www.lesswrong.com/posts/PmaBozEroBg73a5Di/the-epsilon-fallacy
1 correction found
Practically all of the reduction in US carbon emissions over the past 10 years has come from that shift.
Coal-to-gas switching was important, but studies and EIA analyses do not show it caused "practically all" of the U.S. emissions decline; other factors such as renewables and slower electricity-demand growth accounted for large shares too.
Full reasoning
This claim overstates the role of coal-to-gas switching.
The post was published on March 17, 2018, so its "past 10 years" claim refers roughly to the late-2000s through 2018. For that period, peer-reviewed and government analyses do not find that natural-gas substitution explains nearly all of the U.S. carbon decline.
- A 2016 Nature Communications reanalysis of U.S. emissions trends found that fuel switching to natural gas accounted for 28.2% of the overall U.S. emissions reduction from 2007 to 2013 by one method, and 20.4% to 40.7% by another.
- An EIA analysis published in October 2018 said that from 2005 to 2017, slower electricity-demand growth and changes in the electricity generation mix played nearly equal roles in reducing U.S. power-sector CO2 emissions.
- Another EIA breakdown published in June 2021 found that, from 2005 to 2019, about 65% of the power-sector CO2 decline came from coal-to-gas switching and about 30% came from increased renewable generation.
So natural gas was a major contributor, but the evidence does not support saying it caused "practically all" of the reduction. A substantial share came from other drivers, especially renewables and slower growth in electricity demand.
3 sources
- Correspondence: Reassessing the contribution of natural gas to US CO2 emission reductions since 2007 | Nature Communications
As a share of the overall reduction of emissions from 2007 to 2013, this method attributes 28.2% to greater use of natural gas in electricity generation... point estimates imply that the share of emissions reductions that is due to low natural gas prices is between 20.4 and 40.7%.
- Carbon dioxide emissions from the U.S. power sector have declined 28% since 2005 - U.S. Energy Information Administration (EIA)
Slower electricity demand growth and changes in the electricity generation mix have played nearly equal roles in reducing U.S. power sector CO2 emissions... The power sector has become less carbon intensive as natural gas-fired generation displaced coal-fired generation and as the noncarbon sources of electricity generation—especially renewables such as wind and solar—have grown.
- Electric power sector CO2 emissions drop as generation mix shifts from coal to natural gas - U.S. Energy Information Administration (EIA)
Although both the increased use of renewables and the shift from coal-fired to natural gas-fired generation contributed to reductions in electric power sector CO2 emissions, the shift from coal to natural gas had a larger effect. Of the 819 million metric ton decline... approximately 248 million metric tons (30%) ... is attributable to the increase in renewable generation... almost 532 million metric tons (65%) ... is attributable to the shift from coal-fired to natural gas-fired electricity generation.