2014 saw a slight rise in US carbon emissions

The US Energy Information Administration has run the numbers on 2014's carbon emissions, and some of them are quite good. The amount of CO₂ emitted per unit of energy dropped by 0.3 percent, and the energy use per unit of GDP dropped by 1.2 percent. However, since the GDP grew even faster, the overall emissions of the US rose by 1.7 percent. While the overall trend has been downward for the last decade, we're in a position where any rise presents a challenge for the country's long-term energy goals.

In absolute numbers, the US' energy consumption produced 5.4 billion metric tons of carbon dioxide last year, a figure that was 51 million metric tons above 2013's numbers. Both commercial and residential sectors contributed a bit under 20 million metric tons to that increase; industry actually saw an 11 million metric ton drop, largely due to a transition to natural gas. The biggest contributor to the rise was transportation, where low fuel costs spurred an increase of 24 million metric tons.

This slight rise came despite 2.4 percent GDP growth. In general, the US no longer sees its GDP growth tightly coupled to energy use, and the transition to natural gas and renewables is limiting the carbon emitted by energy use.

For the past decade, all the numbers look good. Population went up by seven percent, and GDP per capita rose by 2.4 percent. Despite this, CO₂ emissions dropped by over 10 percent. But even a small rise in emissions now will make reaching future emissions targets that much harder.