Wednesday, September 7, 2011

Is flying worth it, environmentally speaking?

The previous post celebrates bicycling as the most fuel efficient way to travel, and compares mileage on a bicycle to other forms of locomotion.  Missing from that list, however, is travel by airplane. The post before that relates a first-hand view of bicycling in Germany. Preaching bicycling to save fuel, and then waxing poetic about a (plane) trip to Germany?   Sounds hypocritical.   

It is.  But.  Here's my case, in two (maybe three) posts, for air travel. 

First, the bad news.

Jet Mileage:  The numbers depend on the size and make, passenger load, wind direction, cruising altitude, etc., but here's a rough estimate. According to British Airways, a 747-400 plane that cruises at 575 mph with 75%  of the seats full carries one passenger about 52.2 miles for every gallon of fuel burned.  That's better mileage than a Prius, and much better than the average American car.  Of course, you generally travel many, many more miles in a plane.  

The case is worse for, say, delegates who recently used private jets to fly to a climate change conference. A Gulfstream G550 business jet burns about 16 miles per gallon of fuel per passenger if loaded with 16 passengers.  An Eclipse Aviation 500 with 4 passengers:  22 mpg.  Better mileage than many American SUV's.  Not saying much considering the total fuel spent.   

Of course, the problem is not just fuel, but also carbon emissions.  A typical 350 passenger jet burns 45 or 50 gallons of fuel per minute, and a 3500 mile flight requires about 13,000 gallons of fuel, which will produce 191 tons of CO2, over 1,000 pounds per person.  

Then there are jet vapor trails, which cause cloud formations; and jets spew other greenhouse gases into the stratosphere.  The fuel itself produces more CO2 per unit than fuels made for cars.

So, for those who can afford it in this economic climate, but worry about environmental implications, there is a strong case to chill out on the vacations to Europe.  

Why do I feel OK about air travel anyway?   This opens a Pandora's box.  Look for future entries on Educating Ourselves About the World; and How Flying and Bicycling Change Time ...

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