The primary sources.
What is it we do that causes an overproduction of greenhouse gases? There are six primary sources that result from human activity, including electricity production, transportation, industry, commercial and residential, agriculture, and land use. Electricity production is at the top of this list because it is the largest contributor of greenhouse gases, which occurs from the burning of fossil fuels. "Of the total amount of U.S. greenhouse gases emitted in 2011, about 86% were energy related and 92% of those energy-related gases were carbon dioxide from the combustion of fossil fuels" (Energy in Brief). The next largest contributor is the burning of fossil fuels from our various modes of transportation. In 2012 alone, the burning of petroleum accounted for 2.3 billion metric tons of energy-related carbon dioxide emissions (Energy in Brief). Industry comes in as the third largest contributor, even though greenhouse gas emissions have actually declined in this sector since 1990 while others have increased (Sources). In industry, burning fossil fuels for energy produces the emissions, but also certain chemical reactions used to make products. Commercial and residential emissions do not include electricity use, but specifically the burning of fuel for heat as well as for cooking needs. Waste and waste management also fall under this category. Agriculture adds emissions to the mix from various practices to manage soils, livestock (yes, livestock such as cattle produce methane during their digestion), and manure management. Finally, the last sector is land use. This is an important sector because it has two sides to it. Deforestation releases huge amounts of carbon dioxide because trees naturally sequester it, so the destruction of forests are detrimental. But, in the total US greenhouse gas emissions by economic sector for 2011, land use is not included because it actually removed more carbon dioxide than was emitted. To read more about the individual sectors and their contributions, click here. |
It is pretty clear we burn a lot of fossil fuels, but why should we care? Click the button below to take a closer look at carbon, and how it's effecting the Earth.
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References
"Energy in Brief: What Are Greenhouse Gases and How Much Are Emitted by the United States?" EIA. U.S. Energy Information Administration, 25 July 2013. Web. 13 Apr. 2014.
"Sources." EPA. Environmental Protection Agency, n.d. Web. 13 Apr. 2014.
"Sources." EPA. Environmental Protection Agency, n.d. Web. 13 Apr. 2014.