Scope 3: the largest part of your carbon footprint is also the one nobody really controls.

You've measured your direct emissions. You've calculated those from purchased energy. And then you opened the Scope 3 chapter - and suddenly the perimeter multiplied. Suppliers, transport, customers, end-of-life. Data you don't have, categories you don't know how to prioritise, responsibilities that don't depend on you alone.

If this has happened to you, you're not alone. Scope 3 is the point where most companies slow down - not for lack of willingness, but because the method that works for Scope 1 and 2 no longer applies. The perimeter is too wide, the data too distributed, the responsibilities too shared.

The problem is not Scope 3 itself. It's how you approach it. In this article we explain why it's so complex, where the impact actually concentrates by sector, and how to build an approach that works - progressive, focused, genuinely useful.

Scope 1, 2, 3: a quick map

Before going deeper into Scope 3, it helps to clarify how emissions are divided according to the GHG Protocol, the international standard for corporate carbon footprint measurement.

SCOPE 1

Direct emissions from owned or controlled sources: combustion in boilers and furnaces, company fleet, refrigerant gases, industrial processes.

SCOPE 2

Indirect emissions from purchased energy: electricity, heating, cooling and steam.

SCOPE 3

All other indirect emissions across the value chain - upstream (suppliers, materials, inbound logistics) and downstream (product use, end-of-life, outbound transport, investments).

Fonte: GHG Protocol Corporate Standard

Scope 1 and 2 are relatively straightforward: data exists, processes are under control, boundaries are clear. Scope 3 is a different story entirely.

How much does Scope 3 weigh? Numbers that change the picture

The reason Scope 3 cannot be ignored is arithmetic, before it's regulatory.

70–90%

of a company's total emissions come from Scope 3

11,4×

how much supply chain emissions outweigh Scope 1+2 combined (CDP, 2024, 23,000+ companies)

Sources: GHG Protocol; CDP Supply Chain Report 2024; McKinsey (~90% estimate for the average company)

To understand what these numbers mean in practice: Unilever reports that 95% of its carbon footprint lies in the value chain, not in direct operations. Ford estimates that vehicle use alone accounts for 75% of its Scope 3. HP found that its 30 largest suppliers are responsible for 80% of Scope 3 emissions from its directly contracted suppliers.

The conclusion is clear: a company that optimises Scope 1 and 2 without touching Scope 3 is working on a minority share of its actual climate impact.

Why Scope 3 is so difficult to manage

Understanding what Scope 3 is is straightforward. Managing it is not. There are four structural challenges that companies face - regardless of size.

The perimeter is enormous. The GHG Protocol divides Scope 3 into 15 categories across the entire value chain. Without a clear priority, the risk is trying to cover everything - and ending up with an unmanageable system.

Data often doesn't exist (or isn't standardised). Unlike Scope 1 and 2, supply chain emission data is rarely directly available. Companies work with estimates, average databases, proxies. Waiting for perfect data before starting is one of the fastest ways to never start at all.

Responsibilities are distributed. A significant share of emissions depends on suppliers and partners who don't always have the tools to measure them. Engaging them requires time, coordination, and a gradual approach - you cannot ask all suppliers to report simultaneously.

Information is fragmented internally. Procurement, logistics, R&D, operations: each function holds a piece of the puzzle. Aggregating them coherently requires a method, not just goodwill.

The most relevant part of a company's carbon footprint is also the least controllable. That is precisely why it requires a different approach.

The result of these four obstacles? Many companies stall. Or build complex systems that produce data that is hard to read - and even harder to use for decision-making. Globally, according to Clarity AI, only 60% of companies include Scope 3 in their reporting - and among those who do, only 46% provide complete methodological disclosure (KPMG, 2024).

Where the impact actually concentrates: a sector perspective

Not all 15 Scope 3 categories carry the same weight. And what matters changes radically from one sector to another. Starting from this awareness is the first step toward building a workable approach.

