US greenhouse gas emissions have increased for the first time in 13 years, driven by fossil fuel combustion, Environmental Protection Agency has reported.
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Net emissions increased 3.2% year on year in 2018, but have decreased 10.2 % from 2005 levels, according to the latest "Inventory of U.S. Greenhouse Gas Emissions and Sinks." In 2018, total gross US greenhouse gas emissions have increased by 3.7% from 1990 to 2018, down from a high of 15.2% above 1990 levels in 2007.
"The increase in total greenhouse gas emissions between 2017 and 2018 was driven largely driven by an increase in CO2 emissions from fossil fuel combustion," according to the EPA study, which estimates the total national greenhouse gas emissions and removals associated with human activities across the United States. "The increase in CO2 emissions from fossil fuel combustion was a result of multiple factors, including increased energy consumption from greater heating and cooling needs due to a colder winter and hotter summer in 2018 (in comparison to 2017)."
The major fuel-consuming economic sectors contributing to CO2 emissions from fossil fuel combustion are transportation, electric power, industrial, residential and commercial.
Fossil fuel combustion accounted for 92.7% of US CO2 emission in 2018, according to the report.
Total emissions of CO2 increased by 5.9% from 1990 to 2018, the EPA said. Since the Industrial Revolution, global atmospheric concentration of CO2 have risen about 46%, mostly due to the combustion of fossil fuels for energy.
"Given how hard the current administration has been working to rescind/revoke/revile regulations that limit air pollution and mitigate climate change, it's tempting to conclude that these recent jumps are all due to Trump," Meredith Fowlie, associate professor in the Department of Agriculture and Resource Economics, wrote for the University of California Berkeley Energy Institute Blog, published Monday. "The truth, of course, is more complicated. One or two years of increasing emissions does not a trend make," Fowlie wrote. "But the underlying drivers tell us something about where we need to be focusing our attention."
Much of the progress made in the last decade to reduce emissions has occurred in the electric power sector, specifically CO2, according to Fowlie.
"With the rise of cheap natural gas and increasing renewable energy penetration, the carbon intensity of electricity production has decreased by more than 25% since 2008," Fowlie wrote. "Sulfur dioxide intensity has dropped by more than 80%."
Electricity generators used 32% of US energy from fossil fuels and emitted 35% of the CO2 from fossil fuel combustion in 2018, according to the EPA report. The mix of fossil fuels used impacts emissions as the electric power sector is the largest consumer of coal in the United States.
The amount of coal and the percent of total electricity generation from coal has decreased from 54% of generation in 1990 to 28% in 2018, which corresponds with an increase in natural gas and renewable generation, according to the report.
The reductions in power sector emissions have been able to offset increased emissions from other sectors, but things seem to be changing, Fowlie wrote.
The transportation sector's GHG emissions have increased 22.4% since 1990, according to the EPA report. That is thanks to commercial airplanes and heavy-duty trucks, Fowlie wrote. Although, there has been a trend in recent years to electrify the transportation industry.
Industrial GHG emissions have also been on the rise, up 5% year on year in 2018, according to the EPA report. Residential CO2 emission rose 14.2% year on year for 2018, as commercial increased, up 10.9% from 2017 to 2018.
This recent uptick should be a "wake-up call," Fowlie wrote.
"But this is not what we are seeing at the federal level," Fowlie wrote. "The list of air quality and climate change regulations that have been dismantled since 2016 is long and getting longer."
The Regional Greenhouse Gas Initiative is the first mandatory market-based program in the United States to reduce greenhouse gas emissions. RGGI states include Connecticut, Delaware, Maine, Maryland, Massachusetts, New Hampshire, New Jersey, New York, Rhode Island and Vermont. New Jersey rejoined January 1 after an eight-year hiatus.
Other states that could join RGGI include Virginia and Pennsylvania.
Virginia legislature in February authorized the state joining RGGI, after last year's attempt to implement RGGI via regulations was block by the General Assembly.
Pennsylvania Governor Tom Wolf issued an executive order in October 2019 instructing the state Department of Environmental Protection to join RGGI.