Energy-related carbon dioxide (CO2) emissions in the US fell by nearly 4 per cent last year and are now at their lowest level since 1994, according to official figures published by the US Energy Information Administration.
The 3.8 per cent downturn from the 2011 figure is seen as significant because it coincided with a period of modest economic growth. Emissions are now more than 12 per cent lower than at their peak in 2007.
Since 1990, only the recession year of 2009 saw a larger percentage decrease. This will undoubtedly be seized on by President Barack Obama as evidence that his policy of encouraging renewable energy is working.
De-coupling
The latest decline suggests a degree of "de-coupling" between economic growth and rising emissions, as it was the largest in a year with positive growth in per capita economic output – admittedly by only 2 per cent.
A large drop in “energy intensity” (consumption of energy measured against GDP) assisted the 2012 decline. Half of it came from the residential sector, due to a fall in heating demand in the very warm first quarter of the year.
Since 2007, residential sector electricity-related CO2 emissions have declined to levels last seen in the late 1990s. The next biggest decline was in the transport sector, which accounted for 22 per cent of the overall downturn.
Vehicle miles travelled in 2012 were flat compared to 2011, while more energy-efficient cars are continuing to enter the market – following the Obama administration’s insistence on higher standards as a condition for its bailout of the auto industry.
Cheaper natural gas – much of it derived from "fracking" – competed favourably with coal, which has a much higher carbon content, with electricity companies using more gas. This "substantially reduced" the carbon intensity of power generation.
Climate conference
Although China has outstripped the US to become the world's biggest emitter of greenhouse gases, the latest figures will be cited by the US delegation at next month's UN climate conference in Warsaw as proof that Americans are "doing their bit".
