This fifth, biennial State of the Climate report draws on the latest monitoring, science and projection information to describe variability and changes in Australia’s climate. Observations and climate modelling paint a consistent picture of ongoing, long-term climate change interacting with underlying natural variability.
These changes affect many Australians, particularly the changes associated with increases in the frequency or intensity of heat events, fire weather and drought. Australia will need to plan for and adapt to some level of climate change. This report is a synthesis of the science informing our understanding of climate in Australia and includes new information about Australia’s climate of the past, present and future. The science underpinning this report will help inform a range of economic, environmental and social decision-making and local vulnerability assessments, by government, industry and communities.
- Australia’s climate has warmed by just over 1 °C since 1910, leading to an increase in the frequency of extreme heat events.
- Oceans around Australia have warmed by around 1 °C since 1910, contributing to longer and more frequent marine heatwaves.
- Sea levels are rising around Australia, increasing the risk of inundation.
- The oceans around Australia are acidifying (the pH is decreasing).
- April to October rainfall has decreased in the southwest of Australia. Across the same region May–July rainfall has seen the largest decrease, by around 20 per cent since 1970.
- There has been a decline of around 11 per cent in April–October rainfall in the southeast of Australia since the late 1990s.
- Rainfall has increased across parts of northern Australia since the 1970s.
- Streamflow has decreased across southern Australia. Streamflow has increased in northern Australia where rainfall has increased.
- There has been a long-term increase in extreme fire weather, and in the length of the fire season, across large parts of Australia.
- Concentrations of all the major long-lived greenhouse gases in the atmosphere continue to increase, with carbon dioxide (CO2) concentrations rising above 400 ppm since 2016 and the CO2 equivalent (CO2-e) of all gases reaching 500 ppm for the first time in at least 800,000 years.
- Emissions from fossil fuels continue to increase and are the main contributor to the observed growth in atmospheric CO2.
- The world’s oceans, especially in the southern hemisphere, are taking up more than 90 per cent of the extra energy stored by the planet as a result of enhanced greenhouse gas concentrations.
- Global sea level has risen by over 20 cm since 1880, and the rate has been accelerating in recent decades.
- Globally averaged air temperature has warmed by over 1 °C since records began in 1850, and each of the last four decades has been warmer than the previous one.
Australia is projected to experience:
- Further increases in sea and air temperatures, with more hot days and marine heatwaves, and fewer cool extremes.
- Further sea level rise and ocean acidification.
- Decreases in rainfall across southern Australia with more time in drought, but an increase in intense heavy rainfall throughout Australia.