This content forms part of the issues brief on climate change.
Predictions for Australia
Climate change is now a ‘global existential risk’ and a ‘direct threat to the security of Australia’Sherri Goodman, former US Under Secretary of Defence
Australian climate change risks are likely to further increase and intensify as global temperatures continue to rise. As the driest inhabited continent on Earth with a highly variable climate, Australia’s natural ecosystems, cities and regional communities are all extremely vulnerable to even relatively low rises in temperature. Key risks from projected changes in the Australian climate include the following.
Heatwaves, fire and drought
A warming and drying climate with increased incidence of heatwaves is projected to lead to an increase in extreme fire-danger days and bush fires in South Eastern Australia. Increased frequency and severity of heatwaves will to lead to a significant increase in health risks. Droughts are projected to increase in length and geographical area, leading to increased water shortages, particularly in southern Australia.
Storms and more floods
More frequent and intense storms and rainfall events are predicted with increases in storm and flood damage to ecosystems, housing and infrastructure. Sea level rise is also likely to increase the risk of tidal surges and flooding in coastal regions and communities.
Agriculture and food production
While Australian farming techniques have been developed to cope with Australia’s harsh and variable climate, there are severe limits to the capacity of agriculture to adapt to more extreme changes in temperature and rainfall. Impacts from current climate change projections include:
- Reduced agricultural production due to rising temperatures, reductions in average rainfall and more frequent and severe extreme weather events.
- Significant changes to the total area in which crops are likely to be viable.
- Fewer food surpluses, with the likelihood of deficits in some years. This will have important consequences for Australian farm exports as well as for domestic food security.
Key challenges from climate change for Australian cities include:
- Destructive impacts on urban populations and on housing, transport and energy infrastructure of more frequent heatwaves and extreme weather events. Recent research has confirmed the risk that Australian cities such as Melbourne and Sydney may well experience daily temperatures of 50°C if global warming exceeds 2°C.32
- Destructive impacts of sea-level rise and storm surge on Australia’s coastal settlements.
- Significant financial costs likely to be required to pay for the investment needed to strengthen the climate change resilience of Australian cities and towns.
- Pressures on urban infrastructure arising from domestic and international climate related migration and refugee flows.
The Australian defence forces and security organisations have indicated growing concern about the likely security implications of climate change including: The potential for climate change to act as a ‘threat multiplier’ through increases in the frequency and intensity of extreme weather events and through the impacts of climate change on regional societies and economies. The displacement, (by drought, food shortages, sea level rise and storms) of up to 250 million people across west Asia, south Asia, south-east Asia and Indonesia by the end of this century. The abandonment of low-lying Pacific islands and of severe economic disruption in China, Bangladesh and Indonesia, creating a class of dislocated national populations.
‘Australia lies in the region most vulnerable to the impact of a changing climate, including security threats, resulting from both the onset of long term trends and increased extreme weather events. The security and humanitarian risk is significantly higher than in other regions of the world. Australia’s geographic position means it cannot afford to take climate security lightly.’Rear Admiral (Retired) Neil Morisetti, former UK Government Climate and Security Envoy
Human health risks
Health risks from climate change and from ongoing reliance on fossil fuels include:
- Injury, illness and death from extreme weather events including fires, floods and storms.
- Increasing morbidity and mortality from heatwaves. Groups at particular risk from heatwaves include children, elderly people, people living in cities and people with pre-existing and chronic medical problems.
- Increasing risks of infectious and vector borne diseases.
- Adverse mental health impacts including post-traumatic stress disorder following extreme weather events and disasters. Rising levels of anxiety and depression about future climate change risks and consequences.
- Higher levels of respiratory disease caused by air pollutants and allergens from coal fired power stations and petrol fuelled motor vehicles.
As illustrated in the above infographic from the British Medical Journal, there is extensive and increasing evidence of the potential co-benefits for health – and for the natural environment if decisive action is taken to reduce emissions and address climate change risks.
Australian nature impacts
Land species and ecosystems
The effects of climate change on many species of Australian flora and fauna is already evident and includes:
- Changes in the geographic range, genetics and life cycles of many animals and plants (for example earlier flowering of plants and changes in bird migration patterns).
- Accelerating losses of populations and species, particularly groundwater-dependent plants and animals.
- Warm-adapted species increasing at the expense of cool-adapted species.
- An expansion of new ‘problem’ species and pests, for example insects that can impact food production.
- Rapid transformations in the location and composition of many vulnerable Australian ecosystems including, in particular:
- the alpine zone, which is already experiencing the impacts of reduced snowfalls;
- the wet tropics of north Queensland;
- low-lying freshwater swamps (particularly in Northern Australia) affected by saltwater intrusion;
- inland rivers and wetlands affected by reduced rain and increased evaporation of groundwater;
- groundwater-dependent plants and animals.
Coral reefs and other marine ecosystems
Rising water temperatures and ocean acidification are already causing severe and widespread coral bleaching to the Great Barrier Reef and other Australian coral reef ecosystems. Other current and future impacts of climate change on marine ecosystems include:
- the destruction of kelp forests;
- the southwards shift in distribution of many fish species;
- changes in fish migration and reproduction patterns;
- disruption to fisheries and aquaculture from ocean warming and acidification, from new marine diseases and from the increased incidence of alien fish species in Australian coastal waters.