From A Fresh Squeeze:

Producing 0.55 billion tons of carbon dioxide pollution annually, the aviation industry is responsible for 2% of all global emissions.

That may seem small. But pollution from air travel, including heat-trapping water vapor trails and CO2, can cause twice the damage because emissions are released at such high altitudes.

Green travelers, take heart: Some of the industry's key players are taking steps to help remedy the situation.

To start, they're buying greener planes. The Boeing 787 Dreamliner uses about 20 percent less fuel per passenger compared to common commercial jets. Major airlines including Virgin, Continental and Delta have already placed orders, which are expected to launch into service beginning in November 2008.

To further address the fuel issue, Virgin Atlantic and others are planning tests of alternative jet fuels in their planes. Still, it may be several years before we see biofuel in commercial aircraft.

Some airlines are also working to reduce their impacts on the ground. Continental reports that electric and low-emissions vehicles make up much of its ground fleet, and that it is also testing alternative fuels such as used cooking oil for its ground operations.

And more and more airports are planning for energy efficiency, following the lead of Boston Logan Airport's Terminal A, the first airport terminal in the U.S. to earn LEED certification.

Finally, travel sites like Expedia and Travelocity have partnered with companies and nonprofits to let customers easily purchase carbon offsets online along with their tickets.

Although the airlines are taking major steps to help curb their impact on global warming, there are still many things you can do to help. See our tips for greener air travel here.