The impact of Donald Trump enacting the climate policies of the rightwing Project 2025 would result in billions of tonnes of extra carbon pollution, wrecking the US’s climate targets, as well as wiping out clean energy investments and more than a million jobs, a new analysis finds.

Should Trump retake the White House and pass the energy and environmental policies in the controversial Project 2025 document, the US’s planet-heating emissions will “significantly increase” by 2.7bn tonnes above the current trajectory by 2030, an amount comparable to the entire annual emissions of India, according to the report.

Such a burst of extra pollution would torpedo any chance the US could meet its goal of cutting emissions in half by 2030, which scientists say is imperative to help the world avert disastrous climate change. It would also, the analysis found, result in 1.7m lost jobs in 2030, due to reduced clean energy deployment that is not offset by smaller gains in fossil fuel jobs, and a $320bn hit to US GDP as a wave of new domestic renewables and electric car manufacturing is reversed.

“The US faces a fork in the road starting in January of 2025 with two climate and energy policy pathways that are highly divergent,” said Anand Gopal, executive director of policy research at Energy Innovation, a non-partisan energy thinktank that conducted the modeling. “These future policy pathways result in stark differences for our health, our pocketbooks, the economy and climate.”

The new analysis provides a glimpse of what could hinge upon November’s presidential election. Kamala Harris, the vice-president and Democratic nominee, has been part of a Biden administration that has overseen a raft of climate-friendly legislation and regulations, most notably the Inflation Reduction Act, which has pumped billions of dollars into new solar, wind, electric car and battery deployment.

This activity has helped create more than 300,000 new jobs in clean energy technologies, as well as doubling the pace of US emissions reductions. America is now on track to cut its emissions 37% by 2030, compared with 2005, putting it within “striking distance” of reaching its climate target, Gopal said.

Such progress would be erased, however, should Trump be elected and fully embrace Project 2025, a comprehensive rightwing blueprint that the former president has distanced himself from, even though 140 people who worked in the last Trump administration contributed to it. JD Vance, Trump’s running mate, wrote the foreword to a book by a leader of Project 2025.

Project 2025 calls for a widespread evisceration of environmental protections, allowing for a glut of new oil and gas drilling, the repeal of the IRA and even the elimination of the National Oceanic and Atmospheric Administration and the National Weather Service so they can be replaced by private companies. The conservative Heritage Foundation, which leads Project 2025, has said a new Trump administration should “eradicate climate change references from absolutely everywhere”.

Adopting this policy wishlist would, compared with business as usual, result in 2.7bn tonnes of extra emissions by 2030 and 26bn tonnes of further emissions by 2050, the point at which the world would need to have eliminated new fossil-fuel pollution entering the atmosphere to avoid climate breakdown, Energy Innovation found.

It would also, according to the new modeling, cause several thousand extra premature deaths by the end of the decade due to worsened air pollution, and cause a bump in Americans’ household costs compared to a path of more ambitious climate action. The Project 2025 team did not respond to a request for comment.

“Project 2025 just seems like the road to hell made with evil intentions,” said Gina McCarthy, the former top climate adviser to Biden. “It really has to be rejected, and I think it summarily will be. Even Trump has realized how extreme it is: he had to publicly disown it.”

In his own commitments, Trump has promised to “drill, baby, drill” for more oil and gas, and to eliminate Biden-era policies that spur the take-up of electric cars. A previous analysis of Trump’s plans by Carbon Brief estimated the impact of his new administration would be even greater than in the latest study, adding an extra 4bn tonnes of greenhouse gases by 2030.

Vance has called the IRA a “green energy scam” that primarily benefits China, although some other Republican lawmakers have begun to warm to the legislation as the majority of the more than $300bn in climate investments has flowed to GOP-held areas. Last week, 18 Republican members of Congress wrote to Mike Johnson, the House of Representatives speaker, imploring him not to gut the spending, as Trump has indicated he should do.

Harris, who enjoys the backing of many green groups, has accused Trump of intending to “surrender our fight against the climate crisis”.

In a speech in Arizona last week, she said: “And, Arizona, every day you feel the impact of extreme heat and drought. You know this crisis is real. He calls it a hoax.”

