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Closer than You Think
Latest U.S. CO2 Pollution Data and Forecasts Show Target Within Reach
How about a little good news for a change?
Despite Congress' failure to enact comprehensive energy and climate legislation, surprising, and underappreciated, progress has been made in reducing U.S. carbon dioxide emissions during the last few years. In 2011, U.S. emissions of energy-related carbon dioxide were 8.7 percent below 2005 levels, despite a 5.5 percent increase in the size of our economy. This remarkable result is due primarily to reduced reliance on coal-fired power plants and increased passenger vehicle efficiency, driven by a combination of policy and market forces.
The forecast for 2020, assuming extensions to existing policies that can be reasonably anticipated, is for a further reduction to 10.5 percent below 2005 levels -- a sharp contrast with the forecast made by the Energy Information Agency (EIA) in 2005 that emissions would rise by 25 percent by 2020. Instead, current trends put the 17 percent reduction target embraced by President Obama squarely within reach.
Recent Trends
U.S. energy-related CO2 emissions in 2011 were 2.4 percent below 2010 levels, and 8.7 percent below 2005 levels. While our economy remains sluggish, these pollution reductions can't be attributed primarily to the recession. The U.S. economy grew by 1.7 percent in 2011, and was 5.5 percent larger than it was in 2005.
Many factors affect U.S. carbon pollution, but almost half of the emission reductions from 2005 to 2011 came from power plants. Total electricity consumption increased by 1.2 percent from 2005 to 2011, implying that the 10.4 percent reduction in emissions from the electric sector is attributable to increased reliance on lower-emitting generation sources. Moreover, had electricity consumption instead increased by 2 percent per year, as had been forecast, these emission reductions would not have materialized.
A similar conclusion can be drawn about reduced emissions in the transportation sector. The total number of miles driven in 2011 was approximately 2 percent lower than it was in 2005, indicating that improved vehicle efficiency was the primary contributing factor to the 7.3 percent reduction in emissions during that period.
Improving Forecasts
Looking forward, the official forecast for 2020 -- assuming no new policies -- is now for carbon emissions to be 9.4 percent lower than they were in 2005, a huge contrast to the EIA's "Reference" forecast that emissions would increase by 25 percent between then and 2020.
The EIA also forecasts an "Extended Policies" case that makes the following "business-as-usual" assumptions:
- the 2017-2025 vehicle standards proposed jointly by EPA and the Department of Transportation are implemented;
- tax credits for various renewable fuels and technologies are extended; and
- the Department of Energy continues to update energy efficiency standards for appliances as required by law and consistent with the Department's strategic plan.
Under these conditions (and not assuming pollution standards for power plants or other stationary sources), the Extended Policies case results in CO2 emissions 1.3 percent lower than the Reference case in 2020 and 8 percent lower in 2035. Relative to 2005, U.S. carbon pollution emissions are 10.5 percent lower in 2020 and 11.7 percent lower in 2035 in this scenario.
Where the Opportunities Exist
Effective implementation of the Clean Air Act has the potential to achieve substantial additional emission reductions, allowing the U.S. to meet or exceed the goal of cutting emissions by 17 percent from 2005 levels by 2020. In the absence of new legislation, federal performance standards for existing power plants provide the largest opportunity to reduce emissions relative to the Extended Policies case. That scenario projects that power plants will emit just over 2 billion metric tons of CO2 in 2020, meaning that a 20 percent reduction from that level would hit the target.
That 20 percent decrease could be reached by a 10 percent reduction in electricity demand, by increasing reliance on renewable sources of electricity by 10 percentage points (i.e., from 14 percent of total generation in the Extended Policies case to 24 percent of total generation), or a combination of these measures, assuming these gains were all used to reduce generation from high-emitting coal-fired power plants.
There are many other accessible emission reduction opportunities, from increasing deployment of Combined Heat and Power systems in industry, to installing solar systems on school roofs, and shifting toward electricity to drive our transportation system. The emission reductions achieved to date and the downward shift in the forecast just begin to scratch the surface of what's possible.
What Changed?
Fuel markets. Between 2005 and 2011, gasoline prices rose 33 percent and the average cost of natural gas used to generate electricity dropped 50 percent, and both of these trends drive down emissions.
- More than 70 percent of oil is used in transportation. Higher gasoline prices reduce the number of miles people travel and encourage them to select more efficient vehicles.
- Low natural gas prices encourage power producers to switch from coal to natural gas, reducing CO2 emissions from power plants. On the other hand, lower natural gas prices can also reduce electricity rates, leading to greater electricity consumption and less investment in renewable energy. That disincentive tends to drive up emissions, but the coal-to-gas switching effect has the biggest impact on EIA's latest forecast because of strong energy efficiency and renewable energy policies in place.
Technology. The cost of building coal plants is up, while the cost of wind and solar power are coming down. In addition, advances in energy efficiency technology, such as L.E.D. lighting and super windows, keep replenishing the low-hanging efficiency fruit.
Policy. Although Congress failed to pass comprehensive energy and climate legislation, the Obama administration has forged ahead using its existing authority to set strong efficiency standards for automobiles and appliances, and strong clean air standards that will reduce mercury, sulfur, nitrogen and carbon emissions from power plants. States are also continuing to lead, with renewable energy standards in 29 states and increasingly effective energy efficiency programs spreading to all regions of the country.
Other Global Warming Pollutants
This issue brief focuses on energy-related carbon dioxide emissions, responsible for about 85 percent of U.S. global warming pollution. But emissions of other global warming pollutants should not be ignored. Total U.S. global warming pollution, expressed in carbon dioxide equivalents, fell by 5.5 percent between 2005 and 2010, less than the reduction in energy-related CO2 during this period because emissions of both methane and HFCs had actually increased.
Actual methane emissions are quite uncertain and many people believe that they are both undercounted and underweighted in the official inventory. Some of the CO2 emission reductions achieved could come at the expense of increased methane emissions if coal-fired power plants are replaced by natural gas-fired plants, and if methane leaks from the oil and gas system are not adequately addressed. Emissions of HFCs currently account for only 2 percent of total U.S. global warming pollution, but that figure is rising as HFCs are used to replace ozone-depleting HCFCs. Better alternatives exist and sound policies could reverse these trends.
Conclusion
It's good news that U.S. emissions of carbon dioxide are, at long last, on a downward trajectory. The new "business-as-usual" forecast for 2020, calling for about a 10 percent reduction from 2005 levels, is not enough to be sure, but it puts the 17 percent reduction target within reach.
With strong standards to reduce carbon pollution from power plants, a robust drive to capture the full range of energy efficiency opportunities, and effective measures to reduce emissions of methane and other heattrapping gases, we can get on track to the deep emission reductions we need to protect our health and environment from the worst consequences of climate change.
last revised 7/19/2012
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