1. Define scope and boundaries

Official references:

• GHG protocol corporate standard (world resources institute & world business council for sustainable development):

  Defines operational boundaries for Scope 1, 2, and 3 emissions.

  Source: ghgprotocol.org

• ISO 14064-1:2018 (greenhouse gas accounting and verification):

  Provides guidelines for organizational GHG inventories.

  Source: iso.org

2. Identify emission sources

Official references:

• IPCC guidelines for national greenhouse gas inventories (intergovernmental panel on climate change):

  Classifies emission sources (e.g., stationary combustion, refrigerants).

  Source: ipcc-nggip.iges.or.jp

• EPA Scope 3 guidance (U.S. environmental protection agency):

  Details scope 3 categories (e.g., procurement, waste, guest travel).

  Source: epa.gov

3. Data collection

Official references:

• Energy data:

  • IEA Electricity emission factors (international energy agency): country-specific grid emission factors.

    • Source: iea.org

    eGRID Database (EPA): U.S.-specific electricity emission factors.

    • Source: epa.gov/egrid

• Refrigerants:

  • IPCC AR6 global warming potential (GWP) values (2021):

    • GWP values for refrigerants (e.g., R-410A, CO₂).

    • Source: ipcc.ch/report/ar6/wg1/

• Water and waste:

  • Water footprint network: embodied energy in water use.

    • Source: waterfootprint.org

  • IPCC waste model: methane emissions from landfills.

    • Source: ipcc-nggip.iges.or.jp/public/2019rf/

4. Emission calculations

Official references:

• Emission factors:

  • UK government GHG conversion factors (DEFRA):

    • Default factors for energy, transport, and waste.

    • Source: gov.uk/guidance/ghg-conversion-factors

  • EPA emission factors hub:

    • U.S.-specific factors for fuels, electricity, and refrigerants.

    • Source: epa.gov/climateleadership

• Formulas:

  • Align with GHG protocol calculation tools:

    • Source: ghgprotocol.org/calculation-tools

5. Tools and software

Official References:

• Hotel Carbon Measurement Initiative (HCMI):

  • Developed by the world travel & tourism council (WTTC) and sustainable hospitality alliance.

  • Source: wttc.org

• CDP (Carbon disclosure project) reporting framework:

  • Guides standardized climate reporting.

  • Source: cdp.net

6. Reporting and verification

Official references:

• ISO 14064-3:2019 (Verification process):

  • Requirements for third-party verification.

  • Source: iso.org

• Science based targets initiative (SBTi):

  • Validates emission reduction targets against climate science.

  • Source: sciencebasedtargets.org

7. Reduction strategies

Official References:

• RE100 Initiative (the climate group):

  • Guides transitioning to 100% renewable energy.

  • Source: there100.org

• Global sustainable tourism council (GSTC) criteria:

  • Best practices for sustainable procurement and operations.

  • Source: gstcouncil.org

8. Case study example

Reference:

• Sustainable hospitality alliance pathways to net positive:

  • Case studies on hotels achieving emission reductions.

  • Source: sustainablehospitalityalliance.org

9. Continuous improvement

Official references:

• Paris agreement (UNFCCC):

  • Guides long-term emission reduction alignment (e.g., net-zero by 2050).

  • Source: unfccc.int

• CDP Climate change questionnaire:

  • Annual benchmarking tool for progress tracking.

  • Source: cdp.net

Key databases for emission factors

1. Ecoinvent: lifecycle inventory data for procurement.

   • Source: ecoinvent.org

2. UNFCCC emission factor database:

   • Source: cdm.unfccc.int