity of
very cold temperatures has decreased since the beginning of the 20th century16.
14 BoM 2011e
15 BoM 2011f
16 Alexander et al 2007; Gallant & Karoly 2010
17
Victoria’s rainfall experienced large variations from year-to-year and decade-to-decade over the
past century. The first half of the 20th century was broadly drier and included two prolonged
drought periods. The second half of the 20th century was characterised by large decadal-scale
fluctuations in rainfall. Figure 20 depicts rainfall trends from 1900-2010 and 1960-2010.
Annual rainfall in Victoria experienced large decadal variations over the past century, with no
clear trend. Over the past 20 years there has been a large decline in autumn rainfall, a small
decline in winter and spring rainfall, and a small increase in summer rainfall.
Trend in annual total rainfall
1900–2010 (mm/10yrs)
Trend in annual total rainfall
1960–2010 (mm/10yrs)
Figure 20. Rainfall trends in Victoria 1900–2010 (left17) and 1960–2010 (right18), as a change
in millimetres per decade. Red indicates drying and green indicates wetting trends in
annual precipitation.
The 13-year drought from 1997–2009 was the longest period of sustained rainfall deficits in
the instrumental record. This drought was characterised by low rainfall during autumn, whereas
previous droughts have been dominated by low winter and spring rainfall. This drought ended
in 2010 which was the fifth wettest year on record. Rainfall in 2010 was 31% above average
for Victoria. Despite this increase in the average annual rainfall, autumn rainfall on either side
of this period has remained below average.
Since the mid-20th century there have also been reductions in the frequency of weather systems
over Victoria that are associated with wetter conditions. This includes reductions in weather
systems that are associated with pressure troughs and cold fronts to the south of Australia19.
A near-permanent area of higher pressure in the subtropical latitudes (the subtropical ridge) has
strengthened and moved further south during the 20th and early 21st centuries. The strength of
the subtropical ridge has been linked to rainfall suppression in Victoria during autumn and early
winter20. The frequency and intensity of some storm systems affecting Victoria has decreased
significantly since the mid-19th century. For example, the number of severe storms affecting the
south-west Victorian coast has decreased by around 40% over 1856–200621.
17 BoM 2011c
18 BoM 2011d
19 Alexander et al 2010; Kiem & Verdon-Kidd 2010
20 Larsen & Nicholls 2009; Williams & Stone 2009; Timbal et al 2010
18
21 Alexander & Power 2009
Snow depths in the Victorian Alps have declined over the mid-20th century to the early 2000s.
The declines during the coldest winter months have been small, but those observed during late
winter and spring have been sizeable, with declines of up to 40% over the period 1962–199022.
The average sea level along the Victorian coastline has risen, consistent with global increases23.
The sea level at Williamstown, for example, has increased at a rate close to the Australian
average of 1.2 mm/year from 1920–200024.
Sea surface temperatures in Australia have warmed since at least 1960, with the ocean
surrounding Victoria showing some of the highest warming. The greatest warming has been
measured in the western Tasman Sea, where increases have been larger than 0.20°C/decade
since the middle of the 20th century25.
4.2 Recent observed weather events
Victoria’s climate is naturally variable and severe weather events such as bushfires and floods
have occurred throughout history. Climate change may lead to changes in the distribution,
intensity and frequency of events like these. Some recent events (such as those described below)
are consistent with scientific understanding of conditions that may be more likely in a warmer
world, compared to natural variability alone. However, it is very difficult to identify the specific
causes of individual extreme weather events.
2009 heatwave
In the summer of 2008–09, much of central, southern and western Victoria experienced
the hottest conditions in more than 70 years. In the last week of January 2009, record high
temperatures were set at several locations26, along with an unprecedented three days above
43.0°C in Melbourne27.
A second heatwave occurred early in February. On 7 February 2009, Victoria recorded its hottest
ever temperature of 48.8°C at Hopetoun (1.6°C above the State’s previous record). Of the
35 long-term temperature-recording stations in Victoria, 24 set all-time hottest temperature
records. These included: Melbourne (46.4°C), Geelong (47.4°C), Walpeup (48.1°C), Horsham
(47.6°C) and Wilson’s Promontory (42.0°C)28.
