SEOUL: More than 30,000 protesters gathered in South Korea's capital in broiling heat on Saturday, demanding more aggressive action by the government to combat global warming.

With temperatures exceeding 30°C, protesters young and old marched in the country's biggest demonstration so far this year, snarling traffic in central Seoul.

They waved large banners reading "Climate justice", "Protect our lives!" and "NO to climate villain (President) Yoon Suk Yeol's administration".

"Truth is, without the air conditioner this summer was not livable and people could not live like people," said Yu Si-yun, an environmental activist leading the protest.

"We are facing a problem not unique to a country or an individual. We need systemic change and we are running out of time to act."

Organised by the 907 Climate Justice March Group Committee, the protest followed a ruling last month by South Korea's top court that the nation's climate change law fails to protect basic human rights and lacks targets to shield future generations.

The 200 plaintiffs, including young climate activists and even some infants, told the constitutional court that the government was violating citizens' human rights by not doing enough on climate change.

South Korea, which aims to be carbon-neutral by 2050, is the biggest coal polluter after Australia among the Group of 20 big economies, with a slow adoption of renewable energy.

The government last year lowered its 2030 targets for curbing industrial greenhouse-gas emissions but kept its national goal of cutting emissions by 40 per cent from 2018 levels.

Even South Korea's kimchi has fallen victim to climate change. Farmers and manufacturers say the quality and quantity of the napa cabbage used in the ubiquitous pickled dish is suffering due to intensifying heat.

"Feel how long this summer is," said Kim Ki-chang, a 46-year-old novelist who was participating in the protest for a third straight year.

"This would be a much bigger threat and survival issue to younger generations than the older ones, so I think the older generation should do something more actively for the next generation."

Seoul has had a record 20 consecutive nights defined as "tropical", with low temperatures remaining above 25°C.

Protest organising committee member Kim Eun-jung said the demonstrators chose the popular Gangnam financial and shopping area this year, not the Gwanghwamun area they used last year, to have their voices heard by the many big corporations there that the group blames for carbon emissions.

  - Reuters