After 30 years of the so-called climate “debate”, the climate denial movement has split and evolved into a number of specific strands. While most countries in the developed world have moved on, Australia has proved a fertile ground for deniers of all stripes.

In 2014 I wrote a play entitled Kill Climate Deniers. I’d already had some run-ins with skeptics, but after Andrew Bolt and Breitbart heard about the project and took aim at me (and its deliberately hyperbolic name), I started hearing from deniers across the whole spectrum.

So to help you distinguish your Ian Plimers from your David Archibalds, this spotter’s guide provides a quick run-down of the different species of denier.

1. The Shill

The first (and most predictable) category of deniers are the simple apologists for the mining or fossil fuel industry. Some are professional industry flacks, some are simply careful to keep the industry on-side. Many politicians belong in this category.

These deniers may understand the science, they may be aware that they’re completely in the wrong, but they’ll willingly lie through their teeth in order to maintain the status quo.

Their main tactic of this group is distraction — talk about anything but the science. “Baseload”, “energy security”, “struggling farmers” — anything except the elephant in the room.

Example: Malcolm Turnbull

2. The Opportunist

There’s always a platform for commentators critiquing efforts to address climate change, especially if they portray an air of calm “rationality”. The committed chancer can find an eager audience by insisting that they are “striking a middle ground” or “seeking balance”.

Exemplified by the likes of Bjørn Lomborg and Bret Stephens, these skeptics are flexible in their use of science. They’ll always acknowledge some degree of scientific reality, but it will, conveniently, never be enough to justify action.

Example: Our very own Andrew Bolt

3. The Heretic

By far the most interesting deniers are the qualified scientists who have chosen to oppose the scientific consensus on climate change.

Long before it reached the general public’s consciousness, climate change was hotly debated among atmospheric scientists. In the early 1980s, it was perfectly reasonable to be skeptical of global warming. Early climate models were clumsy and imprecise, and the evidence for rising CO2 levels was scarce.

As evidence mounted and the models were rigorously tested and improved, a scientific consensus emerged. Most climate scientists came to agree that climate change was happening, and the debate shifted to questions of, “How much warming?” and “What will the effects be?”

Rather than changing their minds, a few of these early doubters instead dug their heels in and doubled-down on their skepticism. They began to receive an eager audience from right-wing outlets as authorative “insiders”.

Playing to that audience, the useful critiques of atmospheric scientists like Richard Lindzen have long since given way to dogma and grandstanding.

Examples: University of Alabama in Huntsville scientists Roy Spencer and John Christy, and Australia’s Bill Kininmonth.

4. The True Believer

Though opposition to climate action is funded by fossil fuel companies and coordinated by thinktanks and lobbyists, it’s not a completely astroturfed movement. Climate denial has struck a strong chord in certain groups, who have tirelessly dedicated themselves to combating the “Anarcho-Green Con”.

These “true believers” have a very specific understanding of what is meant by climate change. They see it as a confected excuse for a massive program of state regulation. Climate scientists, in their view, are the leading edge of a new socialist movement intended to restructure society under a Communist One World Government.

As a commentator on Breitbart astutely put it, “Manmade Globull Warming is a HOAX… a wealth redistribution scheme ginned up by radical extreme leftists who hate free markets and democracy.”

In this community, climate activists are referred to as “watermelons”: green on the outside, red on the inside.

True believers can be found in the comment threads on Andrew Bolt’s blog, on denier forums like Watts Up With That (and its Australian counterpart, Jo Nova), and on countless WordPress or Blogspot blogs packed with lo-res jpgs of hand-drawn graphs.

There’s a healthy dose of conspiracy thinking in these circles (apparently it’s no coincidence that Earth Day happens to fall on Lenin’s birthday), but in some ways, they’re completely right. Addressing climate change will demand massive social change, to a degree that many of us haven’t really comprehended.

These deniers understand the consequences if the science is true — so they can’t allow the science to be true. In some ways, they grasp what’s at stake in this debate more clearly than the rest of us.

Example: Malcolm Roberts

*David Finnigan is a playwright, science-artist and author of Kill Climate Deniers, on at the Griffin Theatre in Sydney.