The extreme heat, exacerbated by the urban heat island effect and combined with the
impacts of the Black Saturday bushfires, had severe impacts on human health29 and critical
infrastructure30 in metropolitan Melbourne.
22 Nicholls 2005; Hennessy et al 2008b
27 Karoly 2009
23 Church & White 2011
28 BoM 2009
24 Church et al 2006
29 DHS 2009
25 Thompson et al 2009
30 QUT 2010
26 BoM 2009
19
Bushfires
Long-term records show a recent increase in fire danger and the length of the fire season
for Victoria in recent decades31. This increase in fire danger is linked to the recent drought in
1997–2009, which was accompanied by higher maximum temperatures.
On 7 February 2009, the Forest Fire Danger Index (FFDI)32 for a number of sites in Victoria
reached unprecedented ratings through a combination of record high temperatures, very low
relative humidity, high wind speeds, and a lack of significant rain in the 35 preceding days33.
1997–2010 drought
The drought, from late 1997 to early 2010, resulted in reductions to Victoria’s average rainfall
of around 15%34. It was Victoria’s longest period of sustained rainfall deficits in the instrumental
record, and is considered the worst drought on record for south-eastern Australia35.
This drought also differed from previous decadal-scale droughts, having been dominated by
autumn rainfall deficits and lacking very wet years to offset the dry years36. Rainfall deficits
during April and May, from 1997 to 2009, were 25% and 31% below average respectively.
These conditions led to significant reductions in runoff, stream flows, water storage levels, and
groundwater recharge, particularly in central and western Victoria37. By 2009, stream-flow
volumes in Victoria were 32% of the long-term average, and the total water storage for Victoria
by mid-2009 was 17%38. During the 13-year drought, inflows into Melbourne’s major reservoirs
dropped by approximately 40%. Melbourne’s total water storage dropped to less than 26% in
June 2009.
Severe flooding in Victoria
Following the drought, Victoria experienced its highest summer rainfall on record in 2010–2011
(Figure 21). Most of the state received record levels of rainfall during this period, with western,
central and north-eastern Victoria particularly affected. This occurrence coincided with a series
of weather phenomena39 – including one of the strongest La Niña events ever observed, one of
the strongest negative Indian Ocean Dipole events observed in the last 50 years, the strongest
observed positive Southern Annular Mode anomaly, and record high sea surface temperatures
to the north of Australia – all of which are associated with enhanced rainfall in Victoria40.
31 Lucas et al 2007
35 CSIRO 2010a
32 A rating that takes into account the drought
factor, temperature, relative humidity and
average wind speed to describe the relative
chance of fires starting, escaping fire efforts
and causing damage (Lucas et al 2007).
36 Gallant & Karoly 2010
33 Karoly 2009
20
34 Verdon-Kidd & Kiem 2009
37 DSE 2010; Mac Nally et al 2011
38 DSE 2010
39 BoM 2011b
40 BoM 2011b; CSIRO 2011
Figure 21. Victorian rainfall deciles for the 9-month period 1 July 2010 to 31 March 201143
Three major flooding episodes during this period resulted in approximately a third of Victoria
suffering flood or storm damage41, with National Disaster Relief and Recovery Arrangements
(NDRRA) extended to 76 local governments in Victoria. However, the high rainfall recharged
Victoria’s water storage levels from 17% in June 2009 to 71% in June 201142.
4.3 Current climate science
Since 1750, approximately 530 billion tonnes of carbon dioxide has been emitted into the
atmosphere by human activities44. As a result, the globally averaged atmospheric concentration
of carbon dioxide rose by 38% between 1800 and 200945.
The most recent Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment
Report in 200746 concluded that as a result of these emissions:
• the average global temperature has warmed over the past 150 years and is continuing
to do so;
• most of this observed warming is very likely caused by greenhouse gas emissions arising
from human activities; and
• continued greenhouse gas emissions at, or above, current rates will very likely cause further
warming and result in many more changes to the global climate system.
