Who came up with the term "clean coal"? It is the most toxic phrase in the greenwash lexicon. George W Bush, by promising to pump hundreds of millions of dollars into the pursuit of advanced "clean" coal technologies, certainly popularised it. But I'd love to know where it came from. Any thoughts out there?

It is, of course, oxymoronic. Coal is about acid rain and peasouper smogs, asthma and mercury contamination, radioactive waste emissions and ripping apart mountains, killing trees, lung cancer and, of course, global warming.

Coal emits more carbon dioxide for every unit of energy generated than any other fuel. Sure you can clean it up a bit – though the toxins you've taken out of the ground have to go somewhere. But clean coal? Just say no.

But the phrase rolls on. Google offers more than a million web pages. We will hear a lot more of it as the UK government wrestles with whether to approve a new billion-pound "cleaner coal" power station – Britain's first coal plant for three decades – at Kingsnorth in Kent.

E.ON, the company that wants to build the station, says Kingsnorth will be "ready" to capture carbon dioxide emissions before they go up the stack. Great, except there is no such technology right now.

This phrase "clean coal" has developed a life of its own thanks to remorseless commercial propagandising. This year a coalition of US coal mining companies and electricity utilities called Americans for Balanced Energy Choices (and recently renamed the American Coalition for Clean Coal Electricity) is paying the advertising agency R&R Partners $35m (£22m) to promote "clean coal" through advertising and other promotional activity.

This is up there with the safe cigarette and "atoms for peace". The industry is fighting back against growing scientific calls to outlaw coal burning, and the rejection of dozens of coal power plants proposals by communities across the US, with several states effectively banning them.

You may have noticed the campaign's effect. Both John McCain and Barack Obama support clean coal. It's neat. Who could be against clean coal? It allows them to oppose dirty coal without antagonising anyone. You may not have spotted that Americans for Balanced Energy Choices sponsored two early presidential debates, during which – guess what – no questions were asked about global warming.

And here in Britain you can see the impact of the new mantra. In Putney, in southwest London, there is a branch of the International Energy Agency that used to be called the Coal Research Centre. It's changed its name – to the Clean Coal Centre. Thanks to its "industrial sponsors" it is able to "provide unbiased information on the sustainable use of coal worldwide." Right. Like the fact there isn't any?

Is clean coal possible in future? Well, if you mean could we capture carbon dioxide emissions and bury them somewhere out of harm's way – in old coal seams or oilfields or salt mines – yes, it is possible. The former British chief scientist Sir David King called it "the only hope for mankind".

But the most authoritative study, The Future of Coal, published last year by the Massachusetts Institute of Technology (MIT), concluded that the first commercial carbon capture and storage (CCS) plant wouldn't come on stream until 2030 at the earliest.

Last year too, the Edison Electric Institute, which represents most US power generators, admitted to a House Select Committee in Washington DC that commercial deployment will require 25 years research costing at least $20bn.

And that was before the US administration last December canned the biggest R&D project on the technology anywhere in the world. It said it was too costly and hinted that, for all their green talk, industry wasn't prepared to back it.

Oh, and if the technology did one day work – and could demonstrate that it could keep liquefied carbon dioxide buried for the thousands of years necessary – it would take decades to build the vast infrastructure needed to deploy on a large scale. Infrastructure that could only be paid for by maintaining a vast dirty coal-burning industry for the duration.

But politicians can be very ill-read if it suits them. The mythology of clean coal has penetrated deep into their thinking round the world because it is so convenient. In Australia, the new green-minded prime minister Kevin Rudd is super-keen on "clean coal" because he imagines it allows him to promise both to meet Australia's Kyoto protocol pledges and to assuage the concerns of industry.

Coal provides most of Australia's electricity and is it most valuable export. But you can't meet current emissions targets with a technology 20 years over the horizon.

Similarly German chancellor Angela Merkel, though a chemist by training, has fallen for the hope that she can both build dozens of new coal-fired power stations and meet her promise to cut German CO2 emissions by 40% by 2020. It won't happen.

The British government is as deep into clean-coal cuckoo land as any of them. John Hutton, until recently business secretary, claimed that a third of British electricity could be generated using CCS by 2030 – clearly pie in the sky. He should fire the adviser who wrote that for him. The mirage of clean coal is designed to coax the world into maintaining its addiction to the most dangerous (and profuse) fossil fuel of all. My bet is that if Kingsnorth is approved, it will never deliver so much as a tonne of carbon dioxide to anywhere other than the atmosphere.

• How many more green scams, cons and generous slices of wishful thinking are out there? Please send your examples of greenwash to greenwash@theguardian.com or add your comments below