Visit the Advertising Association website, search on the phrase "global warming", and it won't even know what you are talking about. It'll ask you whether you really meant "global waddington?" and tell you that your search has no matches. Search on the phrases "carbon footprint" and "carbon emissions" and you get similar results.
When it comes to global warming, it's hard to avoid the feeling that the advertising industry is behaving like someone who has just farted in a crowded lift. It is maintaining an embarrassed silence in the hope it won't be identified as the source of the stink.
It's strange, because when dealing with other topics that threaten its interests, such as advertising to children, plus alcohol and tobacco advertising, the industry has been articulate and voluble. Yet it has been conspicuously silent on the far bigger, more profound question of its role in promoting acquisitiveness and consumption at a time when the human race has to consume less, not more.
It has fallen to the unlikely figure of Sir Martin Sorrell to seriously question - for the first time - in a series of quite extraordinary but little-reported speeches and seminars this year, whether current attitudes to consumption can continue.
"All our instincts as clients, agencies and media owners are to encourage people to consume more - super consumption," he told one conference. He added that people have become used to "the aspiration that you should consume more; the aspiration that you should have a bigger car; the aspiration that you should have a number of holidays, bigger houses and multiple houses. Our view, counter to what you expect our industry to argue, is that conspicuous consumption is not productive, and should be discouraged."
Discourage conspicuous consumption? Remember, that's not some apocalyptic green nutter or an attention-seeking politician talking. It's the chief executive of the world's second-largest marketing services company. And it sounds suspiciously like he has been quietly announcing what amounts to the death of the consumer society as we know it.
As if that wasn't enough, he then went on to voice the hitherto unspoken truth that turning out the lights and recycling paper - minor changes in consumer and business behaviour - will not solve the problem.
In fact, he seems to argue that the way most companies report their environmental efforts are little short of fraudulent. "It is increasingly common for companies to have targets to reduce their carbon footprint - but look closely, almost all of these are ex-growth," he told a room full of Harvard Business School alumni.
"In other words, they will reduce their impact per unit sales, or on the basis of like-for-like operations. Businesses that feel they know how to de-couple growth from increased climate impact are few indeed. Absolute targets are rare."
Sorrell has not only called into question the idea of unrestrained consumption, he has also questioned another fundamental tenet of our society - unconstrained growth. Admittedly, he is not actually confessing to having broken wind in the lift. But he is pointing to the person standing next to him, his client.
This is hardly surprising. After all, the advertising industry has always argued that it is merely a messenger. Despite being a powerful marketing tool, really its effects are puny, with no impact at all on aggregate demand. "There's little, if any, evidence that advertising increases category size. It doesn't create demand, it channels demand from one brand to another. If that's right, advertising has no influence on total consumption," Tim Broadbent, the chief planning officer for Ogilvy & Mather Asia, says.
This may be the prevailing orthodoxy, but it is a view increasingly being challenged by senior advertisers and agency thinkers. "I don't buy the argument that advertising doesn't increase aggregate demand. It's not the only factor, but it does fuel the capitalist sytem," Tim Sefton, the customer director at O2, explains.
It is true that most agencies have made some moves towards "greening" their operations. Euro RSCG, for instance, has embarked on a carbon emissions reduction programme. MindShare is looking into reducing international flights by using more video conferencing. Bartle Bogle Hegarty is developing a way of measuring the carbon footprint of advertising production. Others are talking about sustainable procurement.
But Sorrell's remarks raise two questions of enormous significance to the advertising industry. Is our consumer society really finished? And, if so, what role will there be for the advertising and marketing industry in a world where more consumption is not quite so voguish?
When it comes to the question of the consumer society, Sorrell's view is supported by an all-star cast of planners, predictors, prognosticators - and even the Conservative Party. For a variety of reasons, not simply the environment, they say we are entering a period of such profound change that to all intents and purposes, old-style consumerism is dead - or at least dying.
Futurologist Faith Popcorn, for instance, talks of a significant consumer trend she calls "Lagom", which apparently means "just enough" in Swedish. "It's an approach to design and consumption that explains the essence of brands such as Ikea and Volvo. We see notions of 'minimalism' and 'sustainability' taking on significant currency, as even Americans reject hyper-consumption as not just excessive, but actually damaging to themselves, others and to the planet," she explains.
Over at the WPP-owned marketing consultancy Added Value, talk is of a "consumer tipping point" that will profoundly alter our attitudes to consumption. "It's already happening on the fringes. People are sated with consumption," Cate Hunt, the cultural insight director, says.
She points to phenomena as diverse as the way organic produce has gone mainstream, the rise of vintage and recycled clothing, the growth of urban vegetable growing and the demonisation of 4x4 cars as early evidence of a trend that is still largely restricted to the Western middle classes, but will become far more widespread.
