“Without education, children grow up without the knowledge and skills they need to contribute to the peace and the development of their countries and economies, aggravating an already desperate situation for millions of children,” said Muzoon Almellehan, UNICEF's latest – and youngest – Goodwill Ambassador, speaking from Hamburg, Germany, where she is representing UNICEF at the summit.

“For the millions of children growing up in war zones, the threats are even more daunting: not going to school leaves children vulnerable to early marriage, child labour and recruitment by armed forces,” Almellehan said.

The UN agency has requested $932 million for its education programmes in conflict and disaster zones, but has received less than $115 million.

The greatest needs are in the Central African Republic and Yemen, where the funding gaps are above 70 per cent.

Students are missing out on opportunities to learn in Iraq and Syria, as well. According to a survey cited by UNICEF, pursuing educational opportunities was mentioned as one of the factors leading families and children to flee their homes.

A survey of refugee and migrant children in Italy revealed that 38 per cent of them headed to Europe to gain access to learning opportunities. In Greece, one in three parents or caretakers said that seeking education for their children was the main reason they left their countries for Europe.

UNICEF said that for children who have experienced the trauma of war and displacement, education can be life-saving.

“When I fled Syria in 2013, I was terrified I would never be able to return to school. But when I arrived in Jordan and realized there was a school in the camp, I was relieved and hopeful,” said Muzoon. “School gives children like me a lifeline and the chance of a peaceful and positive future.”

Secretary-General António Guterres is also participating in the two-day summit of the G20, which includes leaders from 19 countries and the European Union.