As many as 35,000 Belgian students walked out of classrooms in Brussels, Liège, and Leuven in the fourth straight week of protests to pressure policymakers to pursue bolder measures in response to the human-made global climate crisis.

Students across the globe have joined the climate strike movement inspired by 16-year-old Swedish activist Greta Thunberg, and are calling on politicians to heed the increasingly urgent warnings from scientists that the international community must immediately phase out fossil fuels and enact other ambitious measures to drive down greenhouse gas emissions.

"The climate is a disaster," 15-year-old demonstrator Allison Debonte told Reuters, adding that she worries her children won't be able to live in Brussels because of the climate crisis.

"It's our planet and the generation before us hasn't done anything," added Julian Rume, 17. "In 20, 30 years, we will all be migrants, we'll all be moved out of our planet."

Aaaaaaand they're back! Here's a timelapse of thousands of young climate change protesters marching through Brussels' city center. Same procedure as every week. #YouthForClimate pic.twitter.com/swIeSJvuQ1 — DW Europe (@dw_europe) January 31, 2019 Be it in Liège, Brussels or Leuven, students are again marching in large numbers for more #climate action, this Thursday. Impressive. #YouthForClimate pic.twitter.com/nzLa4inL1F — Lucas Demuelenaere (@ldemuele) January 31, 2019

Brussels, where an estimated 12,500 students marched on Thursday, is considered the de facto capital of the European Union, as home to several EU institutions. The young strikers have condemned those in power across Europe for failing to cut emissions and transition to renewable energy.

"They left us a planet in a bad shape so it is our job to change that," 17-year-old marcher Manon Wilmart told the Associated Press. "But we can do it. We are younger and we know that we can do it. We are in the mood to change the climate, to change everything."

A 16-year-old named Pauline, in an interview with Deutsche Welle, was optimist that progress is on the horizon: "Me and my friend, we already try to do everything for the climate. I think there is now a lot of attention on this issue. So I really think that the countries will start to mobilize and change something."

"I really think countries will start to mobilize and change," Pauline, a 16 year old student, tells us at #YouthForClimate march in Brussels today. pic.twitter.com/o3jEHCQq9U — DW Europe (@dw_europe) January 31, 2019

Participants and supporters from cities across Belgium shared updates on social media with the hashtags #ClimateStrike and #YouthForClimate:

The actions on Thursday followed an estimated 35,000 students who marched in Brussels last week and about 160,000 protesters in Belgium and France over the weekend.

Thunberg's protests outside the Swedish Parliament last year have garnered her, and the broader youth demand for climate action, international attention—enabling the teenager last week to tell the billionaires attending the World Economic Forum to their faces that they're among some the specific individuals responsible for the climate crisis. She highlighted the protests in Belgium on Twitter and Instagram on Thursday:

Meanwhile, in several other cities around the world, students plan to continue the strike on Friday, with organizers sharing details on social media using the hashtag #FridaysForFuture: