How is it possible that a vegan, car-free, green-living fanatic could have a bigger carbon footprint than the average American? It’s pretty simple: for people who travel a lot — whether for work, pleasure or both — flying can outweigh everything else we do to live green.

Like many science staff at TNC, sometimes I'm a bit self-righteous about green living, and I get frustrated when friends and family (and co-workers) seem to not “get it.” But recently I’ve been trying to objectively look at my overall environmental impact, and I’ve realized that some of the things I obsess over make less of a difference than the things I have given myself a “free pass” to do in the past — especially travel.

For example, a few years ago I attended a conference in Borneo (Indonesia) for work, learning about our projects there and conducting a few days of technical training for local staff. Afterwards, I calculated the emissions for that trip’s flights — a total carbon footprint of 11.7 metric tons of CO2 equivalent,¹ more than the total household energy use (electricity, gas, etc.) of the average American family for a whole year!² While I am hopeful that the trip ultimately led to enough of an improvement in conservation that the flight was worth it, it’s still a pretty scary number.

Which led me to a disturbing realization: all of my efforts to shrink my carbon footprint — from eating vegan/organic/local foods to installing energy-efficient appliances in my home and commuting by bike — are all counteracted if I fly often. Simply staying close to home can have a bigger impact than all those activities, at least in terms of carbon footprint.

This chart comparing the carbon emissions of flight travel to various "green" activities illustrates my point:

Figure 1: Emissions Comparison of Round-Trip Flights with Common ‘Green- Living’ Activities³

As you can see, doing something like cutting out one cross-country flight can reduce your carbon footprint more than eating vegan for a whole year. And while doing some basic insulating at home has about the same impact as replacing old single-pane windows with new Energy-Star ones (and costs way less), you’d do even better to skip a single long flight (or long car trip, especially if driving alone) per year.

Note that, while the average impact each of us has through recycling is quite small, the total impact of recycling is still impressive: almost 16 million tons of CO₂ are saved each year in the United States through recycling, not to mention less landfill waste and less resource use.

So what does this mean for TNC science staff? First, don’t take this analysis as a license to stop doing all the little things that help reduce your carbon footprint. Many of the common "green" actions we take have other environmental benefits besides reducing carbon emissions — for instance, carrying a tote bag to the grocery store reduces plastic, eating a vegan diet saves water over meat-and-dairy intensive diets, etc.⁴

But if, like me, you've been giving Hummer drivers dirty looks while flying on a regular basis, take a moment to think about how you can reduce both the frequency and distance of your travel. For me, it was a wake-up call to calculate my carbon footprint from flying in terms of the average annual Hummer emissions (6.5 metric tons)... and then visualize towing a few Hummers behind me on my bike everywhere I go.⁵

There’s no question that travel is often a necessary part of being a Conservancy scientist: we don’t want to paralyze ourselves, stifle collaboration or just end up feeling guilty. But I also think it’s highly likely that some of our travel has a higher cost than benefit, and that we should be approaching that scientifically, as befits us.

On the cost side we have carbon footprint, actual costs to TNC of the trip (flight, hotel, food, taxis, registration fees, salary cost during the trip, etc.), actual costs to the employee (e.g. child or pet care), and some qualitative costs that are harder to estimate (opportunity cost of not doing your normal job while traveling, decreased productivity due to sleep loss/stress, strain on personal relationships when leaving a family at home, etc.). The benefits are mostly in the hard to estimate category for scientists; we rarely can say “we now have a grant we couldn’t have received without me traveling.” But we can start to think about how much we value benefits of learning, creating and strengthening professional relationships, opportunities to collaborate, practice presenting our work and other benefits. The critical final question is: how many of those benefits can we achieve at a much lower cost through other means? Just as many companies forced to reduce the amount of pollution they emit often ended up saving money, I wonder if TNC Science might be surprised at the unexpected benefits if we dialed back our travel.

I don’t have all the answers, but I’m hopeful we can get creative about how to do better as a division in cutting back on travel. Here are some ideas to get us started, and I’d love to hear more ideas from others:

• We need to use technology better (Skype, WebEx, Nefsis, Google+ "hangouts," Connect, etc.) to meet some of the needs we usually fill by traveling. There is no single technology to completely replace in-person meetings, but by combining them we can get pretty far. TIS has put together a guide to some of the options and is currently working on researching additional options. Contact Joe Pilkington with tech suggestions or ideas.
• TNC’s science culture currently encourages a lot of travel. What can we do to encourage innovation in doing our jobs with less travel? Can we learn tips from the upcoming TNC virtual marketing conference?
• For conferences that alternate location (e.g. Society of Conservation Biology biannual meetings), staff should be encouraged to attend when they’re close, not when they’re somewhere cool and exotic (but far and expensive).
• Should TNC Science buy carbon offsets (ideally, through our own TNC offset program) to help encourage us to account for the environmental cost and work harder to avoid travel? This tactic would add some administrative burden, but helps to make the true costs more explicit.
• Should TNC Science consider more often hiring local short-term help rather than assuming the only/best solution is to fly ourselves all over the world? I hear a lot about people who fly a long way to do something (field work, a short interview or discussion, etc.) for which we could probably find competent local help. Again, if we include the total cost, this route may look like a better option.

