Human activities are one of the main causes of greenhouse gas emissions. These increase the earth's temperature and are emitted from fossil fuel usage in electricity and other byproducts of manufacturing. The major effects of such practices mainly consist of climate changes, such as extreme precipitation and acidification, and warming of oceans. Climate change has been occurring since the start of the Industrial Revolution in the 1820s. Due to humans' heavy reliance on fossil fuels, energy usage, and constant deforestation, the amount of greenhouse gas in the atmosphere is increasing, which makes reducing a greenhouse gas footprint harder to achieve. However, there are several ways to reduce one's greenhouse gas footprint, choosing more energy-efficient eating habits, using more energy-efficient household appliances, increasing the usage of fuel-efficient cars, and saving electricity.
Greenhouse gases (GHGs) are gases that increase the temperature of the Earth due to their absorption of infrared radiation. Although some emissions are natural, the rate at which they are being produced has increased because of humans. These gases are emitted from fossil fuel usage in electricity, in heat, and transportation, as well as being emitted as byproducts of manufacturing. The most common GHGs are carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), and many fluorinated gases. A greenhouse gas footprint is the numerical quantity of these gases that a single entity emits. The calculations can be computed ranging from a single person to the entire world.
The latest climate science is published in the IPCC Sixth Assessment Report. The report presents key scientific findings linking the increase in anthropogenic GHGs emissions in current climate change. According to the report, it is only possible to avoid warming of 1.5 °C or 2 °C if massive and immediate cuts in greenhouse gas emissions are made.
The concept and name of the carbon footprint were derived from the ecological footprint concept, which was developed by William E. Rees and Mathis Wackernagel in the 1990s. While carbon footprints are usually reported in tons of emissions (CO2-equivalent) per year, ecological footprints are usually reported in comparison to what the planet can renew. This assesses the number of "earth" that would be required if everyone on the planet consumed resources at the same level as the person calculating their ecological footprint. The carbon footprint is one part of the ecological footprint. Carbon footprints are more focused than ecological footprints since they merely measure emissions of gases that cause climate change into the atmosphere.
Carbon footprint is one of a family of footprint indicators, which also include ecological footprints, water footprints, and land footprints.
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. 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 negative consequences of those industries (under-age smoking, cigarette butt pollution, and plastic pollution) onto individual choices.
BP made no attempt to reduce its own carbon footprint, instead of 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.