What if Carbon Left Your Tailpipe as Solid Chunks?

Published: January 28, 2020

Kirk Johnson: Many people find it hard to believe that humans are acting as a geologic force, outstripping even volcanoes as a contributor to global climate change. Have you ever thought about how much carbon is in a gallon of gasoline? Let’s weigh it and find out. A gallon of gasoline weighs about 6.3 pounds; 87 percent of that is carbon, and that means there’s five pounds of carbon in a gallon of gasoline.

Narrator (Johnson): Think of that like a five-pound bag of charcoal briquettes.

Johnson: When you burn gasoline, you create carbon dioxide and water. Carbon dioxide is an odorless invisible gas. But think about this: What if the carbon came out of your tailpipe not as carbon dioxide, but as solid chunks of carbon?

Narrator: Kind of like car turds.

So, if the average American car gets around 25 miles to the gallon, that means that every 25 miles, you’re dumping five pounds of car turds out of your tailpipe. The average mileage for each car is about 12,000 miles a year, so that releases over a ton of carbon. In the U.S., there are a total of about 100 million cars on the road, releasing about 330,000 tons of carbon per day. When we include the rest of the world’s one billion cars, we reach 3,000,000 tons of car turds—every day. And that’s just cars. When we add in power plants, factories, aviation and agriculture and multiply it by 365, the total carbon released from human activities in a year is a massive 12.5 billion tons, enough to leave a pile of car turds four miles across and over a mile high.