What is climate change?
The natural greenhouse effect warms the planet and allows humans to live on the Earth. For
millions of years, water vapour, carbon dioxide, methane and other greenhouse gases have
occurred naturally, heating the atmosphere and making Earth habitable.
However, human activities, predominately the burning of fossil fuels, intensive agriculture and
land clearing, are causing greenhouse gas concentrations to rise above natural levels, further
heating the planet. This is called the enhanced greenhouse effect.
As the concentrations of these gases in the lower atmosphere grows, global temperatures
rise, causing changes to weather conditions worldwide. The enhanced greenhouse effect is
often referred to as global warming or climate change.
Over the coming century, climate change is expected to cause:
more frequent extreme events such as extreme rainfall, bushfires and droughts.
Impacts of climate change
A majority of the world's scientists agree that human activities have resulted in observed
increase in global average temperatures, particularly since the middle of the 20th century.
Recent data indicates that the global mean temperature has increased by between 0.2 and
0.6°C since the late 19th century, while Australian average temperatures have increased by
Earth's average temperature might increase by up to 5.8°C over the next 100 years, if
greenhouse gas concentrations continue to increase.
As the average global temperature rises, it will lead to other changes in weather. Storm
patterns and severity might increase, sea levels will rise, and floods and drought may become
more frequent and more severe.
Some changes to the climate are inevitable – even if we stop emitting greenhouse gases
now, the gases we have already released will have an effect. However, we must do
everything we can to avoid further changes, and to adapt to the impacts of climate change.
Observed changes in Victoria's climate
Victoria's climate is already changing. Both maximum and minimum temperatures have
increased by 0.8 to 1.0 degree Celcius since 1950. At the same time, Victoria has
experienced a substantial decline in rainfall - with declines ranging from 10 millimetre per
decade in the west to more than 20 millimetre per decade in central and eastern areas.
The incidence of severe droughts during strong El Niño events has tended to be more
frequent, and it is believed that the impacts of the 2002 drought are likely to have been
enhanced by climate change.
Victoria's future climate
Changes in temperature, rainfall and other aspects of climate that can be expected over
coming decades as a result of continued global emissions of greenhouse gases. Results for
Victoria indicate that:
Average temperatures will increase by around 0.9°C by 2030, with a range of
By 2070 this increase is projected to be around 1.5°C (range of 1.0-2.0°C) under a
low emissions scenario or around 3°C (range of 2.0-4.0°C) under a high emissions
The chance of at least a 1°C warming in 2030 is around 20-30%.
This rises to 80-90% for the 2070 low emission scenario and over 90% for the 2070
high emission scenario. There is a 1-10% chance of a 2°C warming for the 2070 low
emission case and 80-90% for the 2070 high emission case.
As per previous projections, annual, winter and spring rainfall is likely to
decrease, whereas changes in summer and autumn rainfall are less certain.
By 2030 annual rainfall is projected to decrease by around 5% (range of 0-10%)
relative to the climate of the past century. By 2070 the change is projected to be a
decrease of 5-10% (with a range of 0-20%) under a low emission scenario, or 10-
20% (with a range of +5 to -30%) under a high emission scenario. Extreme daily
rainfall is less affected by the drying tendency and may increase.
The chance of an annual average decrease of at least 10% increases over time.
There is a 1 to 10% chance by 2030, 20-30% by 2070 for the low emission case, and
50-60% by 2070 for the high emission case.
We need to reduce greenhouse gas emissions
Throughout history, the Earth’s climate has fluctuated naturally– from seasonal variations to
sweeping shifts on geological time-scales, like ice ages. However, climate change currently
occurring is linked to the build up of greenhouse gases in the atmosphere from human
Atmospheric concentrations of carbon dioxide, a key greenhouse gas, are higher now than at
any time in the last 420,000 years. These raised levels correspond closely to changes in fossil
fuel burning and land clearance.
Emissions of greenhouse gases have risen due to increasing demands for energy, associated
with industrialisation and growing populations, and as a result of changing land use and
human settlement patterns.
