Why we need an “Uncertainty Quantification” in Carbon Calculations

At C Free, accuracy and transparency sit at the heart of everything we do. Carbon accounting is shaping business decisions, sustainability strategies, and government policy across the world; but there’s an important issue that isn’t being talked about enough: uncertainty.

To help tackle this, Adam Forster, co-founder of C Free, has founded and now chairs the Uncertainty Quantification Working Group within the Carbon Accounting Alliance (CAA). This initiative was established to address a fundamental challenge in the field; one that could determine the long-term credibility of carbon accounting itself.

The problem: false precision in carbon footprints

Across industries, carbon footprints are presented as neat, definitive numbers. Dashboards, reports, and tender documents all show polished figures; implying that these values are exact. But behind the scenes, every calculation depends on a series of choices and assumptions.

For example, two carbon accounting professionals might calculate the footprint of the same activity but use slightly different data: one may rely on emissions factors from 2019, another from 2023; one may include a specific fuel blend, another might not. Both results can be reasonable, but they’re rarely identical.

The problem isn’t that either is wrong. The problem is that both are presented as precise, single values without any indication of how much uncertainty lies behind them. And when businesses, investors, and policymakers make decisions based on those figures, that lack of transparency can lead to confusion, or even mistrust.

The solution: show what we don’t know

At C Free, we believe that honesty about uncertainty builds credibility, not confusion. Recognising and reporting uncertainty simply means being clear about how confident we are in each number, based on the quality of the data and assumptions used.

This approach brings three major benefits:

1. Trust through transparency – When two results differ, uncertainty ranges show whether those differences are meaningful or within a reasonable margin. It protects against accusations of inconsistency or manipulation.

2. Better decision-making – A footprint based on robust data should carry more weight than one based on estimates. By communicating uncertainty, clients, buyers, and regulators can see which results are most reliable.

3. Continuous improvement – When clients begin to ask for smaller uncertainty ranges, it drives progress across the industry, improving data quality, methodology, and ultimately, confidence in the entire field of carbon accounting.

Leading the way through the CAA

To help move the industry forward, C Free has founded and now chairs the Uncertainty Quantification Working Group within the Carbon Accounting Alliance.

Our goal is to develop a practical standard for quantifying and reporting uncertainty; one that works for real-world practitioners. This means going beyond the dense and often inaccessible guidance that exists today, and building a consistent, usable framework that anyone in carbon accounting can apply with confidence.

The standard will cover key sources of uncertainty, including:

• The quality and completeness of activity data

• Variability in emissions factors

• Differences in methodological choices

Ultimately, the aim is simple: make uncertainty quantification transparent, consistent, and practical for everyone.

Why this matters to you

For organisations working to reduce their environmental impact, this level of transparency is powerful. It builds trust with stakeholders, strengthens the credibility of sustainability reports, and helps demonstrate real leadership in a space that is becoming increasingly scrutinised.

At C Free, we already apply this philosophy in every calculation we produce. We don’t just show your carbon footprint, we show how confident we are in it. That honesty builds confidence, both internally and externally, in your sustainability journey.

If you’d like to understand the level of certainty behind your own carbon footprint, or explore how uncertainty quantification can make your reporting more robust and credible, get in touch with us at C Free.