Australia: State of the Climate

Key points

Australia

• Australia’s climate has warmed 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.

Global

• Concentrations of all the major long-lived greenhouse gases in the atmosphere continue to increase, with carbon dioxide (CO ₂) concentrations rising above 400 ppm since 2016 and the CO ₂ equivalent (CO ₂-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.

Future

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.