SEOUL -South Korea's top court said on Thursday the climate change law did not protect basic human rights and lacks targets to shield future generations, in a landmark ruling after activists blamed the government for failing to effectively tackle climate change.

About 200 plaintiffs including young climate activists and even some infants filed petitions to the constitutional court since 2020, arguing that their government was violating its citizens' human rights by not doing enough on climate change.

The court asked the legislature to revise the carbon neutrality act by the end of February 2026, acknowledging that the existing law's emission targets did not conform to the constitution by violating the duty to protect basic rights as well as failing to protect future generations against a climate crisis.

Climate advocacy groups said it was the first high court ruling on a government's climate action in Asia, potentially setting a precedent in a region where similar lawsuits have been filed in Taiwan and Japan.

In April, Europe's top human rights court ruled the Swiss government had violated the rights of its citizens by failing to do enough to combat climate change.

The Korean court ruling was met by cheers, tears and applause by the plaintiffs, activists and lawyers, who chanted slogans like "The verdict is not the end, but the beginning".

"I hope today's decision will lead to a bigger change so that children do not have to file this kind of constitutional appeal," said Han Je-ah, 12, one of the plaintiffs.

"The climate crisis is having a huge impact on our lives and there is no time to delay," she told reporters after the ruling.

Kim Young-hee, a lawyer for the plaintiffs, called the verdict "an important decision for the entire society's greenhouse gas reduction".

The court said South Korea's carbon neutrality act, enacted in 2010 and revised later to lay out emissions targets by 2030 and the goal of reaching carbon neutrality by 2050, failed to present "any quantitative levels" for the reductions targets between 2031 and 2049.

"Since there is no mechanism that can effectively ensure gradual and continuous reductions until 2050, it stipulates reduction targets that would transfer an excessive burden to the future," the court said in a statement.

In a statement, the environment ministry said it respected the verdict and would implement follow-up measures.

Koh Moon-hyun, a law professor at Soongsil University, told Reuters the ruling could potentially spark change in other countries.

"The court must have looked at rulings in Europe and changed its stance," he said. "It has created a chance for South Korea to drop its nickname as a climate villain."

Scientists say a global temperature rise beyond 1.5 degrees Celsius (2.7 degrees Fahrenheit) above the preindustrial average will trigger catastrophic and irreversible impact on the planet, from melting ice sheets to the collapse of ocean currents.

South Korea is seeking to reach carbon neutrality by 2050, but remains the second-highest coal polluter among G20 countries after Australia, data showed, with slow adoption of renewables.

Last year, it revised down its 2030 targets for greenhouse gas reductions in the industrial sector but kept its national goal of cutting emissions by 40% of 2018 levels.

  - Reuters