Everyday Sustainability: What Is a Carbon Footprint

Learn What Your Carbon Footprint Means and Why It Matters

While we’ve all heard the term “carbon footprint,” many of us don’t really know what it is. But understanding this concept is the perfect first step toward living more sustainably. We talked to Global Footprint Network to learn what a carbon footprint really is and what it means for your everyday life.

Understanding Your Carbon Footprint: The Basics

What Does the Phrase ‘Carbon Footprint’ Mean?

A “carbon footprint” is a number that estimates the amount of greenhouse gas produced, directly and indirectly, by a person or household’s everyday activities. This number is expressed in tons of carbon dioxide, since CO2 is the most common greenhouse gas created by human activity. However, other gasses, like methane, are also factored into your footprint by converting them into the amount of CO2 that matches their global warming potential.  

How Is Your Carbon Footprint Calculated?

Your carbon footprint is calculated by adding together a number of factors related to your lifestyle using a carbon calculator. There are many different tools out there, but all will ask questions about your daily activities to create a rough estimate of how much carbon dioxide and other greenhouse gasses you add to the atmosphere each year. 

That sounds simple, but calculating a carbon footprint is a complex process. For example, to determine how much your typical meals contribute to your footprint, you can’t just look at the electricity or gas used to cook them. You have to factor in the resources used to raise all of the ingredients, the energy used to process and package them and the fuel used to transport them to the grocery store and your kitchen.

To simplify this process, researchers have broken the country’s overall carbon emissions into several “sectors,” such as agriculture, livestock raising, various types of manufacturing and transportation. They then measured the estimated carbon emissions each sector is responsible for. Online carbon footprint calculators use those totals to calculate your individual footprint. 

Ready to learn what your carbon footprint is? Check out Global Footprint Network’s Ecological Footprint Tool.

If you try out other calculators, you may get different numbers from each tool based on how they make their calculations. But remember that your footprint is always a rough estimate.

What Contributes to Your Carbon Footprint?

Practically everything you do contributes to your carbon footprint. According to David Lin, Research Director for Global Footprint Network, these are the three most significant factors:

Driving your car: "The operation of personal transport equipment is the single biggest contributor to the carbon footprint of the average American citizen. We can reduce our impact by driving less. Walk, bike, carpool, or take public transportation."

Utilities: "Electricity, gas, and other fuels used to power households are the second biggest contributor to carbon footprints in the United States. Americans can mitigate this by powering their homes with renewable energy, using less electricity, and increasing the energy efficiency of their appliances."

Meat Consumption: "The consumption of meat creates the most amount of carbon emissions within the food that we eat. This can be easily remediated by eliminating meat from your diet or limiting your consumption to once or twice a week."

"Walking, biking and eating less meat are also healthy lifestyle changes, which is important because hospital and out-patient services are the third largest contributor to America’s carbon footprint!"

David Lin | Global Footprint Network

Other major factors that contribute to your carbon footprint include:

• How often you fly.
• How much water you use each day.
• How far you travel to work each day.
• Whether you drive a fuel-efficient vehicle.
• Whether you recycle or compost your waste. 
• How often you buy online and have products shipped to you.

Cool, But What’s the Practical Purpose of a Carbon Footprint?

The purpose of a carbon footprint is simply to remind us that whatever we eat, do or use takes energy to produce, ship and function. Everything from the ingredients in your meals to the gas you use to get to work uses up resources—some that aren’t renewable—so we should use those resources responsibly. 

The concept of a carbon footprint also shows us the relationship between our daily choices and the health of our environment by illustrating how our lifestyles contribute to climate change. Understanding that relationship is especially important now that we’re seeing some of the effects of climate change: increasingly destructive storms and more frequent wildfires and floods. We all take part in activities that accelerate climate change; to slow it, we all need to rethink certain aspects of our routines. 

It’s easy to look at the tons of carbon dioxide you produce each year and feel a little guilty. But in reality, knowing your carbon footprint is meant to help you make changes that will have the biggest impact on your contribution to greenhouse gas emissions. 

What’s the Average Carbon Footprint in the U.S.

In the U.S., the average carbon footprint for each individual is 16.5 metric tons (or 6 global hectares) of carbon dioxide per year. That’s more than triple the global per capita average of 4.9 metric tons (or 1.7 global hectares). 

For an even more sobering number, in 2008, students at the University of Michigan researched the average footprints of Americans with different lifestyles. They found that even the lowest American carbon footprints were double the global average.

Our high carbon footprints are especially worrying when it comes to what they mean for our planet's biocapacity. "Biocapacity" refers to an ecosystem's ability to provide all the resources a population uses and absorb its wastes, given our current technology and management practices. According to Lin, the planet’s biocapacity is 1.7 global hectares per person. This means that every human is allotted 1.7 gha to live within the means of our one planet.

"Currently, humanity’s ecological footprint is in overshoot—we’re using 2.8 gha per person on average, which is almost 70 percent greater than the amount of biocapacity available to each person. But the average carbon footprint of Americans is 3.5 times more than the available biocapacity!" 

David Lin | Global Footprint Network

Lin recommends working to bring your own carbon footprint as close to the world average of 1.7 gha as possible. "But an ideal carbon footprint would allow us to live within the means of our one planet," says Lin. "So, well below 1.7 gha."

How Can I Cut My Carbon Consumption?

Don’t let your number scare you. There’s plenty you can do to reduce your carbon consumption and improve your footprint. To make the biggest impact, you can:

• Walk, bike, carpool or use public transportation whenever possible.
• Choose a fuel efficient vehicle when you’re in the market for a new car. 
• Advocate for renewable energy at the local, state and federal level.
• Buy carbon offsets to neutralize carbon emissions you can’t eliminate.
• Use low-flow toilets, showerheads and faucets throughout your home to save water.
• Eat meatless meals once or twice a week—or consider going vegetarian or vegan permanently.
• Install a programmable thermostat so you’re not wasting energy while no one’s home.
• Replace old appliances with Energy Star models when they reach the end of their lives.

For more tips, check out our post on how to reduce your carbon footprint at home.

Knowledge Is Power

Once you know what your carbon footprint means and how it’s measured, you’ll have the data you need to work towards a healthier environment. But it’s not just the planet that benefits. Burning less fuel, eating less meat and using less energy all mean more money in your pocket. Not to mention you’ll be giving yourself a clean, green world to enjoy.

Looking for some help starting your journey to a more sustainable lifestyle? Check out our roundup of 5 Sustainability Apps to Save the Environment.