However, even if Harris wins and secures the Biden climate policies there is still a significant gap to getting the US to net zero. Energy Innovation said that further actions, such as cutting pollution from buildings, restoring degraded land and new regulations upon industry and energy use, will be required if the climate targets are to be hit.

“The benefits of the Inflation Reduction Act have been startling to see,” said McCarthy. “But it is a foundation to do more.”

Ukraine’s president, Volodymyr Zelenskiy, has said his country’s forces are continuing to advance into Russian territory after their surprise offensive, as Kyiv said it had launched a “major” drone attack on four Russian airbases.

Zelenskiy said Ukraine’s troops had advanced several kilometres in the largest attack on Russia since the second world war. Ukraine also claimed to have shot down a Russian Su-34 jet overnight in the Kursk region, where it said it had also captured 100 Russian prisoners.

The claims of the drone strike targeting airbases appeared to be confirmed by Russia, which said it had downed 117 incoming Ukrainian drones overnight.

The strike targeted Russia’s Voronezh, Kursk, Savasleyka and Borisoglebsk airbases, which warplanes use for glide bomb attacks on Ukraine.

Zelenskiy had previously said Ukraine “controlled” 74 Russian settlements, although it was unclear whether or not that meant they were fully occupied by Ukrainian troops.

“Now all of us in Ukraine should act as unitedly and efficiently as we did in the first weeks and months of this war, when Ukraine took the initiative and began to turn the situation to the benefit of our state,” Zelenskiy said in his nightly address on Tuesday.

“Now we have done the exact same thing – we have proven once again that we, Ukrainians, are capable of achieving our goals in any situation – capable of defending our interests and our independence,” he said.

Ukraine’s state television on Wednesday aired footage of its troops pulling down a Russian flag from an official building in the town of Sudzha in the Kursk region. The report showed burnt-out Russian military columns on roads in the area as well as Ukrainian soldiers handing out humanitarian aid to residents and taking down Russian flags from an administrative building.

“The situation still remains difficult,” said Yuri Podolyaka, a Ukrainian-born pro-Russian military blogger. “The enemy still has the initiative, and so, albeit slowly, it is increasing its presence in the Kursk region.”

During the major cross-border incursion, which is entering its second week, Ukraine has attacked several border regions as Russia continues to struggle to respond despite diverting troops from fighting in Ukraine’s eastern Donbas region to counter the advance.

On Wednesday under heavy shelling by Ukrainian forces, Russia’s Belgorod border region joined Kursk in declaring a state of emergency. The Belgorod governor, Vyacheslav Gladkov, described the situation as “extremely difficult and tense” as he said attacks had destroyed homes and caused civilian casualties.

On his Telegram channel, he said efforts were being made to evacuate minors, with about 5,000 children being relocated to camps in safe areas.

Ukrainian officials have said Kyiv has no plans to occupy Russian territory and that the objective is to prevent Russian missile fire into Ukraine.

Analysts sayKyiv’s forces targeted the Kursk region because Russia’s weak command and control structure there made it vulnerable.

“The situation is still highly fluid, but with clear signs that the Russian command and control of responding units is still coming together, with all-important unity of command not yet achieved,” said retired US V Adm Robert Murrett, a professor and deputy director of Syracuse University’s security policy and law institute. “The next two or three days will be critical for both sides.”

The surprise offensive began on 6 August and has rattled the Kremlin amid estimates it could involve as many as 10,000 Ukrainian troops backed by armour and artillery. Despite Kyiv’s stated aims, the operation also appears to be designed to weaken Russia’s offensive in eastern Ukraine by drawing Moscow’s forces away and disrupting supply lines, removing the pressure on several locations where Russia had been making some progress.

That has posed a challenge to Moscow on whether or not to pull troops from the frontline in Ukraine’s east, where achieving a breakthrough is a primary war goal for the Kremlin, to defend Kursk and stop the incursion from ballooning.

