Claims by the energy and emissions reduction minister, Angus Taylor, that Australia’s liquefied natural gas exports are reducing global emissions are “grossly exaggerated”, one of Australia’s most renowned climate scientists has said.

Bill Hare, who has worked in climate science for 30 years, including on UN negotiations, has questioned Taylor’s statement that Australia’s LNG exports cut global emissions by up to 148m tonnes because they replace higher-emission alternatives such as coal.

“Government claims that Australia’s LNG exports are reducing emissions globally are grossly exaggerated and, depending on the real level of methane leakages, reservoir CO2 venting and losses, and where the LNG is coming from in Australia, likely to be wrong,” Hare said.

It is unclear what data the government has to support its claim, but it received advice on the 148m tonne figure from the department.

Guardian Australia sought clarification from the Department of Environment and Energy, and received the following response:

“The Department based the estimate on data for the year to December 2018 from the Department of Industry’s March 2019 Resources and Energy Quarterly; the Department of Environment and Energy’s Australian Energy Statistics - Guide to Australian Energy Statistic 2017 and factors from the National Greenhouse and Energy Reporting (Measurement) Determination 2008.

“The Department compared the emissions that would be produced from the combustion of Australia’s LNG exports for the year to December 2018 against the emissions generated from the combustion of an equivalent amount of energy of black coal.

“Under this comparison, the combustion of LNG exports would generate 197.1 Mt CO2-e, which is around 148 Mt CO2-e less than the emissions generated by the combustion of the same amount of energy of black coal (345.1 Mt CO2-e).”

Taylor’s comments followed the delayed release of the government’s quarterly emissions data for December 2018, which show that Australia’s emissions continue to rise, driven in part by the country’s LNG industry.

The minister defended the increase by saying that Australia’s exports were contributing to emissions reductions in countries that made use of Australia’s LNG in place of coal.

“Australia’s total LNG exports have the potential to lower emissions in importing countries by around 148 Mt CO2-e in 2018 by displacing coal consumption in those countries,” he said in a statement.

He repeated those remarks in an interview with the ABC’s RN Breakfast on Friday, saying there were “148m tonnes of lower emissions as a result of our exports”.

“That is something to be proud of.”

But Hare said any advantage LNG had over coal once it was burnt would be rapidly reduced if the emissions of methane – a much more potent greenhouse gas than carbon dioxide – during production were higher than what was currently estimated.

“Many experts believe that Australia is under-reporting methane losses from natural gas production, with only about 0.5% loss estimated, whereas the IEA [International Energy Agency’] estimates globally over 1%, and in other countries scientific work indicates losses of up to several per cent,” he said.

“This matters because methane, the main gas in natural gas, is much more powerful than CO2, and so loss rates of a few per cent could annul any benefits from displacing coal in the power sector.

“In Western Australia a number of the reservoirs have very high levels of CO2 in the gasfields, which, if emitted, reduces or eliminates the benefits of displacing coal with LNG.”

The director of the Australia Institute’s climate and energy program, Richie Merzian, spent more than nine years as an Australian government climate negotiator to the UN.

He said there was no clear evidence that Australia’s increasing LNG exports were reducing global emissions.

“I’m not sure where he got those numbers,” Merzian said.

“Take Japan, one of our major export recipients in terms of gas. It’s still in the process of shifting from nuclear post-Fukushima, so it’s therefore going from a low greenhouse gas emissions fuel source to a high one.

“Furthermore, the increase in gas exports might lock in gas infrastructure that will make it even harder to transition away from fossil fuels, which is what the Paris agreement is calling for.”

Merzian said if Australia was now trying to argue it should get credit for reducing emissions overseas, it should also take responsibility for fueling the climate crisis as the world’s largest exporter of coal.

“Most countries are very clear about the delineation between domestic emissions and scope three – or emissions that take place overseas from exports,” he said.

“That reflects the UN framework. By blurring the line, as Minister Taylor has done, he’s not only reshaping UN conventions, but he seems to be trying to champion the growth of natural gas exports.”

A spokeswoman for Taylor repeated the government’s position that Australia would meet its emissions reduction target of 26% to 28% on 2005 levels by 2030.

“We will do this while growing the economy, creating jobs, protecting our environment and keeping power prices down,” she said.



