In case you think you only have a carbon footprint if you walk, drive, or are otherwise crossing on (or over) land, think again.  Carbon footprints measure the effects on the climate in terms of the amount of greenhouse gases produced, so a boat may impact the planet as much as a jet liner flying cross-country or a truck packed with tomatoes driving up the Atlantic Coast.

A boat’s engine emits two colorless, odorless gases, Carbon Monoxide (CO) and Carbon Dioxide (CO₂), through the exhaust (even those released underwater rise above the surface and into the atmosphere). CO forms when fuel does not burn completely; there has been a lot of focus in recent years on reducing smoggy CO emissions by fine-tuning engines. The approach to lowering CO₂ is different than making engines which burn hydrocarbon fuels (also known as fossil fuels) more efficiently.   Alternative fuel sources such as ethanol are required, or the engine’s power must come from a different source, such as the sun.

Before you can take steps to reduce your fuel consumption or calculate the cost versus benefit of a replacement source, you need to know how much fuel your boat consumes each season. Some of you may first react by saying, “I don’t want to know,” but information is key to a successful reduction of your carbon footprint. Gather your receipts or ask your marina for a summary, and when you know how many gallons you consumed last year, pull out your charts and figure out the distance you covered in all your summertime outings. This will give you an idea of where you are, and may immediately lead you to decide on some quick ways to reduce fuel consumption— keep the boat exterior cleaner for less drag, go a little easier on the throttle, don’t idle for too long, get on plane quickly, and take the time to lighten the excess load you’re hauling around by mid-season (adiós, Uncle Larry!).

A discussion of the methodology of calculating fuel consumption, measuring CO₂ emissions, and gauging carbon footprints doesn’t make for the best magazine reading (and frankly, is way beyond my pay grade).  However, I am listing resources at the end of this story to help you out with your personal calculation and reduction strategies, including offsetting, which is an alternate to reducing or eliminating boating carbon footprints by making cuts in other areas you control, such as planting trees, adding insulation in your home, and carpooling to work. You can also use the information you learn about your boat’s fuel consumption and carbon footprint to make yourself an eco-smarter buyer when shopping for your next boat or replacing the propellers on your current one.

Boats alone aren’t causing climate change, and reducing the collective carbon footprint of boats won’t cure what plagues us (the average American’s choices of food sources, travel, home heating and cooling, and type of auto may amount to CO₂ emissions of about 20 tons a year). As boat owners who use energy-efficient light bulbs and recycle plastic bottles at home also start consciously working on reducing the carbon footprints of their boats, their tow vehicles, the amount and kind of trash they have left over after snacking and dining aboard, and the sources to make and ship the gear they buy to enjoy on the boat, we may all be able to breathe a little easier.

For more information, check out these resources: www.boatcarbonfootprint.com/#reduce, www.carbonfootprint.com/calculator.aspx , fueleconomy.gov