Aviation and the environment

I’ve been in Geneva this week for a conference on aviation and the environment; more specifically, on what the air transport industry (aircraft and engine manufacturers, aviation fuel suppliers, air traffic control agencies, airport operators, and of course airlines) are doing about the impact of aircraft emissions on global warming and climate change.

It’s a big topic, and an important one.

I’ve been saying for years that when the oil runs out, the era of long-distance air travel will end. But I used to think that wouldn’t be until a generation or so in the future, at least for middle-aged people like me. Now, global warming may force us to confront the consequences of an end to air travel as we know it even sooner than will oil depletion.

What will this mean to our lives and our way of travel? And is there anything we can do to preserve the possibility of world travel for future generations, or to extend it to the vast majority of the world’s population who have never been able to afford to fly?

In 1995, long before this issue was being widely discussed, I wrote as follows in an essay in the Moon Handbooks newsletter, later incorporated into the first edition of “The Practical Nomad: How to Travel Around the World” in 1997:

All travel, and especially long-haul air travel, has adverse ecological consequences. Unlike trains, which if electrified can get power from a variety of renewable sources, airplanes all fly on fossil fuel (“jet fuel” is kerosene). The present window of opportunity for transoceanic air travel affordable to large numbers of people is likely to be, in historical terms, a brief one before the world runs out of oil. There is not, nor will there ever be, sustainable or “low-impact” air travel.

More of the effects of travel on the physical environment are related to transportation, such as petroleum extraction, refining, distribution, and burning, or the cutting of trees and paving of land for roads, than anything about what you do when you get where you are going. It makes no sense to label a trip as “ecotourism” if it involves flying 20,000 km (12,500 miles) — from North America to Asia and back—for only a few weeks. I’ve gone that far for that short a time, but I won’t pretend that it was ecologically responsible….

Given that getting there by air is an unavoidable ecological cost of long-distance travel, ecological responsibility in travel means both minimizing the avoidable environmental costs and trying to make a positive contribution in some other way to offset them. That’s what ecotourism is supposed to be about.

Airplanes can be made more efficient, but all predictions are that without drastic change, the increase in total emissions as a result of continued growth in air travel (and air freight transport) will far exceed any possible reduction in emissions as a result of gains in efficiency. For the foreseeable future, there is no alternative to liquid fuel with the energy density to be usable for aircraft propulsion. The only possible way out would be a renewable liquid fuel.

There was a surprising degree of consensus among both industry representatives and technical experts at the Aviation and Environment Summit that (1) the only hope for sustainable aviation lies in biofuels, and (2) “first generation” biofuels such as ethanol and biodiesel, which are produced from plants that compete for land use with food crops, must be ruled out. Burning food or potential food is not a legitimate way for us to keep flying, or to enable more people to fly.

There was equally strong consensus, and greater confidence — based on several successful flight tests in passenger aircraft within the last year, and on current refinery technology that can produce liquid fuels with the necessary properties from almost any organic raw material — that if enough feedstock (biomass) for biofuels can be found, current aircraft engines can be operated, unmodified, on “drop-in” replacement biofuels.

The air transport industry hopes that “second-generation biofuels” produced from feedstock that doesn’t compete with food crops (e.g. algae harvested from the oceans, or crops grown without irrigation on land on which no food or fodder can be grown) might become commercially viable, and no more costly than increasingly-expensive fossil fuel. That’s still unproven. The most that can be said is that some such crops seem technically “promising”. And that begs the question, of course, of how much people would actually be willing to pay to travel on airplanes powered by burning plant matter rather than petroleum or fuel produced from coal or natural gas.

But at the press conference concluding the summit, Dan Elwell, V.P. of the Civil Aviation Aerospace Industries Association told me flatly that, “There is no Plan B” for sustainable aviation if biofuels don’t turn out to be a viable alternative capable of being produced cheaply enough, in sufficient quantities, without requiring too much land, water, or human labor, and without having adverse effects (such as on land and/or water ecology) that offset any benefit in reduced contribution to global warming. None of the heads of other industry associations on the stage — representing airlines, airport operators, and the industry-wide Air Transport Action Group on the environment and climate change — disputed Elwell’s statement.

