It’s Earth Day this Friday, which makes this an apt time to share my thoughts on sustainable travel. Anyone who can read a thermometer can tell you that our climate is warming, and the science is not out on thermometers. Greenhouse gas emissions are the main culprit — this means tailpipes, manufacturing, heating/cooling, agriculture and of course, flying.
A 2007 IPCC report predicts a 149 percent increase in air traffic by 2030, which under all scenarios is going to produce nearly twice as much carbon dioxide by the aviation industry, even with technological innovations. We need to analyze this figure further to see that air travel, despite its increase, only plays a small part of our overall emissions. Comparing numbers, the aviation industry uses 3 percent of fossil fuels worldwide, while the entire transportation sector uses 20-25 percent. Yes, flying causes carbon dioxide emissions. No, not flying will not even nearly solve our greenhouse gas emissions problem.
If we want to talk mitigating climate change, the discussion is much larger than aviation. Air transport is not an inconsequential part of our emissions, but I’m a little tired of the finger pointing at travelers. It also accounts for roughly eight percent of global GDP — so it’s a net winner when compared to other industries in terms of emissions. I remain convinced that the cultural exchange that results from traveling far outweighs the environmental impacts, which we can mitigate.
Aside from the carbon dioxide emissions of air travel, the environmental impact of flying is quite contentious. Recent attention on the impacts of contrails suggests that it is significantly more due to cirrus cloud formation. Contrails of water vapor form when the hot, moist air from engine exhaust cools in the cold air during cruise. Though they last in the atmosphere for a much shorter time than carbon dioxide, a new paper from Nature Climate Change by Burkhardt and Kärcher suggests that the effect of contrails causes much larger net warming than the carbon dioxide emitted by aircraft. This research was published less than a month ago, and although it remains full of uncertainties, there is possibly a more significant climate warming effect from flying than originally thought. Jet engine technology could be innovated so that water condenses out of exhaust or flight paths could avoid areas of high ice saturation. Regardless, buying carbon-offset credits for your flight has never been a better idea.
Nonetheless, air travel is a small part in comparison to the environmental challenges we face for the future. I propose we work along with the travel industry to make it more environmentally sustainable.
It is important to note the innovations that the airline industry has made to date. A 2007 Corporate Responsibility Report from Delta highlights recycling of plastics, cans and other in flight materials, technology improvements allowing for quieter, cleaner, more fuel efficient engines, with a 10 percent increase over the past decade, installation of winglets increasing fuel efficiency by four percent and recycled paper and soy ink is used on printed materials.
The way that the country flies has also changed. Single engine taxi is a common practice, especially after landing. Electric baggage handling vehicles are becoming all the rage. Continuous descent approaches instead of the stair-step descent save on average 60 gallons of fuel per flight. Air traffic controllers are becoming more efficient at routing planes, and we are building LEED-certified terminals, such as the Boston Logan Terminal A and our very own San Francisco Terminal 2.
Yet there is still a ways to go. For starters, the aviation industry is quite literally locked into using kerosene-based fuels for at least the next 30 years due to the slow rate of technological innovation. Recycling is often voluntary for flight attendants, and some airports are not even equipped to sort trash. An A380 is more fuel-efficient than a hybrid car, but that’s only if it’s full. And I doubt you drive 6500 nautical miles in your Prius everyday. The externality of carbon dioxide emissions must be incorporated into the price of travel.
There are several options, one of which is to crawl back into the cave so to speak, by ceasing to travel. We can perpetuate cultural rifts while we falsely convince ourselves of making huge progress combating climate change, or we can think of solutions. Maybe I’ve been blinded by the sunlight at 34,000 feet, but in my opinion the answer is not necessarily travelling less — it is travelling responsibly. It’s a carbon offset in the price of the ticket. It’s lower carbon alternative fuels, subsidies for drastic innovations in aircraft and engine design. It’s collaboration between environmentalists, policy makers and innovative industry professionals.
If all else fails, just take a vacation and know that I’ve got your back.
Johnny wants to hear your innovative ideas for sustainable flying. Email him at [email protected].