By Jon Fisher, Spatial Scientist, Central Science, The Nature Conservancy

Image credit: peasap/Flickr

Notes:

¹Calculations of carbon footprint from http://carbonfund.org/offset/individuals (which in turn is based on http://www.epa.gov/climateleadership/documents/resources/commute_travel_product.pdf). I used the actual flight pattern which included three layovers; a direct flight from DC to Balikpapan would have been slightly less (9.5 metric tons CO2E). Note that CO2E (or CO₂ equivalent) indicates that factors including radiative forcing and other greenhouse gases like methane have been accounted for, so that their actual impact is measured in how much pure CO₂ would be emitted to have the same impact. In this case, the emissions were multiplied by 2.7 to account for radiative forcing (as per IPCC recommendations). These estimates are the footprint per coach passenger of a typical plane for the distance flown assuming a completely full flight. They do not account for energy used in producing the aircraft or support infrastructure.

²See the “home energy use” section on http://www.epa.gov/cleanenergy/energy-resources/refs.html.

³Chart calculations: See footnote 1 above for details of the calculations. As noted above, I used actual flight patterns I have taken (including layovers where the cheapest flight from DC uses them), and including radiative forcing.

The impact of switching from the average American diet to a vegan one (or from a “red meat” diet to the average one) was calculated in http://pge.uchicago.edu/workshop/documents/martin1.pdf. The average American diet gets 28% of calories from animal sources, of which 54% comes from meat (roughly 60% red meat and 40% chicken and fish). The efficiency of the Camry (28 mpg combined, http://www.fueleconomy.gov/feg/bymodel/2012_Toyota_Camry.shtml) and Prius (50 mpg combined, http://www.fueleconomy.gov/feg/bymodel/2012_Toyota_Prius.shtml) were plugged into the vehicle emissions equation on http://www.epa.gov/cleanenergy/energy-resources/refs.html to generate the projected annual emissions of each vehicle.

The emissions savings from insulation and sealing drafts came from the EPA’s estimate that homeowners can save up to 10% on total energy costs through such activities (http://www.energystar.gov/index.cfm?c=home_sealing.hm_improvement_methodology) combined with the EPA’s estimates of average annual home energy use (see citation #2); the actual impact will vary substantially by home/region, but I didn’t have data on the range of values in the Unite States. The range of emissions savings from replacing single pane with energy star windows (shown as error bars around a mean value) came from http://www.energystar.gov/index.cfm?c=windows_doors.pr_benefits. Note that for windows, a range of emissions is presented as it varies by region, and that if replacing double-pane windows, the savings are much lower.)

The emissions savings from recycling used the figures from http://www.popularmechanics.com/science/environment/recycling/4291576 to calculate the total amount of CO₂ emissions avoided by recycling aluminum, glass, newsprint and #1 plastics in the United States (other less commonly recycled materials were not considered). That figure was then divided by the 2010 U.S. population to get the average amount of CO₂ emissions avoided by recycling per American.

⁴How much water can you save by cutting back on animal products? Replacing a single hamburger with a soy burger saves 579 gallons (http://pge.uchicago.edu/workshop/documents/martin1.pdf), which has about the impact of using no water at home (not counting food/fiber, but including everything else) for more than eight days (based on daily usage from http://www.drinktap.org/consumerdnn/Home/WaterInformation/Conservation/WaterUseStatistics/tab id/85/Default.aspx)! Replacing a half gallon of cow’s milk with soy milk saves 398 gallons or almost six days of water (555 gallons H20 per 1/2 gallon cow’s milk vs 157 gallons H20 per 1/2 gallon soy milk).

⁵See the “passenger vehicle” section of http://www.epa.gov/cleanenergy/energy-resources/refs.html for the basic equation used to calculate emissions. The MPG of the most recent Hummer (16 mpg) came from http://www.fueleconomy.gov/feg/Find.do?action=sbs&id=29370. Using this equation and mpg rating, and assuming the hummer is driven the average number of miles for a year, the hummer’s annual emissions are an estimated 6.5 metric tons of CO2E. The average annual emissions for an average car in the United States are 5.1 metric tons of CO2E. To compare myself to a Hummer driver, I calculated the carbon footprint of all of my flights for this year through August, assumed my monthly emissions rate would be the same for the last 4 months, and came up with 19.3 metric tons of CO2E (about three Hummers worth).