BEIJING - China accounts for more than half of the world's pipeline of new coal mines, risking a significant increase in methane emissions, a new study published on Tuesday showed.

China is developing enough new mines to produce 1.28-billion metric tons of coal each year, said the report by US-based Global Energy Monitor (GEM) which included large mines with at least 1-million tons of annual capacity as of April.

It said 35% of that capacity is already under construction, meaning a surge in production is expected in three to five years.

"Expanding coal production capacity is currently a national policy priority and a political task. State-owned enterprises, which dominate the sector, are often mandated to fulfil this objective," said GEM project manager Dorothy Mei.

China's system of long-term contracts guarantees the profitability of coal companies, Mei added.

China's existing mines have made it responsible for 70% of global coal mine methane emissions from similar sized large mines, and if all the proposed projects are completed, this would rise to 75%, the report said.

"The surge in new production starkly contrasts with China's dual carbon neutrality targets," it said.

Methane emissions come from activities such as energy production, agriculture, and landfill and are short-lived in the atmosphere but much more potent than carbon dioxide as a greenhouse gas. They have driven about a third of the rise in global temperatures since the Industrial Revolution.

China's pipeline accounts for more than half of mines under development globally, and includes projects under all stages of development, including those proposed, permitted as well as already under construction.

By comparison, China's existing current large-scale coal mine capacity is 3.88-billion tons per year, the report found, which is nearly half the global total.

China, the world's largest producer and consumer of the fossil fuel, mined a total 4.66-billion tons of coal in 2023, a record high, data from its statistics bureau showed.