US carbon dioxide emissions related to energy consumption dropped to their lowest point since 1994 last year, according to a US Energy Information Administration report released Monday afternoon.

The decline of coal as a power source in favour of natural gas in the US is a big part of that decline, the EIA reported.

Natural gas power generation increased by 211.8 billion kilowatt hours in 2012 over 2011, while coal power declined by 215.2 billion kilowatt hours last year.

The EIA reported that 2012 was the fifth year in a row that energy-related carbon emissions declined after peaking in 2007, despite GDP growth. Emissions declined 3.8 per cent in 2012 over 2011.

“Although GDP increased by 2.8 per cent in 2012, energy consumption fell by 2.4 per cent in 2012,” according to the EIA report. “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 two per cent or more.”

The total carbon intensity of the US economy declined in 2012 by 6.5 per cent over the previous year, “the largest drop since recordkeeping began in 1949”, mainly because the public has been eschewing coal for natural gas as a primary source of electricity.

The shift from coal to natural gas for electricity generation and slower economic growth were the main factors in reducing US carbon emissions from 2007 to 2012 as compared to the previous 10 years, said EIA analyst Perry Lindstrom.

“Also, population has slowed a bit, which helps,” he said.

The EIA also attributed the carbon emission decline to several other factors, including a warm winter season in the first quarter of 2012, leading to a lower demand for energy to heat homes and businesses.

Residential electricity consumption declined by 3.4 per cent from 2011, partly due to increased home energy efficiency.

US residential carbon dioxide emissions from electricity and direct use of fuels totaled 760 million metric tons in 2012, down from 875 million metric tons in 2010 and 897 million metric tons in 2007.

The US has seen a nearly 10 per cent drop in energy intensity — the measure of British thermal units (Btu) per dollar of GDP — since 2007 largely because people having been driving fewer miles and heating their homes less than they’ve been cooling them.