Australia was a different place in 2011. Julia Gillard’s Labor government, the Greens and a couple of country independents were rewriting the country’s climate policies, including introducing a world-leading carbon pricing system and creating three agencies to back it up.

Those organisations – the Clean Energy Finance Corporation, the Australian Renewable Energy Agency and the Climate Change Authority – have survived and help shape the investment and policy landscape. The carbon pricing system – falsely described as a tax – famously didn’t.

Under the Tony Abbott-led Coalition, Australia became the first country to abolish a functioning carbon price following a campaign that his chief-of-staff, Peta Credlin, later admitted was based on a lie. More than a few people who wanted it scrapped in 2014 quietly regret that decision now, reasoning that a policy based on an unarguable truth – that carbon dioxide emissions have a cost on all of us, and that the cost should be included in the price of goods that pump out CO2 – would have been far better than the uncertainty and mess of the past decade.

Who could possibly have foreseen that? Again, more than a few people. But here we are.

A less-heralded consequential clean energy shift around this time was the decision to split the national renewable energy target in two. Created in 2001 by the Howard government, the target was significantly expanded after Labor was elected later that decade. In January 2011 it was divided into separate schemes to support large-scale renewable energy, which required the creation of solar and wind power stations, and small-scale household installations.

Both have been successes, but it’s the latter – driving Australia’s household rooftop solar boom – that sets the country apart.

It’s difficult to overstate how rapidly Australians have embraced solar power, and how much it has exceeded expectations. In 2011, the forecast was that rooftop solar would eventually contribute 4 terawatt hours of electricity. In the context of the Australian grid, this was next to nothing – barely 2% of total generation. For some, it raised the question of whether it was really worth the cost.

More than a decade on, that number has been eclipsed more than six times over in the five eastern states connected by the country’s main power grid. Rooftop solar panels connected to the National Electricity Market generated 24.6TWh over the last year of data.

Put another way, homes have contributed 11.6% of electricity – nearly as much as windfarms, comfortably more than large-scale solar farms or hydro plants, and twice as much as gas-fired power.

More than 3.7m households and small businesses have solar systems. It means more than one in three homes across the country generate their own power when the sun is out.

Data released by the Clean Energy Regulator last week suggests Australians will install 3.1 gigawatts of rooftop solar capacity this year, roughly continuing the recent pace. Industry group the Clean Energy Council points out that, in capacity terms, Australia now has more rooftop solar than coal-fired power.

It is a wild, globe-leading success story that, as we’ve pointed out before, was something of a happy accident – the result of uncoordinated policies across federal and state governments. There were some initial stumbles, but the most important measure – an upfront national rebate that is processed by and paid to the installer that is progressively wound back as solar becomes more affordable – maintains wide support, including from both major political parties.

The rebate has helped bring down the cost to a level where a system can be effectively paid off via reductions in power bills, over about five years (with some variation depending on where you live). Combined with significant jumps in the cost of large-scale fossil fuel electricity – driven by Russia invading Ukraine, and gas and coal shortages and outages – it has made solar a financial no-brainer for home- and mortgage-owners who can pay the initial cost. Some states offer loans to make that easier.

The rooftop solar expansion will continue, with an expectation there will be more than 70GW connected by 2050. A key question is what lessons the country takes from how it got here.

One must be that any continual expansion needs to be equitable. With home ownership increasingly out of reach for many, Australia needs to consider innovative ways to make the benefits of solar available to renters and people in social housing. There have been some initial steps in this direction, but more will be required.

Another should be a reckoning on the role that household batteries will play in our future electricity supply. Batteries have not received the wave of government incentives that boosted solar. With some exceptions, they mostly still do not make financial sense for households. But analysts have pointed out the lesson from the solar success is that going hard early can bring unanticipated benefits, even while you adjust as you go.

As with the flood of solar energy in the middle of the day, an increase in household batteries – both standalone batteries and those in electric vehicles, which can be used in a similar way – will require changes in how power grids operate and are paid for.

Consumers are likely to be paid less for the electricity they feed into the grid and may be blocked from selling their excess power at peak times. On the upside, electricity use would become more flexible and more efficient.

Given we still run on a system designed to power homes and businesses from a few large generators, the change will be a regulatory challenge, and energy companies may resist significantly more control over energy use being placed in consumers’ hands.

But we live in politically populist times, and the experience with solar suggests a further shift in this direction would be widely welcomed.

