Up in the air, is it a bird? A plane? A carbon emitter?

One of the most impolite questions you could ever ask at any green tech conference has nothing to do with men's room stalls or anything else sexual in nature. It's "How did you get to this meeting?" Most often the honest answer would involve an airplane trip.

In the U.K. the government has been levying a carbon tax on each air passenger's ticket. Now they're preparing to tax the actual airline flights. Flights that have many empty seats would taxed more heavily. One more temptation for the airline to cancel your flight. There are counter-charges that the government in the U.K. is simply pocketing the cash, not using it for environmental projects.

Meanwhile the aviation industry is not rushing ot embrace a new, green future. Last time anyone accused commercial airlines of being innovators was back when they switched to jet planes. Two airlines are taking cautious experimental steps toward test flights using biofuel. One is Air New Zealand. The other is Richard Branson's Virgin Atlantic. Both test flights are promised for the future. Of course, no American airline has made public any intentions about such rash goings-on.

Meanwhile, Boeing has now postponed the launch of its new 787 Dreamliner. Boeing touts the plane as a shade greener, "the 787 will provide airlines with unmatched fuel efficiency, resulting in exceptional environmental performance. The airplane will use 20 percent less fuel for comparable missions than today's similarly sized airplane."

Now it looks like the 787 will not take to air before next spring. Will give us something else to think about during what promises to be the world's longest-ever U.S. Presidential campaign.

So why care about the airlines? If you're in favor of doing something to lower manmade carbon emissions in the face of global warming warnings, you probably already know how much crud those planes put into our only atmosphere. Each flight. I just checked the load from two round-trip tickets, San Francisco to London. A trip my wife and I have made several times as we have kids and grand-kids living in London. Almost 4,000 kilograms of carbon.

How does that compare to the annual average of carbon footprint per person? Each 1000 kilograms is essentially an American ton...so that's almost four tons for us to make that trip. Recent stats show the average carbon output per person in the U.S. is 20 tons. So that would be a quarter of it shot on one trip. Germans have an annual carbon footprint of 9 tons, and our little visit to London would eat up over 40% of that. A recent conference in Germany pointed to 2 tons per year per person as admirable goal. Well, that means nobody flies or there's serious alterations in the aviation industry. Some green tech genius may have an answer, if so, there's big money waiting.