It’s impossible to market green, because there is no such thing as a green. There are only shades of gray. We all pollute.

So why do companies insist on marketing something that does not and cannot exist? Let’s be clear. I’m not saying that companies shouldn’t do anything about pollution; I’m just saying that they shouldn’t talk about it. It is a no-win proposition.

Green marketing lives a precarious existence that depends completely upon relative comparisons. Since no company can be completely green and have no impact on the environment, success depends on making your company seem more environmentally friendly than your competitors. Does anyone really believe there is marketing gold at the end of a rainbow that depends on convincing consumers that one oil company is somehow tidier than another? Or that a technology company with a 10% more efficient server has a claim to green when those servers are dumped into Chinese landfills, mercury and all, at the end of their life spans just like everyone else’s?

Let’s consider this from an audience perspective. People who think that global warming is an issue have wildly different interpretations of what constitutes green. Indeed, think about what I just said about servers. I bet some of you think that I’m being cynical—that any effort to save energy should be applauded, independently of the bigger picture. Some will argue with my definition of the bigger picture, saying it is too big, or not big enough. My point here is that there will be no agreement, no clear mandate affirming that what you are marketing constitutes green.

People who think that global warming is a crock will simply ignore green marketing. They will continue to pick products and services in the ways they always have.

Green by degrees marketing leaves behind a trail that has a tendency to ferment and smell, and certainly will not stand the test of time. If we really do end up in a climate crisis (and I personally believe we will), the vague, incremental promises we are making today will look disingenuous at best and hypocritical at worst.

Green marketing is also incredibly fragile. Each promise interlocks with all the others and with the company’s overall reputation. When a promise breaks, it puts a crack in the entire foundation.

The cracks are widespread already. Late last year, a market research firm examined 1,018 consumer products with 1,753 environmental claims. Of the 1,018 products examined, all but one made claims that are “demonstrably false or that risk misleading intended audiences.”

There is a big potential for backlash, because green is so misunderstood. Another recent survey found that 39% of Americans consciously try to buy green. But only 22% understood that “green” or “environmentally friendly” is a matter of degree. Some 48% said they thought it meant that the product has a beneficial effect on the environment.

If 45 percent of online consumers are willing to pay a premium of at least 5 percent or more for a product that promotes environmentally-friendly attributes, what happens when they get hip to having spent more for something they thought they were getting but didn’t?

But forget about what your products and services say about green for a moment. Let’s consider what your executives say about it. You’ve probably heard by now that Bob Lutz of GM used the same “crock” terminology that I used in the headline of this post to refer to global warming. After criticism spread around the Internet “like ragweed,” as he put it in a blog post back in February, he responded, “My beliefs are mine and I have a right to them, just as you have a right to yours.”

From a green marketing perspective, it was downhill from there:

“Never mind what I said, or the context in which I said it. My thoughts on what has or hasn’t been the cause of climate change have nothing to do with the decisions I make to advance the cause of General Motors. My opinions on the subject – like anyone’s – are immaterial. Really. The point is not why and how did we get where we are, it’s what are we going to do to get where we’re going.”

Then he goes on to criticize those who criticized him, polarizing the debate:

“And I think that many of the people who’ve been spewing their virtual vitriol in my direction in the past week are guilty of taking the easy way out.

Instead of simply assailing me for expressing what I think, they should be looking at the big picture. What they should be doing, in earnest, is forming opinions not about me but about GM, and what this company is doing that is – and will continue to be – hugely beneficial to the very causes they so enthusiastically claim to support.

General Motors is dedicated to the removal of cars and trucks from the environmental equation, period. And, believe it or don’t: So am I! It’s the right thing to do, for us, for you and, yes, for the planet.”

Lutz then reminds readers that he is personally in charge of development of the Chevy Volt, a concept car. Now, the press generally doesn’t pay much attention to concept cars—every manufacturer offers some at the auto trade shows each year to give the gearheads and auto trade press something to speculate about. But because the Volt is supposed to run off of batteries (that haven’t yet been developed) its green aspirations have made it perhaps the most famous car that hasn’t been built (it should be noted that most concept cars never see the light of the production line).

The Volt may also be the most criticized car that doesn’t exist. GM’s unclear production timeline, an estimated base price that has crept ever upward, and planned production numbers that have steadily decreased over time have all led skeptics to question Lutz’ and GM’s commitment to green.

Expectations for the Volt will no doubt continue to build as 2010 approaches. Yet GM continues to stoke those expectations on a web page that features the Volt (with a green colored frame). It’s instructive that all the content on the page is devoted to parrying criticisms.

A look at the comments to Lutz’ blog post is further evidence of how controversial green marketing is. His post attracted many global warming deniers, who applauded Lutz for standing up to the liberal thought police. (I can’t imagine GM’s green marketing has much of an impact on them.) Meanwhile, the global warming believers charged Lutz and GM with hypocrisy for saying that his personal opinions have no bearing on his product leadership. From there, the comments descended into the typical right-left ad hominems.

Have you stepped in any green goo yet?