Methodology Used to Calculate Our Carbon Footprint

Waste Management’s carbon footprint comprises the anthropogenic Scope 1 (direct) and Scope 2 (indirect) GHG emissions from facilities and activities under Waste Management’s operational control in the United States, the U.S. Territories and Canada, and Scope 3 (indirect) GHG emissions. Scope 1 emissions include direct emissions for process-based emissions from landfilling, power generation, fuel for support services and heating, fleet vehicles and refrigerants. Scope 2 emissions include indirect emissions from purchased electricity. Scope 3 emissions include purchased goods and services, capital goods, fuel- and energy-related activities (not included in Scope 1 or Scope 2), business travel, employee commuting, and downstream leased assets. Our carbon footprint calculation relies on company operating data collected from auditable corporate business, legal and accounting records, which have undergone internal quality-assurance checks. Emission factors and methodologies are from the following sources:

  1. U.S. Environmental Protection Agency (U.S. EPA), Mandatory Greenhouse Gas Reporting Rule (MRR), 40 CFR Part 98
  2. EPA, Inventory of U.S. Greenhouse Gas Emissions and Sinks
  3. EPA, eGRID Technical Support document, Chapter 3
  4. DOE, 1605(b) Voluntary Reporting of Greenhouse Gases Program, Technical Guidelines
  5. DOE Energy Information Agency (EIA), Emissions of Greenhouse Gases in the United States, documentation and Emission Factors
  6. International Panel on Climate Change (IPCC), 2006 Guidelines for National Greenhouse Gas Inventories
  7. International Panel on Climate Change (IPCC), Climate Change 2013: The Physical Science Basis. Fifth Assessment Report
  8. International Panel on Climate Change (IPCC), Climate Change 2007: The Physical Science Basis. Fourth Assessment Report
  9. Solid Waste Industry for Climate Solutions (SWICS) Protocol by SCS Engineers, version 2.2
  10. EPA, Climate Leaders Program, Technical Guidance
  11. World Resources Institute (WRI) and World Business Council on Sustainable Development (WBCSD), The Greenhouse Gas (GHG) Protocol
  12. U.S. Community Protocol for Accounting and Reporting of Greenhouse Gas Emissions, Method WW.14

We participate in multiple forms of data verification. First, in conformance with applicable state or provincial GHG emissions-reporting programs, an independent third party is hired to review original data and provide a verification certificate. Accordingly, the emissions from the landfill subject to the Alberta Provincial Mandatory GHG reporting program are third-party verified by RWDI Air, Inc. for 2014 and by GHD for 2015; emissions from two landfills (one in Ohio, one in West Virginia) are verified by Ruby Canyon Engineering as part of the Climate Action Reserve GHG credit registry program; and landfill gas-to-energy emissions from the one landfill in California for which we are required to report third-party-verified GHG emissions under the state of California’s mandatory reporting program are verified by Analytical Environmental Services. Massachusetts modified its GHG inventory program to no longer require third-party verification of facility GHG reports effective third quarter of 2015. All of our facilities subject to the federal Mandatory GHG Reporting Rule for 2015, which includes more than 200 landfills and one waste-to-energy plant, are subject to rigorous validation checks by U.S. EPA as part of its compliance assurance and enforcement program for the reporting rule.

We commissioned Lloyd’s Register Quality Assurance Ltd. to assure our GHG Emissions Inventory for the calendar year 2015. This verification was conducted in accordance with ISO 14064–3:2006 Specification with guidance for validation and verification of GHG assertions to provide limited assurance that the Scope 1, Scope 2 and Scope 3 GHG data was prepared in conformance with World Resource Institute/World Business Council for Sustainable Development GHG Protocol: A Corporate Accounting and Reporting Standard and the internal Waste Management Inventory Management Plan, First Edition. As a result, 100 percent of our carbon footprint is verified by a third party.

Our GHG inventory reflects the most accurate means available to calculate GHG emissions within our industry sector. We worked with leaders in government, industry and academia – including staff of the multistate Climate Registry and the U.S. EPA – in developing our inventory processes and protocols.

