TANDEM  Diversity




Does one have to avoid air travel? No, but it sure helps minimize carbon impact if air travel is limited, flown in economy class, and with light luggage. If we want to offset the impact of our travel we can purchase carbon offsets, and it is best to purchase them from a reputable third party rather than from the airline directly. If we want to go in business class, the offsets will be more costly, and appropriately so.

After reviewing all this, we here at Tandem Diversity still advocate travel with your tandem as an activity rich in benefits for you as a couple and indirectly with benefits for our global community, as by traveling you become better informed more fully engaged global citizens. But it is not without cost, cost to our environment and, if you choose to offset that, cost to your wallet. We make no recommendations, but leave you with the decisions to make on your own. Hopefully the resources summarized here will help with that decision making.


So, it is apparent that air travel contributes significantly to the human impact on our environment. What can we do, if anything, about that? Particularly if we plan or hope to travel.

Travel less. This one is obvious, is a good choice, and is the solution some implement. Travel by automobile, bus, train, etc is not without environmental impact, but all are less impactful than air travel.

Fly responsibly. Flying in economy has less impact than in business or first class since more humans are transported in that class, for the amount of fuel burned. Flying with less and lighter luggage is helpful, for the same reason.

Purchase carbon offsets. If one must fly, or chooses to in spite of its impact, then the carbon added to the environment can be offset by reducing a comparable amount of carbon release someplace else, either in one's own personal life or in carbon reduction projects. Lots has been written about leading a more carbon-responsible life. Spencer and Sheila offer good information on their website. There are two good resources on the web, as mentioned above - the David Suzuki Foundation and the Tufts University paper on sustainability.


First, not all carbon offset programs are equally good at ameliorating our impact on climate. For example, tree planting projects are not permanent and do not address our dependence on fossil fuels, and therefore aren't as beneficial as say, renewable energy projects. Also, various programs are evaluated and validated by reputable third parties. As an example, Gold Standard validation signifies a program that meets stringent requirements.

​So, yes, we can travel by air and we can purchase carbon offsets that reduce carbon emissions elsewhere by an amount comparable to what that air travel is producing, thereby allowing us to remain within our lifestyle objective of living carbon neutral.

How is that done? Well, it turns out there are a couple of ways, one good and one not so much.

Purchase carbon offsets from the airline. This is the not so good option. Not so good because first of all the airline is calculating the carbon offset based just on average fuel consumption, not including other factors such as fare class and vapor production. Also, many of them are only tree planting projects so, though easy (they can be purchased right on the airline website) and cheap, it turns out these airline provided offsets do little but offer salve for the conscience.

Here are some examples based on round trip travel from Vancouver to Amsterdam or from Seattle to Frankfurt, for three airlines:


KLM carbon offsets are purchased from 100% Gold Standard approved clean energy projects. That is good. But they seriously under estimate total climate impact. They are based on an estimate of average fuel consumption only. For our trip, KLM will want only about 12 Euros per person for carbon offsets, not accounting for class of travel.


Delta partners with the Nature Conservancy so most of their projects are tree planting. For our trip they want $18.76 USD total for two persons, not accounting for class of travel.


United allows you to choose forest conservation projects or a wind energy project for carbon offsets you purchase from them. For Seattle to Frankfurt, round trip, United wants between $40 and $80 USD for two travelers, again not accounting for class of travel.

These are just quick examples of the cost if carbon offsets are purchased from the airlines directly.

In our opinion a better approach would be to purchase carbon offsets from independent entities. Tufts University evaluated 13 such programs, rating them on multiple criteria including how accurate their carbon calculators are and their certification. They recommend 10 programs, 4 of these without reservations. Here is a quick summary of how each of the 4 highest recommended programs would charge us for our example Vancouver to Amsterdam round trip:

Atmosfair (www.atmosfair.de)

​This is a Gold Standard rated program that invests in international renewable energy projects. Their carbon calculator takes into account the class in which you are flying, the aircraft type, and the number of stops. You can offset all or half your emissions for the trip. For the international example above, cost for offsetting 100% of emissions for two travelers would be 425 Euros in business class and 227 Euros in economy. The Atmosfair website also gave a graphic comparison between the carbon emissions for our flight vs typical annual car production, typical annual per capita production in India, and typical annual production by a refrigerator. Here is a brief rundown on those numbers:

For our international flight example of round trip between Vancouver and Amsterdam for two travelers, CO2 generation for the two would be 18,470 kg CO2 in business class vs 9,850 kg CO2 in economy class. That compares to other activities such as:

Climate compatible annual emissions budget for one person: 2,300 kg CO2.

