For a fourth week running, thousands of children have skipped school in Belgium to join a protest demanding tougher action against climate change.
As they marched in Brussels, dozens of youngsters staged a protest outside the home of Belgium’s environment minister.
The protests were given new impetus by an open letter from 3,450 Belgian scientists saying “the activists are absolutely right”.
Youth marches have also taken place in Germany and Switzerland.
The Belgian primary and secondary schoolchildren were marching through the city centre from north to south, and they were joined by groups of grandparents.
As the crowds swelled, many were predicting at least as many protesters as the 35,000 who turned out a week ago.
Students have also been mobilising on Fridays in Germany and Switzerland, under the hashtag #FridaysForFuture
At the weekend, tens of thousands of adult protesters marched in cities across France as well as Belgium with the aim of holding monthly events.
But each country has different issues.
Germany has committed itself to phasing out nuclear power by 2022, and at the weekend its coal commission recommended shutting down all coal-fired power stations by 2038.
Belgium has ageing nuclear power stations at two sites near Antwerp and Liège and has increased its reliance on imported energy.
Outside Brussels, youngsters also turned out in the centre of Liège and Louvain (Luik and Leuven in Flemish).
In their open letter, the Belgian scientists said they wanted to provide facts, accusing opponents of disrupting the debate.
Leading Flemish politician Bart De Wever reacted to last Thursday’s march, which attracted 35,000 people, urging children “not to believe in the apocalypse” but to have “confidence in the future and in the power of innovation”.
The scientists said that technology to cut carbon dioxide emissions already existed but there was a need for political courage to take the necessary structural measures.
The young activists want world leaders and corporate bosses to stick to the ambitious goals agreed in Paris in 2015.
The school strikes were the brainchild of 16-year-old climate-change protester Greta Thunberg, who attracted widespread coverage for an appearance at the World Economic Forum at Davos in Switzerland last week.
“My message was that most emissions are caused by a few people, the very rich people, who are here in Davos,” she told the BBC.