Ski country faces facts on airplane #carbon emissions — The Aspen Times Weekly #ActOnClimate #KeepItInTheGround

San Juan Mountains March 2016. Photo credit: Greg Hobbs

From The Aspen Times Weekly (Allen Best):

In early December a friend from Denver and I both traveled to Las Vegas for a conference. I flew, he drove. We both worry about greenhouse gases accumulating in the atmosphere and the strong evidence now emerging of climate disruption. Which of us should have more carbon guilt?

“Flying shame,” the phrase translated from its native Swedish, has come into vogue in some circles. We zoom around the continent, sometimes across great oceans, because we can, and because it’s wonderful compressing great distances with so little effort, so quickly immersing ourselves in new geographies and cultures, and because, as was the case of my friend and I, we thought our work required it.

Quick and easy movement has a cost, though.

If emissions from airplanes were a country, they would rank somewhere between Japan and Germany. That means about 1.5% of global emissions (carbon dioxide equivalent) as of 2012, according to the World GHG Emissions Flow Chart 2014. Other sources, slicing the greenhouse gas pie differently, put it at 2.4%. Residential buildings (11.2%), cars and trucks (10.6%) or even livestock and manure (6.5%) produce more.

Scientists, however, suspect impacts may actually be double or more than those at ground level because of the chemical interactions of emissions at high altitudes…

A slow boat or train?

Perhaps the Swedes were unnerved by their fires above the Arctic Circle. In 2015, Olympic biathlon gold medalist Bjørn Ferry committed to stop flying. Some Swedish celebrities have followed suit. To avoid flying, the adolescent climate activist Greta Thunberg last summer sailed to the U.S. to call for urgent action. She has a following, as was acknowledged by Time magazine with its Person of the Year designation. It’s fair to assume that some snow riders, with their devotion to environmental action, follow Thunberg.

What’s the least carbon-tainted mode of travel to a mountain resort? Bicycle, obviously, although catching a bus will do you well, too. It’s a bit cumbersome, definitely more time-consuming, but you can take a bus from Chicago, for example, to Glenwood Springs, then catch a RFTA bus to Aspen or Snowmass. The state-sponsored Bustang from Denver to Glenwood Springs has won raves. But again, don’t be in a hurry.

You can take the train to Glenwood Springs, too, but few people ride the rails to go skiing. At Colorado’s Winter Park, for example, rails emerge from a tunnel under the Continental Divide within a few dozen yards of ski slopes. But Amtrak delivers just 10,152 travelers to the nearby depot in Fraser annually. A ski train from Denver adds 20,000 passengers annually for day trips.

We fly because we’re in a hurry. Air travel has become more efficient in jet fuel. By the metric of passenger travel achieved on a gallon of jet fuel, air travel has improved from 34 passenger miles per gallon in 1991 to 56 passenger miles today.

Not all air travel is equal, though. Air Force One, with its executive desk and sleeping quarters, of course, has a higher carbon footprint than somebody flying scrunched between other economy passengers. And first-class commercial travel has three times the carbon footprint of economy.

How far you fly also matters. Shorter flights have a greater carbon intensity per mile than long-haul flights. A quarter of the fuel on a single trip can be burned in getting from the ground to 30,000 feet. That makes short-hop flights, say between Denver and Aspen, the most energy intensive.

This rule only applies so far, though. The fuel for every long-haul flight itself requires energy for transport, because of its weight. WorldWatch Institute estimates that the most fuel-efficient distance for airlines is 2,600 miles, a little longer than the trip from New York to Los Angeles. But those added miles still produce more fuel consumption and hence emissions. Shorter, if less efficient, is still less.

What does this mean in practice?

The carbon-tracker website maintained by the International Civil Aviation Organization allows you to calculate your carbon dioxide emissions. For example, an economy round-trip flight between New York City’s JFK Airport and Denver produces 946 pounds of per passenger. That’s the equivalent of 59 bowling balls. Talk about carry-on baggage. A longer distance, say a roundtrip from London’s Heathrow to Denver, produces a fatter footprint as does flying premium instead of economy: 3,934 pounds. OK, you wanted to know: 246 bowling balls.

What makes environmental sense — and economic sense for ski areas — is that when customers fly, they linger. A study of Rocky Mountain resorts by Colorado-based RRC that was commissioned by the National Ski Areas Association found 40% of out-of-state customers who flew stayed six days or longer. Of international travelers, 80% stayed six days or longer. The difference was particularly evident among those who stayed between 10 and 22 nights at the resorts.

“As would be expected, international visitors tend to have the longest stays, followed by out-of-state visitors (and then) in-state visitors,” RRC’s David Becher says.

Driving, in some situations, could be worse than flying. It depends upon the vehicle and the number of occupants. Driving solo from Chicago to Denver in an SUV, for example, will be more carbon intensive than flying economy. But number of occupants, distance and plushness of the jet make this less than straightforward. The best guide to travel comparisons I found was assembled by the Union of Concerned Scientists. (See chart, below).

For the Las Vegas conference, my friend from Denver rented a medium-sized electric hybrid that gets 40 mpg and drove alone. I flew first to Reno and then Las Vegas. My return to Denver was direct.

Who should have less carbon guilt? My research on the carbon-tracker website suggests I was responsible for 240 pounds of carbon emissions compared with 334 pounds for my friend in his rented hybrid car. Had my friend and I gone together by car, we would have had much lower carbon footprints. But we didn’t know of each other’s plans. It gets complicated.

