BRUSSELS (AFP) - Thousands of young people rallied in Belgium to demand action on climate change Thursday (Jan 31) as part of a wave of demonstrations led by high school students aimed at intensifying pressure on governments.

Carrying banners with slogans like "No world, no future" and "Make our planet great again", some 30,000 people took to the streets across the country, with some 12,500 in Brussels.

They are part of a wider network of student-led protest groups that have seen tens of thousands of young people around the world ditch school to demand action against climate change in recent months.

In Belgium the "Youth for Climate" movement has seen schoolchildren and students shun classes every Thursday for the past four weeks.

"Many say we do this to skip school, but we didn't even have class today, our teachers were away," said one student, Elias.

"So we just come because it's important. I don't want to find myself in 20 years with a destroyed climate and tell myself that I didn't do anything."

Brandishing a megaphone, 17-year-old Anuna De Wever told the crowd: "We need change! Now!"

The Flemish high school student has become the high-profile face of the marches, facing death threats online for her activism.

"We must all ask the leaders of our planet to solve this problem right now, to listen to the experts and to swear that the climate will be a priority until we are protected," she said.

Then she added in English: "What do we want? Climate Justice! When do we want it? Now!"

The Thursday protests attracted just 3,000 in Brussels four weeks ago, rising to 12,000 in the second week and peaking last week at 35,000.

A network of campaign groups organised a more general climate march on Sunday that attracted some 70,000 people in Brussels, according to police, with more than 80,000 people estimated to have marched in French towns and cities.

CALL TO ACTION

Protesters, some wearing face paint and masks, were in festive spirits despite the icy weather, with a soundsystem wheeled along to pump out tunes to dance to.

But protesters said their message was serious.

"I think more needs to happen from the government," said Tim, another student.

"It's good that people do this but the big difference will be made by the government."

On the sidelines, around fifty older people "Grand parents for climate", applauded the young marchers.

The demonstrations are part of a wider movement pushing to end political inertia on climate .

One of the most powerful voices to have emerged in recent months is that of Swedish teenager Greta Thunberg, whose message to business and political leaders grabbed the headlines at January's World Economic Forum in Davos, the annual get-together of the rich and powerful.

"Adults keep saying we owe it to the young people to give them hope," she said at the forum.

"But I don't want your hope. I don't want you to be hopeful. I want you to panic."

Thunberg first grabbed the spotlight in August when she began staging school strikes, skipping classes on Fridays to protest in front of Swedish parliament.