Carbon emissions are the human-made greenhouse gases that we put into the atmosphere. These gases disturb the Earth’s natural radiative balance by trapping heat and increasing the temperature of the atmosphere. Carbon emissions from human activities have increased over the past century, and are now at a level that is unprecedented in the modern era.
Human-caused CO2 emissions come mostly from burning fossil fuels for energy. The majority of these emissions are from oil, coal and gas. Other sources include the production of electricity, fugitive emissions from industrial processes, and land-use change (forestry, cropland, etc). Forests and plants act as a natural carbon sink, absorbing more carbon than they emit. However, as forests and vegetation are cleared and burned for agriculture or development, they release CO2.
The most common source of carbon dioxide emissions in the US is electricity generation from fossil fuels. The other large source is transportation, which includes automobiles, trucks, ships and airplanes.
Emissions from manufacturing and industry are also significant. These emissions occur when we make things like cement, iron and steel, electronics, plastics and clothes. Many of these machines run on electricity, which is largely produced from coal and other fossil fuels.
Eating meat is another major contributor to your carbon footprint, with 0.8 tons of emissions from one beef meal a year. Even a single load of laundry produces 0.46 tons of emissions, as it requires electricity to heat water and dry the clothing.