Cars and Carbon Dioxide: How Much Are We Really Putting Into the Air?

Abstract

Cars in the USA and Europe produce billions of tons of CO2 yearly. American vehicles average 27 mpg and emit 5.2 tons of CO2 per year, while European cars get 42 mpg and emit 1.8 tons annually.

How Much CO₂ Does a Typical Car Make? A Simple Guide

Most people drive every day without giving much thought to what comes out of their car's exhaust. However, every gallon of gasoline burned produces carbon dioxide (CO₂), the primary greenhouse gas that contributes to global warming. In this blog, we'll examine the amount of CO₂ produced by a typical car in the United States and Europe, how it is calculated, and what ten years of storage would look like if we were to store it.

Gas Mileage: How Far Can You Go?

In the United States, the average car achieves approximately 27 miles per gallon (mpg) in real-world driving conditions. That means your vehicle can travel 27 miles for every gallon of gas. However, European cars are much more efficient, averaging around 42 mpg.

Why the difference? European cars are often smaller and lighter in size. Additionally, Europe has stricter fuel economy regulations that encourage car manufacturers to develop more efficient vehicles.

The Invisible Weight: CO2 from Burning Gas

When you burn one gallon of gasoline, it creates about 20 pounds of carbon dioxide. How can 6 pounds of gasoline turn into 20 pounds of CO2? It's chemistry! When gasoline burns, the carbon combines with oxygen atoms from the air. The CO2 you create is mainly made from oxygen in the air, not from gasoline.

How I calculated it

Gasoline is primarily composed of carbon (approximately 87%). When you burn it, each carbon atom combines with two oxygen atoms to form carbon dioxide (CO2).

The math looks like this:

One gallon of gas weighs around 6.3 pounds

Carbon in gas: 6.3 pounds × 0.87 = 5.5 pounds of carbon

When carbon becomes CO2, it gets heavier: 5.5 pounds × 3.67 = 20 pounds of CO2

That multiplier (3.67) comes from the fact that a CO2 molecule weighs more than just carbon alone.

The Yearly Toll: How Much CO2 Per Car?

Now, let's combine what we know. How far do people drive? In the USA, the average driver covers about 14,000 miles per year. In Europe, the distance is slightly shorter, around 12,000 kilometers, which is approximately 7,500 miles.

Adding It All Up: CO2 Per Car Per Year

Now let's do the math to see how much CO2 one car produces in a year:

United States:

Miles driven: 14,000 miles per year

Gallons used: 14,000 miles ÷ 27 mpg = 519 gallons per year

CO2 produced: 519 gallons × 20 pounds per gallon = 10,380 pounds (5.2 tons) per year

Europe:

Miles driven: 7,500 miles per year

Gallons used: 7,500 miles ÷ 42 mpg = 179 gallons per year

CO2 produced: 179 gallons × 20 pounds per gallon = 3,580 pounds (1.8 tons) per year

That means the average American car produces almost three times as much CO2 as the average European car each year!

For a single car in the USA, that's about the same as: The inside volume of 7 Walmart Supercenters or 260 average American houses.

Another Simple Explanation

Imagine your car is like a person breathing out. But instead of breathing out a little bit of air, your vehicle breathes out something invisible called CO2 – and it breathes out A LOT of it.

Every time your family drives to school (about 5 miles each way), your car makes about 7 pounds of this invisible gas. That's about as heavy as a bowling ball! By the end of one year, your vehicle has made enough of this gas to fill 10 swimming pools. That's a lot of invisible stuff floating in the air!

All those cars on the highway? They're all making this gas, too. When we add up all the cars in America, we make enough of this gas every year to fill a swimming pool for every single person in the entire country – and then some!

The Total Yearly Impact

There are approximately 280 million cars in the United States and 259 million cars in the European Union (EU). When we multiply these numbers:

USA total: 280 million cars × 5.2 tons = 1.46 billion tons of CO2 per year

Europe total: 259 million cars × 1.8 tons = 466 million tons of CO2 per year

Total Emissions Over 10 Years

Multiply the yearly number by ten:

U.S. car (10 years):

7,840 × 10 = 78,400 pounds (about 39 tons)

European vehicle (10 years):

3,675 × 10 = 36,750 pounds (about 18 tons)

That's a massive amount of gas from just one vehicle.

What Can We Do?

Understanding these numbers helps us see why electric cars, public transportation, and walking or biking when possible are so important. Every gallon of gas we don't use means 20 fewer pounds of CO2. Small changes by millions of people can make a huge difference!

The next time you see a car, remember: it's not just moving people from place to place; it’s also creating tons of invisible gas that enters our air. Being aware of this helps us make more intelligent choices about how we travel.

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Credit where due:

https://www.newscientist.com/article-topic/carbon-capture/

© 2025 Tim Jackson. All Rights Reserved.