WHAT WAS CLAIMED
Australia has already reached net zero because its trees absorb more carbon than humans emit.
OUR VERDICT
Misleading. Only human-driven changes to emissions since 2005 count towards the net-zero target.
AAP FACTCHECK - Australia has not reached net-zero greenhouse gas emissions, contrary to claims made on social media.
The assertion is based on estimates of carbon absorbed by Australia's forests, deducted from the country's emissions total.
But net zero applies only to human-caused emissions and removals.
Australia is among the many industrialised countries that have committed to net-zero emissions, meaning balancing the emissions it produces with those it removes from the atmosphere by 2050.
The social media posts claim the nation has already achieved this target.
In a Facebook video, a man states the average mature tree absorbs about 22kg of carbon dioxide (CO2) each year and that there are an estimated "24 billion standard trees" in Australia.
The man, who appears to be pointing to a response from an AI chatbot, states that Australia emits 465.2 million tonnes of CO2-equivalent (Mt CO2-e).
However, later in the video, he claims the country emits 440 Mt CO2-e.
He appears to conclude that the country's trees absorb more greenhouse gas than it emits.
"So let's do the maths... [it] equals 528 million tonnes that our trees sequest carbon out of the atmosphere," the man says.
"We make, according to them, 440 million... You see what I'm saying? Like even when you just do simple maths it doesn't work out."
Some social media users have shared the video as evidence that the country has already reached net-zero emissions.
"...our growing tree population in Australia totally sequests all of our so called carbon emissions annually - so we are already better than NET ZERO - please check this out and we can save billions annually," one post caption reads.
Another post states: "We were always carbon neurtal [sic]."
However, this is misleading.
Net-zero targets are widely understood to measure solely human-induced carbon emissions and removals, experts have previously told AAP FactCheck.
The Intergovernmental Panel on Climate Change's (IPCC) net zero definition states: "Net zero emissions are achieved when anthropogenic emissions of greenhouse gases to the atmosphere are balanced by anthropogenic removals over a specified period".
Australia's legislated net-zero target uses a 2005 baseline, meaning human-driven changes from that date, such as planting more trees, are counted.
Based on this criterion, Australia's latest greenhouse emissions figures show forests and other land-use changes reduced its emissions by 73.7 Mt CO2-e in the year to June 2025.
However, the country emitted 511.2 Mt CO2-e, meaning its total net emissions were 437.5 Mt CO2-e.
The figure cited by the man in the video also appears to be a net emissions figure that already accounts for some of the CO2 absorbed by the country's trees.
Gross emissions in the year to June 2023 - the year shown in the video - were 526.6 Mt CO2-e, not 440.2 or 465.2 Mt CO2-e as claimed.
Pep Canadell, chief research officer at the CSIRO, has written several papers estimating the amount of carbon absorbed by the natural environment.
Countries don't count historic natural carbon sequestration in their targets because global greenhouse emissions have increased despite these natural carbon sinks, he said.
"Climate change is taking place despite the work of nature removing about half of all carbon dioxide emissions," Dr Canadell told AAP FactCheck.
He said that even if all carbon sequestered by Australia's natural environment were counted toward its target, the country would still not be at net zero.
Between 2010 and 2019, natural ecosystems removed on average about 388 Mt CO2-e each year, according to a 2023 study (pages 3 and 4) co-authored by Dr Canadell.
An additional 11 Mt CO2-e was sequestered by geological weathering.
However, the study found that this was still outweighed by average annual CO2 emissions of 455 Mt over the same period.
These figures do not include Australia's methane and nitrous oxide emissions, which in the year to June 2025 accounted for 29 per cent and four per cent of total emissions, respectively, the climate change department reported (p7).
These figures had a significant level of uncertainty and the estimate for the amount of carbon naturally sequestered has a margin of error of plus or minus 269 Mt CO2-e.
Another study that attempted to estimate the amount of CO2 ecosystems in Australia absorb arrived at a much higher figure.
An annual report published by the Terrestrial Ecosystem Research Network (TERN), an environmental monitoring organisation, estimated the country's vegetation absorbed a net 3242 Mt CO2-e in 2024 (page 12).
Albert Van Dijk, an environmental scientist at the Australian National University, co-authored this report and said the estimate was derived from another paper he co-authored.
The amount of carbon removed annually varied significantly, he told AAP FactCheck.
Prof Van Dijk estimated the country's native environment absorbed on average about 1900 Mt CO2-e per year between 2010 and 2019, well above the country's annual emissions.
The significant difference between the CSIRO and TERN estimates reflects differences in methodology and the inherent difficulties of measuring ecosystem carbon uptake.
However, Prof Van Dijk said that was irrelevant to Australia's net-zero accounting.
"The way national emissions accounting works under international frameworks doesn't count natural uptake, only changes due to human activity," he said.
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