Climate change will affect rainfall
patterns & storm intensity
(Image - Stacey Smithers) |
Climate change and biodiversity in Western Australia
Our researchers are actively working to develop an understanding of the impacts of climate change, especially the impacts on the potentially 'at risk' species, communities and ecosystems of Western Australia. This understanding provides the basis upon which our 'no regrets' management responses to climate change are formulated and undertaken.
What are the causes of long term climate change?
Human activities have altered the
composition of the Earth's atmosphere
(Image - Earth Sciences and Image
Analysis Laboratory, NASA ) |
There are two broad causes of long term climate change:
- The collective effect of changes in the Earth's movement
(Milankovitch Cycles)
Minor alterations in the Earth's orbit around the sun, the tilt of the Earth's axis and a wobble in the Earth's axis, can combine to alter the amount of solar radiation and energy received by the Earth's surface. These long-term influences on the Earth's climate, termed 'Milankovitch Cycles', have influenced the development of glaciations and warmer periods for millions of years. Milankovitch Cycles are independent of human activity.
- The collective effect of changes to the composition of the Earth's atmosphere
(The Greenhouse Effect and global warming)
Human activities, especially fossil fuel combustion and land clearing, have released large quantities of carbon dioxide and other gases into the Earth's atmosphere. These activities have altered the composition of the Earth's atmosphere, increasing the concentration of gases that can trap heat. This trapped heat can directly influence the Earth's climate by raising surface temperatures, influencing rainfall patterns and altering sea levels. This warming is often termed the Greenhouse Effect and produces what is commonly known as global warming.
Increasing greenhouse gas concentrations are expected to have significant impacts on the world's climate on a timescale of decades to centuries.
How has the climate changed in Western Australia ?
- Changes in temperature:
Temperatures throughout Western Australia have risen during the twentieth century. This rise has been mainly due to warmer nights rather than hotter days.
Temperatures have increased by 0.8°Celsius since 1910. Most of this warming has occurred since 1950 (0.14°Celsius increase per decade since 1950). Climate projections recently published by CSIRO indicate that average annual temperatures are likely to continue to rise in Western Australia .
- Changes in rainfall patterns:
Since the 1970's rainfall in parts of south-west Western Australia has fallen significantly mostly in the late autumn and winter months. Recent Indian Ocean Climate Initiative (IOCI) research indicates that by 2030 rainfall may decline by as much as 20 per cent relative to the 1960-1990 level. This means that the number of winter rain days may decrease by up to 17 per cent, and the runoff into south-west Western Australian catchments may consequently decrease by between 5 and 40%.
By about 2085, these changes may further increase, with a predicted 5 to 34 % decline in rainfall, and a 30% decrease in the number of winter rain days. Conversely parts of the Northwest Western Australia have become wetter over recent decades.
- Other Changes:
These fundamental climate changes have had a 'knock on effect' on other important atmospheric and earth processes. These include changes to sea temperatures, evaporation rates, atmospheric circulation, the variability of the Leeuwin Current, river flows, groundwater levels, and the degree of dryland salinity. Further information about these changes can be found in the comprehensive "How has our Climate Changed" series produced by the Indian Ocean Climate Initiative in 2005.
How might climate change affect our biodiversity?
Possible signs of climate
change: coral bleaching
(Image - Shannon Armstrong) |
Climate plays a fundamental role in many of the primary processes of natural systems. Climate is a key factor in determining where individual species of plants and animals can live, grow and reproduce.
Changes in climatic factors such as temperature and rainfall may directly affect the distribution, lifecycles, habitat use, physiology and extinction rates of individual species. In turn these changes may modify the structure and composition of certain ecosystems and communities, by altering competition and other interactions between species. In altered ecosystems, invasive species are likely to thrive, whilst rare species may become extinct.
Climate change may also indirectly affect species and ecosystems by altering important factors such as:
- fire frequency and behaviour
- the degree of dryland salinity
- the spread of diseases such as dieback
- water flows in rivers and wetlands
- the level of groundwater
- the frequency of extreme climatic events (floods, hail, tropical cyclones, drought)
- ocean acidity levels
These factors along with existing environmental stressors may greatly reduce the ability of our biodiversity to adapt to climate change naturally.
Visible signs of the impact of climate change on our landscape may include disappearing wetlands, coral death due to coral bleaching and greater coastal erosion. Visible impacts of climate change on our biodiversity may include changes in the flowering times of native plants, changes to the arrival and departure times of some bird species, a movement away from the usual locations by native animals, a decline in karst (cave) ecosystems, a decline in trees (such as wandoo and tuart) due to water stress, a decline in fish species and a greater spread of weeds and pests.
Why is there uncertainty about the impacts of climate change on our biodiversity?
Climate determines where plants
can live, grow & reproduce
(Image - Stacey Smithers) |
Because ecological systems are very complex and future climate conditions are not easy to predict, it is difficult to confidently project the impacts of climate change on our biodiversity. Modelling climate change impacts on biodiversity requires good information about a large number of factors including the:
- Distribution of species
- Role of climate upon the distribution of species
- Degree to which species can naturally adapt to climate change
- Capacity of species to migrate
- Potential influence of climate change on threatening processes
- Influence of higher atmospheric concentrations of carbon dioxide on plant and animal physiology
- Ecological processes and interactions between species
- Evolutionary history of species and previous responses to natural variations in climate
Much of our current research has only 'scratched the surface' in understanding these factors. While changes to Western Australia's climate have been measured using specialised weather stations, there is currently only one comprehensive ecological monitoring system in the State. This system, FORESTCHECK, has operated since 2001 and is implemented only within the jarrah forest ecosystem. Dedicated ecological monitoring stations are required throughout Western Australia to enable scientists to identify ecological changes and to develop and implement timely responses.