Crossbench MPs have already joined Rewiring Australia’s Saul Griffith in calling for a rapid move in this direction, and both major parties have signalled they are considering household energy packages before the next election. The question now is how far they will go.

The US government is seeking to consider a firefly species as endangered for the first time, according to a proposal from the US Fish and Wildlife Service.

The Bethany Beach firefly, found in coastal Delaware, Maryland and Virginia, is facing increasing dangers to its natural habitat because of climate change-related events. They include sea level rise, which is predicted to affect all sites within the known distribution by the end of the century, and the lowering of groundwater aquifers.

The species is already considered extremely rare and in decline.

Bethany Beach fireflies are one of about 170 species of fireflies. It is noted for having a distinctive flash pattern of two green flashes, also called a double-green flash pattern. These insects, which were first discovered in the 1950s, usually emerge in June and July.

The proposal, announced on Monday, is the first time the US government has attempted to protect a firefly under the Endangered Species Act.

In addition to climate change, these fireflies face growing threats from coastal development and light pollution, the latter of which can interfere with the insects’ ability to use their bioluminescent lights to communicate with each other. This particular firefly only flies and flashes at full darkness.

It is recommended that people who live among Bethany Beach firefly populations take steps to reduce light pollution by turning off their porch lights when they are not in use or setting outdoor lights on a timer.

Fireflies are the latest insect to be considered endangered amid a so-called “bug apocalypse”. It was reported earlier this year that monarch butterfly populations dipped 59% in their winter migration.

The International Union for Conservation of Nature (IUCN) currently list more than 70 species of beetles as endangered, with the Bethany Beach firefly being labeled as “critically endangered”.

Within the past several years, Bethany Beach fireflies have been displaced and populations wiped out because of development on coastal wetlands.

In 2019, a wetland habitat with the largest known population of Bethany Beach fireflies was extinguished due to development in Breakwater Beach, New Jersey. It was reported that the developer found a loophole in the policy that protects designated wetlands, resulting in the firefly population being lost.

A Georgia judge on Monday struck down the state’s six-week abortion ban, ruling that the ban is unconstitutional and blocking it from being enforced.

In a 26-page opinion, the Fulton county superior judge Robert McBurney issued an order that said abortions must be regulated as they were before the state’s law – known as the Life Act – was passed in 2019. The ban was blocked as long as Roe v Wade was the law of the land, but went into effect after the US supreme court overturned Roe in 2022. At the time, Georgia permitted abortions until 22 weeks of pregnancy.

With the decision, abortions past six weeks can resume in the state.

Many women, McBurney wrote, do not even know they are pregnant at six weeks.

“For these women, the liberty of privacy means that they alone should choose whether they serve as human incubators for the five months leading up to viability,” McBurney wrote. “It is not for a legislator, a judge, or a Commander from The Handmaid’s Tale to tell these women what to do with their bodies during this period when the fetus cannot survive outside the womb any more so than society could – or should – force them to serve as a human tissue bank or to give up a kidney for the benefit of another.”

In a footnote, McBurney added: “There is an uncomfortable and usually unspoken subtext of involuntary servitude swirling about this debate, symbolically illustrated by the composition of the legal teams in this case. It is generally men who promote and defend laws like the Life Act, the effect of which is to require only women – and, given the socio-economic and demographic evidence presented at trial, primarily poor women, which means in Georgia primarily black and brown women – to engage in compulsory labor, ie, the carrying of a pregnancy to term at the government’s behest.”

McBurney’s ruling arrives weeks after ProPublica reported that two Georgia women died after being unable to access legal abortions in the months after Roe was overturned.

Reuters contributed reporting

Donald Trump has been accused of invoking plotlines similar to The Purge – a dystopian horror film in which officially sanctioned murder is occasionally legal – as a possible solution to crime in the US after saying it could be eradicated in “one really violent day”.

In what was seen as an extreme display of demagoguery even by his standards, Trump drew cheers from an audience in Erie, Pennsylvania, with a picture of an out-of-control crime spree that he said could be ended “immediately” with one “real rough, nasty day”, or “one rough hour”.

“You see these guys walking out with air conditioners with refrigerators on their back, the craziest thing,” Trump said. “And the police aren’t allowed to do their job. They’re told, if you do anything, you’re gonna lose your pension.

“They’re not allowed to do it because the liberal left won’t let them do it. The liberal left wants to destroy them, and they want to destroy our country.”

