What Are Scope 1 Emissions and Why Do They Matter for Investors?

Scope 1 emissions are the most directly controllable category of greenhouse gas emissions — the GHGs produced by sources owned or directly controlled by a company, from its own combustion of fossil fuels, its industrial processes, and its other on-site operations. They are also the most reliably measured and reported category, because they can be metered, monitored, and verified at the facility level. For investors, Scope 1 data provides the clearest picture of a company's direct operational carbon exposure — the portion of climate transition risk that sits most directly within a company's control and most directly reflects regulatory carbon pricing risk.

Quick definition: Scope 1 emissions are direct greenhouse gas emissions from sources owned or controlled by the reporting organization — including combustion of fuels in owned equipment, industrial processes that produce GHGs, and fugitive emissions from owned operations. They are defined in the GHG Protocol Corporate Accounting and Reporting Standard (the global standard for corporate GHG accounting).

Key takeaways

• Scope 1 emissions include four main categories: stationary combustion (burning fuels in owned boilers, furnaces, heaters); mobile combustion (owned vehicle fleets, aircraft, ships); process emissions (industrial reactions, cement production, aluminum smelting, chemical processes); and fugitive emissions (methane leaks from natural gas systems, refrigerant leaks from HVAC).
• Scope 1 is the highest-quality climate data category: emissions can be calculated from metered energy consumption, fuel purchase records, and process engineering data using the GHG Protocol's calculation methodologies, producing relatively reliable results compared to Scope 3's indirect estimation requirements.
• The most Scope 1-intensive sectors are oil and gas production (extraction and processing), electric utilities (combustion for electricity generation), cement and materials (process emissions), chemicals, and airlines (jet fuel combustion). For these sectors, Scope 1 is the primary carbon exposure metric.
• Investors use Scope 1 data for carbon footprint measurement, carbon intensity screening (exclusion or underweighting of high-intensity companies), carbon pricing sensitivity analysis (how much does a $50/tonne carbon price cost this company?), and climate scenario analysis inputs.
• Disclosure quality and coverage are improving: mandatory Scope 1 reporting for large companies applies in the EU (CSRD), UK (TCFD-aligned for many companies), and Australia, with the SEC climate disclosure rule (under legal challenge) proposing to extend this to large US public companies.

What Scope 1 Includes

Stationary Combustion

Burning fossil fuels in company-owned or -controlled equipment:

• Natural gas combustion in owned boilers, furnaces, and heaters
• Coal combustion in owned power generation facilities
• Diesel combustion in owned backup generators
• Oil combustion in owned process heaters

The GHG Protocol provides emission factors (tonnes of CO₂ equivalent per unit of fuel) for standard fuel types, enabling calculation from metered fuel consumption records. For most manufacturing and commercial operations, stationary combustion represents the largest Scope 1 emission source.

Mobile Combustion

Burning fuels in owned vehicles and transport equipment:

• Fleet vehicles (cars, trucks, delivery vehicles)
• Owned aircraft (corporate jets, airline fleets)
• Owned ships and marine vessels
• Construction equipment and industrial vehicles

For airlines, mobile combustion (jet fuel) is the dominant Scope 1 source. For logistics companies with large owned fleets, mobile combustion is significant. For most office-based service companies, mobile combustion from owned vehicles is minor.

Process Emissions

GHGs produced as a byproduct of industrial processes, independent of energy combustion:

• CO₂ from cement production (calcination of limestone)
• CO₂ from steel production (reduction of iron ore with coke)
• Fluorinated gases (HFCs, PFCs, SF₆) from semiconductor and electronics manufacturing
• N₂O from chemical processes
• CH₄ from fermentation in food processing or agricultural operations

Process emissions require sector-specific accounting methodologies because they are not related to fuel combustion and cannot be calculated using standard energy consumption data.

Fugitive Emissions

Unintended releases of GHGs from operations:

• Methane (CH₄) from natural gas system leaks (pipelines, wellheads, compressors, storage)
• Methane from coal mining operations
• Refrigerant gases (HFCs) from air conditioning and refrigeration equipment leaks
• CO₂ from improperly sealed storage or transmission systems

Fugitive methane emissions are particularly significant for oil and gas operations. Methane has a global warming potential approximately 80 times higher than CO₂ over a 20-year period, making fugitive methane from natural gas operations a high-impact emission source. The accuracy of methane fugitive emission measurement has been a significant controversy — satellite imagery studies (from GHGSat, Carbon Mapper, and others) have documented that many oil and gas operators underreport methane emissions by significant margins.

