Carbon per garment is an accounting discipline, not a slogan

A footprint must first answer the question, "Which emissions belong to this garment, over which period, for what function?" The GHG Protocol Product Standard covers raw materials, manufacturing, transportation, storage, use and disposal.[S01] A result limited to spinning, dyeing or garment assembly may be useful for supplier exchange or process control, but it is not a full life cycle result. Its name must preserve that limitation. "Cradle-to-gate carbon per defined shirt" and "full life cycle carbon per defined shirt" are different statements, not two wordings for the same calculation.[S01][S23]

The boundary is more than a list of stages. It also determines whose electricity is included, whether inbound and outbound freight appear, how packaging and waste are treated, and whether consumer care and final disposal are measured or modelled.[S01][S23] A factory can calculate its own utility emissions with care and still omit most of the garment system if purchased fabric, subcontracted wet processing or product use sit outside the account. Conversely, adding a supplier's cradle-to-gate factor to a full life cycle factor for the same material would introduce emissions twice. Boundary control therefore precedes arithmetic.

A partial account is not necessarily a weak account. A mill may need a gate-to-gate model to manage a boiler, while a buyer may need a cradle-to-gate record for a purchased fabric. The error lies in allowing the result to migrate into a wider claim without adding the missing stages. The GHG Protocol distinguishes cradle-to-gate factors, which stop at the supplier's point of sale, from life cycle factors that continue through subsequent stages.[S23] That distinction gives each module a proper use and prevents a convenient supplier number from becoming an unsupported garment claim.

Before reviewing a total, a reader should be able to inspect five fields: the boundary, the functional unit, the gases and global warming potential (GWP) convention, the activity data, and the emission factors. ISO 14067 confines a product carbon footprint to climate change, while Scope 3 guidance requires transparency about activity data, factors and GWP sources.[S05][S23] Exhibit 1 turns those requirements into a reading test for any garment figure.[S01][S05][S11][S23]

These fields expose different failure modes. An unclear boundary hides omissions. An undefined functional unit hides differences in garment mass, quality or service. An unrecorded GWP convention prevents consistent conversion of non-CO2 gases into CO2e.[S11][S23] Untraceable activity data prevent the reader from returning to a meter, invoice or supplier record. An undated factor can attach the wrong geography or period to an otherwise sound physical measurement. Precision in the final decimal place cannot repair any of these defects.

The functional unit deserves particular restraint here. A kilogram of fabric, one finished garment and one wear are not interchangeable denominators. They support different decisions and require different reference flows.[S01][S23] Moreover, the GHG Protocol Product Standard notes that its primary purpose is tracking a product's greenhouse gas inventory and reductions over time, whereas comparing two or more products for labels or performance claims requires additional methodological prescription on allocation rules and data sources.[S0101] The detailed functional-unit and comparison rules follow in the next chapters. For this opening argument, the requirement is simpler: state exactly what the denominator represents and do not allow it to change during comparison.

Consider a defined cotton shirt with a baseline mass of 250 grams, the reference used in a comparative T-shirt life cycle study.[S31] That mass identifies a reference flow; it does not supply an emission factor, a cotton yield, a factory energy record or a downstream care scenario. Exhibit 2 carries the same illustrative shirt reference through a boundary map without assigning any emissions. It is deliberately not a physical cotton mass balance, because losses, trims and other inputs remain to be measured.[S23][S31]

The exhibit shows why a footprint cannot be inferred from garment mass alone. The upstream module needs material and energy evidence. The factory-gate handover needs a clear statement of what the supplier included. The downstream module needs scenarios for distribution, laundering, service life and disposal, each labelled as observation or assumption.[S01][S23] Only then can the modules form a full life cycle account without gaps or repetition.

ISO 14067 addresses climate change alone and excludes social, economic and other environmental impacts from its scope.[S05] A low carbon result therefore cannot establish low water use, acceptable effluent, low toxicity, fair work or garment durability. Nor can a high result prove the opposite. Carbon accounting earns its place by answering one question well, not by absorbing every question into a single score.

This limitation changes how claims should be written. "Lower CO2e per defined garment under the stated boundary" is a testable proposition if the evidence agrees. "Sustainable garment" is a much broader proposition that the carbon account cannot support on its own.[S05][S32] GFT's carbon workstream therefore sits beside, rather than replaces, the operating records for water, energy, materials, quality and waste in its Cameroon textile programme.