41 Comrie 2011
42 BoM 2011g
43 BoM 2011a
44 Raupach and Fraser 2011
45Ibid
46 IPCC 2007b
21
The overall warming of the climate in Victoria over the past century has been linked to
greenhouse gas-related climate change. The recent decline in autumn rainfall and the
southward shift in some rain-bearing weather systems may also be partially caused by
greenhouse-gas related climate change. Continued global emissions of greenhouse gases,
depending on their level, are likely to lead to warmer conditions in Victoria, reduced rainfall
in some seasons, and sea level rise.
4.4 Global climate modelling
The IPCC estimate that global average temperatures will be 1.8–4.0°C warmer in 2100
in comparison to average temperatures between 1980–1999 (Figure 22)47. More recent research
supports this estimate of potential warming48. Current estimates of global sea level rise range
from 0.5 to 1.0 metres by 2100, although larger values cannot be excluded49.
Figure 22: Multi-model ranges for global average temperature, relative to 1980–1999: solid lines are
global averages under different greenhouse gas emissions scenarios. Shading denotes the standard
deviation of individual models. The orange line is for the experiment where concentrations were held
constant at year 2000 values. The grey bars at right indicate the best estimate (solid line within each
bar) and the likely range for the scenarios.50
If carbon dioxide emissions suddenly stopped, global temperatures would stop growing but
would not drop significantly for at least 1000 years. It would take centuries to remove the
carbon dioxide that has already accumulated in the atmosphere, and allow for the slow
release of heat that is already stored in the oceans.
47 IPCC 2007a
48 Betts et al 2011
49 Steffen 2011
22
50 IPCC 2007a
4.5 Estimates of Victoria’s future climate
Projected temperature changes for Victoria by CSIRO and the Bureau of Meteorology indicate
annual mean increases in 2030 of 0.6°C– 1.3°C relative to 1990. These increases are slightly
higher in summer than in winter. By 2070, the projected increase in annual mean temperature
ranges from 1°C–2.2°C (under a low emission scenario) to 1.9°C – 4.2°C (under a high emission
scenario)51.
Annual average rainfall is likely to decrease, predominately in winter, but there are still likely to
be multi-year wet periods52.
Consistent with other changes, potential evaporation and surface solar radiation are likely to
increase, whilst relative humidity may slightly decrease53. There is no clear signal of a change in
wind speed.
These changes to the Victorian climate may result in substantial increases in the frequency of
very high fire danger days54 and a sea level rise of 0.5–1.1 metres by 210055.
The following more specific changes are likely to be seen in Victoria by mid-century, based on
the current (high emissions) scenario:
• stream-flow reductions are likely to be greater than the changes to rainfall;56
• areas with at least one day of snow cover per year may fall by at least 22%;57
• sea level rise may be slightly less than the global mean, except on the far-east Gippsland
coast, where it is projected to be slightly greater than the global mean;58
• the number of days over 35°C in Melbourne may increase from nine days in 1990,
to 11–13 days per year by 2030; and to 15–26 days in 2070;59
• there may be fewer and heavier rainfall days60, and more consecutive dry days;
• the extent and frequency of droughts in Victoria may more than double by 2050;61
• the frequency of very high fire danger days may substantially increase. Melbourne’s extreme
fire danger days may double (to five days per year), as may that of Mildura (from seven days
to 13 –16 days per year);62 and
• 100-year storm tide return periods between Cape Schanck and Wilsons Promontory may
reduce to one to two years by the end of the century.63
51 CSIRO & BoM 2007b
58 DCC 2009; McInnes et al 2009a
52 CSIRO & BoM 2007a
59 CSIRO & BoM 2007a
53 Ibid
60 Alexander & Arblaster 2009
54 Lucas et al 2007
61 Hennessy et al 2008a; Kirono et al 2011
55 McInnes et al 2009a, 2009b
62 Lucas et al 2007
56 Chiew et al 2009, 2010; CSIRO 2010b
63 McInnes et al 2009a
57 Hennessy et al 2008b
23
5 References
Abbott, I. and Loneragan, O. (1983). Influence of fire on growth rate, mortality, and butt damage in
Mediterranean forests of Western Australia. Forest Ecology & Management 6: 139-153.
