Australia's action on climate change is "insufficient" and the country must adopt a more ambitious response, the Biden administration has warned, ahead of a crucial climate leaders' summit.
The global meeting hosted by President Joe Biden is being convened to push nations around the world to step up their commitment to reduce emissions.
But Australia's approach to cutting greenhouse gas emissions has come under scrutiny during a briefing call with senior Biden administration officials ahead of Prime Minister Scott Morrison's attendance at the summit.
A senior Biden official told reporters there must be a shift in Australia's climate change policies if the country wants to achieve net zero emissions by 2050.
"At the moment, I think our colleagues in Australia recognise that there's going to have to be a shift," the official, speaking on condition of anonymity, said during a briefing call.
“It’s insufficient to follow the existing trajectory and hope that they will be on a course to deep decarbonisation and getting to net zero emissions by mid-century.”
Mr Morrison has not formally committed to the net-zero emissions target - instead saying Australia wants to achieve the goal as soon as possible, relying on technological advancements.
He later defended Australia's commitment to reducing emissions during a press conference - backing its plan to gradually transition to net-zero through harnessing technology.
"I would make this one comment on the anonymous report - the trajectory to any net zero outcome is not linear. Anyone who thinks it is I know doesn't get it," he told reporters.
"The way technology works is there is a long lead time into its development and commercialisation and once the technology is in place, you can see a massive transformation."
However, the approach has been met with scepticism within the Biden administration, with the official telling reporters technology alone can't be relied upon to deliver outcomes without strong emissions targets.
"One view of the world says, don’t worry, technology will solve the problem," the official said.
"The other view of the world says, at the end of the day, technology will contribute but is insufficient on its own to solve the problem, and you have to have a set of policies, you have to have national intent, you have to follow up with actions and commitments.”
Mr Biden is expected to use the summit, which starts on Thursday evening, to announce a new target to cut US carbon emissions by about 50 per cent by 2030, based on 2005 levels.
This would be almost double Australia's current target to reduce emissions by 26 to 28 per cent over the same period under the Paris Agreement.
Mr Morrison said Australia was committed to meeting and beating its targets, citing a 19 per cent reduction in emissions since 2005.
"Many countries make commitments but none of them can claim the same record of achievement that Australia consistently has," he said.
Energy and Emissions Reduction Minister Angus Taylor was earlier also questioned about whether the Australian government is facing mounting pressure to raise the ambition of its emissions targets.
He said the target was considered a "floor" and not a "cap" on the amount that emissions could be reduced.
“Politicians' promises are one thing, delivery is what counts," he told ABC Radio on Thursday.
"Our targets are always a floor on our ambitions not a cap they always have been - We always shoot to meet and beat our targets."
Mr Morrison this week flagged up to $1 billion investment in low-carbon emission projects and research, which he is expected to push as evidence of Australia's commitment to the issue at the summit.
This includes more than $539.2 million in funding for hydrogen and carbon capture of storage projects.
He’s also promised $565.8 million over the next eight years to build international collaboration to drive development on low carbon technologies.
Mr Morrison said the investment sent a "big message" to the global community about Australia's willingness to act on climate change.
However, in contrast, other countries are preparing to sell more ambitious emissions targets during their appearance at the summit.
British Prime Minister Boris Johnson this week committed to cutting carbon emissions by 78 per cent by 2035 ahead of the summit, labelling the response the world's most ambitious climate change target.
Meanwhile, Canadian Prime Minister Justin Trudeau is also reportedly considering a pledge to reduce Canada's carbon emissions 40-45 per cent by 2030 from 2005 levels.
The responses make Australia's approach appear increasingly out of step with global allies and intensify pressure on Mr Morrison to step up the ambition of the country's targets.
Without a formal commitment to net-zero emissions by 2050 - Australia also stands as an outlier compared to allies the United States, the United Kingdom, Canada, Japan and South Korea.
Former Australian climate negotiator Richie Merzian, director of the climate & energy program at progressive think tank the Australia Institute, said Australia's response appears increasingly isolated on the world stage.
"Right now the US is providing encouragement and is nudging Australia to do more - eventually those nudges will become firmer and harder," he told SBS News.
"Australia needs to take up a stronger emissions reduction target - that is what the world tonight will be expecting at the Biden summit."
Research conducted by the Australia Institute released ahead of the summit has compared the ambition of Australia's current emissions trajectory to the target expected to be adopted by President Biden.
The research puts into perspective the impact of the United States' stronger target showing the commitment would reduce its emissions by up to 42 per cent over the next decade.
In contrast, Australia's current target will see a 14 per cent reduction in emissions compared to 2019 levels.
"It is about half of what the US will push for and it is a lot less than most countries - really Australia should be doing a lot more," Mr Merzian said.
The Queensland government has also flagged it would be willing to act alone to deliver more ambitious climate change policies to avoid being "left in the dust" with the federal government ahead of the summit.
"If we're to continue to build on our achievements, we can't expect to wait for the federal government to take action," said Queensland's Environment Minister Meaghan Scanlon on Thursday.
"While we've seen some steps taken by Canberra, we've not yet seen the leadership the world has been crying out for."
In the pre-summit briefing, the Biden official also stated there was "enormous potential" for the United States and Australia to work together towards cutting emissions if the change in its existing approach can be delivered.
"The question of what they do and what they say will certainly affect how and how effectively we can cooperate going forward," the official said.
Mr Morrison is among 40 leaders who have been invited to join the virtual summit to be held across 22 April and 23 April.
The global meeting is being seen as an attempt by Mr Biden to signal his intent to prioritise the issue of climate change early in his administration.