He was one of those people.

You know, those people who mumble to themselves as they shuffle down the aisle of your train carriage.

Those people who, when they speak, spray so much spittle that during this drought they should be employed as part time sprinklers at local parks.

Those people who you just bloody well know are going to walk past every other passenger and plop down in that vacant seat next to you.

So of course he did just that. I nodded to be polite. But to those people a nod is a warm invitation to empty their thoughts – and surplus saliva – all over you.

Off he went, prattling on about how this ‘theory’ that humans are playing a significant role in global warming was nonsense. Australia had always been hot and dry. It was all a conspiracy among climate scientists.

Blah. Spit. Blah. Spit.

There was no point arguing. Debating anyone denying the reality of climate change is pointless.

The evidence is overwhelming. Weather events in the past few years are simply underlining what many scientists now fear is a world warming at a rate that even they have probably underestimated.

Like just last week when an international team of polar scientists revealed they’d found Greenland is shedding ice seven times faster than it did 20 years ago, raising fears Arctic warming is already accelerating toward worst-case scenarios.

Blue Mountains resident Nina Lipscombe captured this photo on Sunday. Photo: Nina Lipscombe

No, the only real question left unanswered is why those people continue to deny what an enormous number of experts believe to be true.

Why has climate change become such a rabid ideological issue for otherwise rational people who have embraced every other contribution science has made to their lives?

These are not stupid people. They are aware the earth is round, not flat. They accept Darwin’s theory of evolution. They acknowledge the universe was probably created 13.8 billion years ago in a Big Bang.

These are people who understand that rigorous scientific method has changed the world for good and bad – from vaccines and life-saving surgery to the construction of the atomic bomb.

Science works – and does so time and time again. The meticulous way it sets about gathering facts and forming hypotheses has propelled our species forward at an incredible rate in the past two hundred years.

But when thousands of climate scientists spend decades collecting and analysing data and discover that anthropogenic emissions – pollutants released by human activity – are contributing to global warming, the deniers cover their ears and start chanting “I can’t hear you!”

The most vocal – those right wing commentators without a science degree among them – cling to a hodgepodge of anomalies and out of context statistics.

Click the photos to see the prominent Australians who claim climate science is yet to be confirmed.

In the self-satisfying echo chamber our world has become, these ‘facts’ then reinforce existing prejudices among those already searching for confirmation of their biases.

It’s why you can’t argue with a climate denialist. It’s like debating those who are adamant the moon landings were a hoax. In the end they will dismiss any evidence you put forward by saying it’s either fabricated, or that you are also part of the conspiracy.

But what is it about climate that drives such anger and defiance of accepted wisdom in so many?

It turns out a growing amount of psychological research is being conducted in this field. The findings are revealing that those people are the sort who prefer the status quo.

They feel safe in a world that has a clear hierarchy with consistent patterns and outcomes – and are comfortable with their place in it.

Despite their attempts to pose as courageous heretics bravely exposing the truth to the rest of us brainwashed simpletons, they tend to be conservative – both socially and politically.

Climate change threatens their universe. It’s a catastrophic upending of their safe and predictable environment.

“Denial happens when climate science rubs us up the wrong way,” wrote David Hall, a senior researcher in politics at Auckland University, in a recent article in The Conversation.

“Instead of making us want to arrest the climate crisis, it makes us resist the very thought of it, because the facts of anthropogenic global heating clash with our personal projects.”

It’s why so many denialists love yelling “gotcha!” whenever they stumble across a random statistic they believe disproves scientific theory.

It’s why the fossil fuel companies and their disinformation campaigns find such an attentive audience.

It’s why so many denialists triumphantly celebrated Donald Trump’s hectoring of teenage activist Greta Thunberg last week, despite the sheer creepiness of a 74-year-old man obsessing over a 16-year-old girl with Asperger’s.

Greta Thunberg at the COP25 Climate Conference in Madrid last Wednesday. Photo: Getty

But here’s the most disturbing thing. Denialists – led by powerful politicians and business leaders – have won the day.

By clouding the debate – by badgering and bullying credible scientists and those who respect them – they have prevented any meaningful action on slowing the rate of global warming.

If it wasn’t so serious you could smile at the irony.

Those people who hate change more than anything else, those people who deal with the horrifying prospect of global warming by pretending it doesn’t exist, have successfully prevented efforts to stop one of the greatest disruptions confronting humanity.

Those people. They’ve certainly earned their place in the hell to come.