American Airlines CEO Gerard Arpey, speaking at the company's annual meeting in Texas on Wednesday:

"The airline industry as it is constituted today was not built to withstand oil prices at $125 a barrel, and certainly not when record fuel expenses are coupled with a weak U.S. economy."

(Make that $133.17 a barrel, at the close of futures trading Wednesday -- yet another new world record!)

According to the Wall Street Journal, in the first quarter of 2008, American "paid $665 million, or 45 percent, more for fuel than last year, while revenues increased by only 5 percent." The industry as a whole could lose more than $7 billion in 2008.

This is bad news for people accustomed to hopping a flight to see their relatives or attend a business meeting on a moment's whim. American is canceling flights, raising ticket prices, and charging additional fees to passengers who want to check baggage. If oil prices stay high, you can figure that other airlines will do the same.

But could it be good news for the planet?

Airline-related emissions are estimated to contribute about 1.5 to 2 percent of annual global greenhouse gas emissions, and that figure is supposed to rise as air travel is projected to surge forward over the next 20 years. In Europe, a fierce political battle has broken out between the U.S., the global airline industry, and the European Union, because EU leaders want the airline industry to be included under its cap-and-trade emissions system by 2011. As it stands, the growth of air traffic in Europe all by itself could negate any emissions cuts that are achieved via the current Emissions Trading System.

But how can air travel possibly continue to grow as robustly as predicted, if fuel costs continue to rise, and ticket prices jump? As someone who lives on the West Coast but has lots of family back East, I know that the relentless rise in airfares over the past two years has changed my consumer behavior. And while there is no doubt that rising global affluence correlates with a proliferation of frequent flier miles, how can, for example, the U.S. airline industry accommodate all those new passengers, while simultaneously losing $7 billion a year?

The woes of the airline industry seem to offer a good example of how the pressures of peak oil could work at cross purposes to the forces that contribute to global warming. If the price of oil stays high, or skyrockets even higher, either the airlines will figure out how to use less fuel, or people will fly less. One way or another, emissions will fall.