How green is green?

The glut of 'green' marketing is deeply deceptive. To label a product 'green', it appears to not be a case of making a green product, but rather making your currently massively 'un-green' product only slightly less damaging. Hence we have adverts for cars with leaves coming out of the exhaust pipes because they've ever so slightly improved the fuel consumption and slightly lowered the emissions. Lets conveniently skirt the fact that combustion engine driven cars are one of the primary causes of environmental damage, any which way you spin it. Bicycle anyone?

Boeing appear to be leaning on this with their new 787 (taken from the guardian)...

I don't think a jet with 20% less fuel consumption can be labeled 'green'. Certainly it's an improvement, but 80% of 'very polluting' is still seriously polluting.

The problem is that we have no yardstick for 'how green is green'. Am I justified in marketing my new product as 'green' if it now bio-degrades in 200 years instead of 400 and uses 5% less fossil fuels in its production? And if I am, then where is the incentive to make truly green products, since we are able to convince consumers that we are green without really having to be. And lets not be naive: companies are being driven to be greener not out of the goodness of their hearts, but because it's become a baseline requirement for marketing. Meaning it is enough to be perceived to be green, actually being so is a luxury.

I guess I just balk at seeing products like cars and jets being marketed as green. It's like marketing guns as safe and processed food as healthy.