Australian opencut coal mine operators may be able avoid reporting hundreds of thousands of tons of methane emissions if a government proposal to change how the releases are estimated is approved, according to Ember.

The plan from the Department of Climate Change, Energy, the Environment and Water would eliminate state-provided emissions factors and required operators to determine their own. But the current proposal doesn’t include crucial safeguards to ensure independent verification and the accuracy of the data, Chris Wright, a climate strategy advisor at the energy think tank, said in a report.

To estimate methane emissions operators have typically multiplied so-called emissions factors — estimates for how much methane a mine might normally release per unit of output — times production. Historically, state governments have provided emissions factors but company-led emissions estimates allows operators to determine their own emissions factors.

“A simplistic shift toward company-led reporting without a critical tightening of existing regulations risks further underestimating Australia’s coal mine methane, and undermines efforts to actually reduce real emissions,” Wright said in the report.

Under Australia’s company-led emissions reporting approach, operators drill borehole samples from their mines and develop 3D models to estimate emissions during production, according to Ember, which cited Australian Coal Association Research Program guidelines. An analysis of three mines that use that method found that since 2016, the operators collectively reported about 8.5 million tons of carbon dioxide equivalent less than they would have using state-based emissions factors.

Neither method accurately captures the nuances of methane emissions from individual mines and a more comprehensive and transparent approach that combines ground based-measurements with top-down verification from satellites or other remote sensing instruments are necessary to ensure accurate reporting, Ember said.

The Australian government is committed to continuous improvement of the country’s emissions reporting, including its methane emissions estimates, a spokesperson for the department said. Submissions on the proposal are currently being reviewed, they said.