US Greenhouse Gas Emissions Dropped in 2019

U.S. greenhouse gas (GHG) emissions in 2019 fell by an estimated 15% from their level in 2005. That’s significant progress toward a target set by the country of a 17% reduction by the end of 2020.

The 2020 target, which the United States agreed to in the Copenhagen Accord, is well short of the 26% to 28% U.S. target for 2025 set in the Paris Agreement that has since been recanted by the Trump administration.

Net U.S. GHG emissions fell 2.1% year over year in 2019, after rising by 2.7% in 2018. The 2019 decline is virtually entirely due to a drop in coal-fired electricity generation, which fell by a record 18% last year to its lowest level since 1975.

The data was reported Tuesday by independent research firm Rhodium Group and is preliminary.

Emissions from the transportation sector remained relatively flat year over year, while emissions in the industrial and buildings sectors rose. The preliminary 2019 emissions levels are much better than 2018 increases in GHG emissions from buildings, transportation and industrial consumption.

Cold weather contributed to most of the 2018 increases in the industrial and buildings sectors. Because 2019 had about the same number of heating degree days as 2018, there was no year-over-year spike as there was between a warmer 2017 and much colder 2018.

Another factor contributing to the decline in emissions last year was somewhat weaker GDP growth. Gross domestic product rose by 2.9% in 2018, much better than the 2.4% increase in 2014 and growth of 2.3% in the first three quarters of 2019. Slower growth translates into lower GHG emissions — not necessarily a good thing all around.

That said, Rhodium Group comments:

Beyond the year-to-year fluctuations in weather and economic growth, it’s clear that US decarbonization success is still largely limited to the 27% of net emissions that come from the power sector. Improvements in vehicle, lighting, and appliance efficiency have been successful in slowing the pace of emissions growth in transportation and buildings (and perhaps even halting it in transportation), but it will require much more than efficiency to achieve meaningful absolute declines. Large-scale fuel substitution (to decarbonized electricity and other zero-carbon fuels) will be required.

Industry now spews out more GHG emissions than the power sector, as the following chart from Rhodium Group shows.

Source: Rhodium Group

The firm’s researchers also noted that if their preliminary estimate of 2019 U.S. GHG emissions is correct, reaching the Copenhagen Accord target of 17% this year will require a decline of 5.3% in GHG emissions, a larger year-over-year drop than in any single year since World War II, except the Great Recession year of 2009.

To meet the Paris Agreement targets, U.S. GHG emissions will need to fall by an average of 2.8% to 3.2% annually in each of the next six years. Since 2005, the annual average decline has been 0.9%. Rhodium Group’s analysts comment: “It’s still possible, but will require a significant change in federal policy—and pretty soon.”