What is climate change and how might it impact Australia?

The climate of the Earth is changing, affecting physical and biological systems across the globe.   Almost certainly, the climate change of recent decades is attributable to rising greenhouse gas concentrations in the atmosphere caused by greenhouse gas emissions from human activity.

Warming has occurred across Australia and in our oceans.  Evidence of impacts on our biological systems is growing.  This warming may have contributed to the current extended drought in eastern and southern Australia but this remains uncertain.

Scientific understanding of all aspects of climate change has dramatically advanced in recent years, clarifying the ensuing risks. The magnitude of climate change and the potential vulnerability of systems to it may have been underestimated by earlier assessments.  The remaining uncertainties need to be part of the risk management process.

Our knowledge of how the climate system will respond is imperfect.  The way human societies develop over the coming decades will influence emissions levels. Ongoing warming of the planet may culminate in dire consequences for both human and natural ecosystems.  The magnitude of these consequences will be a result of the scale of change, how quickly and effectively global emissions can be reduced and the capacity of human and natural systems to adapt.

Some of the likely impacts for Australia include:

  • Reduced water availability, due to rainfall losses and increased evaporation, as well as changed seasonality and levels of rainfall intensity.
  • Coastal communities will face generally higher sea levels and be exposed to increased extreme storm events and sea level variations.
  • Energy security will be affected by changes to daily and seasonal demands, higher thermal loads and impacts of water supply on power-plant cooling.
  • Major infrastructure changes will be needed to cope with higher intensity precipitation, changed rainfall patterns,temperature increases and winds.
  • Health issues include diseases carried by insects such as mosquitoes entering new areas and thermal stress from more frequent extreme temperatures, although some reduction in low-temperature stress.
  • Tourism based on significant ecosystems (Great Barrier Reef, Kakadu and alpine regions) will be disrupted, and tourist areas may also see direct effects of temperature and water supply.
  • Agriculture and forestry productivity will be affected by reduced water availability, extreme weather events and increased fire risk.
  • Oceanic productivity and distribution of marine species will be affected, in turn affecting fisheries.
  • Domestic food security will be weakened as a result of impacts listed above and decreased global food production will have an impact on exports.
  • Natural ecosystems will be affected by temperature changes and water availability, as well as inundation, extreme events, acidification of the oceans, species loss and reduced resilience.

Each of these impacts creates risk, the magnitude of which depends on the rate,nature and size of the climate change, the sensitivity of the various systems to it, and the probability that changes will occur.  Risk can be reduced through natural and planned adaptation.

- Dr Graeme Pearman, Greenfleet National Advisory Council

Find out more...

The above text is an excerpt from Graeme's report to the Australian Government Department of Treasury, entitled Climate change - Risk in Australia under alternative emissions futures which offers an assessment of probable consequences, risk management strategies and adaptation measures for a range of climate change scenarios.

The following websites are also good sources of information:

The Science of Climate Change Q&A - Australian Academy of Science

Climate Change in Australia - developed by CSIRO and the Bureau of Meteorology

Bureau of Meteorology

CSIRO Marine & Atmospheric Research

CSIRO Climate Change Science

Department of Climate Change - federal government department responsible for climate change issues

Intergovernmental Panel on Climate Change (IPCC)

Global Temperature Trends: 2011 Annual Analysis - from NASA

Real Climate - climate science from climate scientists

RCWiki - debunking popular climate change sceptic arguments