The transportation sector’s emissions grew in 2023 due to a rebound in air travel and increased gas consumption as road traffic continued to return to pre-pandemic levels, according to a recent study. This is a contributing factor in the conclusion that pollution rates in the U.S. are not falling fast enough to meet President Joe Biden’s goal of cutting emissions in half by 2030 when compared to 2005 levels.

The report released January 10 from the Rhodium Group, an independent research firm, found that methane leaks coupled with the flaring and venting of methane and carbon dioxide during oil and gas transportation/production drove the bulk of industrial sector emissions increases last year, and led to a slight increase in industrial emissions overall.

According to the Associated Press, the output increases were responsible for pollution rates in the U.S. not falling fast enough to meet the goals. Instead, the U.S. is on track to cut greenhouse gas emissions by roughly only 40% by 2030 when compared to 2005 levels if the country does not make any other changes, said Ben King, an associate director at Rhodium and the study’s lead author. King added that the U.S.’s emissions would have to decline at a rate more than triple the 2023 figure in order to reach the desired levels.

The report showed that climate-altering pollution from greenhouse gases fell by 1.9% in 2023, and is down 17.2% from 2005.

The report said that reducing industrial emissions will require meaningful action to decarbonize other sectors, including the iron, steelmaking, cement manufacturing and chemical production industries.