Is flying or driving better for the environment?

When it comes to climate change and travel, it sometimes seems that we as individuals are more in tune with how to mitigate our small impacts (like swapping out everyday items on a vacation) than our large ones (like minimizing the massive carbon footprint we create just to get to that vacation). But the latter is certainly important: According to the United Nations World Tourism Organization, tourism is responsible for about 5 percent of all carbon dioxide (CO2) emissions in the world — and transportation accounts for 75 percent of that. In 2016, transportation was responsible for the largest portion of all U.S. greenhouse gas emissions.

Of course, you can’t take a vacation without using some sort of transportation — so the question then is which option is your best bet if you want to minimize your carbon footprint? Let’s take a look.

It’s a complicated comparison

In general, ThoughtCo. reported, driving generates less greenhouse-gas emissions than flying; and according to Sierra Club, domestic airliners are less fuel efficient than cars. But there are lots of factors that go into determining a transportation mode’s environmental impact — such as the distance traveled, the number of passengers and the vehicle and fuel types. For example, a hybrid sedan generates less greenhouse gas emissions than a traditional fuel SUV; and, according to Sierra Club, carpooling is more earth-friendly than driving alone (the more people you have in the car, the less each person’s environmental impact will be). As for flying, according to Yale Climate Connections, long flights are more efficient than short ones, because cruising uses less fuel than taking off and landing. Using the same logic, flying nonstop is a more efficient choice than booking a trip with layovers.

The International Council on Clean Transportation (ICCT) completed its own analysis and concluded that for 300 to 500 mile trips, flying may be more efficient than driving alone; but if you have at least two passengers in the car, driving takes the lead. That said, there are exceptions (for example, driving with two passengers in a large vehicle like a full-size van or truck is still less efficient than flying), so it’s worthwhile to consider the specifics of your own trip before making a decision. ICCT’s chart can provide helpful guidance, as can carbon footprint calculators like those from TerraPass, The Nature Conservancy and the International Civil Aviation Organization.

There’s a better option than both flying and driving

The most environmentally friendly way to get to and from your vacation might not be driving or flying. According to the ICCT, buses are more efficient than both cars and planes in most scenarios. Per their chart, a car only becomes a more efficient option than the bus if it’s a small- or average-size hybrid with at least four passengers; or it’s a small- or average-size sedan or any hybrid with at least five passengers.

Similarly, in a report on “Getting There Greener,” the Union of Concerned Scientists stated, “from a carbon perspective, motor coaches and trains are among your lowest-emission options, especially on shorter (less than 500-mile) trips.”

There are ways to reduce your footprint either way

Regardless of your choice, there are steps you can take to minimize your environmental impact. When driving, “try to rent a [hybrid or electric] car...for your trip,” said Samantha Bray, the managing director at the Center for Responsible Travel. “In many cases, savings from the gas will make up the rental cost.” On the road, she added, “accelerate slowly and try to ‘coast’ as much as possible when braking (unless you’re driving a hybrid, in which case braking charges the car), [and] try to maintain speed.”

If you go with air travel, opt for direct flights when possible; and consider booking with an airline that uses biofuel and takes other steps to be efficient. “Research what individual airlines are doing, and try to book on larger planes and/or newer, more fuel-efficient fleets,” Bray said. Sites like Atmosfair provide helpful information on the efficiency of various airlines.

And whether you’re driving or flying, it’s possible to offset your emissions by making donations to projects and organizations that work to reduce greenhouse gas emissions. “There are a variety of nonprofits that provide the tools to locate and donate to projects that are reducing greenhouse gases by developing clean energy alternatives, such as converting waste to biogas, building more fuel efficient cookstoves or constructing wind turbines,” Bray said. She noted that some airlines and car rental companies offer the opportunity to do so when you book. United, Delta and JetBlue, for example, all have offset programs.

You don’t have to purchase an offset through your transportation provider, though. Bray recommended finding a project to donate to through sites like Cool Effect, Atmosfair or another nonprofit organization “that provide[s] advocacy and education around clean energy and climate change, while also passing as much of the donation as possible to the project of your choosing.” She added, “the most important thing is ensuring that the project itself is Gold Standard Certified, which utilizes UN protocols and the Sustainable Development Goals to assess every project.”

Assessing the environmental impact of every trip you take can be overwhelming; but with increasingly available tools like carbon calculators and offset programs, it’s becoming easier and easier to be a conscious traveler.