When a tech company publishes its sustainability report, most of the numbers you read tell only a small part of the story. Data centers are more efficient, renewable energy has increased, operational emissions have dropped by 15%. All true. But all partial.
Because there's one component — often the largest — that almost always remains under the radar: Scope 3 emissions, those coming from the value chain. And in the ICT sector, these emissions can represent between 60% and 90% of the total footprint.
For an ESG manager or CIO preparing their first CSRD report by June 2026, this isn't a technical detail. It's the heart of the corporate climate problem. And above all, it's a methodological challenge that many companies are still underestimating.
Why Scope 3 is so difficult to measure in the ICT sector
While measuring direct emissions (Scope 1) or purchased energy emissions (Scope 2) is relatively straightforward — consumption, invoices, certificates — Scope 3 is another story.
In the ICT sector, complexity derives from three structural factors:
1. Geographic fragmentation of the supply chain
A single smartphone contains components produced in dozens of different countries. Semiconductors come from Taiwan or South Korea, assembly takes place in China or Vietnam, lithium and cobalt extraction is concentrated in Latin America and Africa. Each link in this chain has different carbon intensity, tied to the local electricity mix.
How can you accurately reconstruct the footprint of a product that crosses 15 countries before reaching the market? The honest answer is: with great difficulty. Most companies use average emission factors, which mask enormous variability.
2. Poor transparency of Tier-2 and Tier-3 suppliers
Major Tier-1 suppliers — those with whom ICT companies have direct contracts — often have structured environmental data. But as you move down the supply chain, the situation changes rapidly.
Tier-2 and Tier-3 suppliers — those extracting raw materials, producing intermediate components, managing regional logistics — rarely have robust measurement systems. Many operate in jurisdictions without disclosure requirements. Others consider environmental data commercially sensitive information and don't share it.
Result: ICT companies are forced to make estimates based on proxies and industry averages, with very high uncertainty margins.
3. The complexity of AI and Data-Intensive Workloads
Then there's a specific challenge of the AI era: how do you measure the carbon footprint of training a large language model? How do you attribute emissions between training and inference? How do you compare different systems when shared standards don't yet exist?
The answer is that today there's no consolidated methodology. Estimates vary by orders of magnitude depending on assumptions about hardware, utilization, data center efficiency, and energy mix. And this uncertainty transfers directly into sustainability reports.
2026 changes the rules: from voluntary reporting to legal obligation
Until now, many companies have been able to manage Scope 3 with a "best effort" approach: measure what you could measure, estimate the rest, publish with appropriate methodological caveats.
From June 30, 2026, this will no longer be possible. The Corporate Sustainability Reporting Directive (CSRD) extends its scope to all large EU companies with more than 250 employees. And it requires reporting of Scope 1, 2, and 3 emissions according to ESRS standards, with independent external verification.
This is not narrative reporting. ESRS standards require:
Granular data on the most material Scope 3 categories
Transparent and reproducible methodologies
Verifiable reduction targets aligned with science (preferably SBTi)
Clear governance on data collection and validation processes
For an ICT company that today has fragmented Scope 3 data or relies on summary estimates, this means one thing: you need to build a much more robust measurement system, and you need to do it quickly.
What to do now: build a credible baseline before the deadline
The starting point is not technological. It's strategic and organizational.
First, you need to identify the most material Scope 3 categories for your company. In the ICT sector, these are typically:
Purchased goods and services (semiconductors, hardware components, materials)
Capital goods (IT infrastructure, servers, networking equipment)
Upstream and downstream logistics and transportation
Use of sold products (energy consumption of distributed devices)
End-of-life of products (e-waste and recycling)
Once priority categories are identified, the second step is to structure a supplier engagement process. This means:
Requesting primary data, not estimates
Including environmental clauses in supply contracts
Supporting smaller suppliers in developing measurement capabilities
Integrating climate performance into selection criteria for new partners
The third step — often the most neglected — is building robust internal governance: who is responsible for data collection? How is it validated? How frequently is it updated? What are the escalation processes in case of gaps?
Without this organizational architecture, even the best measurement system remains fragile.
The advantage of first movers
There's a paradox: while many companies see CSRD as a compliance cost, those moving first are gaining concrete competitive advantage.
Companies building robust Scope 3 measurement systems:
Reduce supply chain risks related to energy volatility and environmental regulations
Improve investor relations, who reward transparency and ESG data quality
Position themselves better in tenders, where sustainability requirements are becoming increasingly stringent
Identify hidden cost reduction opportunities in value chain inefficiencies
It's not just compliance. It's building resilience.