The Short Story
Since my retirement in 2009 my wife Patty and I have begun taking some wonderful trips to far flung parts of the globe. Exciting as these trips have been, questions have begun to haunt me. How much have our long distance plane flights contributed to the worldwide problem of climate change? Is there anything we can do to reduce or offset that impact?
As a side note, there are some who doubt that human activities are causing any change to the world's climate. I myself accept the mountain of evidence that human burning of fossil fuel is a major cause of climate change. A review of that evidence is too much to go into here.
This first section is a short look at what we've learned and what we're doing to change our ways and offset our carbon footprint. This part is for those of you who always skip to the end of the book to see how everything turns out. The much longer second part will provide all the details of our investigations. That's for everybody who wants to understand things in depth and look at all the alternatives.
Carbon Dioxide We Produce by Burning Fossil Fuel
Electricity 5,000 lb / year (Now 500 lb/year with new solar panels on our roof.)
Natural Gas 11,000 lb / year
Cars 10,000 lb / year
Plane Travel 14,000 lb / year
My first reaction to this table is – Wow!! It’s mind boggling that air travel is our biggest single carbon impact. It doesn't feel like we fly that much, maybe three round trip flights per year. What can we do to reduce this impact? We've come up with three types of changes that could work:
1) Change our travel behavior to produce less carbon.
2) Change other behaviors to offset our travel carbon impact by producing less carbon in other areas of our lives.
3) Pay a fee to offset our travel carbon.
How We Will Offset Our Air Travel Impact
Of course, we could just travel less to reduce our carbon footprint. But that's a last resort given our family obligations and desire to see the world. So here's a list of the tangible actions we've begun to include in our lives to make up for the fuel burned in flying.
1) Combining Trips - We're going to consciously look at our various travel plans to see how we can combine trips to avoid multiple flights across the country. This means that when we want to travel overseas, say to Europe, we stop off on the East Coast to visit family first and then take off for Europe from there.
2) Cutting Home Heat - As a conscious change to offset our air travel, we're going to accept being colder at home by turning our thermostat down, especially at night.
3) Creating a Carbon Offset Account - We're not totally confident in the carbon offset add-ons offered by the airlines. So we're going to create our own special saving account especially earmarked for funding carbon offset endeavors. We'll put money into this account every time we fly. When an especially appealing carbon offset opportunity presents itself, we'll use the money from this account to invest in it. For now we've decided to put the following amounts into the account:
$25 per round-trip flight for domestic coach seats
$50 per round-trip flight for international business class seats
4) Carbon Offset Opportunities - Our first carbon offset opportunity took us completely by surprise. Reading a local paper, we learned about a program called Oakland Solar Mosaic (http://solarmosaic.com/oakland). Money invested in this project goes to install solar electrical panels on public buildings like schools and civic centers. This is a perfect example of the sort of thing we'd like to invest our offset money in. It's local to our area so we have some confidence that it will get done. It provides jobs and civic improvements in our city. And it generates electricity using solar energy, keeping power generated from fossil fuel from being used.
The Long Form
As I wrote in the short story, my wife and I are really enjoying retirement travel all over the globe. What an amazing planet we live on. But unfortunately, it turns out that plane flights to explore the world are one of the biggest ways to dump carbon dioxide into the atmosphere. How can we reduce or offset this carbon footprint while still being able to travel? This paper will attempt to answer that question and to explore various solutions.
First of all I want to deal with the idea, promulgated by some, that global warming isn't happening or isn't caused by human activity. I myself accept the mountain of evidence that humans burning fossil fuel is a major cause of climate change in our world. A review of that evidence and the concerns of climate change deniers is too much to get into here.
So given the climate change problem, what can we do to reduce our contribution to it? Especially, what can we do to lessen the impact of our travel? One answer is to use the offsets available from many airlines and other websites which assign a fee for each plane flight. But I want to explore this issue in more depth to see what options are available and to focus my response to be the most effective. I’m leery of handing a bunch of money to persons unknown, trusting them to use it in a cost effective manner to eliminate carbon.
How Much Carbon Dioxide Are We Producing?
