Why We Divide Greenhouse Gas Emissions into Three Scopes
Measuring a company's climate impact spans a wide territory — from energy consumption to logistics, raw materials to product use. To make this complexity manageable, the Greenhouse Gas Protocol (GHG Protocol) divides emissions into three scopes. Developed by the World Resources Institute (WRI) and the World Business Council for Sustainable Development (WBCSD), this framework has become the global reference point for corporate carbon accounting (WRI/WBCSD, 2004).
This three-part division is not just a classification tool — it is a practical management framework that directs emission reduction strategies, clarifies responsibility boundaries, and prevents double counting.
Scope 1: Direct Emissions
Definition
Scope 1 covers greenhouse gas emissions from sources owned or directly controlled by the company. These are emissions occurring within the company's physical boundaries.
Enterprise Examples
- Manufacturing facility: CO2 emissions from a cement plant's kilns
- Vehicle fleet: Diesel consumption by company-owned cargo trucks
- Heating systems: Emissions from natural gas boilers in office buildings
- Process emissions: Gases released from chemical reactions at a chemical plant
- Fugitive emissions: Leaks of fluorocarbons (HFCs) from refrigeration systems
Data Sources
Scope 1 data is typically the most accessible. Fuel invoices, natural gas meters, vehicle fuel cards, and refrigerant refill logs provide direct data. Emission factors are sourced from the Intergovernmental Panel on Climate Change (IPCC) or national inventory guidelines (IPCC, 2006).
Scope 2: Indirect Energy Emissions
Definition
Scope 2 covers emissions generated during the production of purchased electricity, steam, heating, or cooling consumed by the company. The emissions physically occur elsewhere, but the company's energy demand is their cause.
Two Calculation Methods
The GHG Protocol defines two calculation methods for Scope 2 and recommends reporting both (WRI/WBCSD, 2015):
Location-based method: Uses the grid emission factor for the region where the company operates. For a company in Turkey, this means applying the grid emission factor published by the national grid operator.
Market-based method: Uses the emission factor of the specific energy product the company purchases. A company that purchases renewable energy certificates (I-RECs, Guarantees of Origin) can report a lower Scope 2 figure using this method.
Enterprise Examples
- Office buildings: kWh consumption shown on electricity bills
- Data centers: Electricity consumed for server cooling and operation
- Retail stores: Electricity for lighting and HVAC systems
- District heating: Heat purchased from a city steam or hot water network
Why It Matters
For many service-sector companies, Scope 2 is the largest component of their total carbon footprint. Energy procurement strategy directly determines the emissions profile — making energy supply contracts a climate decision.
Scope 3: Other Indirect Emissions
Definition
Scope 3 covers all indirect emissions occurring in the company's value chain that are not under the company's direct ownership or control. The GHG Protocol Scope 3 Standard classifies these emissions into 15 categories (WRI/WBCSD, 2011).
15 Categories with Enterprise Examples
Upstream — Supply Chain:
| Category | Description | Example |
|---|---|---|
| 1. Purchased goods and services | Emissions from raw material and service suppliers | Steel suppliers' production emissions for an automaker |
| 2. Capital goods | Emissions from manufacturing purchased equipment and buildings | Production of new manufacturing line equipment |
| 3. Fuel and energy-related (not in Scope 1-2) | Fuel extraction and transmission losses | Extraction and transport of consumed natural gas |
| 4. Upstream transportation | Logistics from supplier to facility | Raw material shipments |
| 5. Waste generated in operations | Waste disposal and recycling | Transport of production waste to landfill |
| 6. Business travel | Employee flights, trains, and hotel emissions | International client visits |
| 7. Employee commuting | Home-to-work transportation | Daily commuting |
| 8. Upstream leased assets | Emissions from leased facilities | Leased warehouse space |
Downstream — Product and Customer:
| Category | Description | Example |
|---|---|---|
| 9. Downstream transportation | Distribution from product to customer | Product distribution to retail points |
| 10. Processing of sold products | Customer processing of intermediate products | Use of sold chemicals at customer facility |
| 11. Use of sold products | End-consumer product use emissions | Lifetime fuel consumption of sold vehicles |
| 12. End-of-life treatment of sold products | Product disposal or recycling | Recycling of electronic waste |
| 13. Downstream leased assets | Use emissions of leased assets | Customer use of leased equipment |
| 14. Franchises | Emissions from franchise operations | Franchise restaurant branch emissions |
| 15. Investments | Portfolio emissions | Emissions from financed projects |
Why Scope 3 Is the Hardest
According to CDP data, Scope 3 emissions account for over 70 percent of the total carbon footprint in many sectors. Yet measuring this scope is the most complex due to data collection challenges:
- No data control: Emissions occur in other companies' operations
- Supply chain depth: Going beyond tier-one suppliers becomes increasingly difficult
- Dependence on estimation methods: When actual data is unavailable, industry averages or spend-based methods are used
- Boundary-setting difficulty: Determining which of the 15 categories are material to the company requires analysis
Calculation Approaches
The Fundamental Formula
The basic emissions calculation formula is the same across all scopes and categories:
Emissions = Activity Data x Emission Factor
For example: 10,000 liters of diesel x 2.68 kg CO2e/liter = 26,800 kg CO2e
Four Calculation Approaches for Scope 3
The GHG Protocol defines four approaches for Scope 3 categories, ranked by data quality:
- Supplier-specific method: Actual emissions data obtained from suppliers — highest accuracy
- Hybrid method: Combination of supplier data and industry averages
- Average-data method: Industry-average emission factors are used
- Spend-based method: Purchasing expenditure x economic emission factor — lowest accuracy but easiest starting point
The practical approach: Conduct a quick initial screening with the spend-based method, identify the highest-emission categories, then transition those categories to supplier-specific methods.
