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Tasmanian Liberals say younger forests are better at sequestering carbon than old-growth forests. The science says otherwise

RMIT ABC Fact Check
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RMIT ABC Fact Check and RMIT FactLab present the latest in debunked misinformation.

CheckMate is a weekly newsletter from RMIT FactLab which recaps the latest in the world of fact checking and misinformation, drawing on the work of FactLab and its sister organisation, RMIT ABC Fact Check.

You can read the latest edition below, and subscribe to have the next newsletter delivered straight to your inbox.

CheckMate July 1, 2022

This week, CheckMate takes an axe to claims about the ability of old-growth forests to store carbon from greenhouse gas emissions.

We also bring you the latest on ivermectin, and round up the week in fact checking over the US Supreme Court decision to overrule its decades-old Roe v Wade judgement.

No, old-growth forests aren't net CO2 emitters, and young forests don't store more carbon

Tasmanian Liberals and Greens have faced off in state parliament over the benefits of old-growth forests, with one MP arguing the science shows newer forests are superior in their ability to offset carbon emissions.

"They [the Greens] don't understand that old-growth forests are actually net carbon emitters," claimed Liberal MP Felix Ellis.

"They don't understand that the best carbon sequestration comes from a young growing forest," he added, with his Facebook video of the exchange garnering more than 115,000 views and winning the endorsement of the state party and the deputy premier.


However, these claims are incorrect.

Belinda Medlyn, a professor at the University of Western Sydney who studies how forests respond to atmospheric carbon dioxide, told CheckMate she could say "unequivocally" that "old-growth forests are not carbon emitters".

"There is zero evidence to show that forests start to emit [CO2] as they age, and considerable evidence to show that they may continue to take [it] up," she said, adding that when it came to which forests were more effective carbon sinks, people often confused the rate of sequestration with the total amount stored.

While old-growth forests may only store around 1 tonne of carbon per hectare per year, Professor Medlyn explained, they "can hold a lot of carbon in the trees, maybe 500 tonnes per hectare".

By contrast, she said, a newly planted hectare of forest may accumulate, say, 5 tonnes of carbon per year "but it has next to no carbon to begin with" so "will take a long, long time to catch up to the old-growth forest".

Brendan Mackey, director of Griffith University's Climate Action Beacon and a coordinating lead author for the UN's Intergovernmental Panel on Climate Change, also rejected Mr Ellis's comments, labelling them "unscientific".

In a statement provided to CheckMate, Professor Mackey and his colleague Dr Heather Keith, an expert in carbon stocks and primary forests, said the two claims were "misconceptions that have been thoroughly disproven by scientific research into forest ecosystems throughout the world".

Critically, they said, "the true mitigation value of native forests resides in their ongoing capacity to sequester and store carbon".

Measuring this requires accounting for the forest's total carbon stock — held in everything from living trees to logs and soil — and the time it remains locked away, which is by definition shorter in areas that have been logged.

Old-growth forest in Willamette National Forest, Oregon. Photo: Wikimedia Commons.
Studies show old-growth forests store more carbon than regrowth harvested forests.(Old-growth forest in Willamette National Forest, Oregon. Photo: Wikimedia Commons. )

Professor Mackey and Dr Keith pointed to a host of studies (e.g. hereherehere and here) which showed that, compared to primary and old-growth forests, "the long-term average carbon stock of regrowth harvested forests is 30-70 per cent lower".

And the evidence shows it is the oldest trees that do much of the heavy lifting — with the largest 1 per cent accounting for half the total carbon stored in above-ground living forest biomass.

In fact, old trees continue to grow, albeit more slowly, and "carbon accumulation increases continuously with tree size", the academics said, noting that under natural conditions, trees can live for 200-2,000 years (and store much of their total carbon in the final stretch).

According to a 2014 study published in Nature, large, old trees "actively fix large amounts of carbon compared to smaller trees" and "at the extreme, a single big tree can add the same amount of carbon to the forest within a year as is contained in an entire mid-sized tree".

CheckMate contacted Mr Ellis for the source of his claims but did not receive a response, and was unable to find relevant data in the stories or reports to which his subsequent Facebook posts linked.

Fact checking the overruling of Roe v Wade

A young woman outstretches her arm as she yells outside the Supreme Court. She has 'my body, my choice' written on her cheeks
The overruling of the landmark Roe v Wade decision sparked protests outside the US Supreme Court.(Reuters: Evelyn Hockstein)

Following the US Supreme Court's decision to overruleoverrule its 1973 Roe v Wade decision, which gave American women legally protected access to abortion, fact checkers have been working overtime to ensure facts are at the forefront of the ongoing debate over the ruling.

PolitiFact, for instance, looked at key statements from the new ruling itself, including an allegation that only six countries outside of the US permitted elective abortion-on-demand after 20 weeks of gestation, which it concluded was only partially accurate.

According to the outlet, there are at least a dozen countries that allow abortion after 20 weeks. Furthermore, it said, definitional issues muddied the claim.

Meanwhile, a statement issued by President Joe Biden claiming that the court's decision made the US "an outlier among developed nations in the world" when it came to abortion rights was deemed correct.

The fact checkers also found that a claim made on Twitter suggesting "15 per cent of abortions are the result of coercion" was mostly false.

