Introduction

The U.S. Public Sector Protocol interprets the GHG Protocol Corporate Standard for public organisations, helping them prepare accurate and consistent GHG inventories. It supports both voluntary and mandatory reporting. The protocol is relevant to all levels of U.S. government and was developed through a stakeholder process involving over 60 experts. Although designed for U.S. use, it has international applicability due to its alignment with the Corporate Standard.

GHG accounting and reporting principles

GHG inventories must adhere to five principles:Relevance, completeness, consistency, transparency, and accuracy. These principles underpin decision-making and ensure the credibility of emissions reporting. They also help in tracking changes and verifying reported data.

Organisational goals and inventory design

Organisations must define the purpose of their inventory—compliance, policy-making, internal tracking, or public reporting. This definition influences boundary setting, data detail, and resource allocation. The protocol highlights initiatives like the Virginia Municipal League’s Green Government Challenge, showing regional action and scoring-based motivation.

Setting organisational boundaries

Public entities are advised to use either the control or equity share approach for consolidation. The control approach, particularly operational control, is recommended. The protocol outlines how to treat complex ownership structures, shared services, and public-private partnerships to prevent double counting.

Setting operational boundaries

Emissions are categorised into three scopes:

• Scope 1: Direct emissions from owned sources

• Scope 2: Indirect emissions from purchased electricity, heat, or steam

• Scope 3: Optional; includes emissions from upstream and downstream activities such as commuting, procurement, and waste

Public sector organisations are encouraged to identify material Scope 3 sources despite their optional status, as these may represent significant risks or opportunities.

Tracking emissions over time

Organisations must designate a base year, with recalculations required when structural changes occur (e.g., mergers or divestitures). Tracking emissions over time supports trend analysis and performance evaluation. Transparency in base year recalculation policies is essential.

Identifying and calculating GHG emissions

The protocol recommends using peer-reviewed, sector-specific or cross-sector tools, such as those from the GHG Protocol Initiative. Public organisations are not required to use a single tool but must document all methodologies and assumptions. Case studies like the National Park Service’s CLIP tool show practical application in facility-level data gathering and emissions estimation.

Managing inventory quality

Inventory quality management involves improving data systems, ensuring transparency, and reducing errors. Organisations should establish formal quality systems that include regular reviews, training, and documentation of methods. Data uncertainties must be identified and managed to maintain report credibility.

Reporting GHG emissions

Reports must include scope 1 and 2 emissions, and optionally scope 3 if data are reliable. Emissions should be presented by gas and activity type, and reported independently from offsets or trading schemes. The report should clarify boundaries, base year, methods, and any exclusions or changes.

Verification of GHG emissions

Although not mandatory, third-party verification is recommended to enhance credibility. Organisations should document the verification process, including criteria, scope, and outcomes. Internal reviews may suffice where external verification is not feasible.

Setting GHG targets

Public organisations may set absolute or intensity-based targets, often in line with broader policy goals (e.g., Executive Order 13514 requiring a 28% reduction in federal scope 1 and 2 emissions by 2020 from 2008 levels). Targets must align with inventory design and be recalibrated if reporting boundaries change.