Water resources and management
Victoria's water resources are likely to become increasingly vulnerable to climate change, due
to projected drying trends over much of the state.
At the same time, demand for water may grow as a result of increasing population, warmer
temperatures and higher evaporation rates. These impacts could, however, be offset if we get
more rain in summer.
Water quality may be affected by changes in the number and types of organisms, water
temperature, carbon dioxide concentration, transportation of water sediment and chemicals,
and the volume of water flow.
Decreases in stream flow, impacts on coastal underground water and intertidal habitats, and
increased salinity will be critical issues for the management of our water supply and natural
Agriculture and primary production
Climate change may affect crops and livestock, depending on their tolerance to increased
maximum and minimum temperatures, moisture availability and tolerance of water stress,
changes in exposure to pests, impacts of storms, and elevated concentrations of carbon
dioxide. Climate change could also have indirect social and economic effects, as regional and
international markets respond to climate change.
Projected warming would also increase the ability of some pest species to survive in winter.
For example, fruit fly numbers could increase under warmer conditions. A warmer climate
would also enable more tropical species to spread southwards. There is also a greater
likelihood of invasion and establishment of exotic animal and plant species.
Human settlement has dominated environmental change in Victoria, and will continue to be a
significant issue in the future. With the additional effects of climate change, human influences
will become more severe as ecosystems progressively lose their natural protective
Climate change is already affecting Victoria's plants and animals. Preliminary research of the
potential effect on the distribution of 42 fauna species in south-eastern Australia indicated that
41 are likely to suffer reduced habitat ranges under climate change scenarios. Of those 41
species, 57 per cent are predicted to lose between 90 and 100 per cent of their range, with a
warming of 3C. Studies of selected flora suggest there may also be reductions in the ranges
of plant habitats.
Ecosystems and species will be forced to respond directly to changing climatic conditions,
and, at the same time will have to cope with, and adapt to, other climate-induced changes in
land use and pests and diseases, particularly invasions by introduced species.
Many of Victoria's ecosystems have a limited ability to adapt to climate change. Those
restricted to small geographic areas, or unable to migrate fast enough to keep pace with
shifting climatic zones, will be particularly vulnerable. However, some ecosystems and
species will be advantaged or unaffected by climate change.
Small alterations in average climate conditions are expected to generate larger changes in
extreme weather events. The number of days over 35°C, and longer and more intense
droughts, are expected to increase in frequency due to climate change. Extreme weather
events may also lead to increased injuries or deaths, property and environmental damage.
A range of direct and indirect climate change impacts may affect Victorian communities.
Flooding and sea-level rise, heatwaves, water shortages, increased frequency and intensity of
storms, greater air pollution and higher urban temperatures pose the greatest threats.
Climate change may have wide-ranging effects on human health. There is concern over the
direct effects of higher summer temperatures and heatwaves; increased risk of respiratory
problems, water quality issues for drinking water; and higher levels of food- and water-borne
Adapting to climate change
Adapting to climate change means taking action to reduce the adverse consequences or to
take advantage of any opportunities that may arise. Despite global and local efforts to reduce
greenhouse gas emissions, some level of climate change is now inevitable, and we will need
to adapt the way we do things to maintain Victoria's social, environmental and economic
Our first response is to reduce greenhouse gas emissions to slow the rate, and reduce the
magnitude of climate change. At the same time, we must prepare to live in a changed
climate. This may involve adjusting our behaviour, the design and delivery of social services
and our infrastructure.
All Victorians need to think about how they can adapt. Some of us have already started to
adapt to climate change by reducing water and energy use. Simple measures for reducing
your greenhouse emissions are easy and quick to introduce.
We also need to consider how we can best manage and prepare our natural assets to lessen
the impacts of climate change. Adjustments can be made now in response to changes that
have already occurred, and in anticipation of projected changes in climate.
Preparing for climate change is not something that governments can do alone – it is a shared
responsibility that requires partnerships across the community so that individuals, businesses,
communities and governments can make prepare effectively and efficiently.
For further information about Climate Change and to read about the impact of climate
change in your region, go to the Department of Sustainability and Environment website
Department of Sustainability and