Dive Brief:
- Greenhouse gas emissions levels from waste-related activities in the United States remained mostly unchanged from 2023 to 2024, according to a report released by the University of Maryland's Center for Global Sustainability. The report uses the same methodology as the U.S. Greenhouse Gas Emissions and Sinks report released by the U.S. EPA annually from 1998 to 2024.
- As with the EPA iterations of the annual analysis, UMD’s report analyzes data on a two-year lag. It found that gross overall U.S. emissions in 2024 totaled 6,205.3 million metric tons of carbon dioxide equivalent, while waste sector emissions totaled 166 million metric tons of CO2e.
- The Trump administration blocked a release of the full report last year, though the EPA did release separate chapters on waste and agriculture, leading environmental groups and researchers to fill in remaining information.
Dive Insight:
Countries are required to prepare and submit high-level reports to the United Nations’ climate change program under a 1992 treaty, and the waste industry and others have come to rely on regular reporting for third-party validation. Some industry groups have responded with skepticism to federal efforts to undo reporting requirements as a result.
The Environmental Defense Fund, which released the full U.S. EPA GHG Emissions and Sinks report last year after filing a Freedom of Information Act request, noted in a release this month that the agency appears to not have begun work on the 2026 version of the report. The environmental group praised UMD scientists’ efforts to replicate the annual report, which it called critical scientific information.
“The GHG inventory is not a political issue – it is a science-based collection of data on the state of GHG emissions within the United States,” the EDF wrote. “Around the world, people and communities continue to act on this exact kind of scientific evidence, working to implement non-partisan solutions such as transitioning to renewable energy and eliminating methane emissions from the oil and gas industry.”
Overall, total U.S. net emissions, which includes carbon sinks, rose 0.2% year over year in 2024, according to the UMD report. Net emissions have declined about 3.8% since 1990, driven largely by declining emissions in fossil fuel combustion, per a summary of trends in the report.
The waste sector, meanwhile, has charted a long-term decline in emissions since 1990, largely led by improvements in landfill gas collection and control. That has led to a significant reduction in methane gas emissions, the most prevalent greenhouse gas for the industry. But in 2024, emissions from the sector were essentially flat year over year.
Diving into subcategories, methane emission levels from landfills were also flat year over year, recording 119.4 million metric tons of CO2e. Methane emissions from wastewater treatment declined slightly, from 21.2 million metric tons of CO2e to 21 million metric tons of CO2e.
Nitrous oxide emissions increased slightly. Small upticks in emissions from wastewater treatment and composting led to 23 million metric tons of total CO2e emissions of nitrous oxide from the waste sector in 2024. The report noted that nitrous oxide emissions from wastewater treatment have increased over time as a result of population growth and people eating more protein. Emissions from composting have also grown fivefold as the amount of waste that's composted has increased more than sixfold since 1990, per the report.
Like previous EPA reports, the UMD report breaks out anaerobic digestion emissions based on the type of facility in discussion. Net methane emissions from stand-alone anaerobic digesters stood at about 12,020 metric tons of CO2e. That's based on the amount of methane recovered through the anaerobic digestion process subtracted from the amount of methane generated. Emissions from on-farm digesters were counted in the UMD report's agriculture section, but they were not broken out.
The report’s authors noted future refinement could include a review of available information present in the EPA’s Greenhouse Gas Reporting Program. But that program, too, has come under fire by the Trump administration, which has worked to wind it down for all reporting entities except oil and gas facilities.
Landfills have reported to the GHGRP for several years. In March, however, the EPA extended the deadline by which facilities must report annual data to the program by several months. The EPA formally proposed to end the GHGRP in September, and received over a thousand comments on the plan. It has not provided an update on that process since.
