A new study of greenhouse gas emissions at the Aspen/Pitkin County Airport arrived at a much lower number than a 2005 city of Aspen study did, primarily because it had a narrower focus.
The new study, recently presented to the Pitkin County commissioners, concluded that air travel associated with the Aspen airport produced 56,421 metric tons of carbon dioxide in 2006. That’s about one-sixth of the 344,487 tons of CO2 emitted by commercial and general aviation flights the city’s Canary Initiative attributed to the airport. The city’s calculation amounts to 44 percent of the total emissions being produced in Aspen.
The biggest differences between the two studies was that the Canary Initiative study included the CO2 produced by a visitor or resident’s entire flight to and from Aspen. For example, if an Aspen visitor came from Miami via Denver, the jet fuel burned between Miami and Denver and then Denver and Aspen was all included in the estimate.
The number also included travelers’ landing or taking off at the Eagle County airport on their way to and from Aspen.
“Most municipal inventories include emissions from industries and businesses within their boundary,” stated the Canary Initiative’s study. “Aspen’s main economic engines are tourism and second-home ownership, and both involve a great deal of travel — and thus fuel use and carbon emissions.”
But in the airport’s study, the primary measurement was the amount of jet fuel dispensed at the Aspen airport.
In 2006, a total of 5,124,148 gallons of jet fuel and aviation gas were poured into planes at the Aspen airport. When burned, that fuel produced 48,981 metric tons of carbon dioxide.
The airport study measured emissions only from the time a plane arrived in Aspen’s air space until the time it entered another airport’s airspace.
It also analyzed the specific “landing and takeoff cycle” — from the time a plane is 3,000 feet above the runway through the taxi process to the gate, and then from takeoff through the “climbout” phase.
This portion of the study is seen as valuable because it will allow the airport to tackle emissions in one area it firmly controls: The taxi in and out process.
The new study by the county airport acknowledged the city’s earlier methodology of counting fuel during the entire length of a round-trip flight by noting that “the net effect of that approach was that the emissions associated with the larger assumed travel distance produced emissions substantially greater than the emissions associated with the fuel dispensed from the Airport.”
Measuring greenhouse gas emissions at airports is still a developing science, but the amount of fuel dispensed at any one airport is an emerging standard.
That approach, if embraced, will minimize double-counting by airports, according to Mary Vigilante, president and owner of Synergy Consultants, Inc., a Seattle firm specializing in aviation environmental planning that worked on the airport study.
The airport’s study also calculated the carbon dioxide produced by airport ground support equipment, cars and trucks traveling to and from the airport, and in airport buildings and facilities.
Jim Elwood, the county’s airport director, and Kim Peterson, the city’s Canary Initiative project manager, agree that both studies are valid and that both provide a solid baseline to work against.
“We realize there is a discrepancy between the two, and we’ve agreed we are counting different things,” Peterson said. “We’re going to continue with our methodology when we do the next update.”
Elwood said it is important for the airport to establish its own baseline, especially so it can work on reducing emissions in areas it can control at the airport. “I think both of our goals is to bring those emission numbers down,” Elwood said, adding that the next step is to develop a specific action plan to reduce the airport’s greenhouse gas emissions.
bgs@aspendailynews.com