Trendspotter Marian Salzman, the marketing director of the US PR agency Porter Novelli, has also noticed a less materialistic bent in society. "The push away from mega-consumption is the mega-trend of the moment. There are no bragging rights in acquisition anymore. We are moving towards a zero-acquisition society."
All these strands are pulled together in an open source book, a "wiki", called "Citizen Renaissance", published as a draft online recently by Jules Peck, a director of the Conservative Party Quality of Life Policy Group, and Robert Phillips, the chief executive of the PR agency Edelman UK (www.citizenrenaissance.com).
It deals with the issues of social change, attitudes to consumerism and the role of business, especially the marketing services industry, in what they say must be a new world order.
If it were only an altruistic concern for the environment at work, the move away from what they call "relative consumerism" or "keeping up with the Joneses" might not be quite so profound, they argue. But it is the result of what Peck and Phillips call "a perfect storm" that makes a period of rapid and radical social change inevitable.
Three seismic shocks are combining to completely reshape our world, they say. "First, climate change has profoundly affected all of our lives. We have awoken to the fact that we are over-consuming the resources of our planet and threatening ourselves in the process." "Second, we are entering a 'wellbeing age', matched by a more selfless and non-relative-materialist and non-growth-obsessed ecological economics. Individualism is out, individuation and community is in. Finally, the digital revolution means we are undergoing a metamorphosis towards a new age of democracy and resurgent citizenship that could threaten the nature of corporate consumer capitalism itself."
All this needs to be distinguished from the current cyclical problems of the world economy, they argue. "The financial crisis and commodity price inflation are sharpening the current feeling that Doomsday is imminent although they are not in themselves the cause of change," Peck says.
But combine all these factors and they say: "A reordering of the current model of mass marketing and consumption is inevitable." Tune in to this or risk all, they warn.
The marketing consultant John Grant, the former planning director of St Luke's and author of The Green Marketing Manifesto, suggests that two more forces will come into play to make consumer change a certainty: government and price.
"In the near future, there will be all sorts of legislation that will directly affect consumption. For instance, a rule that all cars have to meet very stringent fuel efficiency standards will mean that sports cars disappear, almost overnight. Similarly, if the price of raw materials such as cotton reflects their environmental impact, the idea that you can wear a shirt once and throw it away becomes untenable."
Where this leaves marketing, communications and advertising, in particular, depends partly on exactly how consumers react to these forces. If they go into shock and just stop consuming, a serious, long-term recession is likely.
But there will almost certainly be curbs on "irresponsible marketing". "The fact that Sorrell has spoken out means that the torpedo is just yards from the boat. There is more peril to WPP from a total ban on junk mail than anything else," Grant warns.
The real issue, though, is not consumption, he says. It's energy consumption. Although counter- intuitive, it may just be that brands, being purely intellectual constructs with low-carbon footprints, fit in perfectly with this ethos of energy austerity. The ability to conjure value out of nothing could be ideal in this green new world.
Perhaps. But not only will consumers shift their spending to more low-energy goods (local foods, training, education and courses are just some examples), new forms of consumption will probably arise. "We are looking at a complete redesign of modern life," Grant says. So the trend for "fractional ownership, where products are pooled and shared, will explode. Another consumer strategy will be 'treasuring', whereby people buy high-quality artefacts and look after them and repair them when they wear out rather than throwing them away," he adds.
His best guess is that some time in the next five to ten years we will move into a long period of austerity in which the factors already mentioned conspire to make conspicuous consumption not only unfashionable but almost impossible. "Culture is moving into a time of restraint and simplicity. It will mean the advertising industry - including media and marketing - just cannot exist in its current form."
These trends won't affect all advertising: "After all, the average message is 'bread 75p', that won't be hit so hard. It's the high products - fashion products, disposable products and products with momentary lifecycles and inbuilt obsolescence - that will be affected."
Salzman has a similar take. "Advertising will not be able to continue as an industry dedicated to inventing desire," she says. In the new era of austerity, "people will redefine their relationship with brands. They will want to hear about genuine innovation, not froth. Advertising will be much more about product."
But advertising is full of optimists and many see the move to a greener society as a great opportunity. "A key role for marketing is to help people make choices between competing goods, rather than encourage them to consume more per se," Russ Lidstone, the chief strategy officer at Euro RSCG London, says.
In truth, no-one really knows how events will unfold. What is certain is that advertising, like everything else in the world, is going to have to adjust radically and soon. As Sorrell might have said, it needs to cease being part of the problem and rapidly become part of the solution or it will surely find itself marginalised by a combination of government dictat and consumer distaste.