U.S. Carbon Emissions Are At Their Lowest Level In 20 Years

Air pollution! We've got it on the run in the United States, people. Everyone give yourselves a pat on the back because the Environmental Protection Agency announced that carbon emissions 2012 reached their lowest levels since 1994.

The EPA says that emissions last year were 12 percent below their 2007 peak, that we've seen the biggest decrease since the recession-tastic year of 2009, and that energy-related carbon dioxide emissions have declined in 5 out of the last 7 years.


Two reasons for the decline in emissions come to mind immediately:

  • You Jalops aren't out doing donuts in empty parking lots nearly as much as you claim you are
  • It's a complicated outcome that is the result changes in energy sources, new technology, and driver habits

Probably the second one, the more I think about it.

The decline in emissions isn't totally related to cars and transportation, but that is one big part of it. The biggest, however, was in the residential sector. First, 2012 had a relatively warm first quarter, which dampened the need the demand for energy in colder months. Second, an "increase in electricity generation, transmission, and distribution" of electricity led to lower home power-related emissions.


But the second largest factor in the emissions decline was transportation, which accounted for 22 percent of the drop. The EPA attributes this to driving miles staying flat from 2011 to 2012 while more energy-efficient vehicles enter the market. Keep in mind that's just about any new car, not just hybrids and electrics. It's way down from where it was in 2007, the top line in this graph.

Vehicle miles traveled were also lower in 2012 than 2007 by 3.3 percent while vehicle fleet efficiency improved 16 percent between 2007 and 2012.


In addition, the EPA says the "carbon intensity" of the U.S. economy — carbon dioxide per GDP — was down 6.5 percent thanks largely to natural gas competing with more polluting coal than ever before. There was also an increase in wind power generation, but this seems to have been more than offset by a large drop in hydropower generation.


Overall, the drop in carbon emissions appears to be good news, especially as it comes at a time when the economy is slowly improving. Even the EPA will admit it's hard to draw conclusion from one year of data, but let's hope this downward trend continues.


Photo credit Shutterstock

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