The figure is based on a UK survey of about 1,000 women. But while 15 per cent of respondents said they had experienced pressure to terminate a pregnancy, "the women did not confirm whether they got an abortion and weren't asked to specify the source of the coercion", PolitiFact reported.

"The UK survey also found that women had been forced to have sex without contraception, had contraception damaged or withheld from them, and were pressured to continue a pregnancy."

Elsewhere, AFP Fact Check debunked a claim made in May — after a draft of the Roe v Wade overturning was leaked — that the state of Tennessee had banned Plan B (also known as the "morning after pill").

"The claim is false," the fact checkers found. "The state's legislation does impose stricter rules on abortion-inducing medication, but it does not mention Plan B, which is a contraceptive."

CoronaCheck: Is the jury finally in on ivermectin?

Blisters of tablets in front of a box for the drug Ivermectin
The results of a meta-review of ivermectin's effectiveness against COVID-19 are in.(Supplied: WSLHD)

The anti-parasitic drug ivermectin has made headlines throughout the pandemic, with supporters from former MP George Christensen to US podcaster Joe Rogan swearing by its effectiveness as a COVID-19 treatment and boosting its popularity in conspiracy circles.

Faced with the risk of shortages and a lack of supporting clinical data, Australia's medicines regulator, the Therapeutic Goods Administration (TGA), has restricted ivermectin's off-label use, giving rise to a black market trade in illegally imported — and potentially counterfeit — products that has seen some people issued with hefty fines.

But does the drug work against COVID-19?

Though evidence may yet come to light, a meta-review published this week by the Cochrane Library bodes poorly for ivermectin's future as a COVID-19 treatment.

The study's review of the existing literature and 11 randomised controlled trials found that, based on "low-to-high certainty evidence", the drug appeared to offer "no beneficial effect" to people with mild or no symptoms.

For patients admitted to hospital with moderate or severe symptoms, the authors found there was "low-certainty evidence that it has no beneficial effect regarding clinical improvement, viral clearance and adverse events".

A lack of quality evidence meant they were "still uncertain whether ivermectin prevents death or worsening of clinical status or increases serious adverse events in inpatients".

The last time Cochrane conducted a systematic review of the available evidence, experts told CheckMate it was the most robust study on the topic to date, with one describing it as "the gold standard in medical research and very trustworthy".

Fact-checker fest sets its sights on YouTube

three women and two men sit on a stage. the woman in the center has a microphone and is talking
RMIT ABC Fact Check's Sushi Das (centre) takes part in a panel on policy and regulation at the GlobalFact 9 conference in Oslo.(Angela Trajanosk)

Fact checkers from around the world have lambasted Brandon Feldman, director of news and civics partnerships at YouTube, accusing the video-sharing platform of failing to tackle "dangerous" disinformation, despite repeated warnings.

The several hundred fact checkers from 65 countries were gathering in Oslo, Norway, for GlobalFact, the annual conference organised by the Poynter Institute's International Fact-Checking Network (IFCN).

Following a "fireside chat" with IFCN director Baybars Orsek, Mr Feldman faced fiery questions from fact checkers, including those from the UK, Pakistan and Georgia, who accused YouTube of doing little to address disinformation being shared on the platform.

They said that this was despite concerns outlined in a letter to YouTube signed by 80 fact-checking organisations earlier this year, including RMIT ABC Fact Check.

According to the editor-in-chief of PolitiFact, Angie Drobnic Holan, YouTube had made no effort to "raise accurate, credible information in its algorithms".

"We have had a lot of experience with YouTube making videos of fact-checking content," she put to Mr Feldman.

"It doesn't seem to do very well.

"I think most news organisations are extremely frustrated with your platform."

Mr Feldman said YouTube was taking disinformation seriously and was expecting to take action "very soon".

Nobel Prize-winning fact checker faces ban in the Philippines

A bespectcled woman with short hair looks off camera as she poses for a headshot.
Nobel Peace prize winner Maria Ressa's news service Rappler has been ordered to shut down by the government in the Phillipines.(Reuters: Eloisa Lopez/File)

In a move condemned by the International Fact-Checking Network, the government of outgoing Philippine President Rodrigo Duterte has ordered news site Rappler, including its fact-checking division, to shut down.

Headed by Maria Ressa, who was last year awarded the Nobel Peace Prize for her efforts in safeguarding freedom of expression, Rappler is one of the few independent news organisations in the Philippines and has worked to closely monitor Mr Duterte's violent drugs war.

On Tuesday, the Philippine Securities and Exchange Commission issued an order revoking Rappler's business licence, the news site said in a statement.

"The SEC's kill order revoking Rappler's licence to operate is the first of its kind in history — both for the Commission and for Philippine media," Rappler said.

"​​What this means for you, and for us, is that the Commission is ordering us to close shop, to cease telling you stories, to stop speaking truth to power, and to let go of everything that we have built — and created — with you since 2012."

The organisation has confirmed it will appeal the decision, and will continue to publish in the meantime.

In a tweet, the IFCN said it "strongly condemns the decision to prevent Rappler operating and carrying out journalism".

Edited by Ellen McCutchan and David Campbell

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This newsletter is supported by funding from the Judith Neilson Institute for Journalism and Ideas(Judith Nielson Institute)
Posted , updated