The Critical Zone

Calculating Carbon Footprints


Three processes have contributed to human-induced increases in the carbon dioxide content of Earth’s atmosphere. Two of these processes concern emissions: increasing global economic activity and an increase in the use of fossil fuels to drive the economy. The third process is a suggested decline in the efficiency of CO2 sinks on land and oceans in absorbing human emissions. These changes characterize a carbon cycle that is forcing stronger-than-expected and sooner-than-expected climate change.

The United States ranks first in total and per capita emissions among the top twenty carbon dioxide-emitting nations and is responsible for more than 22% of the total annual carbon dioxide introduced to the atmosphere by human activity. For perspective, the United States population stands at ~4.5% of the total global population—our society’s profligate lifestyle is supported by our consumption of a greater proportion of Earth’s resources than the rest of humanity and therefore translates to a greater share of the waste products of human activities, in this case, human inputs of carbon dioxide to the atmosphere.

Although the United States Federal government has a policy regarding greenhouse gas emissions and climate change (see U.S. Climate Policy and Actions), each citizen, church, school, and business—all of us—can play a role in reducing our nation’s carbon dioxide input to the atmosphere. Reducing the amount of energy we use is one important step in the effort to reduce carbon dioxide emissions. To do so, we must first inventory our carbon dioxide emissions by identifying the energy-intensive activities we partake in throughout our day-to-day lives.

Go here to find information that was once available through the link above: January 19, 2018 Snapshot.

You may also be interested in exploring the U.S. Climate Resilience Toolkit, designed to help citizens, communities, businesses, and others to manage climate-related risks and to improve resilience to extreme events.



For this activity, you are to use three different "calculators" to calculate your own carbon footprint. As you use the three calculators, consider these questions:

  • How do the results compare between calculators?
  • To what activity(ies) do you attribute a majority of your personal emissions?
  • How might you best accomplish a reduction in your carbon dioxide emissions?
  • What percentage of total U.S. emissions derive from household emissions versus industry, government, etc.?
  • How might widespread reduction (halved) of U.S. household emissions contribute to a reduction in total U.S. emissions?
  • In a general sense, how might a business-as-usual approach versus a reductionist approach influence climate change and Critical Zone processes?
  • Are there any activities you can engage in that will benefit soil, the central component of the Critical Zone, at the same time as reducing your personal carbon footprint?

I ask you to be honest, with yourselves, with me, and with your classmates. Remember: On average, the U.S. citizenry’s carbon dioxide emissions are grossly out of balance with the rest of Earth’s human inhabitants, so we all play a role in current emission levels. Let’s see what we can learn through a non-judgmental assessment of our community’s lifestyles.

  1. To begin, use the calculator located at the following Environmental Protection Agency (EPA) Web site:
    • Personal Emissions Calculator
    • The EPA calculator is no longer easily available, if at all. Please Google Carbon Footprint calculator and choose a calculator to go along with choosing others described in step 2. Provide a sentence in your report that names the calculator and provide the relevant URL.
  2. Next, use two more calculators, either from the list found on the EPA site or using the one below:
  3. Once you have accomplished these simple personal calculations, use the same calculators you just used to calculate the carbon footprint for your school or business. Address similar questions as above.

Submitting your work

  1. Enter the "Lesson 3 - Carbon Footprint" discussion forum in Canvas.
  2. Post a summary of your responses to the questions above for both your personal carbon footprint and your school/business carbon footprint.
  3. Read postings by other EARTH 530 students to compare your ideas and experiences.
  4. Discuss! Respond to at least one other posting by asking for clarification, asking a follow-up question, expanding on what has already been said, etc.

Grading Criteria

You will be graded on the quality of your participation. See the grading rubric for specifics on how this assignment will be graded.

Check this out!

Interested in determining the potential C footprint for a planned building construction or retrofit? See: the Green Footstep website to learn how to plan and design for C neutrality.

Also, visit Global Footprint Network for yet another C footprint calculator as well as an assessment of various country's standing with respect to their C emissions and more.