In the same week that he called for replacing co-pilots with air stewardesses, Ryanair boss Micheal O’Leary has sparked further controversy by denying the existence of man-made climate change.

The controversial millionaire said the idea that man-made pollution is heating up the planet is “horse *#*!”.

In an interview with The Independent, he said: “We’ve had an ice age. We’ve also had a couple of very hot spells during the Middle Ages, so nobody can deny climate change.

“But there’s absolutely no link between man-made carbon, which contributes less than two per cent of total Carbon Emissions [and climate change].”

He added: “The scientific community has nearly always been wrong in history anyway. In the Middle Ages, they were going to excommunicate Galileo because the entire scientific community said the Earth was flat.

“I mean, it is absolutely bizarre that the people who can’t tell us what the ******* weather is next Tuesday can predict with absolute precision what the ******* global temperatures will be in 100 years’ time. It’s horse ****.”

Greenpeace spokeswoman Joss Garman said in response: “Personally, I wouldn’t trust ‘O’Really’ to tell me the price of a seat on his own airline, but to be fair his position does have the support of such intellectual heavyweights as Nick Griffin, Sarah Palin and George W Bush.”

Separately, O’Leary has also hinted that he could be back in the market for up to 300 aircraft in a multibillion-dollar spend that could dash investors’ hopes of future dividends from Ryanair.

He said the airline had the option of purchasing at least 200 Boeing jets, worth about $15bn (£9.8bn) at list prices. This could even stretch to 300 from either Boeing or Airbus at the right prices. However he said there were no negotiations with either manufacturer at present.

His comments come as Ryanair prepares to pay a €500m dividend next month – its first – after O’Leary pulled out of a deal to buy 200 Boeing jets late last year. He has held out the prospect of paying a second dividend in 2013.

One his early suggestion that the second pilots should be replaced by cabin crew, he said: “It would save the entire industry a fortune”, adding that trains were allowed to have one driver even though this could conceivably cause a crash in the event of a heart attack.

He said: “In 25 years with over about 10m flights, we’ve had one pilot who suffered a heart attack in flight and he landed the plane”.

He conceded that two pilots would be needed on long haul international flights but on Ryanair’s shorter trips, flight attendants could do the job of a co-pilot, who was only there to “make sure the first fella doesn’t fall asleep and knock over one of the computer controls”.