An environmental group is concerned offshore oil and gas industries are underestimating their emissions after an international study found methane leaks were under-reported in the UK.
Research from Princeton University and Colorado State University found greenhouse gas emissions from the UK's offshore oil and gas industry to be about five times higher than the number reported.
The report cited outdated or incorrect emission factors and incomplete data to be behind the inaccurate numbers.
Environment group Friends of the Earth claims platforms and pipelines off Australia's coast have also experienced under-reported methane leaks which release greenhouse gases into the atmosphere.
Information on the US Environmental Protection Agency website says methane has a shorter-lasting effect on climate change but is more than 25 times as potent as carbon dioxide and makes up for about 20 per cent of global emissions.
Friends of the Earth Australia offshore fossil gas campaigner Jeff Waters said it was difficult to predict the amount of methane emitted from offshore oil and gas as it was self-monitored.
"We have to rely on industries that have proven to be untrustworthy in so many ways," he said.
"Friends of the Earth doesn't think that this industry, which has been in breach of so many safety guidelines, and which releases so much gas into the atmosphere, can be trusted."
Mr Waters said energy companies should not be responsible for monitoring their emissions.
"We need the industry regulator to come down harder or for the government to fund their industry regulator enough to be able to measure methane emissions themselves," he said.
Victoria is home to 23 offshore platforms and installations in the Bass Strait with a network of about 600 kilometres of underwater pipelines, operated by ExxonMobil.
Bigger concerns
La Trobe University professor of practice in engineering, Chris Stoltz, said there was not enough proof to conclude that energy companies were deliberately misleading Australians.
"If it's incompetence or accidental, then certain authorities are going to handle it and there's concern for that, but it's not the major concern," he said.
"History shows that some industries are not as honest as others but I'd rather not be too critical until there was more data that could really justify that."
Professor Stoltz said methane emissions from offshore oil and gas were minimal compared to other sources and environmental groups should focus on more significant emitters.
"The amount of methane that's actually been emitted through this accident, if it is an accident, is a hell of a lot less than from a volcano and a hell of a lot less from what China's emitting," he said.
"So if they're really concerned about the impact this is going to have on emissions generally in the world and what it's going to do for rising temperatures and rising sea levels, then maybe they would be better off going and knocking on China's door and saying, 'Hey guys, how are you measuring methane? What are your CO2 or greenhouse emissions?'"
Industry defends approach
The Australian Petroleum Production and Exploration Association (APPEA) said the methane emissions of the oil and gas industry were lower than in other sectors of the economy.
The industry group also said the sector produced less methane than oil and gas producers in other nations.
"Fugitive emissions rates from Australian upstream oil and gas operations in the national inventory are around 0.4 per cent of production, with this figure verified by the CSRIO in a 2019 study," APPEA chief executive Samantha McCulloch said.
"The oil and gas sector is committed to reducing methane emissions further, employing rigorous leak detection and repair programs while monitoring gas field infrastructure and utilising well integrity processes as detailed in a recent APPEA report on methane actions."
She said a number of APPEA members had committed to meet or exceed the Global Methane Pledge.
The ABC contacted ExxonMobil for comment but received no response.
