Frequently Asked Questions
Technical (about this web page): General (discussion of topic):
  • Suggest other questions

    Technical Questions (about this web page)

    I get a "javascript error" when I click / move on the map

    The script has recently been updated (March 2007) and should work OK with most modern browsers such as IE7, Firefox or Safari. However it no longer works with really old browsers such as Netscape 4.x
    If you still get javascript errors, do not worry - these will not damage your computer.
    It would be helpful if you tell me about specific javascript errors, but don't forget to specify which browser and which version you use, the event that led to the error, and preferably the details of the error (problem, line-number) if these are reported.

    Can I see the formulae for all the calculations?

    Click here for a brief explanation of the main calculation of greenhouse gas emissions from you flight. To see the exact formulae, look at mapfunc.js If you know more sophisticated formulae or have other suggestions, please let me know

    I'm only flying a short distance: can I zoom in on one area of the map?

    No: if you're only going a short distance (such as within Europe or North America), it's easy to travel by train or coach. See alternatives to flying
    However, if the map is too squashed, drag the frame border to expand its frame, or use the link above the map to open it in a separate window

    Who created this web site, and Why? has been created by Ben Matthews.
    No project funded the original site, I created it (in 1999) for my own survival - to preserve an inhabitable planet to live on, for us and for future generations. Reducing greenhouse gas emissions from aircraft will be, I believe, one of the toughest nuts to crack in solving the global climate problem. Somebody has to start somewhere.
    More recently, I am working in UCL-ASTR, Belgium. See contact info for more info.
    Incidentally, with the idea that we should try to "practise what we preach", I have not flown on a plane since 1993.

    General Discussion about this topic

    I heard that air travel only contributes X% to greenhouse gas emissions, so what's all the fuss about?

    There are many such figures around -they vary a lot depending on the year for which they calculated, because the air travel industry is now growing by 7% each year and is by far the fastest growing source of greenhouse gases. Also you need to be careful whether such figures include all greenhouse gas emissions from aircraft, or just CO2 emissions, which are only about 1/3 of the total. See "into the sky".

    Most importantly, you need to remember that only a very small fraction of the world's population currently enjoys the luxury of air travel. Many more people aspire to the lifestyle of the "rich world", but the atmosphere could not bear the burden of everybody living such a lifestyle. To achieve a global agreement to reduce greenhouse gas emissions, we will have to distribute emissions quotas more equitably, and people in the "rich world" have to change their lifestyle to set an example. The page "put this in a global context" shows how the emissions from your flight compare with a sustainable yearly emissions budget per person. Here is more about achieving equity in the global climate negotiations.

    Can't we just clean up the exhaust or make aircraft more efficient?

    The energy for pushing an aircraft comes from the production of CO2 and water vapour. As explained in the page "into the sky", there's no way that you can get the energy from fossil fuel without emitting these gases. They are not a by-product that can be "scrubbed" from the exhaust. NOx is a by-product but is produced by combination in the engine of nitrogen and oxygen from air -which is hard to avoid at such high temperatures.
    It is true that the efficiency of aircraft has increased considerably over the last few decades, but many engineers admit that most of the possible efficiency gains have already been made and do not expect further breakthroughs or "free lunches". There is much greater scope for improving the efficiency of land-based transport.
    It is also possible to run trains, or even some cars, using electricity produced from renewable energy sources- solar, wind, wave or hydro power. However there are no electric aircraft -their requirements for energy storage are just too great. Hydrogen-fuelled aircraft have been proposed: -these would still produce water vapour and contrails but not CO2, if the hydrogen was produced using a renewable energy source. However, due to storage and safety considerations it may be several decades before these are developed.

    Won't the plane fly anyway, whether I'm on board or not?

    Airlines operate in a highly competitve market and rapidly adjust the number of flights according to demand from passengers. If people don't give them so much money, they won't be able to fly so many planes in the future.

    Can't I just pay somebody to plant some trees to soak up the CO2 emissions from my flight?

    There are many such "carbon offset" schemes, but the accounting of how much carbon is actually taken up by the trees is very unreliable. In many cases companies are just taking your money and doing what they were going to do anyway -so it doesn't help the climate.
    Trees take a long time -several decades - to grow to maturity. During this time the CO2 emissions from your flight are still warming the atmosphere, and much of this heat will remain for hundreds of years in the oceans.
    In some locations (especially peatlands) planting trees can cause net emissions of CO2 to the atmosphere, because they dry out the soil and allow microorganisms to oxidise it.
    As a carbon storage, trees are not a long-term substitute for fossil fuel under the rocks. They may be decomposed by microorganisms, or burn in forest fires as the climate gets warmer and drier, in both cases returning the CO2 to the atmosphere.
    And finally, remember the CO2 contributes only about a third to the total greenhouse warming effect from aircraft emissions. See "into the sky".

    What about informal discussion -that's the real reason I attend conferences?

    What about the informal discussion at a conference- during the coffee breaks, or the excursions, when people make personal contacts or discuss new ideas and projects? Many people say this is their real reason for attending conferences. Such discussion is important, but big conferences are not the most efficient way to enable it to happen -there is only ever enough time for each delegate to talk to a few others, who often live much closer to each other than to the location of the big conference. It would often be more efficient for individuals to make personal visits to each others workplaces, when they happen to be travelling in that direction anyway for some other reason. Between such visits, the discussions can be continued one-to-one videoconferencing.

    Suggest other questions

    Contact the Author
    But first, have you checked all the pages from the main menu?