Continued warming of Australia's climate, an increase in extreme fire weather and length of the fire season, declining rainfall in the southeast and southwest of the continent, and rising sea levels are some of the key trends detailed in the latest State of the Climate report, released today by the Bureau of Meteorology and CSIRO.
Drawing on the latest climate observations, analyses and projections, the biennial report provides a comprehensive and scientifically rigorous analysis of Australia's changing climate, today and into the future.
"Our science clearly shows that, due to increasing greenhouse gases, such as carbon dioxide, in the atmosphere, Australia's climate is continuing to warm, and the frequency of extreme events such as bushfires, droughts, and marine heatwaves is growing," Director of CSIRO's Climate Science Centre Dr Jaci Brown said.
The Bureau of Meteorology's Manager of Climate Environmental Prediction Services, Dr Karl Braganza, said the report finds the warming trend in Australia is contributing to increases in extreme fire weather and the length of the fire season.
"There has been a significant increase in the frequency of dangerous fire weather days across Australia, particularly during spring and summer, leading to an earlier start to the southern fire season," said Dr Braganza.
"Climate change is influencing these trends through its impact on temperature, rainfall, and relative humidity, and the resulting change to the fuel moisture content."
Between December and February, the Southern Highlands is predicted to experience maximum median temperature of 25.4 degrees.
Meanwhile a mimimum median temperature of 12.6 degrees is expected.
Australia's changing rainfall pattern is another key observation documented in the report, with contrasting trends being observed across the north and south of Australia.
The Southern Highlands is predicted to receive a median rainfall of 34mm between December and February, according to the BoM.
"In the southwest and southeast of Australia we are seeing drier conditions, particularly in the cool season months of April to October. In southwest Australia, for example, cool season rainfall has decreased by around 16 per cent since 1970. These trends are projected to lead to more time spent in drought in the coming decades," said Dr Braganza.
"In contrast, rainfall has increased across most of northern Australia since the 1970s. While highly variable from year to year, there have been more 'wetter than average' years in recent decades."
The oceans around Australia are also being affected by climate change, leading to significant impacts on marine ecosystems. Surface waters are acidifying, and the frequency, intensity and duration of marine heatwaves has 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 has not been enough to make a discernible impact on carbon dioxide levels in the atmosphere.
State of the Climate 2020 is the sixth report in a series published biennially by the Bureau of Meteorology and CSIRO, which together play an integral role in monitoring, measuring and reporting on weather and climate.