Annual emissions for one car (12,000 km, middle class model): 2,000 kg CO2.

Annual emissions in India, per capita: 1,400 kg CO2.

​Annual emissions for a refrigerator: 100 kg CO2.

From these numbers, it seems clear why the carbon offset prices are so high - there's a lot of carbon to be offset.

Climate Friendly (www.climatefriendly.com)

This is an Australian program, Gold Standard certified, that invests in renewable energy. For our trip they want (for 2 travelers) 464.20 AUD for business class and 160.16 AUD for economy.

My Climate (www.myclimate.org)

This is a Gold Standard certified Swiss program that allows you to choose to purchase offsets that support projects in developing countries, or offsets that support a mix of Swiss and developing country projects. For our trip they want between 165 and 516 Swiss francs for economy vs between 318 and 993 Swiss francs for business class.

Native Energy (www.nativeenergy.com)

This is a US based, Green-e and Climate Neutral Network certified program that invests in renewable energy projects, focusing on Native American ownership. For our trip, for two travelers, they want $186 USD for economy and $599 USD for business class.

​From the cost alone, it seems obvious the airline direct offsets are seriously underestimating the carbon impact of the flights.


At Tandem Diversity we advocate traveling with your tandem, for a number of reasons including the impact on your relationship, the impact on your knowledge of the world, and the fun, to name a few. However, we also know we live in a time of change - a change in our climate brought on largely by human activities. Activities that impact our environment via, for example, CO2 production. Activities such as travel, especially air travel. We read with interest a brief summary written by Seattle tandem riders Spencer and Sheila (www.s2cycle.com/category.difference/) looking into the carbon impact of flying and other lifestyle issues. It appears Spencer and Sheila have chosen to severely limit travel by air, as a conscious, in their view responsible, choice. We decided to look into the carbon impact of air travel for ourselves. What we found out was astonishing and the truth is that the summary written by Spencer and Sheila probably underestimates the environmental impact of air travel.

What follows is a brief presentation of resources you can use to look for yourself into this issue, if you are interested, as well as a quick look at what you can do personally to offset the impact of your travel on our environment.

First, the impact of air travel on climate. There are two resources we think one may find succinct and useful. The first of these is the David Suzuki Foundation (www.davidsuzuki.org), and the second is the Tufts University white paper on sustainability (sustainability.tufts.edu/wp-content/uploads/TCI_Carbon_Offsets_Paper_April-2-07.pdf).

The David Suzuki Foundation website provides good overviews of issues, as well as specifics for each of us as environmentally friendly consumers. The Tufts white paper, now a bit dated, looks more specifically at air travel carbon emissions and what can be done, if anything, about them. We recommend taking a good look at both.

The bottom line is that air travel is a significant source of carbon emissions and therefore has significant impact on our climate. It is estimated that aviation accounts for some 4-9% of all human carbon emissions, and everyone knows that air travel is booming, so the total load in the environment is only going to increase. Since 1990, emissions from international air travel have increased 83%. CO2 production by air travel exceeds that of other transport types such as maritime, rail, and road. Furthermore, within the aviation industry there are differences based on type of plane and routes flown. For example, CO2 production per passenger mile is markedly lower for a Boeing 747-400 than for an older DC-10. Most planes produce CO2 emissions between these two plane types.

Carbon production from fuel consumption is only part of the carbon picture when looking at air travel (or at any type of travel for that matter). Burning jet fuel not only produces CO2, but also triggers other high altitude chemical reactions that have a warming effect. In fact, it is estimated the climate impact of aircraft is 2-4 times greater that the effect of their carbon emissions alone. Also, jets produce contrails, trails of ice and water droplets formed during combustion of fuel. These remain in the atmosphere for significant times and tend to trap heat, contributing to global warming. Night flights appear to have the strongest warming impact because during the daytime, contrails can actually reflect some sunlight away from the earth.

Tandem Travel And Carbon - The Changing Climate