Okay, first things first, a clear declaration of opinion and perhaps even bias: I believe in global warming. Let me sharpen that for you. I believe that the recorded changes in the world’s climate are due in significant part to humankind’s activities. And let’s be clear, I don’t believe in it the way I believe that one day I am destined to win the lottery, or that the ways of the Great Punta are truly mysterious. No, my current state of belief derives from the overwhelming scientific evidence. You wouldn’t think that to be an overly controversial position, but there are plenty of people who would have less difficulty with my stance on the Great Punta.

A large number of people on this planet prefer to believe that global warming doesn’t exist or, if it does, then it’s nothing to do with us (it wasn’t me, I wasn’t there!) But when an international organization (IPCC) puts out a report pulling together the work of 800 scientists that say otherwise, just how do you maintain that level of denial? Well, people are talented that way (one word: creationism) and can swear blind and even prove to themselves that black is white and vice versa should the alternative involve changing their worldview or behavior.

Let me give you a flavor, the following are all direct quotes from comments in response to internet articles on global warming on sites from Buzzfeed to the BBC:

• “I’ve never been able to take anyone that believes in global warming seriously.”
• “We all know, even the green lobby, that the warming & cooling phases of the Earth’s continuous evolution is primarily related to its orientation to the Sun over thousands of years.”
• “…as for the world’s scientists. What world’s scientists? There is no consensus. That’s one of the BIG lies told in this whole scam.” (in response to the fact that in the 1970s, 44 out of 51 scientific articles concluded that global warming was a reality… hmmm…, is 86.2745% a consensus or not?)
• “Because the normal condition for the British Isles is to be under several metres of solid ice.”

These comments are just the tip of the rapidly-melting iceberg. So, are all these deniers nuts? Is manmade climate change proven? To take those questions in order: yes, and no. It can’t be “proven” because that’s not how science works. Things are only proven after the event (Professor Plum, lead pipe, library) whereas the scientific method is about coming up with the hypothesis that best explains the observed phenomenon. That hypothesis however, is based on evidence; i.e. facts.

The latest and most comprehensive presentation of the facts and hypotheses is the September 2013 report from the UN’s Intergovernmental Panel on Climate Change (IPCC). It describes global warming (in the ground, the air and the oceans) as “unequivocal”. Based on the current situation, it predicts overall warming this century of between 1.5 and 4.5 degrees Celsius. That doesn’t sound like much but it translates to a rise in sea level of between 26cm and 82cm; time to sell that beach hut. The report concludes that based on the available evidence, it is 95% certain that humans are now the “dominant cause” of global warming.

How do you maintain your denial in the face of that? Well, one possibility was quoted by Noam Chomsky in 2011, “for example, the head of one of the new committees on the environment, …explained that global warming can’t be a problem because “God promised Noah that there wouldn’t be another flood.” Oooookaaay… (backs away slowly).

But why should we care? Different opinions, live and let live, right? Well, the problem comes when the climate change nay-sayer gets into public office. When the person ignoring the evidence is the person we’ve entrusted to make decisions based on it on our behalf…

The weather’s getting warmer and wetter. The seas are rising. The ice caps are melting. The scientific evidence suggesting that it’s our fault is pretty solid but plenty of people prefer not to believe it. That’s their prerogative; it’s a free world (mostly). However, the opinionated naysayer in the bar is not the problem; the problem comes when willful ignorance is practiced by public officials.

Here’s a random but scary example. The Australian Prime Minister, Tony Abbott, once described the science of climate change as “absolute crap.” To which we can only wonder, on what does he base his environmental policies if it isn’t science? Over in the States, allegedly most of Congress is made up of climate change deniers cutting funding for green initiatives.

In the UK, the sixth form debating society otherwise known as the House of Commons recently discussed the absence of evidence for manmade climate change (despite there being plenty) and suggested that even if the UK did meet its own greenhouse gas targets, it wouldn’t make much difference on a global scale. That’s an interesting philosophy: I can’t make a big difference, so why bother at all. The ‘highlight’ of the debate was the accusation that the Meteorological Office (a government agency) covered up evidence that runs contrary to global warming in an effort to perpetuate the ‘myth’. (Actually, the Met Office published its findings – which do not run counter to climate change – on its website, which I’m sure we all agree is really a rather cunning hiding place and the last place anyone would look).

But while we’re talking conspiracy, why not consider the fact that this highly public debate took place just before the release of the latest report from the IPCC (Intergovernmental Panel on Climate Change) which, by drawing on the contributions of 800 scientists worldwide, is the most comprehensive examination of the evidence to date. So, just a week before a definitive report concludes that it is 95% likely that climate change since the1950s is manmade, a bunch of UK MPs publicly claim that there is no such thing as global warming, and even if there is it’s an entirely natural phenomenon outside of our control and that any evidence saying otherwise is highly flawed.

What possible motivation could they have for undermining public confidence in scientific facts? Maybe it’s just that any environmental measures will need decades, even generations to have a significant impact and any one incarnation of government is only in the chair for four years? Maybe it’s because green initiatives are unpopular – nobody wants to take the bus, or turn the lights out, or pay higher petrol prices, etc. – and because no politician wants to lose votes? Maybe there are some influential business concerns (such as energy companies) that contribute a lot of party funding for whom a move away from fossil fuels would mean a drop in their obscene profit margins? Bingo? As the 20th century American writer and commentator Upton Sinclair once said, “It is difficult to get a man to understand something, when his salary depends on his not understanding it.”

Now here’s the rub. The world’s energy requirements are only going to escalate but we still insist on depending on fuel resources that we know are limited. Unless we’re all willing to return to a more basic lifestyle (hah!) then we need alternative energy sources: wind, solar, biofuel, clean fusion, and so on. However, in order to get these options out of the hippy communes and the science fiction novels before the gas and oil run out, we need massive investment in research and development. But guess whose profits that would cut into…?

So, the next time you hear someone (politician or otherwise) saying that manmade climate change doesn’t exist, just remember whose pocket that opinion is lining.