The environmental cost of your next adventure

It’s summer vacation season, but before you jump in your car and head for the beach, take the fast train up to New York for some shopping therapy, or head to the airport primed for world exploration, you might consider the climate costs of your adventure.

A recent study published in Nature Climate Change found that global tourism accounts for about eight percent of global greenhouse gas emissions. This study calculated the amount of carbon produced by tourists by examining carbon flows among 160 countries between 2009 and 2013. In addition to the means of travel—planes, trains, and so forth—the authors say they have included analysis of the energy needed to support the tourism system, including all the food, beverage, infrastructure, maintenance, and retail services that tourists enjoy.

The research shows that when people travel, they tend to spend more on higher carbon transportation, food, and pursuits. On small island destinations such as the Maldives, Cyprus, and the Seychelles, tourism is responsible for up to 80 percent of annual greenhouse gas emissions. The dilemma for these islands: Their current economies heavily rely on tourist income, but their future ecosystem is highly vulnerable to the effects of rising seas brought by climate change.

The study shows that a real need for tourists to recognize the impact they might have on their vacation destination. How much water, waste, and energy do they use, compared to the local population?

A family of four flying round trip from Los Angeles to Cancun, Mexico emits two tons of carbon dioxide? This number shocked me, it seemed illogically big. So I looked into the science behind the number, and that shocked me too. It seems impossible that a gallon of gasoline—weighing about 6.3 pounds—could produce 20 pounds of atmospheric carbon dioxide. But the weight of that carbon dioxide does not come only from the carbon emitted when gasoline burns, but also from the oxygen it binds to in the air.

(For the detail oriented: A carbon atom has a weight of 12, and each oxygen atom has a weight of 16, giving each molecule of carbon dioxide an atomic weight of 44 [12 from carbon and 32 from oxygen]. To calculate the amount of carbon dioxide produced from a gallon of gasoline, the atomic weight of the carbon in the gasoline is multiplied by 44/12, or 3.7. Gasoline is about 87 percent carbon and 13 percent hydrogen by weight; a gallon of gasoline weighs 6.3 pounds. So the carbon in a gallon of gasoline weighs 5.5 pounds [6.3 lbs. x .87]. Multiply the weight of the carbon [5.5 pounds] by 3.7, and you get the weight of the carbon dioxide formed in the atmosphere from burning a gallon of gas—20 pounds!)

If these calculations seem like a lot of work, know that tools are available to help. Sites like carbonfootprint.com host suites of tools that can help you calculate the carbon costs of vacation behaviors, provide suggestions about how to minimize emissions, and include offset options for emissions that cannot be avoided. There is also a helpful checklist of simple things you can do before you leave home that will help you save money and emissions. Exploring how to become less carbon-intensive while on vacation could lead to changes in routine behaviors that allow you to also become more carbon efficient at home.