Issue: Pressures on biodiversity - Climate variability

This is an issue under the Biodiversity theme of the Data Reporting System.

Why we need to know about this issue

Variability in climate is a characteristic of many Australian environments. Native species have adapted to these changes, and populations of species and their habitats, may fluctuate enormously with climatic variation. Because of the long time scales involved in these climatic variations, we have very little data about the corresponding fluctuations in populations and habitats.

More extreme or permanent changes in climate, resulting from human action, could produce rapid and permanent changes in species composition, population and distribution, but impacts may be difficult if not impossible to separate from fluctuations resulting from natural variability.

Human activities appear to be affecting the global climate and the changes are likely to have large implications for Australia's biodiversity.

An increase in mean annual temperature corresponds to a shift in latitude or in altitude. Species' geographic ranges are therefore expected to move upwards in altitude or towards the poles in response to shifting climate zones, in those species capable of moving range relatively rapidly. Species that are unable to tolerate changed conditions within their current range, or that cannot migrate fast enough to keep up with moving climate zones, face eventual extinction. The most vulnerable species will be those with long generation times, low mobility, highly specific host relationships, small or isolated ranges, and low genetic variation. Remnant populations within reserves and ecosystems such as alpine zones, coral reefs and coastal wetlands are likely to be particularly vulnerable.

Life cycle events triggered by environmental cues such as temperature may be altered, and the result may break the coupling of life-cycle interactions between species. These changes will alter their competitive relationships and other interactions with other species. This will lead to changes in the local abundance of species and to changes in the composition of communities.

Changes in atmospheric carbon dioxide concentration, temperature or precipitation will directly affect rates of metabolism and development in many animals, and processes such as photosynthesis, respiration, growth and tissue composition in plants.

Introduced species and diseases threaten many species in the restricted and modified habitats that remain. These threats are likely to be even more damaging to native biodiversity under the influence of changing climates.

Indicators

  • BD-15 Examples of impacts of climate variability on selected species, habitats or ecosystems 
    As there is no continent-wide method of measuring changes that can be directly attributed to climate change across all species and habitats, examples of changes that appear to be directly attributable to this cause is at present the only useful indicator of the pressure of climate change on biodiversity.
  • LD-05 Terrestrial carbon loss rate and rate of land carbon sequestration 
    Although changes in soil carbon in Australia is a relatively small contributor to global climate change, soil carbon and biomass are, along with greenhouse gas emissions, a measure of Australia’s contribution to global climate change.
  • LD-24 Severe drought and wildfire correlation 
    Changes in fire regimes may result from changes in climate, compounding the impacts of changing climate on biodiversity.
  • CO-03 Sea level 
    Changes in sea level are likely to result from changes in global climate and are therefore an indirect indicator for these changes.
  • CO-04 Sea surface temperature variability 
    Changes in sea surface temperature are likely to result from changes in global climate and are therefore an indirect indicator for these changes.
  • CO-44 Marine chlorophyll concentration 
    The capacity of marine plant life to absorb atmospheric carbon and release oxygen is an indirect indicator for the pressure of greenhouse gases on the atmosphere and thus for climate change.
  • CO-60 Sea salinity 
    Changes in sea salinity are likely to result from changes in global climate and are therefore an indirect indicator for these changes.
  • CO-76 Examples of the impact of climate variability on selected coastal and marine species, habitats or ecosystems 
    Changes in distribution and population of species due to climatic change have implications for biodiversity.
  • A-01 Annual variation in the Southern Oscillation Index 
    A number of studies indicate that the El Niño-Southern Oscillation (ENSO) explains 30 - 40% of the year-to-year variability of Australia’s climate, particularly rainfall. The Southern Oscillation Index (SOI) is a well-established measure of this phenomenon. El Niño events are associated with below-normal rainfall and often drought over much of northern and eastern Australia. They generally occur every two to seven years and are generally followed by La Niña events, which are associated with higher rainfall. Changes in the timing of these events may be indicative of longer term changes in climate which may have significant impacts on biodiversity.
  • A-02 Rainfall trends - annual mean rainfall 
    Australia is the driest inhabited continent on earth. Its interior has one of the lowest rainfalls in the world and about three-quarters of the land is arid or semi-arid. Rainfall trends are important from an environmental and an economic perspective. For thousands of years, Australia has experienced strong year-to-year variations in rainfall. These natural variations and any more extreme variations or changes in the normal scope of variation that may result from anthropogenic climate change are important indicators for the pressure of this change on biodiversity.
  • A-03 Rainfall extremes - inter-annual variations in annual extreme rainfall 
    Australia is the driest inhabited continent on earth. Its interior has one of the lowest rainfalls in the world and about three-quarters of the land is arid or semi-arid. Rainfall trends are important from an environmental and an economic perspective. For thousands of years, Australia has experienced strong year-to-year variations in rainfall. These natural variations and any more extreme variations or changes in the normal scope of variation that may result from anthropogenic climate change are important indicators for the pressure of this change on biodiversity.
  • A-04 Temperature trends - annual mean temperature anomalies 
    Trends in temperatures are an indicator of climate variability and change that in turn will have an impact on biodiversity.
  • A-05 Temperature extremes - percentage area of extreme annual mean temperatures 
    Trends in temperatures and their spatial distribution are an indicator of climate variability and change, which in turn have an impact on biodiversity.
  • AAT-15 Glacier movement 
    Understanding the coverage and type of vegetation on the non ice area of Heard Island provides insight into the extent of glacial retreat as a result of climate change which may have implications for biodiversity on the Australian mainland.
  • A-36 Rainfall extremes - percentage area experiencing extreme wet and dry conditions 
    Australia is the driest inhabited continent on earth. Its interior has one of the lowest rainfalls in the world and about three-quarters of the land is arid or semi-arid. Rainfall trends are important from an environmental and an economic perspective. For thousands of years, Australia has experienced strong year-to-year variations in rainfall. These natural variations and any more extreme variations or changes in the normal scope of variation that may result from anthropogenic climate change are important indicators for the pressure of this change on biodiversity.
  • A-37 Temperature trends - spatial trend in mean annual temperatures 
    Trends in temperatures and their spatial distribution are an indicator of climate variability and change, which in turn have an impact on the condition of biodiversity.
  • A-41 Greenhouse - climate change projections 
    Climate change projections can assist in the analysis of climatic pressures and climate driven changes to terrestrial, aquatic and marine biodiversity.
  • A-47 Rainfall deficiencies - drought 
    This indicator shows the level of rainfall deficiency for Australia spatially and over time. This gives an indication of the level of drought conditions in Australia; drought being an ongoing factor for Australia’s climate patterns. These natural deficiencies and any more extreme variations or changes in the normal scope of variation that may result from anthropogenic climate change are important indicators for the pressure of this change on biodiversity.
  • AAT-12 Changes in colonies of plants on Heard Island 
    Understanding the coverage and type of vegetation on the non ice area of Heard Island provides insight into the extent of glacial retreat as a result of climate change which may have implications for biodiversity on the Australian mainland.
  • AAT-14 Ice sheet mass balance and sea ice extent 
    The changes in ice sheets, sea ice and fast ice may be indicators of climate change. In addition, the Antarctic ice sheet and sea ice plays a major role in global climate through its influence on heat exchange between ocean and atmosphere, it assists the formation of Antarctic bottom water which sinks to the depths of the ocean subsequently driving global ocean circulation. This indicator therefore had implications for the impacts of climate change on the Australian continent and biodiversity.

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