ISO 14064-1: The International Verification Framework
ISO 14064-1:2018 provides an international framework for the design, development, management, and reporting of greenhouse gas inventories. Compatible with the GHG Protocol, this standard introduces three important additional requirements (ISO, 2018):
- Comprehensive assessment of indirect emissions: ISO 14064-1:2018 expects all Scope 3 categories to be assessed and material ones to be reported
- Uncertainty analysis: Evaluation of the uncertainty level in emissions data
- Third-party verification compatibility: Reporting structure aligned with independent verification processes
Regulatory standards such as TSRS (IFRS S2) and ESRS (E1) also reference the GHG Protocol or ISO 14064 for greenhouse gas reporting. An inventory aligned with these standards can satisfy multiple reporting obligations simultaneously.
Data Collection Strategy for Enterprise Teams
A Phased Approach
Waiting for perfect data can produce worse outcomes than having no data at all. A phased strategy is recommended:
Year One — Build the Foundation:
- Establish direct measurement infrastructure for Scope 1 and 2
- Conduct a first screening for Scope 3 using the spend-based method
- Identify the 3-5 highest-emission Scope 3 categories
Year Two — Deepen:
- Transition to supplier-specific data collection in priority Scope 3 categories
- Apply the market-based method for Scope 2 as well
- Establish a data quality scoring system
Year Three — Mature:
- Move to hybrid or supplier-specific methods across all material categories
- Initiate independent verification
- Set reduction targets and assess Science Based Targets initiative (SBTi) alignment
Cross-Departmental Collaboration
Greenhouse gas accounting is not a single department's job. Data sources are distributed across the organization:
| Department | Data Provided | Relevant Scope |
|---|---|---|
| Facilities management | Fuel consumption, energy bills | Scope 1, 2 |
| Procurement | Supplier expenditures, material quantities | Scope 3 (Cat. 1-2) |
| Logistics | Transport distances, vehicle types, tonnage | Scope 1, Scope 3 (Cat. 4, 9) |
| Human resources | Headcount, business travel data | Scope 3 (Cat. 6-7) |
| Finance | Investment portfolio, lease information | Scope 3 (Cat. 8, 13, 15) |
| Product development | Product lifecycle data | Scope 3 (Cat. 11-12) |
Common Mistakes
- Focusing only on Scope 1 and 2: Ignoring the largest portion of total impact
- Using only the location-based method for Scope 2: Failing to reflect the impact of renewable energy investments
- Excluding Scope 3 categories without analysis: Rather than assuming each category is immaterial, conduct a screening to make evidence-based decisions
- Inconsistent boundaries across years: The operational or financial control approach should not change from year to year
Conclusion: You Cannot Manage What You Do Not Measure
The Scope 1, 2, and 3 distinction is the foundational building block of carbon accounting. Understanding and applying this framework correctly is a prerequisite for managing climate risks, achieving regulatory compliance, and setting realistic emission reduction targets.
The pursuit of perfection is the enemy of progress. Starting today with a spend-based Scope 3 screening is always more valuable than doing nothing.
Starting Point: Request categorized supplier expenditures from your procurement department for the past 12 months. This single dataset will be enough to estimate roughly 60-70 percent of your Scope 3 using the spend-based method.
References
- WRI/WBCSD (2004, revised 2015). GHG Protocol Corporate Accounting and Reporting Standard. World Resources Institute and World Business Council for Sustainable Development.
- WRI/WBCSD (2011). GHG Protocol Corporate Value Chain (Scope 3) Accounting and Reporting Standard. World Resources Institute and World Business Council for Sustainable Development.
- WRI/WBCSD (2015). GHG Protocol Scope 2 Guidance — An amendment to the GHG Protocol Corporate Standard.
- ISO (2018). ISO 14064-1:2018 — Greenhouse gases — Part 1: Specification with guidance at the organization level for quantification and reporting of greenhouse gas emissions and removals.
- IPCC (2006). 2006 IPCC Guidelines for National Greenhouse Gas Inventories. Intergovernmental Panel on Climate Change.