Manufacturing: emissions are dominated by upstream activities. The "purchased goods and services" category - raw materials, components, semi-finished products - typically concentrates the majority of the impact. A mechanical or chemical manufacturer that doesn't look at its first-tier suppliers is ignoring the core of the problem.

Food & Beverage: the agricultural supply chain and packaging outweigh everything else. Emissions from ingredients and transport can far exceed operational ones. Nestlé, Coca-Cola and PepsiCo already require their first-tier suppliers - covering 70% of emissions - to measure and disclose their carbon footprint.

Pharmaceuticals: chemical synthesis processes, cold chain logistics and special waste management dominate upstream; drug use during patient treatment dominates downstream. Complexity is high on both fronts, with very different dynamics from classic manufacturing.

Retail and electronics: the weight shifts downstream. Product use and end-of-life become the most relevant categories. Ford quantified this precisely: 75% of its Scope 3 comes from vehicle use. Companies that don't measure downstream are looking at the wrong part of the chart.

11,4×

how much value chain emissions outweigh operational emissions on average (CDP, 23,000+ companies, 2024)

For retail and financial services, the ratio can reach 25:1

Source: Council Fire / CDP

These examples illustrate a key point: there is no "standard" Scope 3. There is the one relevant for that specific company, in that sector, with that value chain. And that is where you build an approach that works.

Want to identify where your company's Scope 3 actually concentrates?

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Making it manageable: a progressive approach

The most common mistake is trying to measure everything at once. Companies that handle Scope 3 well do the opposite: they start where it matters most, use available data even if imperfect, and build over time.

First: identify priority categories. Not all 15 categories carry the same weight. Do a rough estimate (even with secondary data or spend-based proxies) to understand where 80% of the impact concentrates. Start there - not with the full list.

Second: start with imperfect data. Perfect data doesn't exist at the beginning - and waiting for it blocks progress. Use average emission factors, public databases (EXIOBASE, ecoinvent), spend-based estimates. Precision improves over time as supplier relationships develop.

Third: engage the supply chain selectively. Don't ask all suppliers to report simultaneously. Segment: identify the 10–20 partners that cover the majority of emissions and start a dialogue with them. Large players (Unilever, HP, P&G) have demonstrated that this approach works - and smaller suppliers often follow when their main client asks.

Fourth: use Scope 3 to decide, not just to report. The real value is not the number in the report. It's understanding which levers - suppliers, materials, logistics, product design - to act on to actually reduce impact. When Scope 3 becomes a decision tool, it stops being a burden and becomes an advantage.

You don't need to be complete from the start. You need to understand what matters most - and start there.

How Kyklos Carbon can help

Turning Scope 3 from a complex exercise into a useful tool requires a method. At Kyklos Carbon, we work alongside companies at every stage of this journey - starting from the company, not from the standard.

Perimeter analysis and priority categories: we identify where the impact actually concentrates along the value chain, sector by sector, avoiding wasted effort on secondary categories.
Progressive data collection approach: we build a system that works even with partial or estimated data - improvable over time, without blocking the process while waiting for perfection.
Supply chain engagement: we support companies in working with their most relevant suppliers, defining the right questions, the right formats and the right sequence.
From Scope 3 to decisions: not just data collection and reporting, but impact analysis to guide concrete choices on procurement, logistics, materials and product design.

The goal is not a complete Scope 3. It's a Scope 3 that works.

Want to make your Scope 3 clearer, more manageable, and more useful for decision-making?

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Conclusion

Scope 3 is not complex because it's impossible to manage. It becomes complex when approached without priorities - trying to measure everything at once, with data that doesn't yet exist, engaging the entire supply chain simultaneously.

The shift happens when you change the question: not "how do I cover the full perimeter" but "where do I act to have the greatest impact". At that point, Scope 3 stops being a burden and becomes what it should be - a tool for making better decisions about your value chain.

The value of Scope 3 lies not in the completeness of the data, but in its ability to guide better decisions over time. 