How Scope 1 Is Measured

Calculation Method

The primary Scope 1 measurement approach uses the GHG Protocol calculation methodology: multiply activity data (fuel consumed, materials processed) by appropriate emission factors to estimate GHGs in tonnes of CO₂ equivalent (tCO₂e).

For example:

• Company consumes 1,000,000 cubic meters of natural gas
• GHG Protocol emission factor for natural gas: 0.002 tCO₂e/cubic meter
• Scope 1 Scope 1 emissions from natural gas: 2,000 tCO₂e

Emission factors are published by the GHG Protocol, national environmental agencies (EPA in the US, Defra in the UK), and the IPCC for international use.

Direct Measurement

For some emission sources — particularly large stationary sources like power plants and industrial facilities — direct measurement using continuous emissions monitoring systems (CEMS) provides more accurate data than calculation methods. Many major industrial facilities have CEMS installed for regulatory compliance purposes, and this data can be used directly in GHG reporting.

Third-Party Verification

Scope 1 emissions can be verified by third-party assurers to limited or reasonable assurance standards. Verification involves checking:

• Completeness of emission sources included
• Accuracy of activity data (fuel consumption records, metering)
• Appropriateness of emission factors used
• Correctness of calculation methodology

Verified Scope 1 data is more reliable for investment analysis than unverified self-reported data. CSRD and the EU Taxonomy require external assurance for sustainability disclosures including GHG data; the SEC's proposed rule would require limited assurance on Scope 1 and 2 disclosures for large companies.

Scope 1 emission flow

Scope 1 in Investment Analysis

Carbon Footprint and Intensity

The most direct investment use of Scope 1 data is calculating portfolio carbon metrics:

Weighted Average Carbon Intensity (WACI): The sum across portfolio holdings of (portfolio weight × company Scope 1 emissions / revenue). This metric, required in SFDR PAI reporting and widely used in ESG fund marketing, measures the portfolio's normalized exposure to Scope 1 emissions.

Absolute Portfolio Carbon Footprint: Sum of (portfolio weight × company Scope 1 absolute emissions). This measures total Scope 1 emissions attributed to the portfolio — relevant for investors with net-zero commitments measured in absolute emissions.

Carbon Pricing Sensitivity

Scope 1 data enables direct carbon pricing sensitivity analysis:

• If carbon price = $50/tonne, and company's Scope 1 emissions = 10 million tCO₂e
• Carbon cost at $50/tonne = $500 million
• If company's EBITDA = $3 billion, carbon cost represents 17% of EBITDA
• For a company with higher margins, the proportional impact may be tolerable; for a commodity business with thin margins, it may be existential

This analysis is most direct for Scope 1 because carbon pricing mechanisms (EU ETS, California Cap-and-Trade, UK ETS) primarily apply to Scope 1 emitters in covered sectors. Utilities, heavy industry, and oil and gas production are typically within the scope of mandatory cap-and-trade programs; their compliance costs from carbon pricing are direct Scope 1 functions.

Exclusion and Underweighting Screens

ESG funds commonly use Scope 1 intensity thresholds for exclusion or underweighting:

• Excluding companies with Scope 1 intensity above a threshold (e.g., excluding coal companies with >100 gCO₂/kWh electricity generation)
• EU Paris-Aligned Benchmarks require excluding companies with Scope 1 intensity above 100 gCO₂/kWh in electricity generation (equivalent to coal power)
• Decarbonization-focused funds apply annual 7-10% Scope 1 intensity reduction targets, selecting companies with declining emission intensity trajectories

Sector Scope 1 Profiles

Different sectors have dramatically different Scope 1 profiles:

Sector	Primary Scope 1 Sources	Typical Scope 1 Share of Total Footprint
Electric utilities	Fuel combustion for generation	95%+
Oil and gas production	Process, fugitive, combustion	10-20% (Scope 3 dominates)
Cement	Process (calcination) + combustion	80-90%
Airlines	Jet fuel combustion	95%+ (Scope 3 upstream + downstream fuel adds more)
Steel	Process (coke reduction) + combustion	80-85%
Technology companies	Minor combustion (data centers)	10-20% (Scope 2 and 3 dominate)
Financial services	Very minor	Less than 5%

For technology and financial services companies, Scope 1 emissions are a small fraction of total footprint — the relevant climate metrics are Scope 2 (purchased electricity for data centers and offices) and Scope 3 (financed emissions for banks, supply chain emissions for technology manufacturers). Focusing on Scope 1 only for these sectors understates climate exposure.

