"A woman is an adult female, and the court has made that absolutely clear." Those were Keir Starmer's words on Parliament's first day back after Easter, following the Supreme Court's unanimous ruling that a woman is defined by biological sex under equality law.

The "casual observer" may remember that as recently as 2022, the prime minister insisted "trans women are women", said The Times. But with the law "now clarified" by the Supreme Court, Starmer "has set out the position he and his party slowly moved towards as last year's election came into view – that biological sex is what matters". Whether everyone in his party agrees with that position is another matter.

What did the commentators say?
This is an "embarrassing" attempt to "rewrite history", said Hannah Barnes in The New Statesman. It was Starmer who dismissed the then Labour MP Rosie Duffield's statement that "only women have a cervix" as "something that shouldn't be said".

"What a difference three years make," said Tom Slater in The Telegraph. While I welcome Starmer's realisation that "you cannot have sex-based rights if you don't believe in sex", his "volte-face" on this issue shows that he is an "anti-conviction politician". Our PM is an "empty, slabheaded receptacle into which any mad idea can be poured, only to be jettisoned when it is politically expedient".

Many Labour MPs will be "uneasy" with this new position, said Henry Zeffman on the BBC. They "believe that trans women are women, and that to be treated with dignity and respect they ought to be able to use the toilets they believe match their gender identity". A "backlash" may now be "brewing".

It may even have begun already. WhatsApp messages leaked to The Mail on Sunday allegedly included Home Office minister Dame Angela Eagle writing that "the ruling is not as catastrophic as it seems" but that the Equality and Human Rights Commission guidance "might be & there are already signs that some public bodies are overreacting".

What next?
Politicians who have campaigned in support of trans rights are pointing to commitments in Labour's general election manifesto to introduce a "trans-inclusive ban on conversion practices" and to "modernise, simplify, and reform" gender recognition law. Those are "still Labour Party policies", said the BBC's Zeffman, and "any sign of backsliding on that and this debate may again become a tense one within Labour's ranks".

The UK government appears set to approve controversial geoengineering experiments that include efforts to dim the Sun.

The Advanced Research and Invention Agency (Aria), the government body that funds technology projects, has set aside £50 million for the project, and specific, small-scale trials are expected to be announced within a few weeks.

'Treating the symptoms'
Most geoengineering trials aim to prevent excessive sunlight from reaching the Earth's surface. This is often done by "launching clouds of reflective particles into the atmosphere" or using "seawater sprays to make clouds brighter", said The Guardian.

If Aria's trials and others like it are successful, and the techniques are adopted on a larger scale, it could "temporarily reduce surface temperatures and the harm the climate crisis is causing" – gaining more time to cut worldwide carbon emissions.

These techniques "would not address the root cause of the climate disease", said Peter Irvine, an earth sciences lecturer at UCL, on The Conversation. But more and more evidence "suggests that it would work surprisingly well at treating the symptoms".

'Meddling with nature'
If scientists want to continue getting these projects off the ground, they "need to learn how to talk to the public about it", said Science. Artificially altering the planet's natural systems "invites concerns about meddling with nature", and the proliferation of misinformation online is "partly behind moves to ban or restrict" such techniques.

This latest "barking mad scheme" in the UK "is like using aspirin for cancer", said American scientists Raymond Pierrehumbert and Michael Mann in The Guardian. If we become reliant on the technology, "the world will be left subject to a catastrophic termination shock" if the intervention then ends. The small scale of the trials is "little comfort" either, because "even small-scale trials risk developing the technology somebody else (think Musk, Trump or Putin) might use for a large-scale deployment".

There are also potential side effects that need to be examined, said Sarah Doherty, an atmospheric scientist working on cloud brightening at the University of Washington. She told The New York Times that altering ocean circulation patterns could impact fisheries, while cloud brightening could change precipitation patterns. But Doherty and many other experts believe "it's vital to find out whether and how such technologies could work", said the paper. "And no one can say when the world might reach that point." 

London's Victoria & Albert Museum has been transformed into a "spellbinding" venue for this "once-in-a-lifetime retrospective" of Maison Cartier, said Evgenia Siokos in The Telegraph.

More than 350 jewels, watches and "gobstopper-sized gems" are on display, spanning everything from the late Queen Elizabeth's diamonds to Princess Grace of Monaco's engagement ring. Visitors are "deftly" drawn into the "spheres of cultural influence" that inspired three brothers, Louis, Pierre and Jacques Cartier, to propel their grandfather's family business to its present-day status as a world-renowned jeweller.

It's a "dazzling" show, said Nancy Durrant in The Times. Curators Helen Molesworth and Rachel Garrahan have "kept it simple", artfully arranging a collection of "exquisite objects of outstanding beauty, quality and ingenuity", along with illustrations from the Cartier archives revealing fascinating details about the design process.

The Cartier-sponsored exhibition could easily have felt like a "foie-gras force-feeding of brand propaganda", said Joe Bromley in London's The Standard. But this is "far from the case", thanks to the "intelligent" curation and "spectacular" treasures on display.

Highlights include the "rather magnificent" Manchester Tiara, made in 1903 for the Dowager of Manchester, with more than 400 rose-cut diamonds and a series of showstopping "Tutti Frutti" pieces – a "pick-and-mix" of precious gems that look, "in spotless glass cabinets, like the contents of an old-world confectionery shop".

Fittingly, the exhibition, running until 16 November, concludes with yet another room of "glittering tiaras", including one made as recently as 2017, said Durrant in The Times. "Who is commissioning this stuff? I'm glad someone still is."

America Will Miss Europe's Dependence When It's Gone
Edward Lucas on Foreign Policy
The "worst-kept secret" of "trans-Atlantic security policy", writes Edward Lucas, is that the US has "sought not only to bind Europe into a common defense against the Soviet Union but also to keep it in a state of tutelage", by "strangling all attempts to build independent European defense structures". Yet Donald Trump's "loose lips" are "sinking deals" between Europe and US arms dealers. The "era of tutelage came at a price", but Americans "may miss it when it's gone".

Princess brain rot and the end of civilisation
Juliet Samuel in The Times
A new portrait of Princess Isabella of Denmark shows the 18-year-old "looking up momentarily from typing into an iPhone", writes Juliet Samuel. We're "in the grip of the sickness of screen addiction" that is "turning out depressed, anxious, self-harming" teenage girls. Social psychologists say students "can no longer think coherently" thanks to an "entire youth" spent on phones. "To me", the princess looks like a girl who needs an "authority figure who loves and respects her enough to make her put her damn phone away".

Istanbul was disgracefully unprepared for the earthquake
Daniel Thorpe for The Spectator
The unpreparedness of Istanbul was "obvious from the first moment" that it was hit by Wednesday's 6.2 magnitude earthquake, writes Daniel Thorpe. Although earthquakes are "inevitable", the "damage can be hugely mitigated through adequate preparation and construction" – but Turkey is "not doing well in that regard". This is a "wake-up call for the authorities", and the question now is whether there will be "rapid" earthquake-resistant redevelopment. "Considering their actions following previous earthquakes, there is little room for optimism."