US carbon emissions fall to lowest levels since 1994 - we hope

The Guardian is reporting that Carbon dioxide emissions fell by 13% in the past five years, because of new energy-saving technologies and a doubling in the take-up of renewable energy, the report compiled by Bloomberg New Energy Finance (BNEF) for the Business Council for Sustainable Energy (BCSE) said.

As described by Bloomberg, the US is in the throes of a major shift in energy production. Coal fell to just 18.1% of America's energy mix last year, down from 22.5% in 2007. Oil use also declined.

The explosion of natural gas production, thanks to fracking, filled much of the gap. America got 31% of its electricity from gas-fired power plants last year.

But the report found steadily expanding installation of wind, solar, hydro and geothermal energy. Renewables represented the largest single source of new growth last year, reaching $44bn in 2012, the report said, the report said.

At least, that's what we hope.

Unfortunately you can justify any argument using the right statistics. So how useful are the stats used here?

Certainly increased investment in renewables and efficiency are having a beneficial impact. But it's a stretch to say this alone is responsible for the 13% drop in CO2 emissions.

A quick look at Net Generation by Energy Source figures shows that electricity generation in the US fell from 4,156.745 GW in 2007 to 4,100.656GW in 2011; a 1.3% decrease caused by economic recession. (Something similar is happening in Australia, too.)

The same recession has caused total distillate usage in the US to plummet to 2009 levels:

A reduction in emissions is a good thing, but we simply can't rely on the destructive impacts of economic decline to produce the majority of the cuts required.

Finally, much of the "decrease" is attributed to CO2 reductions from 'fracking' gas rather than using coal. However, as recent research from Queensland gas fields shows, the fugitive emissions from these fields may be so drastically underestimated that the conversion to gas may well be as bad as (or even worse) than coal.

Ultimately all this underlines the simple point: only renewable energy sources cut emissions; and gas is just another fossil fuel.