US carbon emissions fell to 1994 levels in 2012, despite a growing GDP and the population growing by nearly 3 million. The key to the total emissions decline of 3.8% was a record 6.5% drop in the economy's carbon intensity. That smashes the previous record fall in carbon intensity.
The EIA's must read report on carbon emissions in 2012 says about carbon intensity:
Again, the report is full of important data and is well-worth reading. The data underlines that the US can grow its economy, create 2 million jobs per year, and add 3 million people to its population and cut carbon emissions substantially at the same time, without using magic.
Instead, the combination of using less energy per dollar of GDP and using more zero or low carbon energy is a very real formula for cutting carbon emissions and growing the economy.