Decarbonisation starts with a number

A net-zero ambition is easy to announce and hard to execute. The difference between the two is usually a number — a credible, defensible baseline that an organisation can plan against. Without it, a target is an aspiration; with it, a target becomes a sequence of decisions a business can actually make.

This piece sets out why the baseline comes first, what makes it credible, and how a defensible number turns into a roadmap an operations team can execute.

Why the baseline comes first

Without a baseline, reduction targets are aspirational. With one, a target becomes a sequence of decisions: which emissions sources to address, in what order, with what interventions, and at what cost. The baseline turns strategy into a plan — and it gives every later claim of progress something to be measured against.

Every engagement starts where the client's data actually is and builds towards where international standards require them to be.

A baseline built on weak data produces a target that is hard to defend and a roadmap that is hard to trust. The discipline of getting the number right is what makes everything that follows credible.

What makes a baseline credible

A credible baseline is built on primary activity data wherever it is available, documented methodology where estimation is used, and clearly defined boundaries that say what is and is not included. It is reproducible — another practitioner, given the same data and method, should arrive at the same number. And it is maintainable, so that the organisation can update it year on year without rebuilding it from scratch.

Credibility does not require perfection. Scope 3, in particular, will involve estimation in the early years. What matters is that the estimation is transparent, the assumptions are documented, and the process is designed to improve — so that the baseline is a starting point for an improving number, not a fixed claim.

From baseline to target

Once the baseline is established, target-setting becomes a question of ambition and feasibility rather than guesswork. A target should be ambitious enough to be meaningful and grounded enough to be executable. Frameworks such as the Science Based Targets initiative provide a structured basis for setting targets that are aligned to what the science requires, and that are credible to external audiences.

The target also has to be right for this business — its sector, its growth trajectory, its capital cycle, and the levers it can realistically pull. A target that ignores operational reality tends to be missed, and a missed target carries more reputational weight than a modest one that is achieved.

From target to roadmap

A decarbonisation roadmap is only as credible as the baseline beneath it. The practical path runs from measurement, through materiality and target-setting, to a sequenced set of interventions grounded in operational reality. Sequencing matters: the interventions that deliver the largest, most durable reductions early are not always the most visible, and the most visible are not always the most effective.

• ●Measure the baseline with methodology you can defend.
• ●Set targets that are ambitious and grounded in operational reality.
• ●Sequence interventions by impact, cost, and feasibility — not by visibility.
• ●Build the data systems that will track progress against the baseline every cycle.
• ●Review against the baseline each year and adjust the roadmap as the data improves.

Sequencing interventions

Most organisations have a familiar hierarchy of levers: energy efficiency first, because it often pays for itself; then energy-source switching, where renewable procurement and on-site generation can move Scope 2 quickly; then process and material changes, which are slower and more capital-intensive but move Scope 1; and finally supply-chain engagement, which moves Scope 3 over the longest horizon. The right sequence depends on where the emissions sit, what capital is available, and what the organisation can execute.

The point of sequencing is not to do everything at once. It is to make sure that the early moves are the ones that compound — that reduce the baseline permanently and make the next move cheaper or easier — rather than the ones that merely look decisive.

Industry considerations

In manufacturing, energy efficiency and fuel switching typically deliver the earliest credible reductions. In cement, the harder question is process emissions, where the levers are fewer, more capital-intensive, and longer-horizon — clinker substitution, alternative fuels, and eventually carbon capture or utilisation. In textiles and FMCG, much of the footprint sits in the supply chain, so the roadmap has to include supplier engagement from the start, not as a later phase. In logistics, fleet renewal and fuel-mix transition are the operational core. In each sector, the credible roadmap is the one that addresses the emissions that actually matter for that business, in an order that business can execute.

Monitoring and the feedback loop

A roadmap that is not measured against the baseline is a plan on a shelf. The discipline that makes decarbonisation real is the feedback loop: measure against the baseline each year, understand what moved and what did not, and adjust the sequence accordingly. Over time, the baseline itself improves as data quality rises, and the roadmap becomes more precise as a result.

Decarbonisation is not a single decision. It is a discipline — applied year after year against a number that has to hold up, and a plan that has to keep being honest about what is working.

Key takeaways

• ●A credible baseline is what turns a net-zero ambition into an executable plan.
• ●Build the baseline on primary data and documented methodology; estimate transparently where you must.
• ●Set targets that are both ambitious and grounded in the business's operational reality.
• ●Sequence interventions by impact and feasibility, not by visibility.
• ●Measure against the baseline every cycle and let the roadmap improve with the data.

Further reading

• ●GHG Protocol Corporate Standard — ghgprotocol.org
• ●Science Based Targets initiative — sciencebasedtargets.org
• ●SBTi Corporate Net-Zero Standard — sciencebasedtargets.org