London, November 29 (RHC)-- Tens of thousands of protesters have rallied in cities across the world, demanding more action on climate change and aiming to force political leaders to come up with urgent solutions at a United Nations conference next week.

The demonstrations kicked off in Australia on Friday, where people affected by recent devastating wildfires joined young environmentalists protesting against the government's pro-coal stance.

Students in Sydney and other major cities walked out of class, saying more should be done to combat the country's bushfire crisis, which many see as a result of climate change.

"Our government's inaction on the climate crisis has supercharged bushfires," 18-year-old Shiann Broderic, one of the event's organisers, whose home was destroyed in a bushfire, told Reuters News Agency.

Swedish teenage activist Greta Thunberg, who is travelling across the Atlantic by sailboat to attend the UN climate talks in Madrid, sent a message of support to protesters. "Everyone's needed. Everyone's welcome. Join us," she said on Twitter.

Since starting her one-woman "climate strikes" in Sweden more than a year ago, Thunberg has drawn a huge following around the world and inspired thousands more students to regularly skip school on Fridays and join climate protests.

This Friday's climate strike took place in 2,300 cities in 153 countries around the world, according to estimates by the climate campaign group, Fridays For Future.

Representatives from 200 nations are scheduled to meet in Madrid for the 12-day UN Climate Change conference, COP25, from December 2-13.