The State of the Climate 2022 report, released on 23 November by CSIRO and the Bureau of Meteorology, has found changes to weather and climate extremes are happening at an increased pace across Australia.
This includes an increase in extreme heat events, intense heavy rainfall, longer fire seasons and sea level rise, which according to the CSIRO’s Director of CSIRO Agriculture and Food, Dr Michael Robertson, are already having widespread impacts on Australia’s agricultural industry, affecting food production and supply chains.
Key findings for Australia
The impacts of climate being reported across the world are varied and many. The State of the Climate 2022 report highlights a number of key points for Australia, including:
- Australia’s climate has warmed on average by 1.47 (+/-0.24) degrees since 1910, leading to more frequent extreme heat events.
- Sea surface temperatures have increased an average of 1.05 degrees since 1900. This has led to an increase in the frequency of extreme heat events over land and sea. The ocean does not warm evenly. Some regions are warming several times faster than the global mean.
- Oceans around Australia have continued to become more acidic, with changes happening faster in recent decades.
- Sea levels are rising around Australia, including more frequent extremes that are increasing the risk of inundation and damage to coastal infrastructure and communities.
- There has been a decline of about 15% in April to October rainfall in South West Australia since 1970.
- In South East Australia there has been a decrease of about 10% in April to October rainfall.
- There has been a decrease in streamflow at most gauges across Australia since 1975.
- Rainfall and streamflow have increased across parts of northern Australia since the 1970s.
- There has been an increase in extreme fire weather and a longer fire season across large parts of the country since the 1950s. This had led to larger and more frequent fires, especially in southern Australia.
- There has been a decrease in the number of tropical cyclones observed in Australia since 1982.
- Snow depth, snow cover and the number of snow days have decreased in alpine regions since the late 1950s.
Emissions and temperatures on the rise
The Director of CSIRO’s Climate Science Centre, Dr Jaci Brown, says that concentrations of greenhouse gases, such as carbon dioxide, are at the highest levels seen on Earth in at least two million years. The Australian climate is warming up and the extreme heat events have increased.
Temperatures rising have a strong impact on fire weather as well, with Dr Karl Braganza (Manager Climate Monitoring, Environment and Research Division, Bureau of Meteorology) stating that the length of fire seasons has increased across the country in recent decades. “We’re expecting to see longer fire seasons in the future for the south and east, and an increase in the number of dangerous fire weather days,” he says.
The projected increases in air temperatures, more heat extremes, and fewer cold extremes in coming decades, will affect and have already impacted rainfall trends across the country. The report shows heavy rainfall events are becoming more intense and the number of short-duration heavy rainfall events is expected to increase in the future.
The oceans around Australia have also warmed by more than one degree since 1900. This has contributed to longer and more frequent marine heatwaves. Marine heatwaves are periods when temperatures are in the upper range of historical baseline conditions for at least five days. Heatwaves in the ocean often last longer than heatwaves on land, sometimes multiple months or even years. The increase in heatwaves frequency around Australia has impacted marine ecosystems, habitats, and species permanently.
As the ocean warms, it expands and sea level rises. Ice loss from glaciers and polar ice sheets, together with changes in the amount of water stored on the land, contribute two-thirds of the observed global sea level rise. Rising sea levels pose a threat to coastal communities and coastal ecosystems by amplifying the risks of inundation, storm surge, erosion, and saltwater intrusion into groundwater systems.
Urgent action needed
Minister for the Environment and Water Tanya Plibersek said “this report is sobering reading […] Australia is experiencing climate change now, with impacts being felt by many communities, ecosystems, and industry sectors. […] For our environment, for our communities, this report reinforces the urgent need for climate action.”
Sources: State of Climate 2022 report; CSIRO’ State of the Climate News Release (23/11/22); Minister for the Environment and Water Tanya Plibersek and Minister for Science and Industry Ed Husic Launch of State of the Climate 2022 Report, Media Release (23/11/22).