
A carbon footprint is the total greenhouse gas (GHG) emissions (including carbon dioxide and methane) caused by an individual, event, organization, service, place, or product, expressed as carbon dioxide equivalent (CO2e).

A greenhouse gas is a gas that absorbs and emits radiant energy within the thermal infrared range, causing the greenhouse effect[1]. The primary greenhouse gases in Earth’s atmosphere are water vapor (H2O), carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), and ozone (O3). Without greenhouse gases, the average temperature of Earth’s surface would be about 0 °F, rather than the present average of 59 °F. The atmospheres of Venus, Mars, and Titan also contain greenhouse gases.

The carbon footprint includes direct emissions, such as those that result from fossil-fuel combustion in manufacturing, heating, and transportation, as well as emissions required to produce the electricity associated with goods and services consumed.

A carbon footprint is usually expressed as a measure of weight, as in tons of CO2 or CO2 equivalent per year. The carbon footprint concept is related to and grew out of the older idea of ecological footprint, a concept invented in the early 1990s by Canadian ecologist William Rees[2] and Swiss-born regional planner Mathis Wackernagel[3] at the University of British Columbia.

An ecological footprint is the total area of land required to sustain an activity or population. It includes environmental impacts, such as water use and the amount of land used for food production. The idea of a personal carbon footprint was popularized by a large advertising campaign of the fossil fuel company BP in 2005, designed by Ogilvy[4]. It instructed people to calculate their personal footprints and provided ways for people to “go on a low-carbon diet”.

This strategy, also employed by other major fossil fuel companies borrowed heavily from previous campaigns by the tobacco industry and plastics industry to shift the blame for the negative consequences of those industries (underage smoking, cigarette butt pollution, and plastic pollution) onto individual choices. BP made no attempt to reduce its own carbon footprint, instead expanding its oil drilling into the 2020s.

However, the strategy had some success, with a rise in consumers concerned about their own personal actions, and the creation of multiple carbon footprint calculators. An individual’s, nation’s, or organization’s carbon footprint can be measured by undertaking a GHG emissions assessment, a life cycle assessment, or other calculative activities denoted as carbon accounting.

Once the size of a carbon footprint is known, a strategy can be devised to reduce it, for example, technological developments, energy efficiency improvements, better processes, and product management changed Green Public or Private Procurement (GPP), carbon capture, consumption strategies, carbon offsetting, and others.

Although some production of greenhouse gases is natural, human activity has increased production substantially. Major industrial sources of greenhouse gases are power plants, residential buildings, and road transportation, as well as energy industry processes and losses, iron and steel manufacturing, coal mining, and chemical and petrochemical industries.

Changes in the environment also contribute to the increase in greenhouse gas emissions such as deforestation, forest degradation, land use changes, livestock, agricultural soils and water, and wastewater.

China is the largest contributor to greenhouse gas, causing up to 30% of the total emissions. The United States contributes 15%, followed by the EU with 9%, then India with 7%, Russia with 5%, Japan with 4%, and other miscellaneous countries making up the remaining 30%.
Footnotes
- The greenhouse effect is a process that occurs when energy from a planet’s host star goes through the planet’s atmosphere and heats the planet’s surface, but greenhouse gases in the atmosphere prevent some of the heat from returning directly to space, resulting in a warmer planet. Earth’s natural greenhouse effect makes life as we know it possible and carbon dioxide plays a significant role in providing for the relatively high temperature on Earth. The greenhouse effect is a process by which thermal radiation from a planetary atmosphere warms the planet’s surface beyond the temperature it would have in the absence of its atmosphere. Without the greenhouse effect, the Earth’s average surface temperature would be about −0.4 °F compared to the Earth’s actual average surface temperature of approximately 57.2 °F. In addition to the naturally present greenhouse gases, human-caused increases in greenhouse gases trap greater amounts of heat, causing the Earth to become warmer over time. [Back]
- William Rees, FRSC (born December 18, 1943), is Professor Emeritus at the University of British Columbia and former director of the School of Community and Regional Planning (SCARP) at UBC. Rees taught at the University of British Columbia from 1969–70 until his retirement in 2011–12 but has since continued his writing and research. His primary interest is in public policy and planning relating to global environmental trends and the ecological conditions for sustainable socioeconomic development. He is the originator of the “ecological footprint” concept and co-developer of the method. [Back]
- Mathis Wackernagel is a Swiss-born sustainability advocate. He is President of Global Footprint Network, an international sustainability think tank with offices in Oakland, California, and Geneva, Switzerland. The think-tank is a non-profit that focuses on developing and promoting metrics for sustainability. After earning a degree in mechanical engineering from the Swiss Federal Institute of Technology, he completed his Ph.D. in community and regional planning at the University of British Columbia in Vancouver, Canada in 1994. There, in his doctoral dissertation under Professor William Rees, he worked with Rees in creating the ecological footprint concept and developed the accounting methodology for it. [Back]
- Ogilvy is a New York City-based British advertising, marketing, and public relations agency. It was founded in 1850 by Edmund Mather as a London-based agency. In 1964, the firm became known as Ogilvy & Mather after merging with a New York City agency that was founded in 1948 by David Ogilvy. The agency is part of the WPP Group global agency network. It provides services in five areas: growth and innovation; advertising, brand, and content; public relations and influence; experience; and health. [Back]
Further Reading
Sources
Wikipedia
Britannica
Tabitha Whiting