In a passage that provoked a storm on social media, the former president and Republican nominee then said: “If you had one day, like one real rough, nasty day with the drug stores as an example, where, when they start walking out with …”

He then trailed off in a digression to falsely accuse Kamala Harris, the Democratic nominee, of introducing a practice in California when she was attorney general that exonerated thieves from prosecution of items worth less than $950.

Politico said the remark appeared to be a reference to proposition 47, which downgraded some offenses from felonies to misdemeanor and was signed into law by the state’s former Republican governor, Arnold Schwarzenegger, four years before Harris took office.

Linking that issue to his theme, Trump continued: “You saw kids walk in with calculators. They didn’t want to go over the $950. They’re standing with calculators adding it up. You know, these are smart, smart people. They’re not so stupid, but they have to be taught.

“Now, if you had one really violent day … one rough hour, and I mean real rough. The word will get out and it will end immediately.”

The comments triggered a stream of comparisons to The Purge, a 2013 film that depicts the election of a radical new party called The New Founding Fathers of America following an economic collapse, which then enacts drastic policies to end crime and unemployment.

The criticism was reiterated by Jon Lemire, a host on MSNBC’s Morning Joe, who told viewers: “[Trump] did suggest that there should be an hour of violence, which sounds like the plot of the movie The Purge, which is deeply dangerous.

“We know how his words have inspired violence before, including, but not limited to January 6 … This is an extraordinarily dangerous closing argument and vision for America.”

In the film, the US is depicted as becoming virtually crime- and unemployment-free by 2022 following a policy of legalising all crime, including murder, and making emergency services unavailable for a period of 12 hours each year.

Even before the comparisons, Trump’s campaign issued a denial that his remarks amounted to a policy proposal.

A campaign official told Politico that the ex-president was “clearly just floating it in jest”.

Steven Cheung, the campaign communications director, told the site in a statement that Trump was reasserting his supposed credentials as “the law-and-order president”.

“He continues to reiterate the importance of enforcing existing laws,” he said. “Otherwise it’s all-out anarchy, which is what Kamala Harris has created in some of these communities across America, especially during her time as [California] Attorney General when she emboldened criminals.”

Trump, who was convicted of 34 felonies by a New York court in May on charges relating to hush-money payments to a porn actor but has insisted he is the innocent victim of a witch-hunt, has a history of urging harsh punishments for others accused of crimes.

Last year, he advocated allowing police to shoot shoplifters. In 1989, he notoriously took out a full-page newspaper advert arguing for the death penalty amid an outcry over the violent rape of a jogger in New York’s Central Park. Five Black and Latino boys arrested and jailed for the crime were subsequently found to have been wrongly convicted.

Senior Conservatives are considering pushing for a lifting of the moratorium on fracking in England to become party policy.

At the Conservative party conference in Birmingham, MPs are reflecting on the crushing blow they were dealt at this year’s general election and coming up with policies and ideas to rebuild the party so it can win in 2029. A leadership election is taking place and candidates are laying out their ideas to MPs.

One idea that has come up is fracking. The Conservatives have criticised the energy secretary, Ed Miliband, for Labour’s election pledge to end new oil and gas licences in the North Sea. Some are mooting a return to experimenting with drilling onshore for gas in an effort to lower energy bills.

There has been a moratorium on fracking in England since 2019 because of earthquakes caused by the method. Experts say extracting gas from shale would take years, is far less accessible than once thought and would do little to reduce energy bills. To frack, shale rocks, containing tiny pockets of methane, are blasted with a mixture of sand, water and chemicals to create fissures through which the gas can escape, to be siphoned off at the surface.

Andrew Bowie, the shadow energy minister, is supporting the shadow housing minister, Kemi Badenoch, in the leadership race. He said the next Tory leader should bring back fracking.

“I do support fracking,” he told a fringe event at the conference. “I represent an oil and gas constituency that is dependent in its entirety on the oil and gas industry. The experts will tell you that they are already fracking in the North Sea. I know it isn’t currently party policy to frack but I don’t know what Kemi will do on it.”

The shadow energy secretary, Claire Coutinho, suggested she would back lifting the moratorium, telling the Guardian: “What I am backing is cheap energy no matter where it comes from. If there is evidence that fracking would provide cheap energy then we would look at it. But I think what everyone wants is low bills and cheap energy and we won’t rule anything out.”

