Friday, 3 April 2009

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)]

Link | Posted by Edward on Friday, 3 April 2009, 07:41 ( 7:41 AM)

What about liquid hydrogen?

Clean, absurdly plentiful, etc. Of course, it is a cryofuel, its energy density is not as good as avgas, and it is expensive to produce. Cheap power and punative taxes on carbon fuels would make it a lot more viable. You would probably only see it on ultra-long-range suborbital craft.

Posted by: bbot, 3 April 2009, 18:21 ( 6:21 PM)

No one at the industry summit I attended considered liquid hydrogen to be a likely aviation fuel. There are secondary potential issues of safety, time and expense of conversion to a hydrogen fuel infrastructure, and conversion or production of new aircraft, but the most fundamental issue is that the energy density (amount of energy per weight of fuel) as mentioned, is low, and even lower if you include the weight of the equipment needed to maintain it at the requisite ultra-low temperature. It is conceivable to me that hydrogen could be used, in a long-term future, to power a small number of extremely expensive aircraft. But that's not a focus of current aviation industry research or development, and would be decades away at best. I think the answer I was given that there is no Plan B to biofuels is, at least for now, true.

Posted by: Edward Hasbrouck, 3 April 2009, 20:45 ( 8:45 PM)

You're not a hypocrite. Your life and business is based around travel so for you not to fly would be ridiculous.

I'm not sure what the problem is in using bio-fuels for planes if we use the right now for cars and trucks. The planes are going to flown regardless. Let's try to use the fuel that will be the least damaging to the environment if we can.

Posted by: brian, 4 April 2009, 05:10 ( 5:10 AM)

We had long haul travel long before airplanes. People crossed the Atlantic in ships, went from Europe to China on horseback, etc. We'll have long-haul travel even if it turns out airplanes are not feasible for most travel. I think that fast boats and dirigibles are the most likely forms. Perhaps we'll even get a benefit--the trip will take longer, be more rare, and thus it will be expected that a business traveller will take time to see the place they're visiting.

Posted by: Adam, 4 April 2009, 08:43 ( 8:43 AM)

Maybe a such a book would make good airport reading. You should encourage all public transportation, especially air travel doesn't cut up the environment with more roadways and service buildings. But reality is that executive decision makers always loose creativity and initiative for system improvement - perhaps because of the need to meet all the restrictive regulatory guidelines . I found the following item validating the trend in overdeveloped countries.

By JOSHUA FREED, AP Airlines Writer -- Sun Apr 5, 12:01 am ET MARANA, Ariz. -- Old jets come here, empty engine pods shrink-wrapped in white, tall red tails fading to pink in the desert sun. More will come soon. Some will never fly again. The number of planes in storage has jumped 29 percent in the past year to 2,302, according to aerospace data firm Ascend Worldwide. That includes 930 parked by U.S. operators alone. . .

Airlines have announced plans over the past year to take 1,700 planes out of service as fewer people fly. United Airlines is retiring all 94 of its Boeing 737s by the end of this year, and Northwest Airlines has cut its old DC-9 fleet by about a third.

Posted by: ronald, 5 April 2009, 21:04 ( 9:04 PM)

I strongly believe in the saying "under pressure, everything will become liquid", and that new initiatives to make flying more sustainable will arise. Additionally, for that to happen, the industry will need to invest, which is not possible in a non-profitable environment (so do not limit growth now).

In your article you combine climate change and the need to stop flying altogether. That would save 3% Co2. What about the other 97% of things (held) responsible for it? Is it not wiser to force the building industry (cement manufacturing is about 5% responsible), the other part of the transport industry and other human activities to become more sustainable. In order to speed up that process, people will need to fly probably. Limiting air travel might even be a burden to solve the environmental questions.

Choosing between modes of transport will ultimately be an economical question, and I personally do not believe in a disappearance of air transport. The change in behaviour of choosing a travel mode will be percieved as natural, because it is the outcome of many options (although I doubt there will be many different options in long-haul)

Posted by: Martijn Moret, 6 April 2009, 07:32 ( 7:32 AM)

Lighter-than-air? We know much more about weather than we did 50 years ago.

Was there any serious consideration of that?

Posted by: Doug Faunt, 7 April 2009, 08:54 ( 8:54 AM)

I find the idea of lighter-than-air travel (usually discussed in this context in the form of dirigibles) intriguing. No, it wasn't mentioned at the 2009 Aviation and Environment Summit. But while it may have a renewed future, what I have seen about dirigibles suggests that they would be only a little more fuel efficient than the best heavier-than-air aircraft, but with potentially much higher capital costs per unit capacity.

