South Korea announced a plan to halve its carbon emissions by 2035 and retire most of its coal-fired power plants by 2040, signaling a significant pivot toward a lower-carbon future. Yet this increasingly collides with its rising imports of U.S. liquefied natural gas (LNG), The Associated Press reported.

The country's newly formed Ministry of Climate, Energy and Environment unveiled the updated climate roadmap at last month's United Nations climate conference. The initiative, driven by President Lee Jae Myung's administration, seeks to accelerate South Korea's transition from coal to cleaner energy sources, after years of lagging behind global and regional averages.

However, the government is simultaneously negotiating a sweeping trade agreement with the U.S., which could see Seoul invest up to $350 billion in U.S. projects and import as much as $100 billion worth of American energy products, including LNG.

Though cleaner than coal, LNG is still a fossil fuel, and its emissions, particularly methane, pose serious climate concerns, experts said.

Climate activists warned that this dual-track strategy risks undermining South Korea's own decarbonization goals. If simply replacing coal with gas, we're not transitioning but substituting one fossil fuel for another," said Insung Lee of Greenpeace Korea.

LNG accounted for nearly 20% of South Korea's energy supply in 2024, according to the International Energy Agency. While the government targets reducing that to 10.6% by 2038, the new U.S. deal could make that target elusive.

Depending on the agreement still under negotiation, South Korea will import 3-9 million tonnes of U.S. LNG annually for the next three to ten years. Lee argues that if the pending trade deal increases the total volume of imported LNG, the country risks oversupply, pressuring utilities to burn more gas than needed.

Energy Minister Kim Sung-hwan stated that LNG will serve as a backup to renewables and nuclear energy, which together are intended to anchor South Korea's future energy system. Nuclear provided 31% of domestic electricity, while renewables, despite growth, remained low at just 10.5% of power generation in 2024, far behind Japan's 21% and Spain's 42%.

In early December, South Korea set another goal of boosting its offshore wind power capacity to 4 GW, about 10 times the current level.

To come out of high dependency on fossil fuels, South Korea must accelerate renewable deployment, said an analyst of the Institute for Energy Economics and Financial Analysis. She warned that high fossil fuel reliance could leave South Korean industry at a competitive disadvantage as global sectors face growing decarbonization pressures.

Last month, South Korea joined the Powering Past Coal Alliance, a symbolic but telling gesture of its intent to exit coal. The government aims to shut down 40 of its 61 coal facilities by 2040. This shift is expected to ripple through regional coal markets, particularly affecting exporters like Australia and Indonesia.