A new flight path: How airline passengers can help offset their carbon footprint

As an environmentally-conscious professor at a university that takes pride in its sustainability initiatives, I was curious to find out how much carbon I am personally responsible for emitting. 

From my recent research, I learned that my carbon profile comes to about 46,000 pounds (23 tons) per year. One of the biggest components of this is my air travel, which, in typical years, represents about 10,000 pounds (5 tons) emitted. As a bike commuter, I save 10-15% on my carbon footprint, but air travel far offsets that savings and represents 22% of my carbon footprint. I typically fly about 30,000 miles per year. I co-lead a School of Business trip to South America, usually make a couple of East Coast visits to family, and maybe take a couple of trips somewhere in the Western United States. 

What can I do about it? One option is to minimize my air travel. I care about the environment but have not been willing to eliminate my travels. Another option is to purchase carbon offsets. The idea is to fund projects that capture as much carbon as you emit. Examples are planting trees, funding renewable energy, or replacing burning charcoal with cook stoves. This practice is controversial as many see it as a “cop-out” for solving the real problem. But given our alternatives, I think it is reasonable to fund carbon-capture projects that would not otherwise happen (which is the basis of credible projects to claim “additionality” in the sustainability world). 

I decided to start purchasing carbon offsets for my air travel. Some airlines give you an offset option at check-out. My research revealed that Qantas (an Australian airline) is thought to have the best, most comprehensive program. I looked at Alaska Airlines, which I use to go to the East Coast, but found its current program to be less directly connected to offset projects that I liked. I also found a few good websites that (a) feature specific carbon offset programs that can be directly funded by individuals and (b) were validated by a respected source. Two such sites were green-e.org and goldstandard.org.

I found that there is disagreement and significant variance on the value of carbon, an area that needs to be more standardized and transparent. Visiting several carbon offset travel sites, I found the cost to be $10-30 per ton, so offsetting a round trip to South America (~1.5 tons of carbon per person) would be $15-45. If a plane ticket costs $1,000, this offset fee represents 2-5%. 

Carbon emissions and aircraft efficiency

I learned that the efficiency of aircraft (and, therefore, carbon emissions) varies significantly. Wikipedia has a good page on aircraft efficiency. You’ll see that depending upon the aircraft, the flight distance and how full the airplane is, the equivalent “miles per gallon” for each passenger ranges from 60 to 100. 

Newer aircraft are better. Longer flights are also better because planes burn a lot of fuel taking off. However, very long flights, such as Portland to Santiago, Chile, lose some efficiency; when a plane has to carry so much fuel, it burns more fuel. According to the Wikipedia graph, the optimal distance for aircraft efficiency is approximately 2,500 miles. 

When graduate students travel to South America for the School of Business’ international experience, the planes are usually new (Boeing 787 on my last trip) and reasonably full. So, let’s assume 80 miles per gallon per person. A round trip from Portland to Santiago, Chile is around 12,000 miles. CO2 emissions would equal 3,150 pounds carbon: 

(12,000 miles)/(80 miles/gallon) * (21 pounds carbon/gallon) = 3,150 pounds carbon = 1.58 tons

More countries and airline companies are taking note of aircraft carbon emissions. In 2016, 160 countries signed UN-backed legislation to offset international air travel. Some airlines are intending to offset their emissions by a future date: Delta Airlines announced its intent to offset emissions by 2030. 

None of us can live a truly carbon-neutral life. So, it’s about what we can each choose to do. Maybe someday airplanes will run on biofuel or electricity, but in the meantime, we can educate ourselves about our impacts and consider using offsets to help the planet decarbonize from our air travel.