Badenoch did not rule it out: “I am not laying out specific policies yet, but I know there are colleagues who want to lift the moratorium and we will discuss policies at a later stage.”

The issue is hugely controversial among the public and in the Tory party because of the disruption to communities caused by fracking, including earthquakes. It also counteracts pledges to reduce oil and gas use in the UK.

The former prime minister Liz Truss tried to bring back fracking during her short-lived tenure and a chaotic vote on the matter is seen as one of the reasons for the collapse of her government. Shortly after her administration fell, her successor, Rishi Sunak, confirmed he would keep the moratorium, and that remains Conservative policy.

The environment has not been mentioned much during the leadership contest. In a pitch to MPs at a 1922 Committee event on Sunday night, another contender, Robert Jenrick, said a vote for him would be “yes to net zero, no to Ed Miliband’s mad policies”.

His campaign manager, Danny Kruger, said at a fringe event that the “environmental lobby” had “overreached itself” and the Conservatives were now able to take on Labour’s “madcap” schemes.

Coutinho said she planned to hold Labour to account for “being quiet” on nuclear power, which she said was crucial to a cleaner, cheaper energy system. She also disagreed that the general public cared about the environment above other issues, saying: “We need to be very careful when we talk about what the public care about because predominantly they care about cheap energy. Renewables are not cheap in all circumstances. My view is that you have to prioritise cheap energy in your country.”

A Democratic representative in a key battleground Senate race in Michigan told supporters she’s concerned about Kamala Harris’s chances in the state’s presidential election.

“I’m not feeling my best right now about where we are on Kamala Harris in a place like Michigan,” Elissa Slotkin said at a fundraiser earlier this month, according to Axios. “We have her underwater in our polling.”

Slotkin did not offer more details on specifics of the data to which she was referring, Axios reported. Without seeing the actual poll, it is difficult to assess its credibility. Candidates will sometimes use internal polls to motivate supporters and urge them not to get complacent.

Mail-in ballots started being sent to Michigan voters on Thursday.

Donald Trump gave a speech and held a town hall in Michigan on Friday. Harris’s running mate, Tim Walz, also made an appearance at a football game between the University of Michigan and University of Minnesota on Saturday.

Walz and Trump’s running mate, JD Vance, are also set to square off on Wednesday in the race’s only vice-presidential debate, another milestone moment in the race.

The FiveThirtyEight average of polls shows a very close race in Michigan, with Harris having a narrow lead. Winning Michigan, a state Joe Biden won in 2020 on his way to capturing the White House after Trump carried it in 2016, is key to Harris’ hopes of becoming president.

The simplest path for Harris to win the election and deny Trump a second presidency is to carry the Rust belt states of Michigan, Pennsylvania and Wisconsin. Losing any one of them would complicate her path to winning the electoral college.

Polls also show Slotkin with a wider lead over her opponent, former representative Mike Rogers. Holding on to the seat is a critical part of any chance Democrats have to keep control of the US senate. The Cook Political Report has rated the race to fill the seat of Debbie Stabenow, a Democratic senator, as a highly competitive toss-up.

Slotkin’s comments come as the polls show an extremely narrow race in key battleground states as the presidential campaign enters its final weeks.

Harris holds a 1.9-point lead in 538’s average of the polls in Michigan and has a similar advantage in Wisconsin. She holds a one-point advantage in 538’s average of Pennsylvania polls.

Polls also show an extremely tight race in Georgia, Nevada and Arizona.

The US Environmental Protection Agency is planning to withdraw and reconsider its approval for Chevron to produce 18 plastic-based fuels, including some that an internal agency assessment found are highly likely to cause cancer.

In a recent court filing, the federal agency said it “has substantial concerns” that the approval order “may have been made in error”. The EPA gave a Chevron refinery in Mississippi the green light to make the chemicals in 2022 under a “climate-friendly” initiative intended to boost alternatives to petroleum, as ProPublica and the Guardian reported last year.

An investigation by ProPublica and the Guardian revealed that the EPA had calculated that one of the chemicals intended to serve as jet fuel was expected to cause cancer in one in four people exposed over their lifetime.

The risk from another of the plastic-based chemicals, an additive to marine fuel, was more than 1m times higher than the agency usually considers acceptable – so high that everyone exposed over a lifetime would be expected to develop cancer, according to a document obtained through a public records request. The EPA had failed to note the sky-high cancer risk from the marine fuel additive in the agency’s document approving the chemicals’ production. When ProPublica asked why, the EPA said it had “inadvertently” omitted it.

