Study shows that Trump’s new “Affordable Clean Energy” rule will lead to more CO2 emissions, not fewer

By Tom Yulsman | June 19, 2019 8:46 pm
Global warming spiral
This animated spiral portrays the simulated changes in the global average monthly air temperature from 1850 through the present relative to 1850-1900, and then where they are projected to head if we do nothing to reduce emissions of carbon dioxide. (Source: Jay Alder, USGS)

The Trump administration has rolled back Obama-era climate change rules in an effort to save coal-fired electric power plants in the United States.

The action comes in the form of the “Affordable Clean Energy rule,” which Environmental Protection Administration head Andrew Wheeler signed today.

Unfortunately, research shows that “clean energy” is the opposite of what this rule will produce.

A story today in the Washington Post summarizes the new plan this way:

Unlike the Obama administration’s 2015 Clean Power Plan, the new rule does not set specific greenhouse gas emissions cuts for each state. Instead, it allows state regulators to determine how utilities can improve efficiency and will not force companies to switch from coal to lower-carbon energy sources.

The Trump Administration claims the plan is intended to cut emissions 35 percent below 2005 levels by the end of the next decade. But research published last April in the journal Environmental Research Letters shows that over the long run, it is likely to lead to increased emissions.

According to the study’s authors, that’s the result of a “rebound phenomenon”: Thanks to the efficiency improvements anticipated by the ACE plan, coal plants will operate more frequently, and for longer periods of time. That, in turn, will lead to increased CO2 emissions by 2050 compared to what would happen if there were no rule in place at all.

Moreover, the researchers found that, compared to no policy, by 2030 the new rule will increase sulfur dioxide pollution from coal-fired power in 19 states, and nitrogen oxide pollution in 20 states plus the District of Columbia. This will have negative impacts on human health.

“The key takeaway is that ACE is a free pass for carbon emissions,” says Kathleen F. Lambert, a study co-author and Senior Advisor at Harvard’s Center for Climate, Health and the Global Environment.

The trend of carbon dioxide concentration in the atmosphere as measured on Mauna Loa in Hawaii. The growth rate of CO2 has been accelerating. (Source: NOAA/Scripps Institute of Oceanography)

Carbon dioxide concentrations have been increasing every year — and the rate of increase has been accelerating, as the graphic above shows.

In the 1960s, CO2 as measured on Hawaii’s Mauna Loa increased at a rate of about 0.8 ppm per year. In the 1980s and 1990s, it was 1.5 ppm year. Now, CO2 is increasing at a rate that exceeds 2 ppm per year.

The culprit: Increasing emissions of CO2.

Here’s a summary of the study investigating the likely impact of Trump’s ACE rule, as described in a Harvard release:

  • At the national level, CO2 emissions are projected by the EPA to be 0.8% (14 million short tons) lower in 2030 but 0.6% (11 million short tons) higher in 2050 under ACE compared to no policy.
  • At the state level, COemissions from the power sector are expected to increase by up to 8.7% in 18 states and D.C., under ACE compared to no policy in 2030.
  • At the plant level, CO2 emissions are projected to increase at 28% of the regulated coal-fired power plants under ACE compared to no policy in 2030.
  • Increased generation from coal-fired power plants accounts for the increase in emissions in 14 of the 18 states. Increased natural gas emissions are responsible for the increase in emissions in the remaining four states and D.C.
  • National sulfur dioxide emissions are projected by EPA to be 0.7% lower, and nitrogen oxide emissions are estimated to be 1% lower under ACE compared to no policy in 2030.
  • At the state level, emissions of sulfur dioxide are projected to increase by up to 148% in 19 states, and nitrogen oxide emissions are estimated to increase by up to 9% in 20 states and D.C. under ACE compared to no policy in 2030.
  • Compared to the Clean Power Plan, national CO2 emissions are projected by the EPA to be 3.5% higher, sulfur dioxide emissions are projected to be 6% higher, and nitrogen oxide emissions are expected to be 5% higher under ACE in 2030.


ImaGeo is a visual blog focusing on the intersection of imagery, imagination and Earth. It focuses on spectacular visuals related to the science of our planet, with an emphasis (although not an exclusive one) on the unfolding Anthropocene Epoch.

About Tom Yulsman

Tom Yulsman is Director of the Center for Environmental Journalism and a Professor of Journalism at the University of Colorado, Boulder. He also continues to work as a science and environmental journalist with more than 30 years of experience producing content for major publications. His work has appeared in the New York Times, Washington Post, Audubon, Climate Central, Columbia Journalism Review, Discover, Nieman Reports, and many other publications. He has held a variety of editorial positions over the years, including a stint as editor-in-chief of Earth magazine. Yulsman has written one book: Origins: the Quest for Our Cosmic Roots, published by the Institute of Physics in 2003.


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