The Washington-based Institute for the Study of War thinktank suggested the incursion was unlikely to shift the dynamics of the war. “Russian authorities will likely remain extremely averse to pulling Russian military units engaged in combat from [Donetsk] and will likely continue deploying limited numbers of irregular forces to Kursk … due to concerns about further slowing the tempo of Russian operations in these higher priority directions,” it said on Tuesday.

According to Russian military bloggers, several irregular units that had been deployed to fight in Donetsk were being sent to Kursk, including the so-called Russian Volunteer Corps and a drone unit associated with a Russian biker gang.

The US president, Joe Biden, said on Tuesday that the developments were “creating a real dilemma” for Vladimir Putin.

The operation has at the very least caused embarrassment for the Kremlin as more than 100,000 Russian civilians have been evacuated. The White House said Ukraine did not provide advance notice of its incursion and the US had no involvement in the operation, though Russian officials have suggested Ukraine’s western backers must have known of the attack.

A woman in Belgorod told the Associated Press on Tuesday that the Ukrainian shelling had been intense for about 10 days until Monday, when there was a lull. The number of people in the region who openly supported the war had decreased after the Ukrainian attacks, the woman told AP, speaking on condition of anonymity.

“When explosions started near the city, when people were dying and when all this started happening before our eyes … and when it affected people personally, they stopped at least openly supporting [the war],” she said.

On Monday Putin said Ukraine “with the help of its western masters” was aiming to improve Kyiv’s negotiating position ahead of possible peace talks and to slow the advance of Russian forces.

Four-day-old twins have been killed in an Israeli airstrike in Gaza while their father went to register their birth, he has said, as Israel continued its bombardment of the territory.

Mohamed Abuel-Qomasan said his wife, Joumana Arafa, a pharmacist, had given birth by caesarean section four days earlier and announced the twins’ arrival on Facebook, the Associated Press reported.

On Tuesday, he had gone to register the births at a local government office. While he was there, neighbours called to say the home where he was sheltering, near the central city of Deir al-Balah, had been bombed.

“I don’t know what happened,” he told the AP while sitting at the hospital where their bodies were taken, holding the twins’ birth certificates. “I am told it was a shell that hit the house.”

The strike that killed the newborns – a boy, Asser, and a girl, Ayssel – also killed their mother, Arafa, as well as her mother, the twins’ grandmother. Abuel-Qomasan and his wife had heeded orders to evacuate Gaza City in the opening weeks of the war. They sought shelter in central Gaza, as the army had instructed.

The Israeli military did not immediately respond to a request for comment on the strikes, AP reported.

Elsewhere, a three-month-old baby was the only member of her immediate family to survive an Israeli airstrike near the southern city of Khan Younis in which 10 people were killed including her five siblings, aged five to 12.

The strike late on Monday also killed Reem Abu Hayyah’s parents and the parents of three other children. Reem and the other three surviving children were all wounded in the strike.

“There is no one left except this baby,” said Reem’s aunt, Soad Abu Hayyah. “Since this morning, we have been trying to feed her formula, but she does not accept it, because she is used to her mother’s milk.”

The health ministry in Gaza said 115 newborns had been killed in the territory since the war began. Almost 40,000 people have been killed in Israeli attacks on Gaza since 7 October; thousands more are believed to be buried under the rubble. About 1,200 people were killed when Hamas attacked Israel on 7 October and 250 taken hostage.

The Israeli military claims it tries to avoid harming Palestinian civilians and blames their deaths on Hamas because the militants operate in dense residential areas.

Since 4 July Israeli forces have targeted at least 21 schools – including at one point four in four days – where Palestinians were sheltering, killing hundreds of people, many of them children, according to the UN. Israel claimed the schools were being used by Hamas operatives without providing evidence.

Israel’s offensive has left thousands of orphans – so many that local doctors employ an acronym when registering them: WCNSF, or “wounded child, no surviving family”. The UN estimated in February that about 17,000 children in Gaza were unaccompanied and the number is likely to have grown since.

The Abu Hayyah family was sheltering in an area that Israel had ordered people to evacuate in recent days. It was one of several such orders that have led hundreds of thousands to seek shelter in an Israeli-declared humanitarian zone consisting of squalid, crowded tent camps along the coast.

