Many abandoned boreholes in Queensland are not properly sealed, with some leaking significantly, contributing to the state's greenhouse gas emissions.

A small patch of dry, dead vegetation on farmland served as a visual sign of underground methane leaks, underscoring the subtle indicators of such environmental hazards.

A single methane leak from an abandoned borehole can emit approximately 235 tonnes annually, equating to the climate impact of thousands of cars.

Researchers have identified at least one other severely leaking site that has been sealed by authorities, indicating some progress but highlighting the need for broader action.

Sealing these high-emission boreholes is a low-cost, straightforward process involving excavation, piping, and cementing, which could greatly reduce methane emissions.

The study calls for more extensive surveys, proper registration of boreholes, and government intervention to plug leaks, as current efforts are insufficient.

Researchers from the University of Queensland used advanced technology to identify a significant leak from an abandoned borehole that had been leaking for about 20 years.

One unsealed coal exploration borehole in Queensland emits methane equivalent to that produced by 10,000 cars annually, and there are approximately 130,000 such boreholes in the state.