Ryanair chief Michael O'Leary has dismissed climate change concerns as "complete and utter rubbish".

Speaking to RTÉ Radio One's Countrywide programme, Mr O'Leary said he believes that people's fears about climate change are unfounded.

"I think it's complete and utter rubbish," he said.

"They remind me of these people who used to hang around the market squares 2,000 years ago, saying the end of the world is nigh. You go back to London in the 18th century, they all thought they were going to die of smog."

Mr O'Leary said that nuclear power needs to be considered as a viable future energy source.

"If you're concerned about these issues, the obvious one is more nuclear fuel, but you ask the likes of Mary Robinson, the climate change justice mob, and they recoil in horror because it's not trendy or liberal."

Mr O'Leary, also denied that carbon emissions and beef consumption are the main driving forces of climate change and said he believes that "human ingenuity will find ways of improving the way we breed beef and they way we consume fuel".

When asked if accepted that climate change is happening, Mr O'Leary said that the cooling and warming had been "going on for years" and he didn't accept it was linked to carbon usage.

"I don't accept that climate change is real. I don't accept the link between carbon consumption and climate change.

"I will always be wary of these people saying the world is nigh.

"This nonsense that we'll have to cut back on beef consumption or all become vegans or start riding bicycles is not the way forward."