Why did US energy related carbon emissions fall another 3.8% in 2012 and fall to 1994 levels? Simply put, emissions from coal and oil are dropping substantially.
Plummeting carbon emissions from coal--down 12% in 2012--led the way to US carbon emissions declining another 3.8% in 2012. Emissions from oil dropped also 2%, while natural gas emissions rose 4.5%.
The raw numbers show that emissions from coal and oil fell 212 million tons and 50 million tons respectively for a total of 262 million tons. Emissions from natural gas rose 58 million tons. The net decrease was 204 million tons or 3.8% of the previous year (2011) total.
The rise in gas emissions came, because natural gas generation displaced large amounts of coal-fired generation and natural gas also reduced oil consumption to run power plants, to heat buildings, and marginally to run vehicles. More renewable energy in transportation and power production and more energy efficiency also contributed to declining carbon emissions.