- U.S. carbon emissions peaked in 2007 at 6.0 billion metric tons and have since fallen by 12 percent to 5.3 billion metric tons in 2018.
- Though carbon emissions increased 3 percent from 5.1 billion metric tons in 2017 to 5.3 billion metric tons in 2018, this can be partially explained by stronger economic growth.
- Carbon efficiency has increased dramatically when measured in terms of national output, dropping from 830 million metric tons per billion dollars of real GDP in 1973 to just 283 tons in 2018.
- Each dollar of GDP took 64 percent less carbon to produce in 2018 than 35 years earlier.
- In 2010 the Energy Information Agency projected the U.S. would emit 5,826 million tons of carbon in 2018. The figure turned to be 5,280 million tons, 8.8 percent lower.
- Because of this progress, in 2020 the EIA cut its forecast for emissions in 2035 by 25 percent relative to its 2010 projection.
- This reduction in projected emissions is nearly the equivalent of the total current emissions by Germany, France, and Italy combined.
- The 2020 forecast for tons of carbon dioxide per person in 2035 is also below the 2010 forecast. We can attribute this to technological change and the natural gas revolution. In the 2010 Annual Energy Outlook, EIA projected that carbon emissions from coal would fall by 0.20 percent from 2007 to 2018 and those from natural gas would fall 1.73 percent over the same period.
- In fact, emissions from coal fell 42 percent while emissions from natural gas increased 31 percent, reflecting the adoption of natural gas and resulting in a net decrease in emissions relative to expectations.
The reduction in U.S. carbon emissions has been one of the great untold success stories of the 21st century. It shows that done carefully, moves toward less carbon emissions need not radically reduce the living standards of the American people as some current proposals almost certainly would. The key seems to be to rely on technological improvement as witnessed by the 64 percent decline in carbon emissions per unit of GDP.
Changing the composition of fuel for electricity generation – coal to natural gas – is one such example. 27 percent of US electricity is generated by coal. Total coal consumption dropped by a third in a decade. The natural gas and coal have essentially switched places as the source of electricity generation. But efficiency of use is equally important. Between 2009 and 2018 total electricity generation rose only 5.7 percent. By contrast GDP rose by nearly 25 percent.
Wind and solar power now provide 8 percent of US electricity generation and hydroelectric power provides 7 percent. A cost-effective expansion of wind and solar power over the next twenty years could double the share of total power generation from these two sources. Much of this will happen by market forces assuming projected increases in the efficiency of generation from solar power occurs. Coupled with a continued gradual shift from coal to gas, carbon emissions should be expected to continue to drop both in absolute terms and, even more sharply, in terms of GDP.
The benefits of expanding the great North American carbon sink need also be considered. At the end of the 1990s some scientific studies reported a drop in carbon dioxide levels between the eastern Pacific and the western Atlantic, implying that on net North America “sucked” in more carbon than it emitted. Other studies critical to this finding concluded that the net change was zero, meaning that North America did not emit any net new carbon as the winds blew across the continent. The carbon sink is created by the vast forests and natural prairie that overs the continent. Reforestation programs and smart land use programs can also contribute to further reductions.