The pulp and paper sector includes chemical pulp and paper mills and paper products manufacturing. The emissions reported by this sector decreased significantly from 44.2 million metric tons (MMT) CO₂e in 2011 to 34.9 MMT CO₂e in 2021, a decrease of 21.0 percent. Reported emissions for the sector declined steadily across the time series but the decrease was most notable from 2012 to 2013, when emissions decreased by 3.4 MMT CO₂e (8 percent). The number of reporters has decreased from a high of 233 facilities in 2011 to a low of 214 facilities in 2021.

The pronounced decline in emissions from 2012 to 2013 for this sector can be primarily attributed to methane and nitrous oxide emission factors changes for the chemical pulp and paper mills subsector. For reporting year 2013, EPA revised the emission factors that facilities in the chemical pulp and paper mills subsector use to calculate emissions from the combustion of spent pulping liquor and wood residuals. These new emission factors contributed significantly to the decline in reported emissions for reporting year 2013. The rest of the observed decline in reported emissions was due to changes in production levels and to changes in the fuel mix. The use of coal, coke, and petroleum products as fuel has decreased, while the use of natural gas has increased. Emissions since 2017 have remained relatively steady, with changes in emissions of less than 1 percent each year. The emissions decreased by only 0.09 MMTCO₂e (less than 1 percent) in 2021, compared to 2020.

Breaking down the emissions trends for the two subsectors within the pulp and paper sector, the majority of the emissions for the total sector come from the chemical pulp and paper mills subsector, which accounted for 71.1 percent of the total sector emissions in 2021. The emissions reported by the chemical pulp and paper mills subsector decreased from a high of 30.6 MMT CO₂e in 2011 to a low of 24.4 MMT CO₂e in 2020, a decrease of 20.3 percent. Reported emissions in this subsector have mostly followed the gradual decline observed for the sector as a whole; however, from 2020 to 2021, emissions for this subsector slightly increased by 0.3 MMTCO₂e. The decreasing trend in emissions reported by this subsector is in part due to a decrease in the number of reporters. The number of reporters in this subsector has decreased from a high of 111 reporters in 2012 to a low of 103 reporters in both 2020 and 2021. The shift away from coal combustion and increased reliance on natural gas has also contributed to the decrease in reported emissions for this subsector. Emissions from coal-fired facilities accounted for only 15 percent of emissions in 2021, compared with 42 percent of emissions in 2011. Emissions from natural gas-fired facilities increased over the same period from 34 percent in 2011 to 74 percent in 2021.

Facilities in the paper products manufacturing subsector operate under NAICS codes beginning with 322 (paper manufacturing) and 323 (printing and related support activities). This subsector consists of mills that use non-chemical pulping processes (e.g., mechanical or secondary (recycled) fiber pulping) and non-integrated facilities that produce paper products from purchased pulp; produce secondary fiber from recycled paper; convert paper into paperboard products; operate coating and laminating processes; and print products such as newspapers, books, labels, business cards, stationery, and business forms. Facilities in this subsector report emissions only from stationary fuel combustion. The emissions reported by the paper products manufacturing subsector made up the remaining 28.9 percent of emissions reported by the pulp and paper sector in 2021. The emissions in this subsector decreased from 13.6 MMT CO₂e in 2011 to 10.1 MMT CO₂e in 2021, a decrease of 26.7 percent. Although emissions in this subsector make up a smaller percentage of total sector emissions, it is comprised of a greater number of facilities than the chemical pulp and paper mills subsector. The number of reporters in this subsector has decreased from a high of 123 facilities in 2011 to a low of 111 facilities in 2021. Reported emissions in this subsector have mostly followed the same declining trend reported by the chemical pulp and paper subsector. However, in 2020 reported emissions for this subsector diverged from that of the chemical pulp and paper subsector, with reported emissions increasing by 7 percent from 9.8 MMT CO₂e in 2019 to 10.5 MMT CO₂e in 2020. A slight decrease in reported emissions occurred in 2021 with emissions decreasing by 0.35 MMT CO₂e to 10.15 MMT CO₂e. The increase in emissions in 2020 was likely due to increases in both the number of reporters and the average emissions per facility. The number of reporters increased from 115 in 2019 to 119 in 2020. The average emissions per facility increased from 85,217 MT CO₂e in 2019 to 88,235 MT CO₂e in 2020. In 2021, the number of reporters dropped to 111 but the average emissions per facility increased to 90,991 MT CO₂e. The overall trend in decreasing emissions is also impacted by changes in the types of fuel combusted. Coal combustion has declined every year since 2014, while natural gas combustion steadily increased between 2011 through 2020. Natural gas combustion saw its first decline in 2021, when emissions from natural gas combustion decreased by 100,000 MT CO₂e (1.1 percent).