What is DEC doing to protect our biodiversity from the impacts of climate change?
Climate change is expected to affect
the spread of salinity
(Image - Stuart Halse) |
Reducing the causes of climate change:
One way of lowering atmospheric concentrations of greenhouse gases is to protect existing native vegetation and revegetate on a large scale. Vegetation naturally reduces greenhouse gases by absorbing carbon dioxide. Protecting and increasing existing vegetation are already important components of DEC's land management and nature conservation activities.
Increasing our understanding of the impacts of climate and climate change on WA biodiversity:
To manage climate change scientists need to know the extent to which climate determines where a species is found; and whether climate change will favour rare or vulnerable plants and animals, or contribute to the stresses and forces that endanger them.
In parts of Western Australia, especially in the south-west, the landscape has experienced repeated climate variations over millions of years. As a result, species indigenous to the region may have very broad tolerances for changed or even extreme climate conditions. However, we have a limited understanding of how such cyclic climate variation has affected climatic dependence of the regions plant and animals. Further research is necessary.
Assisting species to adapt to the impacts of climate change:
Gilbert's potoroo: climate change may
impact greatly on vulnerable species
(Image - Tony Friend) |
In many cases, humans may need to intervene to help natural systems to adapt to the impacts of climate change. These interventions include:
- Protecting or establishing habitat corridors:
Corridors allow plants and animals to migrate through the landscape as climate changes alters environmental conditions and habitats.
- Protecting existing, and identifying new, refuges:
Refuges are areas that provide natural sanctuaries for plants and animals. Refuges can protect small populations, geographically restricted populations or remnant populations. Populations that occur in past climatic refuges will also harbour increased genetic diversity that may allow adaptation to future climatic conditions. Identifying the characteristics of future refuges is an important activity as it influences the design of the State's national parks and conservation reserves
- Building resilience to climate change:
One way to protect species and ecosystems from the impacts of climate change is to reduce the effect of existing threatening processes, particularly those that may be exacerbated by climate change. To improve ecosystem resilience DEC actively works to manage and reduce these pressures.
- Safeguarding the most vulnerable species
Vulnerable species are those with long generation times, low mobility, highly specific host relationships, small or isolated areas in which they can live and/or low genetic variation. Where climate change is likely to result in such species becoming locally extinct, seed collection and storage or protection in a garden or zoo will be required. Protecting species in this way is an essential element of a comprehensive biodiversity conservation program, and will be an increasingly important option as climate change proceeds in this century.
What climate change and biodiversity research projects is DEC currently undertaking?
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Climate change may result in
a greater spread of weeds
(Image - Lynley Stone)
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The Science Division of DEC includes climate change research as a component of many of its biodiversity conservation projects and activities. Our climate change activities are managed by the following project:
The DEC is also a collaborative research partner in the following project:
This Collaborative Research Activity on Climate Change and Biodiversity in Megadiverse Ecosystems is supported by the Australian Government's Department of the Environment and Water Resources, the Department of Environment and Conservation of Western Australia and the South African National Biodiversity Institute. This is a collaborative project under the Australia-South Africa Climate Change Partnership.
Further resources
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Climate change may indirectly affect
fire frequency & behaviour
(Image - Roy Wittkuhn)
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- Related on this site
Fire and climate change
- Staff research publications about climate change and biodiversity
Title: Climate change and biodiversity
Authors: McKellar,R., Abbott, I.
Source: Landscope 22(2), pp. 54-61
Publication Date: 2006
Title: Global warming and bushfires
Authors: Noble, I., McKellar, R.
Source: Symposium: Fire in South-Western Australian Ecosystems: Impacts and Management: Program and Abstracts,
Publication Date: 2002
Science and Policy Review January 2007
A review of climate change - biodiversity modelling, done in 1999 by Dr Odile Pouliquen-Young and Professor Peter Newman.
Staff papers on Climate Change
- Research bibliographies
Bibliography from DEC Science Library Database searching on key term climate change & biodiversity
- Websites
Indian Ocean Climate Initiative (IOCI)
IOCI was formed by the WA government to endure that the climate issues of Western Australia are adequately addressed in national science; and that information on climate change and variability to our region is effectively communicated to decision-makers and community.
http://www.ioci.org.au/
Bureau of Meteorology Climate Change Website
Includes observed trends and datasets
http://www.bom.gov.au/climate/change/
Intergovernmental Panel on Climate Change (IPCC)
The role of the IPCC is to assess on a comprehensive, objective, open and transparent basis the scientific, technical and socio-economic information relevant to understanding the scientific basis of risk of human-induced climate change, its potential impacts and options for adaptation and mitigation.
http://www.ipcc.ch/
Western Australian State of the Environment Report 2007-
Climate Change
http://www.soe.wa.gov.au/report/fundamental-pressures/climate-change.html
State of the Environment reports are designed to communicate credible, timely and accessible information about the condition of the environment to decision makers and the community.
WA Office of Climate Change
http://www.dec.wa.gov.au
Act Now for the Future
The State Government has developed ActNow - a virtual one-stop-shop on sustainable living in Western Australia.
http://www.actnow.wa.gov.au/faqs/act-now-faqs/faqs---climate-change.html
Australia's Biodiversity - Impacts of Climate Change
Australian Greenhouse Office
http://www.greenhouse.gov.au/impacts/biodiversity.html
Contact information
Richard McKellar
Greenhouse-Biodiversity Policy Advisor
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