My first step has been to measure exactly how much carbon dioxide our various activities are producing, both in travel and in our day to day life. That means I’m looking for four numbers, the pounds of CO2 produced by our electricity use at home, our natural gas use, our car travel, and our plane flights. (I know I'm leaving out the carbon impact from the production of the things we buy and from their delivery to our stores. This is another issue that will have to be dealt with elsewhere.) Details of the CO2 calculations can be found at the end of this paper in Appendix A. Here are the results in pounds of carbon dioxide produced per year:
Electricity 5,000 lb / year
(This would be our footprint if all our electricity came from our utility, PG&E. We now have solar panels generating 90% of our electricity so our actual footprint is 500 lb / year.)
Natural Gas 11,000 lb / year
Car 10,000 lb / year
Plane Travel 14,000 lb / year
My first reaction to this table is – Wow!! It’s mind boggling that air travel is our biggest single carbon impact. We don't travel all that much. I was expecting that plane trips might be 10-15% of our carbon footprint. But for them to be 35% astounds me.
What can we do to reduce this impact? I can think of three types of changes that could work:
1) Change our travel behavior to produce less carbon.
2) Change other behaviors to offset our travel carbon impact by producing less carbon in other areas of our lives.
3) Pay a fee to offset our travel carbon.
Changing How We Travel
The simplest way to reduce our travel impact would be to travel less. Unfortunately, I don’t think this is a serious option, at least for now. With aging parents in Boston, trips back east are a necessity. Plus we’ve waited all our lives to have the leisure time to be able to visit some of the most beautiful places in the world. We could cut back on such vacations. But we would rather first explore all other avenues to reduce our carbon footprint. Here are some possibilities:
a) Other Modes of Transport – Perhaps some trips could be taken by bus, train, or ship. Unfortunately Patty can’t travel on buses because of her bad back. And ships are not a viable option for many trips, such as across country. So the real alternative here is trains. How do trains compare to air travel in carbon dioxide production? Answering that question will require additional research.
One issue is the speed of trains vs. the speed of flying. We recently tried one Amtrak trip to a city 300 miles away and it took nine hours. That's much more than simply driving there. I fear that until we have high speed trains in the United States, the speed limitation will exclude train travel as an alternative for all but fairly local routes. However, trains are certainly a viable alternative in Europe.
b) More Efficient Airplanes – Each new generation of airplane seems to be more efficient than the one before. As the world gets more and more concerned about global warming, hopefully this trend will increase. It might be possible on some routes for us to select carriers with new, efficient planes. If the cost is higher for those flights, the price difference could be thought of as a form of carbon offset.
In addition, I’ve read on many websites that some airlines are actively researching the use of biofuels in airplanes, replacing the fossil fuels used today. If successful, biofuels could seriously reduce the carbon footprint of airline travel. Burning these fuels would create carbon dioxide just as burning fossil fuels does. But the production of biofuels removes an equal amount of carbon from the atmosphere so the result is a net zero carbon production. One important wrinkle in the creation of biofuels is to make sure that their production does not reduce the world’s food supply. They need to be produced from non-food sources.
c) Combining Trips - We've realized that we can avoid some flights by rolling several trips into a single journey. This year we're traveling to Boston to visit family and rather than returning to California and then flying to Madrid later for an international adventure, we're leaving from Boston instead. This time this plan just happened to be the easiest way to schedule things. But in the future we can consciously look for such opportunities in order to reduce our carbon footprint.
d) Skype – Using video conferencing over the web, we may be able to avoid some trips by having face-to-face video contact. If you've ever watched The Big Bang Theory, the Indian character Raj talks regularly with his parents in India. It looks like a very cool option.
Changing Other Behaviors to Offset Air Travel
What other things can we change in our lives to reduce our carbon footprint? Can those changes be used to offset air travel? Some articles on the web argue that no such changes should be counted against plane trips. The argument is that we should all be making those changes anyway whether we fly or not. But for myself, if I hadn’t thought of a change until I started examining my air travel carbon footprint, I’m willing to count such changes against my flights.
