The Morrison government and the gas industry have defended the role of the fuel as a lower-emissions alternative to coal, despite new research indicating fossil fuel extraction is lifting methane levels more than thought.

A 20-year research collaboration including the CSIRO and Australian Nuclear Science and Technology Organisation (ANSTO) used a tonne of ice cores from Antarctica and Greenland to determine the levels of methane from natural sources before the industrial revolution began in about 1750.

A new study has found the contribution to rising atmospheric levels of methane from fossil fuels may be as much as 40 per cent higher than the oil, gas and coal industries have admitted. Credit:AP

In a paper published on Thursday in the journal Nature, scientists said they found natural geological methane sources such as seepage leaks from coal seams were just a tenth of previous estimates. It means modern industrial processes, including gas drilling, have been leaking more methane into the atmosphere than previously thought.

Andrew Smith, a principal ANSTO research scientist who also participated in the ice extraction and analysis, said "we have proven [the fossil fuel industry] are making pretty big errors" in estimating how much methane was escaping from their operations.