Carbon Offsets and Airplane Use

I recently was asked whether it makes sense to buy individual carbon offsets to compensate for one’s own flying. A complicated question.

For most Americans, the greenhouse (GHG) emissions we are responsible for fall into the following categories:

• carbon stored over several hundred million years as coal and oil; this will be stored again over tens to hundreds of millions of years. The sun has been warming continuously, and will continue to warm, yet the Earth is much cooler today than in eons past, because of the storage of GHG as coal and oil, and the accompanying positive feedback (feedback causing change in the same direction) of increased GHG storage in soil.

• pollutants such as NOx and ozone that accompany the burning of fossil fuels.

• addition of never before seen GHG such as the chlorofluorocarbons (these also damage the ozone layer), and some less common pollutants previously seen such as nitrous oxide from agriculture (and fossil fuel burning)

• reducing the carbon stored in plants, notably trees. First, climate change has led to more forest fires (the increase in forest fires appears to be related to changes in the climate which are likely to be associated with global warming, such as more extreme weather—more fuel buildup followed by more droughts, warmer weather leading to dryer soil in general, and greater stresses on trees which allow bark beetles and other pests to damage or kill trees, making them more susceptible to burning), and these fires are hotter and harder to extinguish.

Additionally, in the far north, bark beetles can now survive an entire generation in the longer summers, and are proliferating. Additionally, as winter temperatures rise, but stay below freezing, snow increases, damaging tree canopies and making trees more susceptible to infestation. Pests are killing more trees, and forest fires in Alaska are increasing.

Also, warmer temperatures decrease the carbon and methane stored in the soil as the Earth cooled. If this moves up the list in terms of importance, we will already be in big trouble from climate change. And getting into much bigger trouble.

And exporting agriculture to the tropics especially has lead to deforestation.

For Americans and most wealthy people, the biggest part of the solution is to reduce the amount of GHG we take out of long-term storage. We need to rapidly and radically cut back on the amount of fossil fuels burned. We could do this by capping our own use and trading permits to minimize costs. This would raise the price of GHG-emitting behavior, and could include an added tax if the US and other countries sell rather than distribute permits. This added tax could A) raise revenue, and B) aid consumers in seeing the costs of their behavior, as the price begins to more accurately reflect these costs, and make more efficient cars, light bulbs, and appliances more attractive (along with paying for research and development in efficiency). Charging for permits would speed the transition from today’s carbon intensive technologies, as lower GHG technologies become more competitive.

Especially important for people who use airplanes is to see that air travel is included in future cap and trade programs.

Alternatively, we can help pay for the developing world (and some of the less well off first world) to replace planned coal plants or other fossil fuel alternatives with solar panels and wind, replace more expensive incandescent bulbs with cheaper compact fluorescent bulbs (but these cost more for the first one), and so on. We can do this by taxing our own energy use. Or there are several ways to contribute voluntarily, such as But these organizations generally state that it is possible for the average American to pay for GHG behavior with small annual fees, perhaps $100/year. Not likely.

Which is the most important, if you really need to fly? I would think that committing lots of time to laboring with national legislators (or in CA, with a few recalcitrant state legislators) on changing US behavior, making GHG cap and trade programs mandatory at a national level, along with involuntary taxes on our energy use, is important. Voluntary contributions are better than nothing, but not nearly as important as changing US behavior. (Though some of the trees projects that have been funded may have been worse than nothing.)

More on airplanes
Some discussions on air travel compare the merits of flying to driving. Airlines claim that because of higher seat occupancy, they get close to 47 passenger miles/gallon. This is misleading for two reasons. First, air travel is perhaps two to three times as bad as car travel per gallon burned from a climate change perspective, primarily because it deposits water vapor and other GHG so high in the atmosphere. See the Summary for Policy Makers and full report of Aviation and the Global Atmosphere, from 1999.

Secondly, people travel a certain number of hours, not a certain number of miles. People travel much further since airplanes have become available.

Whatever solution we each find must fit the goal. Step one of the goal is by 2015 to reduce world GHG emissions to 2005 levels, or even below. This will require major reductions in US GHG emissions and commensurate reductions in other rich countries.

2 Responses to “Carbon Offsets and Airplane Use”

  1. Calvin Jones says:

    Hi there, nice post, aviation is certainly one of the biggest chalenges we face in terms of climate change mitigation. In the EU steps are being taken to create an emissions trading scheme for just aviation (for technical reasons it cant currently be in the existing EU ETS).

    I have a couple of recent posts about this and one feature article (in the side bar) about uk govorment policy and aviation.

    I`d be interested i a link exchange if you are keen.

  2. Ramsay says:


    Thanks for your thoughtful commentary.

    I work for and wanted to comment on your statement that it’s
    “not likely” that the “average American” can offset their emissions for $100
    per year.

    At, for $99 you can offset the per capita amount of CO2 for
    an American (about 23 tons CO2 equivalent). This offset consists of
    third-party verified tons of CO2 from renewable energy, energy efficiency,
    and reforestation.

    In fact, if anything, $100/year is too expensive in our opinion. If you
    look at the Chicago Climate Exchange, North America’s premier carbon trading
    market, tons of CO2 trade for $4.50/ton which is up from only $2 to $3/ton
    in the past year or so. And this market features many large players such as
    Ford, Dupont, AEP, and more than 100+ other members, including If these companies can purchase certified tons of CO2 for
    well under $5/ton, why shouldn’t average citizens also be able to do so?

    Our mission is to educate about climate change and to help people “reduce
    what they can, offset what they can’t.” In the face of little political
    action on climate change, we felt it necessary to give ordinary citizens
    something that they can do to show that dealing with climate change
    is simple and cost-effective.

    We are working hard to be an important part of the solution to this problem.

    best regards,
    Ramsay Huntley