Claims by scientists that climate change was man-made was “nonsensical”, he said.
Mr Healy-Rae dismissed a State of the Climate report published this week by 450 scientists which found that greenhouse gases contributed to 2015 being the hottest year on record.
The Independent TD said: “I have to reiterate what I have been saying for many, many, years now. There has always been change in our climate.
“We know going back through the ages this country was very, very, warm in the 12th and 13th centuries.
“And in the 15th and 16th centuries it was cold. In 1740 we had a famine that cleaned out practically a third of our population because they did not have any food.
“They had to have hay for the cattle and they didn’t have any crops because of the weather. They did not have any fuel for the fire because they could not save any turf and they perished and starved.”
He refused to believe recent changes were man-made.
“I don’t accept it because there are superior influences causing climate change,” he said.
“There are hundreds of scientists who believe we are not changing it.
“Climate change has always evolved. We have other reasons like volcanoes exploding and blocking out the sun and comets dropping which caused climate change.
“There are so many different things happening naturally, thunder and lighting, are you saying we are responsible for that?” he asked on Newstalk Breakfast.
“We have the Gulf Stream that comes up from the Azores from Mexico and we have El Nino that brings extreme cold water, the North Atlantic drift.
“The positions of those streams have always been changing and as a result changed the temperature and our weather.
“There are superior influences causing these. We have thunder and lightning. To say that man is changing the weather is nonsensical.”
However, Green senator Grace O’Sullivan said that catastrophic changes were under way and these were not just down to weather cycles but pumping greenhouse gases into the atmosphere.
She said this week’s report should set off alarm bells throughout the world.
“This will affect every continent, every country, every region,” she said.
“The UN has said this year is showing signs of being warmer again. We will have huge catastrophic problems going forward. Everyone has to start taking action.”
However, Mr Healy-Rae did not agree. He said there were far more cattle, which have been blamed for greenhouse gases, in the country now but there were still problems with the weather in the 1600s and 1700s.