Although the law requires the agency to address unreasonable risks to health if it identifies them, the EPA’s approval document, known as a consent order, did not include instructions on how the company should mitigate the cancer risks or multiple other health threats posed by the chemicals other than requiring workers to wear gloves.

After ProPublica and the Guardian reported on Chevron’s plan to make the chemicals out of discarded plastic, a community group near the refinery in Pascagoula, Mississippi, sued the EPA in the US court of appealsfor the District of Columbia Circuit. The group, Cherokee Concerned Citizens, asked the court to invalidate the agency’s approval of the chemicals.

Over several months when ProPublica and the Guardian were asking questions about the plastic-based chemicals, the EPA defended its decision to permit Chevron to make them. But in the motion filed on 20 September, the agency said it would reconsider its previous position. In a declaration attached to the motion, Shari Barash, director of the EPA’s new chemicals division, explained the decision as based on “potential infirmities with the order”.

Barash also wrote that the agency had used conservative methods when assessing the chemicals that resulted in an overestimate of the risk they pose. The EPA’s motion said the agency wanted to reconsider its decision and “give further consideration to the limitations” of the risk assessment as well as the “alleged infirmities” identified by environmental groups.

Asked last week for an accurate estimate of the true risk posed by the chemicals, the EPA declined to respond, citing pending litigation. The EPA also did not respond when asked why it did not acknowledge that its approval may have been made in error during the months that ProPublica was asking about it.

Chevron, which has not begun making the chemicals, did not respond to a question about their potential health effects. The company emailed a statement saying: “Chevron understands EPA told the court that the agency had over-estimated the hazards under these permits.”

As ProPublica and the Guardian noted last year, making fuel from plastic is in some ways worse for the climate than simply creating it directly from coal, oil or gas. That’s because nearly all plastic is derived from fossil fuels, and additional fossil fuels are used to generate the heat that turns discarded plastic into fuels.

Katherine O’Brien, a senior attorney at Earthjustice who is representing Cherokee Concerned Citizens in its suit, said she was concerned that, after withdrawing its approval to produce the chemicals, the EPA might again grant permission to make them, which could leave her clients at risk.

“I would say it’s a victory with vigilance required,” O’Brien said of the EPA’s plan to withdraw its approval. “We are certainly keeping an eye out for a new decision that would reapprove any of these chemicals.”

Ministers are being urged to overhaul the “nightmare” compensation scheme for flood victims after it emerged that nearly 80% of businesses in some parts of England had been denied support.

After heavy downpours caused chaos across much of England and Wales this week, new figures laid bare the “opaque” and inconsistent level of help available to those whose properties lay in ruin.

In Calderdale, West Yorkshire, where hundreds of homes have been battered by a series of storms in recent years, only 17% of businesses received government help in the wake of Storm Ciara in 2020.

The government’s Property Flood Resilience (PFR) scheme allows flood victims to apply for a grant of up to £5,000 to help repair the damage and make them more resilient to future storms.

However, campaigners have called for the Defra scheme to be overhauled due to the complex rules governing how the money is handed out, resulting in disparities across England.

Data obtained by Greenpeace’s Unearthed investigative unit found that on average, 72% of applicants to the PFR scheme in England were successful in 2020, the most recent year for which figures are available.

In Tunbridge Wells, all 42 of the homeowners and businesses who applied for the grant that year received a payout. But the success rate was far lower in other parts of England.

In Telford and Wrekin, where floods again caused havoc last week, barely half of those who applied in 2020 received support.

In Calderdale, which includes the flood-prone valleys of Hebden Bridge and Mytholmroyd, only 48% of the 519 homes and businesses who requested help in 2020 received any money. Of the 194 businesses, only 33 were successful.

Calderdale Council said one reason for the low acceptance rate was that many of the properties flooded in 2020 had already received a PFR grant in 2015.

Tracey Garrett, chief executive of the National Flood Forum, a charity that helps flood victims, said: “There are no rules or governance around how the grant is activated. It’s all very opaque. We need proper governance on it so it’s clear when it is activated and how to access it.”

Heather Shepherd, a flood consultant, described the PFR grants process as a “nightmare” and said there was a lack of support for flood victims generally.

Lynn Shortt, 63, said she received no help from the scheme after her home in Attleborough, Norfolk, was badly flooded in Christmas 2020. They were deluged again last year, when Storm Babet destroyed everything on the ground floor.

