Reviewing “Carbon Footprint” as European Union Drafts Carbon Tax

human-caused greenhouse gas emissions under scrutiny with eu tax plan

By Jonny Lupsha, Current Events Writer

What is a carbon footprint and what are its real numbers? Both are used to measure the amount of greenhouse gas emissions people create on a daily basis, which affect our environment. A proposed carbon tariff by the E.U. raises questions.

Emissions flowing into the air with the sun setting in the background
According to the EPA, 23 percent of 2019 greenhouse gas emissions came from industry burning fossil fuels for energy and certain chemical reactions necessary to produce goods from raw materials. Photo By Tatiana Grozetskaya / Shutterstock

As part of the European Union’s massive plan to combat climate change, the bloc of nations has proposed a border carbon tax on certain goods incoming from nations with more lax carbon emissions regulations. The tariff is intended to counteract the problem of companies in a carbon-restrictive country outsourcing production to more lax countries at cheaper prices, then importing their own goods.

When talking environmental friendliness, the term “carbon footprint” is inescapable—but what is it? How does it translate to real numbers? In his video series The Mathematics of Everyday Life, Dr. Mohamed Omar, Associate Professor of Mathematics at Harvey Mudd College, explained both.

Greenhouse Gas Emissions 101

“Greenhouse gases are gases that absorb and remit heat to the Earth,” Dr. Omar said. “As a consequence, these gases keep the Earth warmer than it would be otherwise. On Earth, the primary greenhouse gases include water vapor, carbon dioxide, methane, and nitrous oxide.”

While these gases occur naturally in the atmosphere, burning fossil fuels—among other human activities—increases their concentration unnaturally. Humanity’s carbon footprint is the total amount of greenhouse gas emissions caused by our normal daily activities, from driving in cars to recycling. The scientific community agrees upon standards of measurement, such as Kelvin for temperature and kilograms for weight, and greenhouse emissions are no different. According to Dr. Omar, they measure them in carbon dioxide.

“Because of this, the scientific community has agreed upon measuring the emission of any greenhouse gas based on the amount of carbon dioxide it would take to generate the same emission,” he said. “So, the generally agreed-upon standard measure for measuring carbon footprint, the amount of greenhouse gases released by human activity, is carbon dioxide equivalent, or CO2e for short.

“For any type of greenhouse gas and any specific amount of it, the CO2e indicates the amount of carbon dioxide that would have an equivalent emission.”

Equivalency in Numbers

As an example, Dr. Omar said to imagine that an industrial region emits 10 tons of methane and one ton of nitrous oxide into the atmosphere. Methane has 80 times the emission as an equal weight of carbon dioxide, while nitrous oxide has 300 times. Then, 10 tons of methane at 80 times the emission of carbon dioxide makes 800 tons of carbon dioxide. One ton of nitrous oxide multiplied by 300 times adds 300 tons to the emission.

So, 10 tons of methane and one ton of nitrous oxide is equivalent to 1,100 tons of carbon CO2e.

“We can get a good sense of U.S. greenhouse gas emissions by looking at the total emissions by sector,” Dr. Omar said. “[In 2018,] the biggest contribution to greenhouse gas emissions [was] transportation, at 28% of all emissions. This contribution [included] the burning of fossil fuels for our various modes of transportations from land vehicles, like cars, trucks, and trains, to other modes of transportation like ships and trains.”

More than 90% of transportation emissions are petroleum-based, which is the beginning of a distinct trend. The second-leading cause of carbon emissions, electricity, makes up 27% of emissions, and nearly two-thirds of that comes from burning fossil fuels like natural gases and coal. Likewise, the third-largest cause of carbon emissions is the industry sector, which makes up 22% of emissions. The majority of those emissions also comes from burning fossil fuels, though some come from chemical reactions needed to produce goods.

Industry lies at the center of the E.U.’s border carbon tax.

Edited by Angela Shoemaker, The Great Courses Daily

About Jonny Lupsha, News Writer 856 Articles
Jonny is a freelance writer and novelist who lives in Sterling, Virginia. He has written for The Great Courses since 2017 and enjoys studying the courses as much as writing about them. Contact Jonny at