Adams, M.A. (1996) ‘Distribution of Eucalypts in Australian landscapes: Landforms, soils, fire,
and nutrition’. In: Attiwill, P.M., Adams, M.A. (Eds.), Nutrition of Eucalypts. CSIRO Publishing,
Collingwood, Australia, pp. 61-76.
Adams, M.A. and Attiwill, P. (2011) Burning Issues: Sustainability and Management of Australia’s
Southern Forests. CSIRO Publishing, Collingwood, Victoria.
Alexander, L.V. and Arblaster, J.M. (2009) Assessing trends in observed and modelled climate extremes
over Australia in relation to future projections. International Journal of Climatology, 29: 417–435.
Alexander, L.V., Hope, P., Collins, D.A., Trewin, B., Lynch, A.H. and Nicholls, N. (2007) Trends in
Australia’s climate means and extremes: A global context. Australian Meteorological Magazine,
56: 1–18.
Alexander, L.V. and Power, S. (2009) Severe storms inferred from 150 years of sub-daily pressure
observations along Victoria’s “Shipwreck Coast”. Australian Meteorological and Oceanographic
Journal, 58: 129–133.
Alexander, L.V., Uotila, P., Nicholls, N. and Lynch, A. (2010) A new daily pressure dataset for Australia
and its application to the assessment of changes in synoptic patterns during the last century. Journal
of Climate, 23: 1111–1126.
Betts, R.A., Collins, M., Hemming, D.L., Jones, C.D., Lowe, J.A. and Sanderson, M.G. (2011) When
could global warming reach 4°C? Philosophical Transactions of the Royal Society A, 369: 67–84.
BoM (2009) The exceptional January-February 2009 heatwave in south-eastern Australia. Special
Climate Statement 17, National Climate Centre, Australian Bureau of Meteorology, Australia.
BoM (2011a) Nine-monthly rainfall deciles for Victoria 1 July 2010 to 30 March 2011 [Map].
Retrieved 30 September 2011, from Australian Bureau of Meteorology http://www.bom.gov.au/jsp/
awap/rain/index.jsp?colour=colour&time=history%2Fvc%2F2010060120110228&step=6&map=decil
e&period=9month&area=vc
BoM (2011b) Record wet January brings unprecedented flooding to northwest Victoria. Special Climate
Statement 26, National Climate Centre, Australian Bureau of Meteorology, Melbourne, Australia.
BoM (2011c) Trend in annual total rainfall 1900-2010 [Map]. Retrieved 30 September 2011, from
Australian Bureau of Meteorology http://www.bom.gov.au/cgi-bin/climate/change/trendmaps.cgi?ma
p=rain&area=vic&season=0112&period=1900
BoM (2011d) Trend in annual total rainfall 1960-2010 [Map]. Retrieved 30 September 2011, from
Australian Bureau of Meteorology http://www.bom.gov.au/cgi-bin/climate/change/trendmaps.cgi?ma
p=rain&area=vic&season=0112&period=1960
BoM (2011e) Trend in maximum temperature 1910-2010 [Map]. Retrieved 30 September 2011, from
Australian Bureau of Meteorology http://www.bom.gov.au/cgi-bin/climate/change/trendmaps.cgi?map=tm
ax&area=vic&season=0112&period=1910
BoM (2011f) Trend in minimum temperature 1910-2010 [Map]. Retrieved 30 September 2011, from
Australian Bureau of Meteorology http://www.bom.gov.au/cgi-bin/climate/change/trendmaps.cgi?map=tmi
n&area=vic&season=0112&period=1910
BoM (2011g) Water storages in Victoria [Graph]. Retrieved 30 September 2011, from
Australian Bureau of Meteorology http://water.bom.gov.au/waterstorage/awris/#urn:bom.gov.
au:awris:common:codelist:region.state:victoria
24
Chiew, F.H.S., Teng, J., Vaze, J., Post, D.A., Perraud, J.M., Kirono, D.G.C. and Viney, N.R. (2009)
Estimating climate change impact on runoff across southeast Australia: Method, results, and
implications of the modeling method. Water Resources Research, 45: W10414.
Chiew, F.H.S., Kirono, D.G.C., Kent, D.M., Frost, A.J., Charles, S.P., Timbal, B., Nguyen, K.C. and Fu,
G. (2010) Comparison of runoff modelled using rainfall from different downscaling methods for
historical and future climates. Journal of Hydrology, 387: 10–23.
