Carbon accounting treats carbon dioxide and methane as interchangeable. They are not – and that difference matters for how wool and textile brands measure real climate progress.

For fashion and textile brands, most greenhouse gas emissions fall under Scope 3 – raw materials, processing, manufacturing and end of life. Material and supplier decisions therefore shape whether or not a brand meets its climate targets.

Wool fiber carries a distinctive emissions profile because methane from sheep production can represent a significant share of its carbon footprint. This is because carbon accounting converts methane and carbon dioxide into a single carbon-dioxide-equivalent figure. While this is useful for inventories, it does not show how emissions pathways affect atmospheric warming.

Carbon dioxide and methane behave differently

Carbon dioxide is long-lived. It accumulates in the atmosphere and its warming effect continues for centuries. Halting further warming requires net-zero emissions. Methane, meanwhile, is short-lived, remaining in the atmosphere for around a decade. Reducing methane can lower its warming effect quickly.

This does not make methane reductions unimportant – strong cuts can limit peak warming. But methane’s effect on temperature depends on whether emissions are rising, stable or falling, unlike carbon dioxide, which accumulates over time regardless.

The split-gas approach

A split-gas approach can be useful as it considers methane separately from carbon dioxide when building emissions-reduction pathways. Long-lived gases follow pathways toward net zero, while methane can align with climate targets through sustained reductions rather than net zero. This reflects methane’s real-time behavior in the atmosphere.

One advantage is that this lets progress in methane-exposed supply chains be recognized. This complements rather than replaces carbon-dioxide-equivalent reporting, and translates into pathways that reflect each gas’s effect.

Many brands currently calculate material emissions using carbon-equivalent reporting based on industry averages. International Wool Textile Organisation commissioned a report exploring how the split-gas approach could apply to textile companies with wool in their supply chains. It found that two pathways can appear equivalent as carbon-dioxide equivalents, but have dramatically different effects on actual temperature.

For brands, this means examining methane and carbon dioxide separately, not just the combined total. Better primary data can help make verified reductions visible, helping direct investment toward suppliers making genuine progress. The gas behind the number matters as much as the number itself.

Photo: Woolmark