At the same time, none of the members of the panel of CEO’s earlier in the day were willing to say, when I asked them directly, what level of air travel might be environmentally sustainable. “Let’s be clear, the solution to this problem is not to stop flying or reduce your flying”, said Willie Walsh of British Airways. “I think everyone in this room agrees that’s not the answer.”

Samer Majali, Chairman of the Board of Governors of the airline association IATA as well as CEO of Royal Jordanian Airlines, went even further in his answer to my question, declaring flatly that, “I don’t believe there should be any limits on growth” of air travel.

For many years, I’ve devoted myself to encouraging people to travel more, especially to the most different places from which, I still think, we have the most to learn. Many of those, of course, are places we currently have no way to get to except by air. Am I wrong to encourage types of travel that require air travel, or to choose to fly myself?

I flew 5,000 miles from San Francisco to Geneva and back, at my own expense, as part of the process of trying to find a way out of my own internal ambivalence:

I’m not a climate change denier, and I believe that there are practical and ethical limits to growth. I think people should avoid flying where there are other less environmentally harmful alternatives. (“Less harmful” is a more honest characterization of any powered transport than “eco-friendly”.) Much air travel is wasteful, even perhaps ethically “wrong”.

But I haven’t stopped flying. I continue to believe that long-haul travel, even by air, can in particular cases have a net positive effect on the world, mainly through the secondary effects of the permanent changes it can bring about in our worldview, which result in changes in how we go on with our lives.

Does this make me a moderate on this issue, or merely a hypocrite? Am I alone in asking these questions, or in making a serious effort to find the answers?

It’s unclear to me if each mile I fly contributes more to global warming than each mile I travel in a car, but I rarely drive the sorts of distances that I cover on intercontinental flights. There are potential alternatives to fossil fuel for surface transportation and many other current uses of energy, most obviously through electrification and production of electricity from renewal sources, and through replacement of fossil-fuel heating and cooling with passive solar building designs. But current means of storing electricity, such as batteries, are too heavy to use for aircraft propulsion. As carbon dioxide emissions from other sources are reduced, aviation will constitute a larger and larger share of greenhouse gas emissions.

Air traffic is projected to grow rapidly for the next several decades. This is not because of increases in per-capita air travel in the First World, but because of the growing numbers of people in the rest of the world who are just beginning to be able to afford to fly. Today, most of the air miles are flown by a relatively tiny percentage of people, predominantly from the world’s wealthier countries. Equal access to air travel for all people worldwide, or even for a significant minority of people in “developing” countries, would mean vastly more total air travel — even if we in the First World drastically reduce our per-capita flying. This makes it likely that aviation’s contribution to global warming and oil depletion will rise quickly, both in absolute terms and even more as a proportion of total emissions.

Since returning from my most recent trip around the world, I’ve become increasingly caught up in these thoughts, and the research to which they have led. But I haven’t found anything that really explores both the technological prospects and possibilities, and what this means or will mean for travellers and the future of travel, in our generation and those to come.

Will a sustainable future include long-haul travel at all? If so, what will that future look like and how do we get there? (Trains? Trolleybuses? Passenger ships? Changes in patterns of living from sprawl to clustering, to living closer to our work, and to using more locally-produced goods?) If not, what do we do? In particular, what can we do now to make it more likely that such an alternative transportation, land use, and housing and employment infrastructure is developed and put in place before oil depletion and/or global warming eliminate current options such as air travel and air freight?

I’m beginning to think that this may be the topic of my next book, but I’m not sure enough people would want to buy it: Do travellers want to think about being forced, much less about choosing, to change our travel lifestyle? Where might this issue be by the time I could research and write a book and get it into print, most likely a couple of years from now? And, of course, would any publisher pay me enough of an advance to afford the necessary research and writing time?

I’m also working with Ethical Traveler to try to organize a public forum on these questions in the San Francisco Bay Area later this year.

Please let me know what you think, in comments on this blog entry or by e-mail.

[Follow-up: Peak Travel: Envisioning a post-air-travel age (9 October 2014)]

[Follow-up: Air travel, global warming, and the COVID-19 pandemic (26 JUune 2021)]