Fracked gas imports from the United States are not needed to keep the lights on in Ireland and would have a carbon footprint far greater than coal, scientists have warned.
Professor Robert Howarth, of Cornell University, New York, said the methane content of fracked gas made it 100 times more powerful than carbon dioxide in terms of greenhouse gas emissions.
Taking into account the energy needed to liquefy the gas into the form of LNG and ship it to Ireland, he estimated the carbon footprint would be 44pc greater than coal.
"From the standpoint of climate change, LNG is a very poor fuel choice," Prof Howarth told the Oireachtas climate change committee. "I urge Ireland to prohibit the importation of fracked shale gas from the United States."
Prof Howarth was backed by Professor Barry McMullin, of Dublin City University, who rejected the Government's argument that gas would be needed as a back-up energy source for years to come even when most power came from renewable sources.
"It's absolutely going in the opposite direction of where climate action is going. Fossil fuel, in particular fracked gas, has a very short horizon future," he said.
Dr Paul Deane, of University College Cork, also said it was questionable whether shale gas was needed for energy security. "It is not entirely obvious that LNG infrastructure will be needed in Ireland," he said. "We have looked at many scenarios and the lights stay on in all our simulations."
The committee invited the experts as the Government pressed ahead with formally reinforcing its support for a plan by Shannon LNG to build a terminal in the Shannon estuary to receive fracked gas from the US even though fracking is illegal in Ireland.
The project is being challenged in the courts but the Government has backed its inclusion on a list of EU 'projects of common interest', which allows it to apply for European funding.
Julia Walsh, of the New York-based campaign group Frack Action, told the committee her own state had banned fracked gas pipelines passing through its territory from gas fields in Pennsylvania, where there were serious concerns over the health effects of fracking.
She said the result was a glut of gas in need of a market and Ireland was being targeted.
"If Ireland imports fracked gas at the Shannon LNG terminal then you will be locking yourself into over a decade of complicity in harming people and children in Pennsylvania," she said.
The committee heard it was possible a very small amount of fracked gas was already in the Irish energy supply through imports from the UK.
Fianna Fáil TD John Brassil asked why this should be considered any different from the fact that Ireland receives nuclear electricity generated abroad when nuclear power stations are illegal here.
Dr Deane replied: "It's a hypocrisy but it's a hypocrisy that we have become comfortable with."