Many families have ignored the evacuation orders because they say nowhere feels safe, or because they are unable to make the arduous journey on foot, or because they fear they will never be able to return to their homes, even after the war.

Associated Press contributed to this report

Mark Zuckerberg has raised eyebrows by commissioning a giant sculpture of his wife, Priscilla Chan.

In a photo of the statue, posted to Instagram, the Facebook CEO and co-founder said he was “bringing back the Roman tradition of making sculptures of your wife”.

The large sculpture was made by Daniel Arsham, a New York-based artist who has collaborated with brands including Tiffany and Dior. Chan is rendered in green and appears to be mid-stride, with a large silver cloak flowing behind her.

Zuckerberg’s photo shows Chan standing next to the statue, which appears to be roughly 7ft tall and has been placed under a tree. In the comments Chan wrote: “The more of me the better?” along with the heart emoji.

People magazine, which declared Zuckerberg to be “the ultimate wife guy!”, reported that in Roman times statues were sometimes made to honor dead loved ones or to “refer to significant relatives and to make meaningful associations”.

The statue received a largely positive response from Zuckerberg’s followers.

“Omg so beautiful, lucky girl,” one person wrote, while the account “The Billlionaires [sic] Lifestyle”, which posts pictures of rich people and expensive things, posted: “This need [sic] to be in [a] museum”, accompanied by the applause and fire emojis.

Not everyone was impressed, however. Andrew Mwangi wrote: “This is the most billionaire thing to do ever”, and a user called deviletter said: “yikes. this is quite unflattering”.

Zuckerberg did not post the photo on Facebook, although he did recently post a video of him surfing while wearing a tuxedo and holding an American flag.

A mural celebrating the Italian Olympic volleyball champion Paola Egonu has become the target of “vulgar racism” after the athlete’s skin in the image was spray-painted pink.

The mural by the street artist Laika was defaced within a day of being unveiled on a wall close to the headquarters of the Italian Olympic committee (Coni) in Rome.

The image featured Egonu, who spearheaded Italian women’s volleyball’s first-ever gold medal win at the Paris Olympics, as she jumps to hit a ball with the words “stop racism”. The words were also erased by the vandals, who are yet to be identified.

Egonu, 25, was born in Italy to Nigerian parents.

Called Italianità, the mural was also Laika’s response to a passage in a bestselling book by a controversial army general and MEP, Roberto Vannacci, in which he wrote that even though Egonu was “Italian by citizenship … her physical features” did not “represent Italianness”.

Vannacci, who was elected to the European parliament in May with the backing of Italy’s far-right Lega, reiterated his view on Sunday after Egonu emerged as the top scorer in the women’s volleyball final against the USA.

The defacing of the mural was widely condemned by politicians from across the spectrum.

Antonio Tajani, Italy’s deputy prime minister, said: “I want to express solidarity with Paola Egonu and the most total disdain for this serious gesture of vulgar racism.”

Elly Schlein, the leader of the opposition Democratic party, said: “Racism is disgusting and must be countered.” She vowed to continue her party’s fight for a change in law that would grant citizenship at birth to children born in Italy to foreign parents, regardless of their parents’ citizenship, thus bringing the country into line with other European states. At present, children born in Italy to foreign parents can only apply from the age of 18.

Roberto Gualtieri, the mayor of Rome, said the vandalism was “a vile insult to a great Italian, who has brought the colours of our country to the top of the world, and to an artist committed to fighting against xenophobia”.

Simone Giannelli, a member of the Italian men’s volleyball team, said the vandals were “heartless, without dignity and without humanity”.

In 2022, Egonu took a break from the national team after receiving racial abuse online following Italy’s defeat to Brazil in the world championship semi-finals. “Reading those things and hearing them made me doubt myself more. And the worst one was, ‘Is she Italian?’ I was devastated,” she later said in an interview with Al Jazeera.

A mural celebrating the Italian Olympic volleyball champion Paola Egonu has become the target of “vulgar racism” after the athlete’s skin in the image was spray-painted pink.

