Young environmental activists in Italy are planning to miss school as thousands join climate crisis protests in major cities on Friday.

Some 475,000 people took part in the first global climate strike in Italy on 15 March and a similar number are expected to join the latest demonstrations in cities including Rome, Milan, Turin, Florence, Naples, Bologna and Bari. But only if they are allowed to skip school. Earlier this week the education minister, Lorenzo Fioramonti, urged schools to consider as “justified” the absence of children taking part in the mobilisation against the climate emergency.

He said on Facebook the climate strike was “essential” for students’ future, which was “threatened by environmental devastation and an unsustainable economic growth model”.

However, many schools are only obliging after receiving a letter requesting permission from parents and if the child has maintained good attendance throughout the year.

David Wicker, a representative of the Turin branch of Fridays for Future Italia, is planning to miss school regardless. Despite the high expected turnout, he worries that environmental issues are not yet a major concern for children and adults alike.

“I would urge adults to join the movement too,” he said. “Unfortunately, it is not recognised as an official strike by labour unions. One day off work won’t change your career but it will change your future.”

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It comes as world leaders wrap up the UN climate action summit in New York. The Italian prime minister, Giuseppe Conte, urged his counterparts against “indifference” as news emerged that a massive portion of a Mont Blanc glacier was in danger of collapse. “It must shake us all and force us to mobilise,” he said.

Conte promised to make environmental action a priority in a speech before the new left-leaning government, a coalition of the Five Star Movement (M5S) and Democratic party, was voted into power earlier this month. Although M5S had long prioritised the environment in its campaigning, the subject appeared to take a backseat during the party’s 14-month coalition with the far-right League.

Sergio Costa, an M5S politician who kept his role as environment minister in the new alliance, has been more proactive, saying in New York this week that “courageous and revolutionary” policies were needed. The ministry is drafting a range of measures, including giving shoppers a 20% discount on supermarket goods that are sold loose in an attempt to cut back on plastic waste. Some 2.2m tonnes of plastic wrapping is discarded in Italy each year and in 2016 less than half of that was recycled, according to WWF figures.

Pollution is also a major issue, especially in Italy’s northern cities. And while Italy’s greenhouse gas emissions have been decreasing over the past decade, the country was criticised this year by the European Climate Foundation for failing to provide an adequate plan to further reduce emissions and dependency on fossil fuels.

“We hope the new government recognises the climate emergency and declares it so at the summit,” said Wicker. “We want them to divest in fossil fuels and invest in green energy resources, while improving public transport and make it more affordable.”

The biggest climate strike in history took place last Friday, with several million people across an estimated 185 countries taking part. More than 2,400 separate strikes are expected globally on Friday, according to the group Fridays For Future. As well as Italy, especially large turnouts are expected in India, New Zealand, Sweden and the US.