Friday’s top story: 49 people have been killed after a gunman opened fire on Muslims attending prayers in Christchurch. Plus: global student climate protests

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Good morning, I’m Mattha Busby with today’s essential stories.

Dozens of people killed in New Zealand mosque terror attack

New Zealand has suffered the worst mass shooting in its history 49 people killed in attacks targeting Muslims at two mosques in the city of Christchurch. The prime minister, Jacinda Ardern, described the atrocity as a terrorist attack and said Friday had been one of New Zealand’s darkest days. A man in his late 20s has been arrested and charged with murder. Police haven’t named him, but a man identifying himself as Brenton Tarrant, a 28-year-old born in Australia, broadcast livestream footage on Facebook of him driving to a mosque, entering and shooting randomly at people inside.

Ideology. The suspected gunman published a “manifesto” outlining his motivations in which he espoused far-right and anti-immigrant views.

City in shock. The mayor of Christchurch, Lianne Dalziel, said: “This has come as a bolt from the blue ... It just feels like it’s not what would happen in a place like New Zealand.”

Schoolchildren in 100 countries strike to protest against inaction on climate change

Facebook Twitter Pinterest Students protest as part of a climate change strike to demand urgent political action in Brisbane, Australia. Photograph: Dan Peled/EPA

Hundreds of thousands of children in more than 100 countries are skipping school in a global strike to urge politicians and corporations to take concrete action against climate change, a year after the movement began when the teenager Greta Thunberg held a solo protest outside the Swedish parliament. More than 1,600 climate strike events are planned worldwide.

Why? A number of young climate activists have written letters for the Guardian explaining their motives for today’s strike. “The climate alarm has sounded, and the time has come for us all to realise that there is still time to act,” one said.

Quiz. Climate champion or climate dunce? Take this test to find out

MPs vote to delay Brexit, with EU figures appearing supportive

Facebook Twitter Pinterest An EU flag flies outside parliament in London as pro and anti-Brexit protesters gather. Photograph: James Veysey/REX/Shutterstock

Brexit is likely to be delayed by at least three months after the UK parliament overwhelmingly opted to ask the EU for an extension to article 50, which set a withdrawal date of 29 March. Splits in Theresa May’s cabinet were again exposed when eight ministers were among a majority of Tory MPs who unsuccessfully voted to effectively keep the threat of no deal in place, in contravention of the government’s motion. The European council president, Donald Tusk, tweeted that he would appeal to EU states to allow a long extension, and it is likely they will acquiesce.

“She didn’t listen .. to my ideas on how to negotiate it,” Donald Trump said as he renewed his criticism of May’s handling of Brexit. He also said he regretted how the issue was “tearing a country apart”.

Senate rejects Trump national emergency ploy to fund US-Mexico wall

Facebook Twitter Pinterest Trump takes a moment to ponder during a briefing on drug trafficking at the southern border at the White House on 13 March. Photograph: UPI/Barcroft Images

Trump threatened to use his presidential veto for the first time after the US Senate voted to overturn his declaration last month of a national emergency in order to divert billions of taxpayer funds to build his long-promised US-Mexico border wall without congressional approval. In a rare move, 12 Republican senators joined the Democrats to vote 59-41 to block the president’s manoeuvre. Soon after the vote, Trump tweeted: “VETO!”

‘Unconstitutional’. The Kansas senator Jerry Moran, a Republican, said he believed “the use of emergency powers in this circumstance violates the constitution” and would edge the US closer towards “the path of an all-powerful executive”.

Crib sheet

Ireland’s prime minister, Leo Varadkar , who is gay, said people should not be judged by their sexual orientation following a St Patrick’s Day breakfast at US vice-president Mike Pence’s residence. Varadkar made his comments in the presence of a conservative Christian once called “the face of anti-LGBTQ hate in America”.

A French gynaecologists’ union has threatened to halt abortions in an attempt to force the government to meet doctors in a dispute over what it claims is a lack of insurance funds for colleagues convicted of medical errors.

The US House of Representatives voted unanimously to demand the full findings of Robert Mueller’s Russia investigation be made public in a symbolic action designed to pressure the attorney general, William Barr, to release as much information as possible when the inquiry ends.

Punchy and the Kool-Aid man: a new study has found that tobacco companies adapted their advertising skills to help sell sugary drinks to children, even inventing the single-serve juice box.

Must-reads

Facebook Twitter Pinterest Composite of Julia Roberts and Lucas Hedges. Photograph: Invision/AP

Ben is Back: Julia Roberts and Lucas Hedges on their family affair

Hedges – Manchester by the Sea, Three Billboards Outside Ebbing, Missouri - plays Roberts’ drug-addicted son in the forthcoming film Ben is Back. They chat Pretty Woman, Meghan Markle and sexual fluidity with Amy Nicholson.

Can the legal cannabis business have broad gains for Native Americans?

Native Americans are embracing cannabis legalisation and opening dispensaries 40 years after new casinos transformed reservations but only enriched the few. Will the legal marijuana business benefit many more people?

2019 is on course to be the worst year for measles in the US in decades

Measles was officially eradicated in 2000, but is now at its most prevalent in the US since 1992. Experts have blamed “vaccine hesitancy”, fuelled by a now-debunked study that incorrectly linked the MMR jab with autism.

Meet the passenger who just just missed Ethiopian Airlines flight 302 to Nairobi

“Even if I was saved it was also a huge burden in my mind, knowing what had happened to everyone else. I felt the ground slipping away from under my feet,” says Antonis Mavropoulos, a Greek chemical engineer.

Opinion

The climate strike children are right to demand that their lives should not be sacrificed to satisfy our greed, writes George Monbiot.

At the heart of capitalism is a vast and scarcely examined assumption: you are entitled to as great a share of the world’s resources as your money can buy … regardless of who might be deprived.

Sport

The family of the Olympic cyclist Kelly Catlin who killed herself last week at the age 23 believe that a concussion sustained in a cycling accident sent her life into a tailspin. Her brother Colin said she had told him that her mind was racing, that she was feeling extremely, almost uncontrollably violent and that she struggled to memorise things, which had been a proud skill.

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