Over 20,000 protesters hold a massive rally near Gangnam Station in southern Seoul, urging both the government and individuals to take active measures to combat the climate crisis, Saturday. Yonhap

Over 20,000 Koreans from all walks of life gathered in a massive rally in the heart of Gangnam District, Seoul, Saturday, calling for immediate action from both the government and individuals to address the climate crisis.

Amid an unusual early-autumn heatwave with temperatures exceeding 30 degrees Celsius, a coalition of 611 civic and environmental groups filled the 600-meter, four-lane road from Sinnonhyeon Station to Gangnam Station in southern Seoul.

Under the slogan "Let's Change the World, Not the Climate," participants held hand signs made of paper boxes and called for solutions to various environmental issues. They urged a shift to renewable energy and the suspension of development projects that harm the ecosystem.

"There is no place for people's livelihoods in efforts to increase electricity demand for economic growth or to expand nuclear risks and greenhouse gases," the groups said in a joint statement. "Let's march together to address the climate disaster and global injustice, and to protect a life of equality and dignity."

Park, a 21-year-old university student based in Gyeonggi Province who joined the protest, said she felt "a sense of crisis" throughout the unprecedented heat this summer. Korea has experienced a record number of heat stroke cases, heat-related deaths, and the longest streak of tropical nights.

"I'm devastated by the lack of substantial actions taken by the government," she said.

"I couldn't shake the thought that the Earth will be ruined if things continue like this. Despite this, I'm devastated that I haven't heard anything about the president taking action on the issue. That's why I decided to come here today," Park said.

Her friend, surnamed Kim, 22, shared a similar perspective.

"This is the only Earth we have, and we need to continue living on it," she said.

A protester holds a sign calling for climate justice during a rally in southern Seoul, Saturday. Yonhap

The protest followed a landmark ruling by the Constitutional Court on Aug. 29, which found that the government's carbon reduction law does not conform to the Constitution.

In a constitutional petition filed by young people and civic groups, the court ruled that the law, which sets greenhouse gas emission reduction targets through 2030, fails to protect people's basic human rights beyond 2031.

"If current greenhouse gas reduction efforts are insufficient, the burden on future generations will increase," the ruling said. It also emphasized the need to ensure "equal basic rights between current and future generations" to prevent passing on excessive burdens.

The ruling acknowledged that the government's lack of plans to address the climate crisis could result in the infringement of people's basic rights.

Saturday's rally was the fourth of its kind, with the first climate protest march beginning in 2019.

This year, the event was relocated from its usual venue in the Gwanghwamun area to the business district of Gangnam for the first time.

"It is a place where Samsung Electronics, POSCO, GS Caltex, and Google Korea, which generate profits by emitting a large amount of greenhouse gases, are gathered," a member of the event's organizing committee said.

The protesters stopped at the headquarters of Google Korea, GS Caltex, Coupang Rocket Research Institute, and POSCO Center on Gangnam Avenue, shouting, "Let's fight the destruction of the ecosystem and reckless development," and "Let's fight climate disasters and inequality."

Participants of a climate rally stage a die-in in the Gangnam area, Seoul, Saturday. Yonhap

After arriving at Samsung Station, the participants staged a "die-in" performance, lying down on the road as if dead to mourn the lives lost to climate disasters.

Following Swedish environmental activist Greta Thunberg's refusal to attend school in 2018, large-scale climate crisis rallies have been held every September, a month recognized globally for climate action.