Because a broadly accepted protocol for estimating the carbon mass balance of landfills does not yet exist, Waste Management, along with other public and private owners/operators of landfills, funded development of the Solid Waste Industry for Climate Solutions (SWICS) protocol by SCS Engineers.1 The protocol represents a first step in refining existing U.S. EPA models and protocols using peer-reviewed, published research to improve landfill GHG emission estimation. We employed the SWICS protocol in estimating the emissions associated with the landfill operations reported in our company-wide carbon footprint and the voluntary GHG reporting protocols in which we participate. (U.S. EPA’s Science Advisory Board views some sources of biogenic carbon dioxide emissions – including landfill gas and biogenic materials in waste – as carbon neutral, so these are not included in our footprint.)

Beginning with 2013 emissions, we aligned our reporting with that of U.S. EPA, which continues to refine its default assumptions and scope of reporting under its mandatory reporting program. If and when we find that U.S. EPA’s rule omits a facility previously included in our carbon footprint, we will calculate a default representing the proportion of emissions thereby omitted and increase the reported emissions included in our footprint to allow our emissions to be compared year over year. As part of this process of aligning our reporting with that of U.S. EPA, beginning with our 2013 emissions reporting, we are using the modified 100-year global warming potentials (GWPs) promulgated by U.S. EPA in its November 29, 2013, revisions to 40 CFR Part 98 (78 Fed. Reg. 71904). Pertinent to Waste Management’s carbon footprint, U.S. EPA revised the GWP for methane from 21 to 25 and the GWP for nitrous oxide from 310 to 298.

In 2014, Waste Management contracted with EnerNOC, a leader in energy intelligence software, to collect and pay utility invoices, as well as to track usage data as part of an enterprise-wide Utility Bill Management (UBM) Program spearheaded by our supply chain procurement managers. When fully implemented, the UBM system will track compressed natural gas, natural gas, propane, landfill gas, delivered heat and water service, and waste.

Information for the UBM Program is audited prior to bill redirection by Waste Management to ensure correct processing of all future invoices. We review data through EnerNOC’s online dashboard and have the capability to run reports on consumption, cost and MTCO2e on a facility, region, division, country and enterprise-wide basis. With this new approach, our data collection and reporting program is more robust and transparent than ever before.

Our calculation of the potential GHG reductions or “avoided emissions” that our operations enable includes the following:

  • Production of renewable waste-based energy that replaces electricity generated from fossil fuels.2
  • Potential avoided GHG emissions associated with annual production and use of renewable natural gas (RNG).
  • Recycling of postconsumer materials (e.g., paper, aluminum and plastics) using U.S. EPA’s WARM Model (
  • Permanent carbon storage in landfills of biogenic materials that do not decompose in an anaerobic, landfill environment. Carbon storage in landfills can significantly offset GHG emissions from landfills as recognized by the United Nations Intergovernmental Panel on Climate Change, U.S. EPA’s U.S. Inventory of GHG Emissions and Sinks, the Oregon Climate Trust and the California Air Resources Board – all of which recognize carbon storage in landfilled material as a “sink” in calculating carbon emissions inventories.3 We have used the SWICS protocol to calculate the amount of carbon permanently stored in landfills from the annual disposal of organic waste – i.e., carbon that will not decompose in the landfill to produce methane.

1 SCS Engineers, Inc., Current MSW Industry Position and State-of-the Practice on LFG Collection Efficiency, Methane Oxidation, and Carbon Sequestration in Landfills for SWICS (Long Beach, CA: SCS Engineers, January 2009).

2 Avoided fossil-fuel-generated electricity emissions are calculated using megawatt hours of electricity supplied to the grid multiplied by EPA eGRID emission factors.

3 SCS Engineers, Inc., 2009; EPA, Solid Waste Management and Greenhouse Gases: A Life-Cycle Assessment of Emissions and Sinks, 3rd Edition (Washington, DC: U.S. EPA, September 2006).