CO2 emissions in the U.S. rose by 3.4 percent following three years of decline -- the largest increase in the past eight years and the second largest in the past two decades, Rhodium Group said in a report.
The report only offered estimates for energy consumption, but a report published by the Global Carbon Project offered data showing a similar rise in U.S. carbon emissions.
Last year’s increase occurred even though coal consumption in the U.S. was down and a record number of coal-fired power plants were retired, according to Rhodium Group’s report. In coal's place, natural gas filled in and made up the majority of energy consumption, resulting in a 1.9 percent increase in emissions in the power sector.
The Rhodium Group predicted that if the country's trajectory remains the same, it will not meet its commitments under the Paris Agreement on climate change.
The report said in order for the U.S. to reach those commitments, which equate to a 26-28 percent reduction in carbon emissions from 2005 levels by 2025, the country will need to "reduce energy-related CO2 emissions by 2.6 percent on average over the next seven years — and faster if declines in other gasses do not keep pace".
However, this may not matter for the U.S. since President Donald Trump announced he would be pulling out of the agreement in 2020.
Trump set off a new policy on the environment by ending a number of federal environmental protections.
The report noted that researchers do not expect a similarly large increase in carbon emissions for 2019 but emphasized emission reduction challenges facing the U.S.