I do recognize that if I was going to make a change anyway, that carbon saving does not count toward our air travel carbon. For example, we put up solar panels to generate electricity last year. That drastically cut down our carbon footprint. I would not count these panels as an offset for our air travel.
One good candidate for behavior change is in our house heating. Of the 11,000 lb/year of carbon we produce from natural gas, about half comes from heating our house. We can save a considerable amount of that in several ways. One is to improve our house insulation. But a behavior change which involves little investment is to simply turn down our thermostat, especially at night. We should be able to significantly reduce the amount of heating fuel we burn by dressing more warmly and turning our heat down or off. We can measure how much carbon we save by this method by comparing our monthly natural gas usage against prior years. This won’t offset all the carbon of our air travel but it will be a good start.
Carbon Offset Payments
Finally we come to paying carbon offset fees for our air travel. We want to divide this issue into two parts. The first is to determine how much money we want to charge ourselves as a carbon offset fee for our flights. The second concerns what we do with that money. By separating these two questions, we’re able to begin creating a carbon offset fund before we’ve nailed down exactly what we do with the money. We can also radically expand the possibilities for what can be done with carbon offset fees, beyond the kinds of activities funded by traditional carbon offset companies.
Carbon Offset Fee Amount
There are various resources which can provide guidance for these fees. One could simply compare several carbon offset providers to get an average amount per ton of carbon dioxide. Then that amount can be applied to the amount of carbon for the flights we take in a year as calculated by one or more of the carbon calculators available on the web. I’ve examined several such websites and you can see details about them in Appendix A below. After looking over the results of their calculations, we've decided to charge ourselves the following:
$25 per round-trip flight for domestic coach seats
$50 per round-trip flight for international business class seats
Based on these amounts, our 2011 travel of 2 domestic trips each and 1 international trip each will total $200 for our carbon offset account. This is more than most of the carbon offset websites would charge for our travel but it feels good to us. And it's simple so if we decided to have a stopover on our way back we wouldn't need to change our calculations.
One very good resource for carbon offsets and flying is an in depth analysis done at Tufts University in 2006 and revised in 2007. This is titled “Voluntary Offsets For Air-Travel Carbon Emissions” by Anja Killmuss and Benjamin Bowell. It’s available on the web at the following link: http://sustainability.tufts.edu/downloads/TCI_Carbon_Offsets_Paper_April-2-07.pdf
Carbon Offset Activities
Once we have a carbon offset fund set up, there are several possible ways we can put this to use. For any of these, there are some important points we need to consider.
- Would the offset be done whether or not offset money is used to pay for it? This is often called “Additionality.” For example, offset money could be invested in the planting of trees. But would the trees be planted anyway? That’s the critical question.
- Does the offset activity actually take place? How can one verify that the offset seller actually did what they said they were going to do?
- Double counting – It’s important that an offset activity not be sold to multiple people purchasing carbon offsets. Two people shouldn’t pay for planting the same tree.
- Permanence – Does the offset continue to exist for a long time. If a tree is planted, how do we verify that it’s not cut down the following year?
- Verification – There are independent organizations and companies who can answer all these questions. In buying carbon offsets from someone, it’s important to check that there’s been independent verification that the offsets satisfy all these issues.
Uses of offset funds:
1) A simple way to buy carbon offsets is to use the money in our own lives to fund projects which will reduce our carbon footprint. For example, we could buy extra insulation for our house to reduce our use of natural gas for heating, lessening our carbon footprint. In this case, we would have to do our own verification. This requires great self-honesty to be able to state that we weren’t going to perform an improvement except as a carbon offset. On the other hand, because we perform the offset activity ourselves, we can be sure it gets done. And there’s the added bonus that the offset could improve our lives.
2) We could pay the money directly to a carbon offset company which will use it to fund programs to sequester carbon dioxide from the atmosphere or to prevent carbon from getting into the air in the first place.
3) We can avoid the middle-man (the company selling carbon offsets) by paying the money directly to non-profit programs which do the same thing as the programs the carbon offset companies fund. This would have the added bonus of making the carbon offset donation tax deductible.
