Climate Change: Position statement by the Ecological Society of
Australia
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Summary
Climate change is likely to have significant impacts on Australia
's biota and society in the next century. The Intergovernmental
Panel on Climate Change recently concluded that there is sufficient
evidence to support these predictions. Alterations in soil characteristics,
water and nutrient cycling, plant productivity, species interactions
(competition, predation, parasitism, etc.) and the composition
and function of ecosystems were identified as highly likely responses
to the predicted increases in atmospheric CO2 concentration and
temperature, and shifts in rainfall regimes. In addition, impacts
on biodiversity are likely to be exacerbated by changes in the
occurrence of disturbances such as wildfire and insect outbreaks.
The Ecological Society of Australia (ESA) believes that a focused
program of climatic and ecological research, prediction and monitoring
is required to address the needs of maintaining the diversity
and integrity of terrestrial and aquatic ecosystems under a changing
climate. The primary goals of these activities would be to better
understand and forecast the consequences of global environmental
change for biological diversity and to form a more certain basis
for Australia 's response by way of mitigation and adaptation.
The ESA emphasises the importance of all environmental change,
since it will be the direct and indirect cumulative effects of
all changes, including human-induced climate change, which ultimately
decides the fate of ecosystems and their biota.
The Ecological Society of Australia believes that a strong but
precautionary commitment is required from government, industry
and the community to mitigate and adapt to the predicted impacts
of climate change on Australia 's unique native biota. Alternative
measures should be subject to risk assessment to determine their
benefits relative to their costs, both in monetary terms as well
as other potentially adverse ecological impacts.
Is our climate changing?
There is now strong scientific consensus that the world's
atmosphere and climate are changing. The carbon dioxide concentration
has increased 25% above pre-industrial levels and continues to
rise at 0.4% per year. Global mean temperature has risen by 0.5°C
this century and mean night temperatures have risen by an even
greater amount. In the northern hemisphere, three of the last
eight years have been hotter than any year since, at least, 1400
AD.
What kinds of climate changes are predicted?
Recent models of climate change suggest the following
scenarios for Australia :
• temperature rises for a doubling of CO2 are around
1-2°C for the southern coast of Australia , and 2-3°C for the
rest of Australia .
• precipitation increases of up to 0.5mm per day
are expected over much of the region, rising to 2 mm per day
in northern Australia and Queensland in summer.
• extreme weather, including intense rainfall and
severe drought, is predicted to occur more frequently over different
parts of the continent.
• sea level is projected to rise about 50 cm above
current levels by the year 2100, although the actual rates of
rise in specific regions and localities will vary substantially.
While a number of uncertainties surround these predictions, they
give an indication of potential changes and demonstrate that patterns
of climate change will be complex and vary from place to place.
What are the projected ecological impacts?
Changes in temperature, water availability and atmospheric
composition will affect most plants, animals and micro-organisms
in some way. Any increase in climate variability, especially in
extreme events, would have greater ecological effects than a change
in mean conditions. A diverse range of ecological impacts have
been predicted, although the magnitude and rate of changes remain
uncertain. Some examples are listed below:
• changes in patterns of land use as land suitability
alters with changing climate, potentially leading to increased
rates of habitat loss
• changed distributions of bioclimatic habitats:
some species may be unable to persist at their present locations
due to diminution of suitable habitat (e.g. alpine habitats,
coral reefs)
• increased plant growth rates due to elevated temperatures
and atmospheric CO2, although these effects will vary among
species and between sites
• changed competitive and predatory interactions
between co-occurring species that may result in elimination
of some species.
• changes in the thermal and chemical structure
of rivers and lakes from increased water temperatures, increased
evaporation, and changes in inflows and flooding that will directly
affect the nutrient status of aquatic ecosystems, the distribution
and diversity of species, and the overall ecosystem productivity.
• contraction of coral reefs and estuarine wetlands
due to the rate of rising sea levels.
• localised terrestrial extinctions associated with
changes in fire regimes resulting from altered frequency of
high fire-danger weather in different regions.
Responding to climate change
The ESA recognises that costs and benefits fall differently
on different ecosystems and different sectors of society. It believes
Australia 's response should be an appropriate mix of research,
mitigation and adaptation and strongly supports action in the
following priority areas.
Research
ESA supports sound scientific research that aims to:
• refine climatic modelling to develop more accurate
and finer scale predictions of climate change;
• identify organisms and habitats most threatened
by predicted climate changes;
• predict changes in the structure, suitability
and distribution of habitats of native and introduced species;
• predict changes in populations of plants and animals
as a consequence of changes in habitats, species interactions
and disturbance regimes;
• improve understanding of mechanisms and capabilities
of dispersal and migration in a wide range of species and the
interaction between landscape fragmentation and the mobility
and dynamics of plant and animal populations;
• evaluate suggested management interventions both
in terms of ecological viability and likely costs and benefits.
• develop new and more effective mitigation and
adaptation measures.
Mitigation
ESA supports the implementation of the following measures
to mitigate changes in global climate:
• reduce the rate of greenhouse gas emissions in
agricultural and industrial sectors by:
i) fostering replacement of fossil-fuel energy systems by non-polluting
energy system
ii) drastically reducing the rate of native vegetation clearance
• restore vegetation cover to enhance fixation of
atmospheric carbon. Planting programs should be designed to
be compatible with conservation of locally indigenous biota.
Adaptation
ESA supports the following strategies to assist native
biota to adapt to changing climatic regimes:
• retention of native vegetation and design of conservation
reserves to foster representation, persistence and migration
of native flora and fauna
• precautionary management of disturbance regimes
(including fire)
• consideration of climate change impacts in recovery
plans
• ex situ conservation and, if appropriate, translocation
or assisted migration of key species threatened by climate change.
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