Church, J.A. and White, N.J. (2011) Sea-level rise from the late 19th to the early 21st Century. Surveys
in Geophysics, 32: 585–602.
Church, J.A., Hunter, J.R., McInnes, K.L. and White, N.J. (2006) Sea-level rise around the Australian
coastline and the changing frequency of extreme sea-level events. Australian Meteorological
Magazine, 55: 253–260.
Clarke, H.G., Smith, P.L. and Pitman, A.J. (2011) Regional signatures of future fire weather over
eastern Australia from global climate models. International Journal of Wildland Fire, 20: 550–562.
Comrie, N. (2011) Review of the 2010–11 flood warnings & response: Interim report. State
Government of Victoria, Melbourne.
CSIRO & BoM (2007a) Climate change in Australia – Technical report 2007. CSIRO, Australia.
CSIRO & BoM (2007b) Victoria Temperature Change. Accessed September 2011 from Climate
Change in Australia website http://www.climatechangeinaustralia.gov.au/victemp5.php and
http://www.climatechangeinaustralia.gov.au/victemp15.php
CSIRO (2010a) Program annual report 2009/10. South East Australian Climate Initiative (SEACI),
Canberra, Australia.
CSIRO (2010b) Climate variability and change in south-eastern Australia: A synthesis of findings from
Phase 1 of the South Eastern Australian Climate Initiative (SEACI). CSIRO, Australia.
CSIRO (2011) Factsheet: The Millennium Drought and 2010/11 floods. South Eastern Australian
Climate Initiative (SEACI), CSIRO.
DCC (2009) Climate change risks to Australia’s coast – A first pass national assessment. Australian
Government Department of Climate Change, Canberra, Australia.
DCCEE (2011) National Greenhouse Accounts Factors. Australian Government Department of
Climate Change and Energy Efficiency, Canberra, Australia.
DeBano, L.F., Neary, D.G. and Ffolliott, P.F. (1998). Fire’s effects on ecosystems. New York, USA, John
Wiley & Sons.
DHS (2009) January 2009 heatwave in Victoria: An assessment of health impacts. Victorian
Government Department of Human Services, Melbourne, Australia.
DSE (2010) Victorian water accounts 2008–2009: A statement of Victorian water resources. Victorian
Government Department of Sustainability and Environment, Melbourne, Australia.
Gallant, A.J.E. and Karoly, D.J. (2010) A combined climate extremes index for the Australian region.
Journal of Climate, 23: 6153–6165.
Grierson, PF, Adams MA, Attiwill, PM (1991) Carbon sequestration in Victoria’s Forests. Report to the
State Electricity Commission, Victoria.
Hennessy, K., Fawcett, R., Kirono, D., Mpelasoka, F., Jones, D., Bathols, J., Whetton, P., Stafford
Smith, M., Howden, M., Mitchell, C. and Plummer, N. (2008a) An assessment of the impact of
climate change on the nature and frequency of exceptional climatic events. Bureau of Meteorology
and CSIRO, Australia.
25
Hennessy, K.J., Whetton, P.H., Walsh, K., Smith, I.N., Bathols, J.M., Hutchinson, M. and Sharples,
J. (2008b) Climate change effects on snow conditions in mainland Australia and adaptation at ski
resorts through snowmaking. Climate Research, 35: 255–270.
IPCC (2007a) Climate Change 2007: The Physical Science Basis. Contribution of Working Group I
to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge
University Press, Cambridge, United Kingdom and New York, NY, USA.
IPCC (2007b) Climate Change 2007: Synthesis Report. Contribution of Working Groups I, II and III to
the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. Intergovernmental
Panel on Climate Change, Geneva, Switzerland.
Karoly, D.J. (2009) The recent bushfires and extreme heat wave in southeast Australia. Bulletin of the
Australian Meteorological and Oceanographic Society, 22: 10–13.
Kiem, A.S. and Verdon-Kidd, D.C. (2010) Towards understanding hydroclimatic change in Victoria,
Australia – preliminary insights into the ‘Big Dry’. Hydrology and Earth System Science, 14: 433–445.
