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Australia’s mean temperature has risen by approximately 1.4 degrees Celsius (°C), since 1910, according to the State of the Environment Report, released July 19,2022.
Some regions are more impacted than others. Central and eastern interior parts have warmed by more than 2°C, while north-western Australia and some south-eastern coastal areas have recorded the lowest rise of 0.5-1°C, noted the data released by the Australian government.
Also read: UK heatwave: Temperature crosses 40°C
The 2021 State of the Environment Report is a mandatory assessment conducted every five years. Australia has witnessed a 10 per cent increase in the intensity of short-duration (hourly) extreme rainfall events in some regions in recent decades, according to the report.
The southwest part of Western Australia saw its average rainfall dropping by 15-20 per cent between 1970 and 2020. Low rainfall and high evaporation are taking a toll on Australian rivers. Since 2016, water storage in many had fallen below 10 per cent, highlighted the report.
Over the last five years, extreme events such as floods, droughts, wildfires, storms and heatwaves have affected every part of Australia, the report’s authors wrote in The Conversation.
Australia’s fire season has shown an increasing trend since the 1950s. The 2019-2020 bushfire was due to a long preceding dry spell, the report stated. Further, the heat and particulate matter in the bushfire smoke plumes have triggered the formation of thunderstorms in recent years.
These clouds can generate dangerous and unpredictable fire behaviour, including wind direction changes, cloudbursts and lightning. Invasive plants, predominantly grasses, are increasing the risk of fire events in some areas of the country, the report found.
The 2019-2020 bushfire event, the report found, also had short-term impacts on air quality. Extreme events can have a high impact when subsequent events multiply the effect of initial events.
Certain extreme events are linked. For example, drought years carry the risk of bushfires. A flood could follow a bushfire, too.
“In other cases, multiple events in rapid succession, even if not meteorologically related, can have multiple impacts beyond those that would be expected from the individual events alone,” the report read.
Sea temperatures are also on the rise. Since 1900, they have increased by approximately 1.1°C, the report stated.
Warmer waters expand in response to heat, causing sea levels to rise. Sea-level rise in Australia is above the global average of 3-3.5 millimetres per year. The rate of warming is generally slightly higher in eastern Australian waters than in the west.
The number of tropical cyclones in the Australian region has declined since the 1980s. In the ten seasons from 2010-11 to 2019-20, the country recorded an average of 8.9 cyclones per year, about 20 per cent below the 1981–2010 average, data showed.
The report also covered Antarctica, the Southern Ocean and subantarctic islands. It stated that patterns in sea ice formation are becoming increasingly unpredictable even as glaciers and ice sheets continue to melt.
The report also presented changes in ecosystems in Australia. The country has lost more mammal species in the last two centuries than any other, the report pointed out.
In June 2021, more than 1,900 Australian species and ecological communities were known to be threatened and at risk of extinction.
As many as 100 species in Australia are listed as extinct or extinct in the Wild. These include 38 vascular plants, 34 mammals, 10 invertebrates, nine birds, four frogs, three reptiles, one fish and one protist (a single-celled organism).
The report, however, warned that extinction numbers could be significantly higher due to limited surveys.