4) We could donate the money to organizations which lobby governments to regulate greenhouse gas emissions. This is an interesting alternative because while personal carbon offsets feel good to us as individuals, it will be hard to get enough participation to make a significant impact on the world’s carbon load. Political action, such as California’s requirement that a certain percentage of electricity be generated from renewable sources, can have a much bigger effect.
We have friends who think this would be the best use of carbon offset money. We considered this but decided most of our offset dollars will go to reduce our carbon footprint. We already donate a lot of money to political causes. The carbon offset amounts would not add significantly to that total.
Appendix A - Carbon Calculations
Electricity
Our energy provider, Pacific Gas & Electric (PG&E), has a webpage with the current amount of carbon dioxide produced for each kilowatt hour (KWh) used by a customer. The website can be found at this link. It indicates that PG&E produces 0.524 pounds of carbon dioxide for every KWh. In 2009 (2010 is confused because we installed solar electric panels partway through the year) we used 9,000 KWh. That's 4,716 pounds of CO2 which I've rounded up to 5,000.
Since we haven't gone through a complete year with our solar panels, it's impossible to know what our carbon footprint is currently. When the panels were installed, our installer projected that they would provide almost as much power as we've used previously. I made a wild guess that we will end up using 10% of the PG&E power we used previously.
Natural Gas
The same PG&E website indicates that their customers produce 13.446 pounds of CO2 for every therm used. We use about 800 therms per year which works out to 10,757 pounds of CO2, roughly 11,000 pounds.
Cars
We have two cars. One is a Toyota Camry which gets roughly 30 miles/gallon. We drive it about 10,000 miles per year. The other is a Honda Civic getting roughly 35 MPG. We drive that one about 6,000 miles per year.
There are two ways to calculate our cars' carbon footprints. One is to use various calculator websites.
www.terrapass.com says we produce 12,462 pounds of CO2 per year.
www.carbonfund.org says we produce 9,900 pounds of CO2 per year.
We can also calculate our driving footprint using a formula. By dividing a car's MPG into the miles driven we get gallons of gas used per year. That is multiplied by the pounds of CO2 created by burning a gallon of gas. The US EPA has a website which gives this figure as 19.4 pounds of CO2 per gallon. Using our cars' mileages and the number of miles each is driven, this works out to almost the same CO2 production as www.carbonfund.org calculated, about 10,000 pounds of CO2 per year.
Plane Travel
Our air travel varies from year to year but in general, we take two trips back east and one international trip every year. I'm using our projected 2011 travel in the calculation below. That includes two trips from San Francisco to Boston in coach and one trip from Boston to Madrid in business class for two people.
There is huge variation in the calculation of CO2 produced by each flight depending on which carbon footprint calculator is used. Some sites factor in more details about each flight, such as number of stops and type of plane. Some sites factor in other climate change emissions besides CO2, such as water vapor, nitrogen oxide, and methane. The carbon emission is multiplied to reflect these additions. The multiplier is called a forcing factor. Many researchers believe that a forcing factor is appropriate and necessary to reflect the full impact of air travel.
I put the question to our friend, environmental economist Jim Boyce at the University of Massachusetts in Amherst, MA. He, in turn, forwarded my email to his co-author, Matt Riddle. Matt wrote this:
I also haven't looked into non-co2 contributions to global warming from airplanes, but I have doubts about whether it's appropriate to include things like water vapor, since I believe effects on amount of water vapor in atmosphere would not last as long as co2. Maybe they already account for that, but multiplying co2 emissions by 2.7 seems like a lot to me.
Based on Matt's doubts, we decided to use the actual CO2 amount for each flight, with no added forcing factored in, at least for now. We decided that 14,000 pounds of CO2 was a good average to use.
Forcing CO2
Calculator Website CO2 Factor with Factor Offset Price
Atmosfair 14,800 lb 2.7 40,000 lb 432 Euros
Nativeenergy 14,000 lb 2.0 28,000 lb $160
Terrapass 13,000 lb 1.0 13,000 lb $83
Carbonfund 13,000 lb 1.0 13,000 lb $64
(with no forcing)
Carbonfund 13,000 lb 2.7 34,400 lb $172
(with forcing)