King, K, de Ligt, R, Cary, G. (2007) Fire regimes, forest and carbon dynamics under climate change in
SE Australia: Implementation of FIRESCAPE / FullCAM model for the ACT / NSW high country region
of SE Australia. Landscape Fire Group, Fenner School of Environment and Society, Australian National
University.
Kirono, D.G.C., Kent, D.M., Hennessy, K.J.and Mpelasoka, F. (2011) Characteristics of Australian
droughts under enhanced greenhouse conditions: Results from 14 global climate models. Journal of
Arid Environments, 75: 566–575.
Larsen, S.H. and Nicholls, N. (2009) Southern Australian rainfall and the subtropical ridge: Variations,
interrelationships, and trends. Geophysical Research Letters, 36, doi: 10.1029/2009GL037786.
Lucas, C., Hennessy, K.J., Mills, G. and Bathols, J.M. (2007) Bushfire weather in south-east Australia:
Recent trends and projected climate change impacts. Report to the Climate Institute of Australia,
Bushfire Cooperative Research Centre and CSIRO, Australia.
Mac Nally, R., Cunningham, S.C., Baker, P.J., Horner, G.J. and Thomson, J. R. (2011) Dynamics of
the Murray-Darling floodplain forests under multiple stressors: The past, present and future of an
Australian icon. Water Resources Research, 47: W00G05.
McInnes, K.L., Macadam, I. and O’Grady, J. (2009a) The effect of climate change on extreme sea
levels along Victoria’s coast. Report to the Victorian Government Department of Sustainability and
Environment, CSIRO, Australia.
McInnes, K.L., O’Grady, J. and Macadam, I. (2009b) The effect of climate change on extreme sea
levels in Port Phillip Bay. Report to the Victorian Government Department of Sustainability and
Environment, CSIRO, Australia.
Nicholls, N. (2005) Climate variability, climate change and the Australian snow season. Australian
Meteorological Magazine, 54: 177–185.
Penman, T.D., Kavanagh, R.P., Binns, D.L. and Melick, D.R. (2007). Patchiness of prescribed burns in
dry sclerophyll eucalypt forests in South-eastern Australia. Forest Ecology & Management 252: 24-32.
QUT (2010) Impacts and adaptation response of infrastructure and communities to heatwaves:
the southern Australian experience of 2009. Queensland University of Technology, Report for the
National Climate Change Adaptation Research Facility, Gold Coast, Australia.
Raupach, M. and Fraser, P. (2011) Climate and greenhouse gases. In H. Cleugh, M. Stafford Smith, M.
Battaglia and P. Graham (eds.) Climate change: Science and solutions for Australia, CSIRO Publishing,
Collingwood, Australia, pp. 15–34.
26
Schimel, D. and Baker, D. (2002) The wildfire factor. Nature 420, 29-30.
Steffen, W. (2011) The critical decade: Climate science, risks and responses. Climate Commission
Secretariat, Australian Government Department of Climate Change and Energy Efficiency, Canberra,
Australia.
Thompson, P.A., Baird, M.E., Ingleton, T. and Doblin, M.A. (2009) Long-term changes in temperate
Australian coastal waters: Implications for phytoplankton. Marine Ecology – Progress Series, 394:
1–19.
Timbal, B., Arblaster, J., Braganza, K., Fernandez, E., Hendon, H., Murphy, B.F., Raupach, M., Rakich,
C., Smith, I., Whan, K. and Wheeler, M. (2010) Understanding the anthropogenic nature of the
observed rainfall decline across south eastern Australia. CAWCR Technical Report No. 026, Centre for
Australian Weather and Climate Research, Australian Bureau of Meteorology, Australia.
Verdon-Kidd, D.C. and Kiem, A.S. (2009) Nature and causes of protracted droughts in southeast
Australia: Comparison between the Federation, WWII, and Big Dry droughts. Geophysical Research
Letters, 36, doi: 10.1029/2009GL041067.
Williams, A.A.J. and Stone, R.C. (2009) An assessment of relationships between the Australian
subtropical ridge, rainfall variability, and high-latitude circulation patterns. International Journal
of Climatology, 29: 691–709.
27