The mural by the street artist Laika was defaced within a day of being unveiled on a wall close to the headquarters of the Italian Olympic committee (Coni) in Rome.

The image featured Egonu, who spearheaded Italian women’s volleyball’s first-ever gold medal win at the Paris Olympics, as she jumps to hit a ball with the words “stop racism”. The words were also erased by the vandals, who are yet to be identified.

Egonu, 25, was born in Italy to Nigerian parents.

Called Italianità, the mural was also Laika’s response to a passage in a bestselling book by a controversial army general and MEP, Roberto Vannacci, in which he wrote that even though Egonu was “Italian by citizenship … her physical features” did not “represent Italianness”.

Vannacci, who was elected to the European parliament in May with the backing of Italy’s far-right Lega, reiterated his view on Sunday after Egonu emerged as the top scorer in the women’s volleyball final against the USA.

The defacing of the mural was widely condemned by politicians from across the spectrum.

Antonio Tajani, Italy’s deputy prime minister, said: “I want to express solidarity with Paola Egonu and the most total disdain for this serious gesture of vulgar racism.”

Elly Schlein, the leader of the opposition Democratic party, said: “Racism is disgusting and must be countered.” She vowed to continue her party’s fight for a change in law that would grant citizenship at birth to children born in Italy to foreign parents, regardless of their parents’ citizenship, thus bringing the country into line with other European states. At present, children born in Italy to foreign parents can only apply from the age of 18.

Roberto Gualtieri, the mayor of Rome, said the vandalism was “a vile insult to a great Italian, who has brought the colours of our country to the top of the world, and to an artist committed to fighting against xenophobia”.

Simone Giannelli, a member of the Italian men’s volleyball team, said the vandals were “heartless, without dignity and without humanity”.

In 2022, Egonu took a break from the national team after receiving racial abuse online following Italy’s defeat to Brazil in the world championship semi-finals. “Reading those things and hearing them made me doubt myself more. And the worst one was, ‘Is she Italian?’ I was devastated,” she later said in an interview with Al Jazeera.

Heavy rains in Sudan have killed dozens of people, compounding hardship in a country that is already facing multiple crises.

At least 68 people have been killed in Sudan as a result of rains that have plagued different parts of the country this year, the interior ministry said.

The downpours, the heaviest recorded since 2019, have affected the western, northern and eastern parts of the country, flooding neighbourhoods and destroying houses, farms and infrastructure. About 27,000 people have been displaced since June as a result of the flooding, according to the UN.

In the town of Rokero in the Jebel Marra region of West Darfur state, at least 12 people were killed.

Abdallah Hussein Adam, a traditional leader in the area, said: “Normally in Jebel Marra, we don’t have floods. It rains a lot but the water passes by. This year it’s different.”

He told the Guardian they had found the bodies of nine people, but three were still missing.

Jebel Marra is a farming region, and Adam said he was worried the flooding would reduce production.

“Last year we didn’t produce much as a result of lacking the rain and [because of] the fighting, but this year we also cannot produce as a result of the floods. It will cause famine; the prices of everything went three times higher.”

Nearly 50,000 families live in Jebel Marra, among them thousands of displaced people who moved from other areas because of fighting that started last year between the Sudanese army and the paramilitary Rapid Support Forces and which has had devastating effects.

About 16,000 people have been killed in the civil war, which has created the world’s largest displacement crisis, with millions displaced in and outside the country.

International rights groups have accused the warring parties of mass rape and other atrocities.

The conflict has also left half the population in a state of food insecurity and pushed many into starvation. The rains have exacerbated difficulties caused by the fighting in delivering aid.

Early this month, organisations that monitor world hunger declared famine at a displacement camp outside El Fasher, the capital of Darfur.

Othman Belbeisi, the regional director for the Middle East and north Africa at the International Organization for Migration, said the combination of famine, flooding and other challenges had worsened Sudan’s humanitarian crisis to a “catastrophic, cataclysmic breaking point”.

“Without an immediate, massive and coordinated global response, we risk witnessing tens of thousands of preventable deaths in the coming months,” he said.