My friend does buy carbon offsets when traveling, whether by car or by plane. Such offsets have become more common. Air travelers flying into and out of a few mountain resort communities are now participating in an offset program called Good Traveler. Good Traveler was initiated in 2016 by the San Diego International Airport, which chose the Basalt-based Rocky Mountain Institute to manage it. It now has 17 U.S. airports, including major hubs in San Francisco and New York City. The Aspen-Pitkin County Airport joined the Good Traveler program in 2020…


Burning biofuels, instead of fossil fuels, would theoretically reduce emissions. But they have been unable to achieve scale.

In 2018, just 2 million liters of alternative jet fuel were produced, compared with the 360 billion liters of jet fuel consumed that year. Note the “m” and the “b.” Some suspect that lifecycle carbon costs of biofuels make them little better than conventional fossil fuels, too.

Electrification of planes has produced excitement of late. All-electric planes began use in 2019 at a Denver-area airport for training of pilots. In December, a Vancouver company attracted international attention when it conducted a 10-minute demonstration flight of a 17-passenger seaplane retrofitted to operate on batteries. Harbour Air hopes to begin commercial operations within two years, planning an eventual fleet of 40 e-planes for short hops along the Pacific Coast in the Seattle-Vancouver area.

Ampaire has made slower-moving, short-range and smaller aircraft such as are used to shuttle passengers among the Hawaiian Islands its goal. Peter Savagian, the company’s senior vice president of engineering, told an Aspen audience in November that such short-haul flights were responsible for one-third of global air emissions. NASA awarded Ampaire and another company, IKHANA, contracts to pioneer hybrid diesel/electric configurations for the 19-passenger Twin Otter.

Advances in battery storage will be needed for longer distances. The newest batteries hold just 2% the energy of liquid fuel, Wired magazine explained in a 2017 story. In other words, 1,000 pounds of jet fuel yields about 14 times more energy than a 1,000-pound battery.

In his talk at an Aspen Institute symposium titled “The Future of Aviation in a Carbon Constrained World,” Savagian counseled patience.

“It will be decades before the largest aircraft are likely to be fully electrified,” he said. But when that happens, both airlines and consumers will benefit, he added. His company projects savings of 90% from electrified airplanes and maintenance costs cut 50%. Those savings, in turn, will allow airlines to cut fares by 15%, producing 40% more volume.

Speaking at the same event, Aspen-area resident Amory Lovins — a co-founder of the Rocky Mountain Institute — maintained that airplane manufacturers could use carbon-fiber composite materials to make airplanes three to five times more energy efficient.

“Many components made of metal today should not be,” Lovins said. He cited a simple $20 coffee pot. Replaced by a higher-tech model with energy consumption, it saves weight and hence fuel. “You take a pound out of a typical airplane and it’s worth around $2,000 in net-present value in fuel costs.”

Lovins has credentials. In 1976, amid the Arab oil embargos, he wrote a landmark essay published in Foreign Affairs magazine that talked about climate change, renewable energy and energy efficiency. Both businesses and governments responded to his vision sluggishly. Time has mostly proven him correct.

Price signals are needed to spur airlines to more rapid adoption of fuel-saving technology…

Some think we’re in such a climatic pickle that we need to explore high-risk geo-engineering strategies.

For example, can temperature rise of accumulated greenhouse gases be counteracted by reflecting more sunlight away from the Earth’s surface with giant mirrors in space? Another idea calls for spraying aerosols into the stratosphere, which is about 10 kilometers above the Earth’s surface, simulating the effect of volcanic eruptions. A volcano eruption in the Philippines in 1991 cooled global temperature by 0.6 degrees Celsius for about two years.

Direct air capture is another idea, part of a broader set of solutions called negative emissions technology. This idea seeks to withdraw carbon dioxide or other greenhouse pollutants from the atmosphere. This is already being done in British Columbia by a company called Carbon Engineering. The company was founded in 2009 by David Keith, then a professor at the University of Calgary. Keith, with backing from Bill Gates and Murray Edwards, succeeded in removing CO2 from the atmosphere in 2015 and converting it into fuel in 2017 at the prototype between Vancouver and Whistler. Now, with backing from oil producers Chevron, Occidental and BHP, he’s trying to accomplish this at scale.

But Keith, in a 2013 book called “A Case for Climate Engineering,” warned against seeing geo-engineering as the solution to climate change. “Our gadget-obsessed culture is all too easily drawn to a shiny new tech fix,” he said. Best, he said, would be to avoid creating emissions.

Locally, emissions reduction has come up in plans to upgrade the Aspen-Pitkin County Airport. A citizens’ group appointed by the Board of County Commissioners early identified “carbon emission reduction” as a core community value that needs to be applied to the new facility. Varied ideas about what that means have come up as community outreach and the planning process played out over the past year.

Some have suggested the airport itself should be carbon neutral or negative. It has little carbon footprint, however, compared with the planes that use it. A report to the commissioners early last year estimates 81,000 metric tons annually of emissions, a 30% increase between 2014 and 2017. Commercial and private jet traffic makes up more than 94% of those emissions.

In aviation, as in so much else, it’s easier to create problems than solutions. A case in point is Denver International Airport, the fifth-busiest airport in the U.S. and a hub for many connecting flights to Aspen and other ski towns. The airport plans to add 39 new gates to accommodate growing traffic. Nowhere in the stories announcing the expanding airlines was mention of the carbon footprint.

Allen Best writes about energy, water and other topics from a base in metropolitan Denver. More of his work can be found at

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