Shortt, who has multiple sclerosis, said she and her 73-year-old husband, Hans Shortt, had spent about £28,000 repairing the damage, taking money from a fund intended to pay her future nursing home bills, which, she said, had been “completely emptied”.

Shortt said they had been “strung along” since making their first PFR application in 2020 but were last month told they were being considered for help after last year’s flood.

“It’s just a complete mockery. It’s nonsensical,” she said. “I can absolutely categorically state this has got me down very badly. Your whole life has been whipped out from underneath you. The minute it starts to rain heavily, I can start to feel my heart racing. It’s horrific.”

Although the Shortts were advised to apply for the grant by Norfolk county council, the authority was not eligible for the 2019 and 2020 PFR schemes because it did not meet the eligibility criteria of 25 flooded properties, Defra said.

A spokesperson for Norfolk county council said it did not find out that it would be ineligible for the schemes until after households had lodged their applications.

A Defra spokesperson said: “Protecting communities from flooding is an absolute priority for this government, which is why we will launch a flood resilience taskforce to turbocharge the delivery of flood defences and natural flood management.

“The PFR grant helps make homes more resilient in case of future flooding events and grant funding is paid once the works are done, to ensure appropriate use of public money.

“Local authorities are responsible for assessing and approving individual applications for the PFR grant, which alongside the Flood Recovery Framework is only activated following severe weather events with wide area impacts. With localised flooding incidents, we would expect local authorities to have well-established contingency arrangements in place.”

More than 20 scientific experts have written to the UN’s food agency expressing shock at its failure to revise or withdraw a livestock emissions report that two of its cited academics have said contained “multiple and egregious errors”.

The alleged inaccuracies are understood to have downplayed the potential of dietary change to reduce agricultural greenhouse gases, which make up about a quarter of total anthropogenic emissions and mostly derive from livestock.

In the joint letter, which the Guardian has seen, the scientists say they are dismayed that the UN Food and Agriculture Organization (FAO) has failed to remedy “serious distortions” originally identified by the academics Paul Behrens and Matthew Hayek, which the Guardian reported on earlier this year.

Behrens and Hayek say a separate complaint has received short shrift. They say a “technical dialogue” promised by the FAO never materialised, beyond an invitation to a muted webinar where they could type questions into a Q&A box.

“There has been no serious response,” Behrens said. “They partially addressed one of the points in the webinar in an unscientific way. But they gave no response at all to the vast majority of our complaints. Our concerns have barely been acknowledged, let alone seriously engaged with. It’s been like hitting a brick wall. The FAO has made grievous errors that need urgent correction to maintain its scientific credibility.”

One of the signatories to the letter, Jennifer Jacquet, a professor of environmental science and policy at the University of Miami, compared the FAO’s complaints process unfavourably with those of a science journal, “where you could at least expect a correction to the article”.

The FAO’s “pathways toward lower emissions” study was originally billed as “an updated comprehensive overview” of global livestock emissions and was launched at last December’s Cop28 climate summit.

Behrens and Hayek said it inappropriately used their work on now outdated nationally recommended diets (NRDs), double-counted meat emissions, mixed different baseline years in analyses, and omitted the opportunity cost of carbon sequestration on non-farmed land.

Correspondingly, the emissions savings from farming less livestock were underestimated by a factor of between six and 40, Hayek estimated.

In an initial response to complaints, seen by the Guardian, the FAO’s chief scientist, Beth Crawford, described the report’s NRD-based emissions forecast for 2050 as “a rough estimate”. She said: “This methodological choice was made because there is no global database on dietary preferences and no policy instrument that supports the adoption of alternative diets based on balanced environmental, economic and social criteria.”

She did not touch on other points raised by the pair, such as alleged double counting and mixed baseline years, which Hayek said “are related to their misuse of our scientific data”.

Crawford’s response said the FAO had received a “rigorous and thorough review” supporting its conclusions from a group of scientists led by three named academics.

The joint letter, which was also signed by 78 environmental groups, said: “It is not acceptable for the FAO, a respected UN institution, to gloss over these serious errors as a ‘rough estimate’ when the data and policy recommendations it provides are so internationally influential. A higher standard of scientific rigour is required.”

Jacquet said: “It seems clear to me that some of the choices made by the FAO in their methodology were just there to uphold the status quo of increasing meat production and consumption.”

The FAO was contacted for a response.