The US is leading a push to end Sudan’s almost 16-month conflict through mediation, but neither warring party has confirmed participation in ceasefire talks scheduled for Wednesday in Switzerland.

A week after a judge ruled the tech giant illegally monopolized the online search market, the US Department of Justice is considering options that include breaking up Alphabet’s Google, worth some $2tn, according to reports from the New York Times and Bloomberg News.

Divesting the Android operating system was one of the remedies most frequently discussed by justice department attorneys, the reports said.

Officials were also considering trying to force a possible sale of AdWords, Google’s search ad program, and a possible divestment of its Chrome web browser, according to the reports.

A justice department spokesperson said it was evaluating the court’s decision and would assess the appropriate next steps consistent with the court’s direction and the applicable legal framework for antitrust remedies.

The spokesperson said no decisions had yet been made. A Google spokesperson declined to comment. Google is planning to appeal the ruling. It faces another antitrust suit by the US justice department set to go to trial next month.

The justice department’s other options include forcing Google to share data with competitors and instating measures to prevent it from gaining an unfair advantage in AI products, the reports said, citing people familiar with the matter.

During the trial, it was revealed that Google paid companies, including Apple, more than $26bn in 2021 alone to remain the default option for search in Safari. Those deals allowed Google to build a monopoly over search and unfairly suppress competition, the judge found.

Shortly after the judge made his ruling, the competing search engine DuckDuckGo proposed banning those exclusive agreements.

The verdict, delivered last week, held that Google violated antitrust law, spending billions of dollars to create an illegal monopoly and become the world’s default search engine. The ruling is seen as the first big win for federal authorities taking on the market dominance of big tech.

Federal antitrust regulators have sued Meta Platforms, Amazon.com and Apple in the past four years, claiming the companies illegally maintained monopolies.

Microsoft had settled with the justice department in 2004 on claims it forced its Internet Explorer web browser on Windows users.

JK Rowling and Elon Musk have been named in a cyberbullying lawsuit filed in France by the Olympic champion boxer Imane Khelif.

Khelif, who was the subject of a global gender eligibility row during her Olympic run, became Algeria’s first gold medallist in women’s boxing and its first boxer overall to win gold since 1996.

On Wednesday, her attorney Nabil Boudi, said they had filed a criminal complaint over alleged “acts of cyber-harassment” to the Paris public prosecutor’s office on Friday.

The legal action was filed against X, which under French law means it was filed against unknown persons, Variety reported. It claims the 25-year-old was the victim of “misogynistic, racist and sexist” cyberbullying.

That “ensures that the prosecution has all the latitude to be able to investigate against all people”, including those who may have written hateful messages under pseudonyms, Boudi said.

The lawyer added that the complaint mentioned famous figures too. “JK Rowling and Elon Musk are named in the lawsuit, among others,” he said, adding that Donald Trump could also be part of the investigation.

“Trump tweeted, so whether or not he is named in our lawsuit, he will inevitably be looked into as part of the prosecution.”

Khelif faced accusations over her gender after it was revealed that she was banned from competing in the 2023 boxing world championships because she failed a gender eligibility test administered by the International Boxing Association (IBA).

But the International Olympic Committee (IOC) has disputed this test, and before the Paris events stripped the IBA of recognition as boxing’s governing body and expelled it from the Olympics over issues including corruption, financial transparency and governance.

Khelif was born female and has never identified as transgender or intersex. Asserting her gender, the IOC said: “Scientifically, this is not a man fighting a woman.”

The issue received widespread attention after the Italian boxer Angela Carini abandoned her match against Khelif in the 66kg boxing competition after just 46 seconds, claiming: “I have never felt a punch like this.”

Khelif was then inundated with abuse, mostly via social media, particularly X. The comments escalated after high-profile figures began posting about the issue.

In a message to her 14.2 million followers on X, Rowling posted a picture from Khelif’s fight with Carini and wrote: “The smirk of a male who knows he’s protected by a misogynist sporting establishment enjoying the distress of a woman he’s just punched in the head, and whose life’s ambition he’s just shattered.”

In another tweet, the Harry Potter author said: “I don’t claim Khelif is trans. My objection, and that of many others, is to male violence against women becoming an Olympic sport.”