Posted by: Edward Hasbrouck, 7 April 2009, 14:49 ( 2:49 PM)

The planes will be flying their flights, regardless of whether you are on them or not. And yes, I DO have strong doubts about the validity of global warming.

Posted by: Timothy G, 8 April 2009, 20:07 ( 8:07 PM)

Who's to say that the next fuel will be any better? Yea, it MIGHT be better for the "Earth" but it might damage something else.


Posted by: jdr, 9 April 2009, 14:33 ( 2:33 PM)

What about all those ever so important military flights ...
CO2 IMHO another way of introducing just another tax.
One vulcano eruption blows out more CO2 into the atmosphere, than 1 year of all human travel, breathing, farting and so on...

Posted by: charlie8888, 9 April 2009, 15:15 ( 3:15 PM)

You mean........WE are not the only ones that are the cause of this thing called 'global warming?' NO WAY!

What about those 'scientists' that claim otherwise?

Posted by: jdr, 10 April 2009, 11:55 (11:55 AM)

I'm surprised not to see you put more stress on train travel. It's true it won't get you across oceans, but for my last RTW trip I did 17,000 miles of forward travel by train from Scotland to Saigon (detour around Europe kicked the mileage up). You could have flown to London and then taken trains to Geneva.

I'm finding airplane travel so miserable these days that I'm seriously considering taking boats across the Atlantic instead of planes - except I might have to take a plane to get to the boat! I suspect we may need to look at some sci-fi options for air travel - would rocket ships be more fuel-efficient? Power to get up, and gravity to get down.

Posted by: thursdaysd, 11 April 2009, 12:25 (12:25 PM)

I do put great stress on trains, and I did travel by train from Geneva to Paris to London (even though, in this particular case, it cost substantially more than flying directly from Geneva to London would have cost). It's important to substitute mass transit for individual cars where possible, and (in general) to electrify that mass transit where possible. That means, as I've written abvout extensively, both more trains and electrification of trains, as well as the underappreciated and often overlooked electric trolleybus.

But that won't get us across oceans.

Posted by: Edward Hasbrouck, 13 April 2009, 04:43 ( 4:43 AM)

I would prefer a book on how to travel, not by air. By air you learn little and see nothing. Except for speed and time expenditure, air is a total negative in my view. Methods other than air explored by you would be of great interest and lead to our greatly increased empowerment of the local people and places; all the right things in that one change. Thank you for the question!

Posted by: Anonymous, 13 April 2009, 22:58 (10:58 PM)

Thank you for the post, that was very interesting reading!

Posted by: John, 16 April 2009, 01:59 ( 1:59 AM)

I think it is hard to convince people not to travel by air, which is one of the fastest and convenient way of shifting one place to another especially for long distance. Maybe focus should be put on how to use less polluting fuels.

Posted by: Beijinger, 20 April 2009, 06:14 ( 6:14 AM)

Edward, Thanks for your thoughts. I share your concerns and agree that the future will be different. Has to be different.

Posted by: Anonymous, 22 April 2009, 05:29 ( 5:29 AM)

Thanks for the great information. I too have wondered if their is a better means of traveling. I heard an interesting fact that after 9/11 all flights were canceled, but the temperature of the Earth increased for that week.

Did you hear about that study? I can't remember the details because it was so long ago, but it was very interesting.

Keep up the good work.

Posted by: human directionals, 28 May 2009, 13:35 ( 1:35 PM)

Interesting and Informative post!!!

Posted by: Anderson, 7 April 2010, 06:10 ( 6:10 AM)

it's a tough question, We all want to travel and see the world , we want to help our world and our environment but the only way to get to the corners of the earth is by air.Not really sure what the answer is , but we may be finding out pretty soon

Posted by: rich, 27 May 2010, 08:30 ( 8:30 AM)

This is the reason why solar planes are being developed.
In my opinion, air aviation is here to stay with us. It is just the type of fuel or how it will be powered that would differ.

Posted by: Anonymous, 29 April 2012, 10:09 (10:09 AM)

WTM (World Travel Mart) Responsible Tourism Day opening keynote 2015: Kevin Anderson on "The Ostrich or the Phoenix?"

Kevin Anderson:

WTM 2015 follow-up session: "Carbon Debate -- is the Travel and Tourism Industry doing enough to address Climate Change?"

Discusssion at

Posted by: Edward Hasbrouck, 10 November 2015, 07:50 ( 7:50 AM)
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