Energy-related carbon dioxide emissions declined again in 2012, making it the fourth year of decline in the last five years, according to the Energy Information Administration (EIA).
The overall carbon intensity of the U.S. economy declined by 6.5 percent in 2012, which is the largest drop since records have been kept (1949). Only 1952 and 1981 had declines that exceeded 5 percent.
"Energy-related carbon dioxide emissions" are emissions released at the location where energy is used to generate electricity, transportation and manufacturing.
The energy-related carbon dioxide emissions declined 3.8 percent in 2012, EIA stated. "The 2012 downturn means that emissions are at their lowest level since 1994 and over 12 percent below the recent 2007 peak," according to EIA.
Additionally, emissions have declined five of the last seven years.
The decline in energy-related carbon dioxide emissions occurred when the U.S. economy grew in 2012. "Although GDP increased by 2.8 percent in 2012, energy consumption fell by 2.4 percent," EIA said. "With population growth of about 0.7 percent, per capita output rose by about 2 percent in 2012. The emissions decline was the largest in a year with positive growth in per capita output and the only year to show a decline where per capita output increased 2 percent or more."
How on Earth did energy-related carbon dioxide emissions decline when the U.S. had a population increase and economic growth?
Answer: natural gas and milder weather.
Because of a decline in the use of coal and an increased use of natural gas, the carbon intensity of electricity generation was substantially reduced. Coal usage declined by 215 billion kWh while natural gas increased 211 billion kWh in 2012 when compared to 2011. Wind increased slightly by 19 billion kWh and hydro declined by 42 billion kWh.
A mild heating season helped dampen energy demand and related emissions in 2012, EIA said.
"Half of the overall energy decline was from the residential sector, where a very warm first quarter of the year lowered energy demand and emissions," according to EIA.
Alex Mills is president of the Texas Alliance of Energy Producers. The opinions expressed are solely of the author.