The State of the Climate report, released today by the Bureau of Meteorology and CSIRO, shows a warming temperature has increased the frequency of 'extreme weather events' such as heatwaves and fire weather.
Australia's climate has warmed on average by 1.44 degrees since 1910.
Research Director at CSIRO's Climate Science Centre, Dr Jaci Brown, said while 2019 was the hottest year on record, it wouldn't be unusual in coming decades.
"In fact, we think of this decade being hot, but this decade will be one of the coolest in the next hundred years," she said.
BOM Climate Environmental Prediction Services manager, Dr Karl Braganza, said longer fire seasons with more days of extreme risk meant less opportunity to reduce fuel loads during cooler months.
Climate change has influenced bushfire patterns through its impact on temperature, rainfall and humidity that affects fuel moisture content.
"We don't necessarily feel the 1.44 degrees increase in Australian average temperature, but we feel those heatwaves and we feel the fire weather," he said.
Over the short term the wet weather associated with the La Nina weather pattern is expected to persist through spring and summer, but Dr Braganza said there were still dry parts of the country in Queensland, South Australia and Victoria.
He said southern Australia is one of the most fire prone regions on the globe.
Drawing on the latest climate observations and projections, the biennial report is designed to deliver up-to-date information to aid decision making.
Other key findings include declining rainfall in the southeast and southwest of the country and rising sea levels in line with global trends.
The report states oceans around Australia are being affected by climate change, with significant impacts on marine ecosystems.
Surface waters are acidifying, and the frequency, intensity and duration of marine heatwaves have increased.
"These trends, which are projected to continue in the coming decades, are already posing a significant threat to the long-term health and resilience of the coral reef ecosystems around Australia's coast," Dr Brown said.
COVID-19 lockdowns and economic downturn helped reduce global emissions in 2020, but it has not been enough to make a noticeable impact on carbon dioxide levels in the atmosphere.
Measurements taken at the Cape Grim Baseline Air Pollution Station in Tasmania show carbon dioxide levels have been increasing since pre-industrial times with fossil fuel emissions the main driver of growth.