Real-world examples

ExxonMobil Scope 1 disclosure: ExxonMobil's annual report and sustainability report disclose Scope 1 GHG emissions from oil production, refining, and chemical operations. ExxonMobil's Scope 1 emissions in 2022 were approximately 110 million tonnes CO₂ equivalent. This represents only a fraction of total lifecycle emissions from ExxonMobil's products (Scope 3 Category 11 product combustion represents over 500 million tonnes), but the Scope 1 figure is the basis for ExxonMobil's regulatory compliance costs in covered markets.

Cement industry Scope 1 intensity: Cement companies like HeidelbergMaterials (formerly HeidelbergCement) and Holcim face structural Scope 1 emission challenges because approximately 60% of cement's Scope 1 emissions come from the calcination of limestone — a chemical process that emits CO₂ that cannot be eliminated by switching to renewable energy. Reducing cement process emissions requires carbon capture, which is currently expensive and not widely deployed. This structural Scope 1 intensity makes cement a challenging sector for ESG investors applying strict Scope 1 thresholds.

Common mistakes

Treating Scope 1 as the complete picture for oil and gas companies: For oil and gas companies, Scope 1 emissions (from production and processing) represent approximately 10-20% of the total lifecycle emissions from their products. A company that reduces Scope 1 by improving operational efficiency while maintaining or growing production has reduced its Scope 1 intensity but has not reduced the total climate impact of its products. Scope 3 Category 11 (use of sold products) is the dominant emission category for oil and gas companies.

Ignoring fugitive methane: Methane fugitive emissions from natural gas operations have a global warming potential 80 times higher than CO₂ over 20 years. A natural gas utility with good combustion efficiency but high methane leakage may have worse climate impacts per unit of energy delivered than a coal plant, depending on leakage rates. Scope 1 reporting that underreports or omits fugitive methane significantly understates climate impact for natural gas operations.

FAQ

Are Scope 1 emissions the same as direct emissions?

Yes — Scope 1 and direct emissions are synonymous. The GHG Protocol defines Scope 1 as emissions from sources owned or controlled by the company, which are direct in the sense that the company directly controls and owns the emitting source. Scope 2 and 3 are indirect — from external sources connected to company activities.

How do companies that don't own manufacturing facilities report Scope 1?

Companies with asset-light business models — tech companies, financial services firms, most service businesses — have minimal Scope 1 emissions because they don't own manufacturing facilities or large vehicle fleets. Their Scope 1 is primarily vehicle fuel for company-owned vehicles and natural gas for owned office heating. Their material GHG footprint is typically in Scope 2 (purchased electricity for offices and data centers) and Scope 3 (supply chain, employee commuting, business travel, financed emissions for banks).

Related concepts

• Why Climate Metrics Matter
• Scope 2 Emissions
• Scope 3 Emissions
• Carbon Footprint Portfolio
• TCFD Framework
• ESG Glossary

Summary

Scope 1 emissions — direct GHGs from owned and controlled sources including stationary combustion, mobile combustion, process emissions, and fugitive emissions — are the highest-quality climate data category because they can be calculated from metered activity data using the GHG Protocol's standardized methodology. The most Scope 1-intensive sectors are electric utilities, cement, airlines, oil and gas, and steel. Investors use Scope 1 data for portfolio carbon footprint measurement, carbon pricing sensitivity analysis, and exclusion/underweighting screens. Scope 1 alone understates climate exposure for most sectors — Scope 3 dominates for oil and gas, and Scope 2 matters significantly for technology and financial services. Fugitive methane emissions are a particularly important and often under-reported Scope 1 category for natural gas operations.

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