Scope 3 emissions are the hardest to measure but often the largest source of a company's carbon footprint

Scope 3 emissions are the greenhouse gases produced indirectly by a company or organization, but not from operations they own or control directly. For a car manufacturer, Scope 3 includes the emissions from driving the vehicles they sold, extracting raw materials for parts, shipping products, and disposing of cars at end of life. For an oil company, it includes emissions from burning the fuel they sell. For a retailer, it includes emissions from customers traveling to stores and from waste in landfills.

Scope 3 is almost always the largest piece of a company's total emissions — often 70 to 90 percent — but it is also the hardest to measure and the hardest to control. A manufacturer cannot force a customer to drive less, and an oil company cannot control how efficiently a car burns its fuel. That gap between size and control is why Scope 3 matters: it shows where the real environmental impact lives, even when a company cannot directly reduce it.

If you are reading about vehicle emissions, you will encounter Scope 3 when looking at a manufacturer's climate claims, a fuel company's carbon footprint, or a battery maker's environmental impact. Understanding what it includes and what it does not will help you judge whether those claims are meaningful.

Key Takeaways

  • Scope 3 emissions come from activities outside a company's direct control — such as driving a car after it is sold, mining materials for parts, or burning fuel a company produces.
  • Scope 3 is typically the largest part of a company's total emissions but the hardest to measure because it depends on customer behavior and third-party suppliers.
  • Different industries count Scope 3 differently: a car maker counts vehicle use, while a battery maker counts mining and processing of raw materials.
  • A company's Scope 3 number is often an estimate based on industry averages, not a precise measurement of actual emissions.

How Scope 3 differs from Scope 1 and Scope 2

Scope 1 is direct emissions from sources a company owns or operates — a factory's natural gas furnace, a delivery truck's engine, or a power plant's smokestacks. Scope 2 is indirect emissions from purchased electricity, steam, or heating. Scope 3 is everything else: emissions that happen because of a company's products or services, but outside its fence.

The three scopes form a hierarchy of control. A company can install a solar panel and when ready cut Scope 2. It can retrofit a truck engine and cut Scope 1. But it cannot force a customer to drive a car less, so Scope 3 sits beyond its direct reach. This is why Scope 3 is often called "value chain" emissions — it traces the full chain of activities tied to a product, from raw material to disposal.

For vehicles specifically, Scope 3 dominates. A car's lifetime emissions are roughly 75 to 80 percent from driving it (Scope 3 for the manufacturer) and 20 to 25 percent from making it (Scope 1 and 2 for the factory). An electric vehicle shifts this balance — it produces zero tailpipe emissions during use, so Scope 3 shrinks — but manufacturing emissions (Scope 1 and 2) stay roughly the same or even grow because battery production is energy-intensive.

What counts as Scope 3 for different industries

Scope 3 categories vary by industry because the value chain is different. The Greenhouse Gas Protocol, the standard most companies follow, lists 15 possible Scope 3 categories. A company does not have to count all of them — it counts the ones that matter to its business.

For an automaker, the biggest Scope 3 sources are vehicle use (customers driving cars), extraction and production of raw materials (steel, aluminum, plastics), and end-of-life vehicle disposal. For an oil or gas company, Scope 3 is almost entirely the combustion of fuel sold — the emissions from burning gasoline or diesel in cars and trucks. For a battery maker, Scope 3 includes mining lithium and cobalt, transporting raw materials, and eventual recycling or disposal of batteries.

A company may also count Scope 3 from business travel, employee commuting, waste disposal, or leased assets. The point is that Scope 3 captures the ripple effects of a company's products and services, even when the company itself does not produce the emissions.

Why Scope 3 numbers are often estimates, not measurements

Scope 3 is almost always calculated from averages and assumptions, not from direct measurement. A car manufacturer cannot track every car it sold and measure how much each one actually emits — it does not have access to real-world driving data for millions of vehicles. Instead, it uses industry averages: the typical car in a given region, driven a typical number of miles per year, with typical fuel economy.

This means a company's published Scope 3 number is a model, not a fact. If actual cars are driven more than the average, real emissions are higher. If they are driven less, real emissions are lower. If fuel economy improves faster than expected, real emissions fall. The number is useful for tracking trends and comparing companies, but it is not a precise measurement of what actually happened.

Some companies are starting to use real-world data — telematics from connected vehicles, actual fuel sales, recycling rates from dismantlers — to refine their Scope 3 estimates. But most still rely on published averages from government agencies or industry groups. When you see a company's Scope 3 claim, it is worth asking what assumptions went into it.