Musk, who owns X, shared a post from the US swimmer Riley Gaines that said “men don’t belong in women’s sports” and added: “Absolutely.”

Meanwhile, Trump posted a picture from the fight accompanied by the message: “I will keep men out of women’s sports!”

Boudi told Variety that although the complaint mentioned names, “what we’re asking is that the prosecution investigates not only these people but whoever it feels necessary”. He added: “If the case goes to court, they will stand trial.”

The lawyer said that while the lawsuit was filed in France, “it could target personalities overseas”.

Khelif’s coach, Pedro Diaz, said the bullying the boxer endured during the Olympics “incredibly affected her” and “everyone around her”.

“The first time she fought in the Olympics, there was this crazy storm outside of the ring,” said Diaz, who has helped train 21 Olympic champions prior to Khelif. “I had never seen anything so disgusting in my life.”

Following her victory on Saturday over China’s Yang Liu, Khelif said: “I am fully qualified to take part in this competition. I’m a woman like any other woman. I was born a woman, I have lived as a woman, I competed as a woman, there’s no doubt about that.

“[The detractors] are enemies of success, that is what I call them. And that also gives my success a special taste because of these attacks.”

If you have noticed a sudden accumulation of wrinkles, aches and pains or a general sensation of having grown older almost overnight, there may be a scientific explanation. Research suggests that rather than being a slow and steady process, aging occurs in at least two accelerated bursts.

The study, which tracked thousands of different molecules in people aged 25 to 75, detected two major waves of age-related changes at around ages 44 and again at 60. The findings could explain why spikes in certain health issues including musculoskeletal problems and cardiovascular disease occur at certain ages.

“We’re not just changing gradually over time. There are some really dramatic changes,” said Prof Michael Snyder, a geneticist and director of the Center for Genomics and Personalized Medicine at Stanford University and senior author of the study.

“It turns out the mid-40s is a time of dramatic change, as is the early 60s – and that’s true no matter what class of molecules you look at.”

The research tracked 108 volunteers, who submitted blood and stool samples and skin, oral and nasal swabs every few months for between one and nearly seven years. Researchers assessed 135,000 different molecules (RNA, proteins and metabolites) and microbes (the bacteria, viruses and fungi living in the guts and on the skin of the participants).

The abundance of most molecules and microbes did not shift in a gradual, chronological fashion. When the scientists looked for clusters of molecules with the largest shifts, they found these transformations tended to occur when people were in their mid-40s and early 60s.

The mid-40s ageing spike was unexpected and initially assumed to be a result of perimenopausal changes in women skewing results for the whole group. But the data revealed similar shifts were happening in men in their mid-40s, too.

“This suggests that while menopause or perimenopause may contribute to the changes observed in women in their mid-40s, there are likely other, more significant factors influencing these changes in both men and women,” said Dr Xiaotao Shen, a former postdoctoral scholar at Stanford medical school and first author of the study who is now based at Nanyang Technological University Singapore.

The first wave of changes included molecules linked to cardiovascular disease and the ability to metabolise caffeine, alcohol and lipids. The second wave of changes included molecules involved in immune regulation, carbohydrate metabolism and kidney function. Molecules linked to skin and muscle ageing changed at both time points. Previous research suggested that a later spike in ageing may occur around the age of 78, but the latest study could not confirm this because the oldest participants were 75.

The pattern fits with previous evidence that the risk of many age-related diseases does not increase incrementally, with Alzheimer’s and cardiovascular disease risk showing a steep uptick after 60. It is also possible that some of the changes could be linked to lifestyle or behavioural factors. For instance, the change in alcohol metabolism could result from an uptick in consumption in people’s mid-40s, which can be a stressful period of life.

The findings could help target interventions, such as increasing exercise during periods of more rapid muscle loss, the authors said. “I’m a big believer that we should try to adjust our lifestyles while we’re still healthy,” Snyder said.

The findings are published in the journal Nature Aging.

For more than a century, archaeologists have known that some of the stones at Stonehenge came from Wales and were transported – somehow – about 125 miles ( 200km) to the site of the Neolithic monument on Salisbury Plain.

