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Being a greener traveler isn’t as simple as swapping one mode of transport for another.
What type of transportation should you take if you want to leave the smallest carbon footprint? The answer is not that simple.
The flight shame movement has taken off on the basis that flying is terrible for the environment. But for those who want to do better by planet Earth and reduce their climate change–inducing carbon footprint, simply reducing their reliance on air travel will only address one small slice of the problem.
In the United States, the overall transportation sector is the biggest producer of greenhouse gas emissions, according to the U.S. Environmental Protection Agency (EPA). In 2017 (the most recent year for which data is currently available), transportation accounted for 29 percent of greenhouse gas emissions, followed by electricity at 28 percent, and industry at 22 percent.
Within the transportation sector, road vehicles are actually the biggest culprit, accounting for a whopping 82 percent of those emissions, with aircraft accounting for 9 percent, and rail for 2 percent (ships, boats, and other forms of transportation account for 7 percent combined), according to the EPA.
It’s a similar story on the global front. In the European Union, road transport accounted for 72 percent of transportation-related CO2 emissions in 2016, according to a report released by the European Parliament this year. The next largest contributor was water transport (boats and ships), at 13.6 percent, followed by air travel at 13.4 percent. Rail only contributed 0.5 percent.
So, why does air travel get such a bad rap? Well, that’s because when you look at the emissions attributable to an individual passenger traveling by car versus rail versus air, air travel does pretty miserably. For instance, according to the site EcoPassenger, which calculates per-passenger carbon emissions between destinations in Europe, for a person traveling from London to Paris during a popular travel time (so when trains and planes are likely to be more full and thus more efficient), the CO2 output would be 122 kilograms if that person flew, versus 48 kilograms if he or she drove or 15 kilograms by train.
And if you’re wondering where cruise ships fall into the lineup, they don’t have a strong track record either. The International Council on Clean Transportation recently concluded that even the most efficient cruise ships emit between three and four times more CO2 per passenger, per kilometer than an airplane.
Rail travel, however, is consistently one of the lowest emitters. It’s not surprising that the flygskam or “flight shame” movement inspired by Swedish climate activist Greta Thunberg has put the emphasis on converting air travel to much less impactful rail journeys.
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National rail operator Amtrak reports that one of its electric trains emits .074 kilograms of greenhouse gases (CO2 ) per passenger mile, compared with .227 kilograms of greenhouse gases per passenger mile for short-haul flights (flights less than 300 miles), and .137 kilograms of greenhouse gases per passenger mile for longer flights (flights between 300 and 2,300 miles). That translates into 70 percent fewer emissions for a rail journey when compared to a short-haul flight and about half the emissions for a rail journey when compared to a long-haul flight.
In short, if you opt to take a train versus a plane, your carbon output for that journey will likely be quite a bit lower. But that’s definitely not as easily done in the United States, which as the fourth largest country in the world has huge expanses to cross, and where the rail system is notoriously behind in sophistication and scope compared to its international counterparts, including the high-speed rail networks of Europe.
So, what if you opt to drive instead of fly? Well, that’s where the issue becomes more complicated. For one, depending on the distance and the passenger load, driving may not result in a considerably lower emissions output. A recent BBC article citing U.K. government energy data noted that CO2 emissions per passenger, per kilometer traveled were .171 kilograms for a passenger car with one person in it, versus .102 kilograms for a long-haul flight, and .133 kilograms for a shorter-haul domestic flight within the United Kingdom.
Sure enough, the more people in the road-based vehicle, the lower the per-passenger emissions, with CO2 emissions per passenger, per kilometer traveled being .043 for a bus, and .041 for each person in a car with four people traveling in it (versus only one, cited above). The lowest emitter (once again) was high-speed rail, at .006 kilograms, according to the U.K. government data.
Additionally, if you opt out of a flight and choose to drive instead, you are joining the masses on the road to be part of what is in fact the biggest overall contributor to greenhouse gas emissions in the transportation sector. A lot more people drive in this world than fly. The aviation industry accounts for about 2 percent of global carbon emissions, according to the Natural Resources Defense Council. So that means that if everyone were to stop flying, just 2 percent of the problem would be solved.
While some people might be craving a simple, impactful solution to reducing their travel carbon footprint—and sure, making a statement by not flying, for instance, is certainly significant—the reality is that for those who want to make a lasting and longer-term difference, a more thoughtful approach to transportation decisions will be needed.
According to David Reichmuth, Ph.D., a senior engineer with the Union of Concerned Scientists’ Clean Vehicles Program, for travelers looking to reduce their impact, they should be thinking about several factors.
“There’s a lot we can do to make [transportation] cleaner and have fewer emissions. So, for passenger vehicles, having both more efficient gasoline vehicles but then also switching entirely from petroleum to electricity allows for reducing both tailpipe emissions and climate-changing emissions,” said Reichmuth.
Reichmuth added that concerned travelers should be thinking about greener vehicles, whether that is their own cars (which he argues is where the biggest impact could be made within a given household) or by being more informed about how efficient their aircraft, bus, or train is. Even within rail travel, for instance, there is a wide range of emissions output depending on the types of trains—diesel trains are typically more polluting than electric trains, and some electric trains are less efficient than others. He also said travelers should think about avoiding vehicle use when possible by walking or biking and should consider taking greater advantage of public transit opportunities and carpooling.
One way to be more informed about each mode of travel is to calculate and compare the carbon emissions output of a given trip. Thankfully, there are numerous, free, online calculators that help travelers do this now. The International Civil Aviation Organization, which is part of the United Nations, has a version for air travel that is intended for use in buying carbon offsets. The site offCents, meanwhile, allows users to calculate emissions for their rail, car, or airplane travel, with the aim of recommending corresponding offset programs, which users can contribute toward to offset their journeys.
Ultimately, the biggest factors impacting emissions related to travel are decisions that are made at the policy level—regulations that dictate what kind of emissions standards manufacturers must abide by.
Travelers who want to see their journey truly become greener should speak up. The airline industry is beginning to take notice of growing concerns about climate change and has begun to make some serious strides when it comes to scaling back on emissions, as well as offsetting them (they are also being required to do so by national and international regulations that have been put into place).
“To the extent that you can, take an active role in advocating for these policy actions. That can be at the local level,” said Reichmuth, noting that many municipalities have their own individual climate goals and action plans that citizens can get involved in. At the state and federal level, people can also advocate for and support clean vehicle policies that could ultimately result in travelers having a larger, and ideally greener, range of vehicles and modes of transportation to choose from.
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