Climate change: It’s here, says Australia’s peak science orgs

Climate change is impacting Australia today and will further impact human lives.

That’s the takeaway from the biennial State of the Climate report published by the nation’s leading scientific organisations, the CSIRO and the Bureau of Meteorology.

It reports Australia’s climate has heated by an average of 1.47 degrees since 1910.

While that figure is limited to the Australian continent only, it is notably 0.03 degrees shy of the 1.5-degree cap sought by the Paris Climate Agreement.

Sea temperatures have risen by 1.05 degrees on average since 1900, burdening oceans with more frequent extreme heatwaves and acidification.

Sea level rise has been recorded around Australia, with the report noting increased “risk of inundation and damage” to infrastructure and communities along the coast.

Data published in the report shows an increase in the temperature anomaly (which are departures from a three-decade averaging period from 1961-90) from the middle of the century.

Such is the extent of surface temperature change, that the recent La Niña events in Australia – which bring cooler, wetter conditions – were warmer than an El Niño (warmer, drier) event in the decades prior.

In releasing the report, Australia’s environment minister Tanya Plibersek and science minster Ed Husic described its contents as “sobering reading” and proof of “the urgent need for action on climate change.”

They also emphasised their government is one that “believes… listens… and acts” in line with science.

That language is stronger than the previous government’s, but effective action requires a significant turnaround in mitigation and carbon reduction activities. Historically, Australia has been one of the world’s highest per capita carbon emitters and although recent declines in carbon dioxide output from Australia have been recorded, it also remains a top fossil fuel exporter. Mining and export industries globally may also be underreporting their carbon output by two thirds.

Greenhouse gases still going up

Continued increase of greenhouse gases in the atmosphere are driving current climate changes. Carbon dioxide concentration in the atmosphere is now 414.4 parts per million, marking an almost 50% increase on pre-industrial levels.

But methane and nitrous oxides have also rapidly increased in atmospheric concentration. Methane is now around 158% more than pre-industrial levels, and 83 times stronger at trapping heat than CO₂. The majority of this methane comes from fossil fuel extraction and use, and agriculture and waste.

Climate experts have again taken the release of this report ,following similar global reports published this month, to continue calls to end fossil fuel use.

“The consequences of our continued use of fossil fuels are clear in Australia, like elsewhere,” says Melbourne University climate science lecturer, Dr Andrew King.

“The [report] comes on the back of what feels like a never-ending series of extreme events from the drought and heat of 2019 and 2020, to the more recent floods. Australia is experiencing more extreme heat, more fire weather, and more short-duration extreme rain. These types of extreme weather will only get worse until we approach global net-zero emissions.”

Health professionals like cardiologist Dr Arnagretta Hunter from the Australian National University, emphasised the physiological risks posed by a warming climate.

“Climate change is the major threat to health and wellbeing this century,” Hunter says.

“Reducing greenhouse gas emissions as fast as possible is so important for our future, as is attention to complexity of climate adaption. This report offers incentives for both rapid mitigation and for increased attention for climate adaptation in communities around Australia.”

Bleak outlook for Australia as fossil fuel use increases

The State of the Climate report presents several increased risks for Australia, among them increases in extreme heatwaves, extreme fire weather, longer fire seasons, and rainfall decline across much of the continent.

When heavy rainfall does occur, it’s more intense. That’s because seven percent more moisture can be retained by the atmosphere for every degree of additional warming.

Sea level rise across the globe has recorded a 25cm increase since 1880, half of which has occurred in the last fifty years. This is due, in part, to melting ice sheets in the Arctic and Antarctica. But despite an increase in sea ice in the 35 years leading up to 2014, the marked decline in ice coverage recorded since is attributed to atmospheric and ocean temperature changes.

“The warming of our oceans is contributing to longer and more frequent marine heatwaves, and this trend is expected to continue into the future,” says Dr Jaci Brown, the director of the CSIRO Climate Science Centre.

“We’re seeing mass coral bleaching events more often, and this year, for the first time, we’ve seen a mass coral bleaching on the Great Barrier Reef during a La Niña year. The rate of sea level rise varies around Australia’s coastlines, but the north and south-east have experienced the most significant increases.”