Scope 3 and electric vehicles

Electric vehicles change the Scope 3 picture for automakers because they eliminate tailpipe emissions during use. For a traditional car, Scope 3 vehicle-use emissions dwarf everything else. For an EV, those emissions drop to near zero (though they are not quite zero — electricity generation produces some emissions, which count as Scope 3 for the car maker).

This shift means that for an EV, manufacturing emissions become a much larger share of the total. Battery production is energy-intensive, and mining lithium, cobalt, and nickel produces emissions. An EV's Scope 3 also includes emissions from electricity generation during charging — but this number depends on the grid's energy mix. An EV charged on a coal-heavy grid has higher Scope 3 than one charged on a renewable-heavy grid, even though the car itself is identical.

When comparing an EV to a gas car on climate impact, the Scope 3 numbers tell different stories. The gas car's Scope 3 is dominated by driving emissions. The EV's Scope 3 is dominated by manufacturing and grid emissions. Over a car's lifetime, the EV typically wins on total emissions, but the comparison depends on how long the car is driven and how clean the electricity grid is.

How companies use Scope 3 in climate commitments

Many large companies have made public climate commitments that include Scope 3 reductions. An automaker might pledge to cut Scope 3 emissions per vehicle by 50 percent by 2030. An oil company might commit to reducing Scope 3 from fuel sales. A battery maker might target lower emissions from mining and processing.

These commitments are often harder to achieve than Scope 1 and 2 reductions because they require changing customer behavior or supplier practices, not just company operations. An automaker can reduce Scope 3 by making cars more efficient (so customers emit less when driving) or by shifting to electric vehicles (so customers emit nothing from tailpipe). An oil company can reduce Scope 3 only by selling less fuel or by helping customers use fuel more efficiently — neither of which is in its financial interest.

This tension is why Scope 3 commitments are worth scrutinizing. A company that commits to Scope 3 reductions is promising to influence activities outside its control. Some companies do this through product innovation, efficiency improvements, or supply chain changes. Others make commitments that are difficult to verify or that rely on assumptions that may not hold.

Questions to ask when you see a Scope 3 claim

When a company publishes a Scope 3 number or makes a Scope 3 commitment, a few questions help you judge whether it is meaningful. First, what assumptions went into the calculation? What average driving distance, fuel economy, or grid emissions mix did they use? Second, which Scope 3 categories did they include, and which did they leave out? A company might count vehicle use but not end-of-life disposal, or count fuel combustion but not upstream extraction.

Third, how is the company planning to reduce Scope 3? If the plan relies on customers changing behavior (driving less, charging on renewable energy), that is harder to control than a plan that relies on product changes (making cars more efficient, using lower-carbon materials). Fourth, how will the company measure progress? If it is using the same assumptions and averages as before, the number might improve on paper without real-world emissions actually falling.

These questions do not mean a company's Scope 3 claim is false or useless. They mean that Scope 3 is inherently uncertain, and understanding the uncertainty helps you decide whether the claim tells you what you actually want to know.

Frequently Asked Questions

Is Scope 3 the same as a product's carbon footprint?

Not quite. A product's carbon footprint usually means the total emissions from making it and using it — both Scope 1, 2, and 3 combined. Scope 3 is just the indirect part. For a car, the carbon footprint includes manufacturing (Scope 1 and 2) plus driving (Scope 3). For gasoline, the carbon footprint is mostly Scope 3 (the emissions from burning it).

Why do companies report Scope 3 if they cannot control it?

Because Scope 3 is where the real environmental impact is. A company that reports only Scope 1 and 2 is ignoring the largest part of its footprint. Reporting Scope 3 is a way of being honest about impact, even when the company cannot directly reduce it. It also shows investors and customers where the company's climate risk and opportunity actually lie.

Can Scope 3 emissions go down if a company does nothing?

Yes. If customers drive cars less, or if the electricity grid becomes cleaner, Scope 3 emissions fall even if the company makes no changes. This is why Scope 3 numbers can be misleading — a company might claim progress when the real cause is external. Good reporting explains what drove the change.

Do electric vehicles have zero Scope 3 emissions?

No. An EV has zero tailpipe emissions, but Scope 3 includes emissions from electricity generation during charging. If the grid is powered by coal, an EV's Scope 3 is higher than if the grid is powered by wind or solar. Over a lifetime, an EV typically has lower total Scope 3 than a gas car, but it is not zero.

How do I know if a company's Scope 3 number is accurate?

You cannot know for certain — Scope 3 is an estimate by definition. But you can check whether the company explains its assumptions, which categories it included, and how it measured progress over time. Companies that are transparent about uncertainty are usually more reliable than those that present Scope 3 as a precise fact.