Now, a “jaw-dropping” study has revealed that one of Stonehenge’s central megaliths is not Welsh at all – it is actually Scottish.

In a discovery described by one of the scientists involved as “genuinely shocking”, new analysis has found that the largest “bluestone” at Stonehenge was dragged or floated to the site from the very north-east corner of Scotland – a distance of at least 466 miles (about 750km).

The astonishing finding that the megalith, which is known as the “altar stone”, was transported by prehistoric people from at least as far as present day Inverness, and potentially from the Orkney islands, “doesn’t just alter what we think about Stonehenge, it alters what we think about the whole of the late Neolithic”, said Rob Ixer, an honorary senior research fellow at University College London (UCL) and one of the experts behind the study, which was published in Nature on Wednesday.

“It completely rewrites the relationships between the Neolithic populations of the whole of the British Isles,” he told the Guardian. “The science is beautiful and it’s remarkable, and it’s going to be discussed for decades to come … It is jaw-dropping.”

The altar stone is not one of Stonehenge’s famous trilithons – the immense, lintel-topped sarsen stones, which originate from a mere 16 miles (25km) away, and which today form its outer circle. Instead, the huge sandstone block, 5 metres long and weighing 6 tonnes, lies flat and semi-buried at the heart of the monument, trapped under two fallen sarsens and barely visible to visitors.

Made of a sedimentary rock called old red sandstone, the altar stone is classed as a non-local bluestone and was long thought to have been brought from somewhere in Wales, just as a separate group of Stonehenge’s bluestones are now known to have been quarried in the Preseli Hills in Pembrokeshire.

The altar stone was an outlier, however, and research in recent years led archaeologists, including Ixer, to question whether its origins were Welsh at all.

The new study, which involved experts from Curtin University in Perth, Australia; the University of Adelaide; Aberystwyth University; and UCL, aimed to find out more by examining the stone’s chemical composition and the age of minerals within it.

Taken together, these give a characteristic “age fingerprint” to the sandstone, said Nick Pearce, a professor of geography and earth sciences at Aberystwyth who is another of the report’s co-authors.

“With that age fingerprint, you can match it to the same sort of rocks around the UK – and the match for the age fingerprint was a dead ringer for the Orcadian Basin in north-east Scotland,” he said. “It was completely unexpected to us.”

While identifying the exact site will take further work, the experts have narrowed the potential source area to encompass Orkney; a triangle of land around present-day John o’Groats in Caithness; and a narrow coastal strip stretching south as far as the Moray Firth around Inverness and east to present-day Elgin. Small areas of old red sandstone on Shetland are also theoretically possible sources, but were considered unlikely, Ixer said.

The finding may be astonishing, but the science is not controversial, said Pearce. “It’s very, very well-established science. It’s not something that people can look at say: ‘Oh no, that can’t be right.’”

The odds of the stone coming from elsewhere are “fractions of a percent”, he said.

For many, the biggest question will be one not explored in detail in the scientific paper: how on earth did Stonehenge’s builders transport the giant stone from Scotland to Wiltshire?

“Given major overland barriers en route from north-east Scotland to Salisbury Plain, marine transport is one feasible option,” said the lead author, Anthony Clarke, of Curtin University.

But the archaeologist and writer Mike Pitts, who was not involved in the research but whose work on Neolithic monuments includes the book How to Build Stonehenge, said he believed it was more likely the stone was dragged overland than floated by sea.

He said: “If you put a stone on a boat out to sea, not only do you risk losing the stone – but also nobody can see it.” Instead, a land journey, perhaps taking many years, would engage people en route, with the stone “becoming increasingly precious … as it travels south”, he added. Impossible as it may seem today, an overland journey “was easily within the reach of Neolithic technology”.

“[The study] is exciting and it’s so significant,” said Pitts. “It’s long been known that the bluestones come from Wales, but this identifies links with a quite different part of Britain, and significantly more distant from Stonehenge. So it suggests that the site was known not just to people in the south, but over a much wider area – and that opens suggestions for the whole way we think about Neolithic Britain.”