US carbon emissions have dropped sharply and surprisingly since their peak in 2007. Here are 8 key facts to help understand how and why, and data is in the Environment section at:
1. Total US energy related carbon emissions peaked at 6,020 million tons in 2007.
2. Of that 2007 peak total, coal emissions were 2,172 million tons and oil emissions were 2,603 million tons. The remainder came from natural gas.
3. By the end of 2011, total emissions fell 9% or 549 million tons to 5,471 million tons.
4. Of the 2011 total, coal accounted for 1,867 million tons and oil 2,299 million tons.
5. Between 2007 and 2011, emissions from coal and oil fell respectively 305 million tons and 304 million tons, while natural gas emissions increased 61 million tons, as gas displaced coal to make electricity.
6. Coal's market share of electricity generation dropped from about 48% to 42% of America's power from 2007 to 2011.
7. During the first 5 months of 2012, total carbon emissions fell 144 million tons, when compared to the first 5 months of 2011.
8. During the first 5 months of 2012, coal emissions were down 18% or 132 million tons, when compared to the same period of 2011. During April 2012, gas-fired generation actually equaled coal-fired generation, with both providing 32% of the nation's electricity.
9. Oil emissions fell 2% or 18 million tons for January to May 2012, when compared to January to May 2011.
10. About 80% of the decline in carbon emissions from coal in 2012 during the first 5 months is the result of natural gas displacing coal generation, as renewable generation has fallen so far in 2012 and nuclear power is stable. The small portion of the 2012 decline not attributable to gas is a product of 2% decline in electricity sales compared to the same period in 2011.