Former Prime Minister, Malcolm Turnbull recently called out “climate deniers” within The Coalition party.

Speaking on ABC’s Q&A program, the former PM said it “was nuts” that those on the right were questioning the existence of climate change.

“The Coalition has a fundamental problem in dealing with climate change because there is a group within the Liberal Party and the National Party who deny the reality of climate change,” he said.

The concept of climate deniers is not new. Back in 2010, Insight invited the late internationally renowned climatologist, Stephen Schneider to take on a room full of Australian climate change sceptics.

Nine years on, what do some of those people think now? Have their opinions changed?

Mark - builder

2010: “Well, I believe nature has its ways of balancing itself and if we went into an extreme global warming I'm sure it's got its own methods of cooling itself.”

2019: “I’m still 100 per cent certain of this and the difference between the environmental scientists and real scientists is very wide. Because environmental scientists look for the funding from the government and the real scientists work for CSIRO and other organisations for $60,000 a year – that’s the difference. I’m still not convinced any data exists that there is global warming and we have a couple of fires - which is also part of nature cleaning itself and balancing itself, the ecosystem does that - and everyone starts screaming it’s the global warming. It takes a lot more than that to change my mind.”

Dr Ian – general practitioner

2010: “I understand that carbon dioxide that man produces is 3% of what nature produces. How can small changes to our production of CO2 impact upon something as large as the Earth? It seems absurd. I'm saying there's homeostasis in the Earth that small extra production of carbon dioxide would easily be absorbed into.”

2019: “Subsequent to nine more years research I have seen nothing, any peer reviewed literature, using repeatable scientific experiments that have disavowed me of my previous opinion.

I don’t want people to think that I don’t care about the environment, I care passionately and deeply about the environment, I have no agenda, I’m a doctor, I used to be an engineer, I have a scientific background, I’m not a fool and a lot of people are in my situation - decent caring citizens of the world. We don’t hold the view we do because we are pig headed we do it because we need scientific proof.

Since carbon dioxide has risen from nought point nought three per cent to nought point nought four in the past 200 years, which people claim is a catastrophe, it’s actually been associated with greening, more plant growth, and lots of farmers pump carbon dioxide into greenhouses to grow the produce. The more carbon dioxide there is the easier it is to grow crops to feed the people of the world. Unless carbon dioxide levels are more there are going to be a lot more starving people.”

Tania – Stay at home mum

2010: “I think CO2 is actually beneficial for us. It's heating up the Earth, it's producing vegetation, it's producing food, I don't see what all the drama is. It's only going up a slight amount and yet we're going to change our whole economy over this slight amount that's actually helping us. It's beneficial.”

2019: “My views are sort of the same, I don’t think we should change our whole economy over climate change. We shouldn’t destroy our economy over a slight amount of C02.”

Peter - train driver

2010: “No I don't believe in it [man made climate change] at all. I believe in climate change, the climate always changes but I haven't seen any evidence to date that discounts natural climate change and I've seen nothing in any of the literature that I've read that indicates that anything is abnormal with the warning or the rate of warming.”

2019: “Climate change is a 4.6 billion year concept, it’s still a hypothesis that C02 that mankinds level of .001026 can possibly heat the rest of the planet, it’s just a natural warming trend that seems to have flattened out. We’ve produced over a quarter of all C02 that mankind ever produced since the late 90s, people might say it’s the highest year ever, but it’s pretty sparse really it’s only the western world that has had 160 years of any thermometer readings. I agree that it is a warming trend but it’s nothing out of the ordinary, not superstitious enough or guilt ridden enough to say its mankind. Mankind does a lot of damage in a lot of ways but not this way.”

The climate expert

Climate change expert, Dr Ian McGregor, says climate sceptics make up only a small percentage of the Australian population – but it’s hard to sway their opinion.

“As we age we get more entrenched in our views so it’s harder to change,” he explains.

“When people get these entrenched beliefs they look for information that tries to confirm their beliefs.”

As for Australia’s current bushfire crisis being nature’s way to clean the environment, he admitted that “you can’t directly link climate change to bushfires” but climate change is making them worse.

“If you have hotter conditions, and Australia has certainly had record temperatures for the last 10 years, and combined with the drought we’re having, you have hot dry conditions which are much more conducive to more extreme bushfires and we’ve had more extreme bushfires in the year than any previous year by far so climate change is making bushfires worse.”

Do only real scientists work for the CSIRO?

“If you went to the CSIRO website you’d see huge reports on climate change that CSIRO scientists have worked on.”

You can watch Insight's program, The Sceptics, on SBS On Demand.